svn merge ^/branches/released . --username marha

1 files changed, 1794 insertions, 0 deletions

diff --git a/mesalib/src/mesa/main/mipmap.c b/mesalib/src/mesa/main/mipmap.c
new file mode 100644
index 000000000..3dca09d9f
--- /dev/null
+++ b/mesalib/src/mesa/main/mipmap.c
@@ -0,0 +1,1794 @@
+/*
+ * Mesa 3-D graphics library
+ * Version:  7.1
+ *
+ * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+/**
+ * \file mipmap.c  mipmap generation and teximage resizing functions.
+ */
+
+#include "imports.h"
+#include "mipmap.h"
+#include "texcompress.h"
+#include "texformat.h"
+#include "teximage.h"
+#include "image.h"
+
+
+
+static GLint
+bytes_per_pixel(GLenum datatype, GLuint comps)
+{
+   GLint b = _mesa_sizeof_packed_type(datatype);
+   assert(b >= 0);
+
+   if (_mesa_type_is_packed(datatype))
+       return b;
+   else
+       return b * comps;
+}
+
+
+/**
+ * \name Support macros for do_row and do_row_3d
+ *
+ * The macro madness is here for two reasons.  First, it compacts the code
+ * slightly.  Second, it makes it much easier to adjust the specifics of the
+ * filter to tune the rounding characteristics.
+ */
+/*@{*/
+#define DECLARE_ROW_POINTERS(t, e) \
+      const t(*rowA)[e] = (const t(*)[e]) srcRowA; \
+      const t(*rowB)[e] = (const t(*)[e]) srcRowB; \
+      const t(*rowC)[e] = (const t(*)[e]) srcRowC; \
+      const t(*rowD)[e] = (const t(*)[e]) srcRowD; \
+      t(*dst)[e] = (t(*)[e]) dstRow
+
+#define DECLARE_ROW_POINTERS0(t) \
+      const t *rowA = (const t *) srcRowA; \
+      const t *rowB = (const t *) srcRowB; \
+      const t *rowC = (const t *) srcRowC; \
+      const t *rowD = (const t *) srcRowD; \
+      t *dst = (t *) dstRow
+
+#define FILTER_SUM_3D(Aj, Ak, Bj, Bk, Cj, Ck, Dj, Dk) \
+   ((unsigned) Aj + (unsigned) Ak \
+    + (unsigned) Bj + (unsigned) Bk \
+    + (unsigned) Cj + (unsigned) Ck \
+    + (unsigned) Dj + (unsigned) Dk \
+    + 4) >> 3
+
+#define FILTER_3D(e) \
+   do { \
+      dst[i][e] = FILTER_SUM_3D(rowA[j][e], rowA[k][e], \
+                                rowB[j][e], rowB[k][e], \
+                                rowC[j][e], rowC[k][e], \
+                                rowD[j][e], rowD[k][e]); \
+   } while(0)
+
+#define FILTER_SUM_3D_SIGNED(Aj, Ak, Bj, Bk, Cj, Ck, Dj, Dk) \
+   (Aj + Ak \
+    + Bj + Bk \
+    + Cj + Ck \
+    + Dj + Dk \
+    + 4) / 8
+
+#define FILTER_3D_SIGNED(e) \
+   do { \
+      dst[i][e] = FILTER_SUM_3D_SIGNED(rowA[j][e], rowA[k][e], \
+                                       rowB[j][e], rowB[k][e], \
+                                       rowC[j][e], rowC[k][e], \
+                                       rowD[j][e], rowD[k][e]); \
+   } while(0)
+
+#define FILTER_F_3D(e) \
+   do { \
+      dst[i][e] = (rowA[j][e] + rowA[k][e] \
+                   + rowB[j][e] + rowB[k][e] \
+                   + rowC[j][e] + rowC[k][e] \
+                   + rowD[j][e] + rowD[k][e]) * 0.125F; \
+   } while(0)
+
+#define FILTER_HF_3D(e) \
+   do { \
+      const GLfloat aj = _mesa_half_to_float(rowA[j][e]); \
+      const GLfloat ak = _mesa_half_to_float(rowA[k][e]); \
+      const GLfloat bj = _mesa_half_to_float(rowB[j][e]); \
+      const GLfloat bk = _mesa_half_to_float(rowB[k][e]); \
+      const GLfloat cj = _mesa_half_to_float(rowC[j][e]); \
+      const GLfloat ck = _mesa_half_to_float(rowC[k][e]); \
+      const GLfloat dj = _mesa_half_to_float(rowD[j][e]); \
+      const GLfloat dk = _mesa_half_to_float(rowD[k][e]); \
+      dst[i][e] = _mesa_float_to_half((aj + ak + bj + bk + cj + ck + dj + dk) \
+                                      * 0.125F); \
+   } while(0)
+/*@}*/
+
+
+/**
+ * Average together two rows of a source image to produce a single new
+ * row in the dest image.  It's legal for the two source rows to point
+ * to the same data.  The source width must be equal to either the
+ * dest width or two times the dest width.
+ * \param datatype  GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT, GL_FLOAT, etc.
+ * \param comps  number of components per pixel (1..4)
+ */
+static void
+do_row(GLenum datatype, GLuint comps, GLint srcWidth,
+       const GLvoid *srcRowA, const GLvoid *srcRowB,
+       GLint dstWidth, GLvoid *dstRow)
+{
+   const GLuint k0 = (srcWidth == dstWidth) ? 0 : 1;
+   const GLuint colStride = (srcWidth == dstWidth) ? 1 : 2;
+
+   ASSERT(comps >= 1);
+   ASSERT(comps <= 4);
+
+   /* This assertion is no longer valid with non-power-of-2 textures
+   assert(srcWidth == dstWidth || srcWidth == 2 * dstWidth);
+   */
+
+   if (datatype == GL_UNSIGNED_BYTE && comps == 4) {
+      GLuint i, j, k;
+      const GLubyte(*rowA)[4] = (const GLubyte(*)[4]) srcRowA;
+      const GLubyte(*rowB)[4] = (const GLubyte(*)[4]) srcRowB;
+      GLubyte(*dst)[4] = (GLubyte(*)[4]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] + rowB[j][2] + rowB[k][2]) / 4;
+         dst[i][3] = (rowA[j][3] + rowA[k][3] + rowB[j][3] + rowB[k][3]) / 4;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_BYTE && comps == 3) {
+      GLuint i, j, k;
+      const GLubyte(*rowA)[3] = (const GLubyte(*)[3]) srcRowA;
+      const GLubyte(*rowB)[3] = (const GLubyte(*)[3]) srcRowB;
+      GLubyte(*dst)[3] = (GLubyte(*)[3]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] + rowB[j][2] + rowB[k][2]) / 4;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_BYTE && comps == 2) {
+      GLuint i, j, k;
+      const GLubyte(*rowA)[2] = (const GLubyte(*)[2]) srcRowA;
+      const GLubyte(*rowB)[2] = (const GLubyte(*)[2]) srcRowB;
+      GLubyte(*dst)[2] = (GLubyte(*)[2]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) >> 2;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) >> 2;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_BYTE && comps == 1) {
+      GLuint i, j, k;
+      const GLubyte *rowA = (const GLubyte *) srcRowA;
+      const GLubyte *rowB = (const GLubyte *) srcRowB;
+      GLubyte *dst = (GLubyte *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i] = (rowA[j] + rowA[k] + rowB[j] + rowB[k]) >> 2;
+      }
+   }
+
+   else if (datatype == GL_BYTE && comps == 4) {
+      GLuint i, j, k;
+      const GLbyte(*rowA)[4] = (const GLbyte(*)[4]) srcRowA;
+      const GLbyte(*rowB)[4] = (const GLbyte(*)[4]) srcRowB;
+      GLbyte(*dst)[4] = (GLbyte(*)[4]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] + rowB[j][2] + rowB[k][2]) / 4;
+         dst[i][3] = (rowA[j][3] + rowA[k][3] + rowB[j][3] + rowB[k][3]) / 4;
+      }
+   }
+   else if (datatype == GL_BYTE && comps == 3) {
+      GLuint i, j, k;
+      const GLbyte(*rowA)[3] = (const GLbyte(*)[3]) srcRowA;
+      const GLbyte(*rowB)[3] = (const GLbyte(*)[3]) srcRowB;
+      GLbyte(*dst)[3] = (GLbyte(*)[3]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] + rowB[j][2] + rowB[k][2]) / 4;
+      }
+   }
+   else if (datatype == GL_BYTE && comps == 2) {
+      GLuint i, j, k;
+      const GLbyte(*rowA)[2] = (const GLbyte(*)[2]) srcRowA;
+      const GLbyte(*rowB)[2] = (const GLbyte(*)[2]) srcRowB;
+      GLbyte(*dst)[2] = (GLbyte(*)[2]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+      }
+   }
+   else if (datatype == GL_BYTE && comps == 1) {
+      GLuint i, j, k;
+      const GLbyte *rowA = (const GLbyte *) srcRowA;
+      const GLbyte *rowB = (const GLbyte *) srcRowB;
+      GLbyte *dst = (GLbyte *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i] = (rowA[j] + rowA[k] + rowB[j] + rowB[k]) / 4;
+      }
+   }
+
+   else if (datatype == GL_UNSIGNED_SHORT && comps == 4) {
+      GLuint i, j, k;
+      const GLushort(*rowA)[4] = (const GLushort(*)[4]) srcRowA;
+      const GLushort(*rowB)[4] = (const GLushort(*)[4]) srcRowB;
+      GLushort(*dst)[4] = (GLushort(*)[4]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] + rowB[j][2] + rowB[k][2]) / 4;
+         dst[i][3] = (rowA[j][3] + rowA[k][3] + rowB[j][3] + rowB[k][3]) / 4;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_SHORT && comps == 3) {
+      GLuint i, j, k;
+      const GLushort(*rowA)[3] = (const GLushort(*)[3]) srcRowA;
+      const GLushort(*rowB)[3] = (const GLushort(*)[3]) srcRowB;
+      GLushort(*dst)[3] = (GLushort(*)[3]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] + rowB[j][2] + rowB[k][2]) / 4;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_SHORT && comps == 2) {
+      GLuint i, j, k;
+      const GLushort(*rowA)[2] = (const GLushort(*)[2]) srcRowA;
+      const GLushort(*rowB)[2] = (const GLushort(*)[2]) srcRowB;
+      GLushort(*dst)[2] = (GLushort(*)[2]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] + rowB[j][0] + rowB[k][0]) / 4;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] + rowB[j][1] + rowB[k][1]) / 4;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_SHORT && comps == 1) {
+      GLuint i, j, k;
+      const GLushort *rowA = (const GLushort *) srcRowA;
+      const GLushort *rowB = (const GLushort *) srcRowB;
+      GLushort *dst = (GLushort *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i] = (rowA[j] + rowA[k] + rowB[j] + rowB[k]) / 4;
+      }
+   }
+   else if (datatype == GL_FLOAT && comps == 4) {
+      GLuint i, j, k;
+      const GLfloat(*rowA)[4] = (const GLfloat(*)[4]) srcRowA;
+      const GLfloat(*rowB)[4] = (const GLfloat(*)[4]) srcRowB;
+      GLfloat(*dst)[4] = (GLfloat(*)[4]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] +
+                      rowB[j][0] + rowB[k][0]) * 0.25F;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] +
+                      rowB[j][1] + rowB[k][1]) * 0.25F;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] +
+                      rowB[j][2] + rowB[k][2]) * 0.25F;
+         dst[i][3] = (rowA[j][3] + rowA[k][3] +
+                      rowB[j][3] + rowB[k][3]) * 0.25F;
+      }
+   }
+   else if (datatype == GL_FLOAT && comps == 3) {
+      GLuint i, j, k;
+      const GLfloat(*rowA)[3] = (const GLfloat(*)[3]) srcRowA;
+      const GLfloat(*rowB)[3] = (const GLfloat(*)[3]) srcRowB;
+      GLfloat(*dst)[3] = (GLfloat(*)[3]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] +
+                      rowB[j][0] + rowB[k][0]) * 0.25F;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] +
+                      rowB[j][1] + rowB[k][1]) * 0.25F;
+         dst[i][2] = (rowA[j][2] + rowA[k][2] +
+                      rowB[j][2] + rowB[k][2]) * 0.25F;
+      }
+   }
+   else if (datatype == GL_FLOAT && comps == 2) {
+      GLuint i, j, k;
+      const GLfloat(*rowA)[2] = (const GLfloat(*)[2]) srcRowA;
+      const GLfloat(*rowB)[2] = (const GLfloat(*)[2]) srcRowB;
+      GLfloat(*dst)[2] = (GLfloat(*)[2]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i][0] = (rowA[j][0] + rowA[k][0] +
+                      rowB[j][0] + rowB[k][0]) * 0.25F;
+         dst[i][1] = (rowA[j][1] + rowA[k][1] +
+                      rowB[j][1] + rowB[k][1]) * 0.25F;
+      }
+   }
+   else if (datatype == GL_FLOAT && comps == 1) {
+      GLuint i, j, k;
+      const GLfloat *rowA = (const GLfloat *) srcRowA;
+      const GLfloat *rowB = (const GLfloat *) srcRowB;
+      GLfloat *dst = (GLfloat *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i] = (rowA[j] + rowA[k] + rowB[j] + rowB[k]) * 0.25F;
+      }
+   }
+
+   else if (datatype == GL_HALF_FLOAT_ARB && comps == 4) {
+      GLuint i, j, k, comp;
+      const GLhalfARB(*rowA)[4] = (const GLhalfARB(*)[4]) srcRowA;
+      const GLhalfARB(*rowB)[4] = (const GLhalfARB(*)[4]) srcRowB;
+      GLhalfARB(*dst)[4] = (GLhalfARB(*)[4]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         for (comp = 0; comp < 4; comp++) {
+            GLfloat aj, ak, bj, bk;
+            aj = _mesa_half_to_float(rowA[j][comp]);
+            ak = _mesa_half_to_float(rowA[k][comp]);
+            bj = _mesa_half_to_float(rowB[j][comp]);
+            bk = _mesa_half_to_float(rowB[k][comp]);
+            dst[i][comp] = _mesa_float_to_half((aj + ak + bj + bk) * 0.25F);
+         }
+      }
+   }
+   else if (datatype == GL_HALF_FLOAT_ARB && comps == 3) {
+      GLuint i, j, k, comp;
+      const GLhalfARB(*rowA)[3] = (const GLhalfARB(*)[3]) srcRowA;
+      const GLhalfARB(*rowB)[3] = (const GLhalfARB(*)[3]) srcRowB;
+      GLhalfARB(*dst)[3] = (GLhalfARB(*)[3]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         for (comp = 0; comp < 3; comp++) {
+            GLfloat aj, ak, bj, bk;
+            aj = _mesa_half_to_float(rowA[j][comp]);
+            ak = _mesa_half_to_float(rowA[k][comp]);
+            bj = _mesa_half_to_float(rowB[j][comp]);
+            bk = _mesa_half_to_float(rowB[k][comp]);
+            dst[i][comp] = _mesa_float_to_half((aj + ak + bj + bk) * 0.25F);
+         }
+      }
+   }
+   else if (datatype == GL_HALF_FLOAT_ARB && comps == 2) {
+      GLuint i, j, k, comp;
+      const GLhalfARB(*rowA)[2] = (const GLhalfARB(*)[2]) srcRowA;
+      const GLhalfARB(*rowB)[2] = (const GLhalfARB(*)[2]) srcRowB;
+      GLhalfARB(*dst)[2] = (GLhalfARB(*)[2]) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         for (comp = 0; comp < 2; comp++) {
+            GLfloat aj, ak, bj, bk;
+            aj = _mesa_half_to_float(rowA[j][comp]);
+            ak = _mesa_half_to_float(rowA[k][comp]);
+            bj = _mesa_half_to_float(rowB[j][comp]);
+            bk = _mesa_half_to_float(rowB[k][comp]);
+            dst[i][comp] = _mesa_float_to_half((aj + ak + bj + bk) * 0.25F);
+         }
+      }
+   }
+   else if (datatype == GL_HALF_FLOAT_ARB && comps == 1) {
+      GLuint i, j, k;
+      const GLhalfARB *rowA = (const GLhalfARB *) srcRowA;
+      const GLhalfARB *rowB = (const GLhalfARB *) srcRowB;
+      GLhalfARB *dst = (GLhalfARB *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         GLfloat aj, ak, bj, bk;
+         aj = _mesa_half_to_float(rowA[j]);
+         ak = _mesa_half_to_float(rowA[k]);
+         bj = _mesa_half_to_float(rowB[j]);
+         bk = _mesa_half_to_float(rowB[k]);
+         dst[i] = _mesa_float_to_half((aj + ak + bj + bk) * 0.25F);
+      }
+   }
+
+   else if (datatype == GL_UNSIGNED_INT && comps == 1) {
+      GLuint i, j, k;
+      const GLuint *rowA = (const GLuint *) srcRowA;
+      const GLuint *rowB = (const GLuint *) srcRowB;
+      GLfloat *dst = (GLfloat *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         dst[i] = (GLfloat)(rowA[j] / 4 + rowA[k] / 4 + rowB[j] / 4 + rowB[k] / 4);
+      }
+   }
+
+   else if (datatype == GL_UNSIGNED_SHORT_5_6_5 && comps == 3) {
+      GLuint i, j, k;
+      const GLushort *rowA = (const GLushort *) srcRowA;
+      const GLushort *rowB = (const GLushort *) srcRowB;
+      GLushort *dst = (GLushort *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const GLint rowAr0 = rowA[j] & 0x1f;
+         const GLint rowAr1 = rowA[k] & 0x1f;
+         const GLint rowBr0 = rowB[j] & 0x1f;
+         const GLint rowBr1 = rowB[k] & 0x1f;
+         const GLint rowAg0 = (rowA[j] >> 5) & 0x3f;
+         const GLint rowAg1 = (rowA[k] >> 5) & 0x3f;
+         const GLint rowBg0 = (rowB[j] >> 5) & 0x3f;
+         const GLint rowBg1 = (rowB[k] >> 5) & 0x3f;
+         const GLint rowAb0 = (rowA[j] >> 11) & 0x1f;
+         const GLint rowAb1 = (rowA[k] >> 11) & 0x1f;
+         const GLint rowBb0 = (rowB[j] >> 11) & 0x1f;
+         const GLint rowBb1 = (rowB[k] >> 11) & 0x1f;
+         const GLint red = (rowAr0 + rowAr1 + rowBr0 + rowBr1) >> 2;
+         const GLint green = (rowAg0 + rowAg1 + rowBg0 + rowBg1) >> 2;
+         const GLint blue = (rowAb0 + rowAb1 + rowBb0 + rowBb1) >> 2;
+         dst[i] = (blue << 11) | (green << 5) | red;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_SHORT_4_4_4_4 && comps == 4) {
+      GLuint i, j, k;
+      const GLushort *rowA = (const GLushort *) srcRowA;
+      const GLushort *rowB = (const GLushort *) srcRowB;
+      GLushort *dst = (GLushort *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const GLint rowAr0 = rowA[j] & 0xf;
+         const GLint rowAr1 = rowA[k] & 0xf;
+         const GLint rowBr0 = rowB[j] & 0xf;
+         const GLint rowBr1 = rowB[k] & 0xf;
+         const GLint rowAg0 = (rowA[j] >> 4) & 0xf;
+         const GLint rowAg1 = (rowA[k] >> 4) & 0xf;
+         const GLint rowBg0 = (rowB[j] >> 4) & 0xf;
+         const GLint rowBg1 = (rowB[k] >> 4) & 0xf;
+         const GLint rowAb0 = (rowA[j] >> 8) & 0xf;
+         const GLint rowAb1 = (rowA[k] >> 8) & 0xf;
+         const GLint rowBb0 = (rowB[j] >> 8) & 0xf;
+         const GLint rowBb1 = (rowB[k] >> 8) & 0xf;
+         const GLint rowAa0 = (rowA[j] >> 12) & 0xf;
+         const GLint rowAa1 = (rowA[k] >> 12) & 0xf;
+         const GLint rowBa0 = (rowB[j] >> 12) & 0xf;
+         const GLint rowBa1 = (rowB[k] >> 12) & 0xf;
+         const GLint red = (rowAr0 + rowAr1 + rowBr0 + rowBr1) >> 2;
+         const GLint green = (rowAg0 + rowAg1 + rowBg0 + rowBg1) >> 2;
+         const GLint blue = (rowAb0 + rowAb1 + rowBb0 + rowBb1) >> 2;
+         const GLint alpha = (rowAa0 + rowAa1 + rowBa0 + rowBa1) >> 2;
+         dst[i] = (alpha << 12) | (blue << 8) | (green << 4) | red;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_SHORT_1_5_5_5_REV && comps == 4) {
+      GLuint i, j, k;
+      const GLushort *rowA = (const GLushort *) srcRowA;
+      const GLushort *rowB = (const GLushort *) srcRowB;
+      GLushort *dst = (GLushort *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const GLint rowAr0 = rowA[j] & 0x1f;
+         const GLint rowAr1 = rowA[k] & 0x1f;
+         const GLint rowBr0 = rowB[j] & 0x1f;
+         const GLint rowBr1 = rowB[k] & 0x1f;
+         const GLint rowAg0 = (rowA[j] >> 5) & 0x1f;
+         const GLint rowAg1 = (rowA[k] >> 5) & 0x1f;
+         const GLint rowBg0 = (rowB[j] >> 5) & 0x1f;
+         const GLint rowBg1 = (rowB[k] >> 5) & 0x1f;
+         const GLint rowAb0 = (rowA[j] >> 10) & 0x1f;
+         const GLint rowAb1 = (rowA[k] >> 10) & 0x1f;
+         const GLint rowBb0 = (rowB[j] >> 10) & 0x1f;
+         const GLint rowBb1 = (rowB[k] >> 10) & 0x1f;
+         const GLint rowAa0 = (rowA[j] >> 15) & 0x1;
+         const GLint rowAa1 = (rowA[k] >> 15) & 0x1;
+         const GLint rowBa0 = (rowB[j] >> 15) & 0x1;
+         const GLint rowBa1 = (rowB[k] >> 15) & 0x1;
+         const GLint red = (rowAr0 + rowAr1 + rowBr0 + rowBr1) >> 2;
+         const GLint green = (rowAg0 + rowAg1 + rowBg0 + rowBg1) >> 2;
+         const GLint blue = (rowAb0 + rowAb1 + rowBb0 + rowBb1) >> 2;
+         const GLint alpha = (rowAa0 + rowAa1 + rowBa0 + rowBa1) >> 2;
+         dst[i] = (alpha << 15) | (blue << 10) | (green << 5) | red;
+      }
+   }
+   else if (datatype == GL_UNSIGNED_BYTE_3_3_2 && comps == 3) {
+      GLuint i, j, k;
+      const GLubyte *rowA = (const GLubyte *) srcRowA;
+      const GLubyte *rowB = (const GLubyte *) srcRowB;
+      GLubyte *dst = (GLubyte *) dstRow;
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const GLint rowAr0 = rowA[j] & 0x3;
+         const GLint rowAr1 = rowA[k] & 0x3;
+         const GLint rowBr0 = rowB[j] & 0x3;
+         const GLint rowBr1 = rowB[k] & 0x3;
+         const GLint rowAg0 = (rowA[j] >> 2) & 0x7;
+         const GLint rowAg1 = (rowA[k] >> 2) & 0x7;
+         const GLint rowBg0 = (rowB[j] >> 2) & 0x7;
+         const GLint rowBg1 = (rowB[k] >> 2) & 0x7;
+         const GLint rowAb0 = (rowA[j] >> 5) & 0x7;
+         const GLint rowAb1 = (rowA[k] >> 5) & 0x7;
+         const GLint rowBb0 = (rowB[j] >> 5) & 0x7;
+         const GLint rowBb1 = (rowB[k] >> 5) & 0x7;
+         const GLint red = (rowAr0 + rowAr1 + rowBr0 + rowBr1) >> 2;
+         const GLint green = (rowAg0 + rowAg1 + rowBg0 + rowBg1) >> 2;
+         const GLint blue = (rowAb0 + rowAb1 + rowBb0 + rowBb1) >> 2;
+         dst[i] = (blue << 5) | (green << 2) | red;
+      }
+   }
+   else {
+      _mesa_problem(NULL, "bad format in do_row()");
+   }
+}
+
+
+/**
+ * Average together four rows of a source image to produce a single new
+ * row in the dest image.  It's legal for the two source rows to point
+ * to the same data.  The source width must be equal to either the
+ * dest width or two times the dest width.
+ *
+ * \param datatype  GL pixel type \c GL_UNSIGNED_BYTE, \c GL_UNSIGNED_SHORT,
+ *                  \c GL_FLOAT, etc.
+ * \param comps     number of components per pixel (1..4)
+ * \param srcWidth  Width of a row in the source data
+ * \param srcRowA   Pointer to one of the rows of source data
+ * \param srcRowB   Pointer to one of the rows of source data
+ * \param srcRowC   Pointer to one of the rows of source data
+ * \param srcRowD   Pointer to one of the rows of source data
+ * \param dstWidth  Width of a row in the destination data
+ * \param srcRowA   Pointer to the row of destination data
+ */
+static void
+do_row_3D(GLenum datatype, GLuint comps, GLint srcWidth,
+          const GLvoid *srcRowA, const GLvoid *srcRowB,
+          const GLvoid *srcRowC, const GLvoid *srcRowD,
+          GLint dstWidth, GLvoid *dstRow)
+{
+   const GLuint k0 = (srcWidth == dstWidth) ? 0 : 1;
+   const GLuint colStride = (srcWidth == dstWidth) ? 1 : 2;
+   GLuint i, j, k;
+
+   ASSERT(comps >= 1);
+   ASSERT(comps <= 4);
+
+   if ((datatype == GL_UNSIGNED_BYTE) && (comps == 4)) {
+      DECLARE_ROW_POINTERS(GLubyte, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D(0);
+         FILTER_3D(1);
+         FILTER_3D(2);
+         FILTER_3D(3);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_BYTE) && (comps == 3)) {
+      DECLARE_ROW_POINTERS(GLubyte, 3);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D(0);
+         FILTER_3D(1);
+         FILTER_3D(2);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_BYTE) && (comps == 2)) {
+      DECLARE_ROW_POINTERS(GLubyte, 2);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D(0);
+         FILTER_3D(1);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_BYTE) && (comps == 1)) {
+      DECLARE_ROW_POINTERS(GLubyte, 1);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D(0);
+      }
+   }
+   if ((datatype == GL_BYTE) && (comps == 4)) {
+      DECLARE_ROW_POINTERS(GLbyte, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D_SIGNED(0);
+         FILTER_3D_SIGNED(1);
+         FILTER_3D_SIGNED(2);
+         FILTER_3D_SIGNED(3);
+      }
+   }
+   else if ((datatype == GL_BYTE) && (comps == 3)) {
+      DECLARE_ROW_POINTERS(GLbyte, 3);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D_SIGNED(0);
+         FILTER_3D_SIGNED(1);
+         FILTER_3D_SIGNED(2);
+      }
+   }
+   else if ((datatype == GL_BYTE) && (comps == 2)) {
+      DECLARE_ROW_POINTERS(GLbyte, 2);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D_SIGNED(0);
+         FILTER_3D_SIGNED(1);
+       }
+   }
+   else if ((datatype == GL_BYTE) && (comps == 1)) {
+      DECLARE_ROW_POINTERS(GLbyte, 1);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D_SIGNED(0);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_SHORT) && (comps == 4)) {
+      DECLARE_ROW_POINTERS(GLushort, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D(0);
+         FILTER_3D(1);
+         FILTER_3D(2);
+         FILTER_3D(3);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_SHORT) && (comps == 3)) {
+      DECLARE_ROW_POINTERS(GLushort, 3);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D(0);
+         FILTER_3D(1);
+         FILTER_3D(2);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_SHORT) && (comps == 2)) {
+      DECLARE_ROW_POINTERS(GLushort, 2);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D(0);
+         FILTER_3D(1);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_SHORT) && (comps == 1)) {
+      DECLARE_ROW_POINTERS(GLushort, 1);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_3D(0);
+      }
+   }
+   else if ((datatype == GL_FLOAT) && (comps == 4)) {
+      DECLARE_ROW_POINTERS(GLfloat, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_F_3D(0);
+         FILTER_F_3D(1);
+         FILTER_F_3D(2);
+         FILTER_F_3D(3);
+      }
+   }
+   else if ((datatype == GL_FLOAT) && (comps == 3)) {
+      DECLARE_ROW_POINTERS(GLfloat, 3);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_F_3D(0);
+         FILTER_F_3D(1);
+         FILTER_F_3D(2);
+      }
+   }
+   else if ((datatype == GL_FLOAT) && (comps == 2)) {
+      DECLARE_ROW_POINTERS(GLfloat, 2);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_F_3D(0);
+         FILTER_F_3D(1);
+      }
+   }
+   else if ((datatype == GL_FLOAT) && (comps == 1)) {
+      DECLARE_ROW_POINTERS(GLfloat, 1);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_F_3D(0);
+      }
+   }
+   else if ((datatype == GL_HALF_FLOAT_ARB) && (comps == 4)) {
+      DECLARE_ROW_POINTERS(GLhalfARB, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_HF_3D(0);
+         FILTER_HF_3D(1);
+         FILTER_HF_3D(2);
+         FILTER_HF_3D(3);
+      }
+   }
+   else if ((datatype == GL_HALF_FLOAT_ARB) && (comps == 3)) {
+      DECLARE_ROW_POINTERS(GLhalfARB, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_HF_3D(0);
+         FILTER_HF_3D(1);
+         FILTER_HF_3D(2);
+      }
+   }
+   else if ((datatype == GL_HALF_FLOAT_ARB) && (comps == 2)) {
+      DECLARE_ROW_POINTERS(GLhalfARB, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_HF_3D(0);
+         FILTER_HF_3D(1);
+      }
+   }
+   else if ((datatype == GL_HALF_FLOAT_ARB) && (comps == 1)) {
+      DECLARE_ROW_POINTERS(GLhalfARB, 4);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         FILTER_HF_3D(0);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_INT) && (comps == 1)) {
+      const GLuint *rowA = (const GLuint *) srcRowA;
+      const GLuint *rowB = (const GLuint *) srcRowB;
+      const GLuint *rowC = (const GLuint *) srcRowC;
+      const GLuint *rowD = (const GLuint *) srcRowD;
+      GLfloat *dst = (GLfloat *) dstRow;
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const uint64_t tmp = (((uint64_t) rowA[j] + (uint64_t) rowA[k])
+                               + ((uint64_t) rowB[j] + (uint64_t) rowB[k])
+                               + ((uint64_t) rowC[j] + (uint64_t) rowC[k])
+                               + ((uint64_t) rowD[j] + (uint64_t) rowD[k]));
+         dst[i] = (GLfloat)((double) tmp * 0.125);
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_SHORT_5_6_5) && (comps == 3)) {
+      DECLARE_ROW_POINTERS0(GLushort);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const GLint rowAr0 = rowA[j] & 0x1f;
+         const GLint rowAr1 = rowA[k] & 0x1f;
+         const GLint rowBr0 = rowB[j] & 0x1f;
+         const GLint rowBr1 = rowB[k] & 0x1f;
+         const GLint rowCr0 = rowC[j] & 0x1f;
+         const GLint rowCr1 = rowC[k] & 0x1f;
+         const GLint rowDr0 = rowD[j] & 0x1f;
+         const GLint rowDr1 = rowD[k] & 0x1f;
+         const GLint rowAg0 = (rowA[j] >> 5) & 0x3f;
+         const GLint rowAg1 = (rowA[k] >> 5) & 0x3f;
+         const GLint rowBg0 = (rowB[j] >> 5) & 0x3f;
+         const GLint rowBg1 = (rowB[k] >> 5) & 0x3f;
+         const GLint rowCg0 = (rowC[j] >> 5) & 0x3f;
+         const GLint rowCg1 = (rowC[k] >> 5) & 0x3f;
+         const GLint rowDg0 = (rowD[j] >> 5) & 0x3f;
+         const GLint rowDg1 = (rowD[k] >> 5) & 0x3f;
+         const GLint rowAb0 = (rowA[j] >> 11) & 0x1f;
+         const GLint rowAb1 = (rowA[k] >> 11) & 0x1f;
+         const GLint rowBb0 = (rowB[j] >> 11) & 0x1f;
+         const GLint rowBb1 = (rowB[k] >> 11) & 0x1f;
+         const GLint rowCb0 = (rowC[j] >> 11) & 0x1f;
+         const GLint rowCb1 = (rowC[k] >> 11) & 0x1f;
+         const GLint rowDb0 = (rowD[j] >> 11) & 0x1f;
+         const GLint rowDb1 = (rowD[k] >> 11) & 0x1f;
+         const GLint r = FILTER_SUM_3D(rowAr0, rowAr1, rowBr0, rowBr1,
+                                       rowCr0, rowCr1, rowDr0, rowDr1);
+         const GLint g = FILTER_SUM_3D(rowAg0, rowAg1, rowBg0, rowBg1,
+                                       rowCg0, rowCg1, rowDg0, rowDg1);
+         const GLint b = FILTER_SUM_3D(rowAb0, rowAb1, rowBb0, rowBb1,
+                                       rowCb0, rowCb1, rowDb0, rowDb1);
+         dst[i] = (b << 11) | (g << 5) | r;
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_SHORT_4_4_4_4) && (comps == 4)) {
+      DECLARE_ROW_POINTERS0(GLushort);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const GLint rowAr0 = rowA[j] & 0xf;
+         const GLint rowAr1 = rowA[k] & 0xf;
+         const GLint rowBr0 = rowB[j] & 0xf;
+         const GLint rowBr1 = rowB[k] & 0xf;
+         const GLint rowCr0 = rowC[j] & 0xf;
+         const GLint rowCr1 = rowC[k] & 0xf;
+         const GLint rowDr0 = rowD[j] & 0xf;
+         const GLint rowDr1 = rowD[k] & 0xf;
+         const GLint rowAg0 = (rowA[j] >> 4) & 0xf;
+         const GLint rowAg1 = (rowA[k] >> 4) & 0xf;
+         const GLint rowBg0 = (rowB[j] >> 4) & 0xf;
+         const GLint rowBg1 = (rowB[k] >> 4) & 0xf;
+         const GLint rowCg0 = (rowC[j] >> 4) & 0xf;
+         const GLint rowCg1 = (rowC[k] >> 4) & 0xf;
+         const GLint rowDg0 = (rowD[j] >> 4) & 0xf;
+         const GLint rowDg1 = (rowD[k] >> 4) & 0xf;
+         const GLint rowAb0 = (rowA[j] >> 8) & 0xf;
+         const GLint rowAb1 = (rowA[k] >> 8) & 0xf;
+         const GLint rowBb0 = (rowB[j] >> 8) & 0xf;
+         const GLint rowBb1 = (rowB[k] >> 8) & 0xf;
+         const GLint rowCb0 = (rowC[j] >> 8) & 0xf;
+         const GLint rowCb1 = (rowC[k] >> 8) & 0xf;
+         const GLint rowDb0 = (rowD[j] >> 8) & 0xf;
+         const GLint rowDb1 = (rowD[k] >> 8) & 0xf;
+         const GLint rowAa0 = (rowA[j] >> 12) & 0xf;
+         const GLint rowAa1 = (rowA[k] >> 12) & 0xf;
+         const GLint rowBa0 = (rowB[j] >> 12) & 0xf;
+         const GLint rowBa1 = (rowB[k] >> 12) & 0xf;
+         const GLint rowCa0 = (rowC[j] >> 12) & 0xf;
+         const GLint rowCa1 = (rowC[k] >> 12) & 0xf;
+         const GLint rowDa0 = (rowD[j] >> 12) & 0xf;
+         const GLint rowDa1 = (rowD[k] >> 12) & 0xf;
+         const GLint r = FILTER_SUM_3D(rowAr0, rowAr1, rowBr0, rowBr1,
+                                       rowCr0, rowCr1, rowDr0, rowDr1);
+         const GLint g = FILTER_SUM_3D(rowAg0, rowAg1, rowBg0, rowBg1,
+                                       rowCg0, rowCg1, rowDg0, rowDg1);
+         const GLint b = FILTER_SUM_3D(rowAb0, rowAb1, rowBb0, rowBb1,
+                                       rowCb0, rowCb1, rowDb0, rowDb1);
+         const GLint a = FILTER_SUM_3D(rowAa0, rowAa1, rowBa0, rowBa1,
+                                       rowCa0, rowCa1, rowDa0, rowDa1);
+
+         dst[i] = (a << 12) | (b << 8) | (g << 4) | r;
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_SHORT_1_5_5_5_REV) && (comps == 4)) {
+      DECLARE_ROW_POINTERS0(GLushort);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const GLint rowAr0 = rowA[j] & 0x1f;
+         const GLint rowAr1 = rowA[k] & 0x1f;
+         const GLint rowBr0 = rowB[j] & 0x1f;
+         const GLint rowBr1 = rowB[k] & 0x1f;
+         const GLint rowCr0 = rowC[j] & 0x1f;
+         const GLint rowCr1 = rowC[k] & 0x1f;
+         const GLint rowDr0 = rowD[j] & 0x1f;
+         const GLint rowDr1 = rowD[k] & 0x1f;
+         const GLint rowAg0 = (rowA[j] >> 5) & 0x1f;
+         const GLint rowAg1 = (rowA[k] >> 5) & 0x1f;
+         const GLint rowBg0 = (rowB[j] >> 5) & 0x1f;
+         const GLint rowBg1 = (rowB[k] >> 5) & 0x1f;
+         const GLint rowCg0 = (rowC[j] >> 5) & 0x1f;
+         const GLint rowCg1 = (rowC[k] >> 5) & 0x1f;
+         const GLint rowDg0 = (rowD[j] >> 5) & 0x1f;
+         const GLint rowDg1 = (rowD[k] >> 5) & 0x1f;
+         const GLint rowAb0 = (rowA[j] >> 10) & 0x1f;
+         const GLint rowAb1 = (rowA[k] >> 10) & 0x1f;
+         const GLint rowBb0 = (rowB[j] >> 10) & 0x1f;
+         const GLint rowBb1 = (rowB[k] >> 10) & 0x1f;
+         const GLint rowCb0 = (rowC[j] >> 10) & 0x1f;
+         const GLint rowCb1 = (rowC[k] >> 10) & 0x1f;
+         const GLint rowDb0 = (rowD[j] >> 10) & 0x1f;
+         const GLint rowDb1 = (rowD[k] >> 10) & 0x1f;
+         const GLint rowAa0 = (rowA[j] >> 15) & 0x1;
+         const GLint rowAa1 = (rowA[k] >> 15) & 0x1;
+         const GLint rowBa0 = (rowB[j] >> 15) & 0x1;
+         const GLint rowBa1 = (rowB[k] >> 15) & 0x1;
+         const GLint rowCa0 = (rowC[j] >> 15) & 0x1;
+         const GLint rowCa1 = (rowC[k] >> 15) & 0x1;
+         const GLint rowDa0 = (rowD[j] >> 15) & 0x1;
+         const GLint rowDa1 = (rowD[k] >> 15) & 0x1;
+         const GLint r = FILTER_SUM_3D(rowAr0, rowAr1, rowBr0, rowBr1,
+                                       rowCr0, rowCr1, rowDr0, rowDr1);
+         const GLint g = FILTER_SUM_3D(rowAg0, rowAg1, rowBg0, rowBg1,
+                                       rowCg0, rowCg1, rowDg0, rowDg1);
+         const GLint b = FILTER_SUM_3D(rowAb0, rowAb1, rowBb0, rowBb1,
+                                       rowCb0, rowCb1, rowDb0, rowDb1);
+         const GLint a = FILTER_SUM_3D(rowAa0, rowAa1, rowBa0, rowBa1,
+                                       rowCa0, rowCa1, rowDa0, rowDa1);
+
+         dst[i] = (a << 15) | (b << 10) | (g << 5) | r;
+      }
+   }
+   else if ((datatype == GL_UNSIGNED_BYTE_3_3_2) && (comps == 3)) {
+      DECLARE_ROW_POINTERS0(GLushort);
+
+      for (i = j = 0, k = k0; i < (GLuint) dstWidth;
+           i++, j += colStride, k += colStride) {
+         const GLint rowAr0 = rowA[j] & 0x3;
+         const GLint rowAr1 = rowA[k] & 0x3;
+         const GLint rowBr0 = rowB[j] & 0x3;
+         const GLint rowBr1 = rowB[k] & 0x3;
+         const GLint rowCr0 = rowC[j] & 0x3;
+         const GLint rowCr1 = rowC[k] & 0x3;
+         const GLint rowDr0 = rowD[j] & 0x3;
+         const GLint rowDr1 = rowD[k] & 0x3;
+         const GLint rowAg0 = (rowA[j] >> 2) & 0x7;
+         const GLint rowAg1 = (rowA[k] >> 2) & 0x7;
+         const GLint rowBg0 = (rowB[j] >> 2) & 0x7;
+         const GLint rowBg1 = (rowB[k] >> 2) & 0x7;
+         const GLint rowCg0 = (rowC[j] >> 2) & 0x7;
+         const GLint rowCg1 = (rowC[k] >> 2) & 0x7;
+         const GLint rowDg0 = (rowD[j] >> 2) & 0x7;
+         const GLint rowDg1 = (rowD[k] >> 2) & 0x7;
+         const GLint rowAb0 = (rowA[j] >> 5) & 0x7;
+         const GLint rowAb1 = (rowA[k] >> 5) & 0x7;
+         const GLint rowBb0 = (rowB[j] >> 5) & 0x7;
+         const GLint rowBb1 = (rowB[k] >> 5) & 0x7;
+         const GLint rowCb0 = (rowC[j] >> 5) & 0x7;
+         const GLint rowCb1 = (rowC[k] >> 5) & 0x7;
+         const GLint rowDb0 = (rowD[j] >> 5) & 0x7;
+         const GLint rowDb1 = (rowD[k] >> 5) & 0x7;
+         const GLint r = FILTER_SUM_3D(rowAr0, rowAr1, rowBr0, rowBr1,
+                                       rowCr0, rowCr1, rowDr0, rowDr1);
+         const GLint g = FILTER_SUM_3D(rowAg0, rowAg1, rowBg0, rowBg1,
+                                       rowCg0, rowCg1, rowDg0, rowDg1);
+         const GLint b = FILTER_SUM_3D(rowAb0, rowAb1, rowBb0, rowBb1,
+                                       rowCb0, rowCb1, rowDb0, rowDb1);
+         dst[i] = (b << 5) | (g << 2) | r;
+      }
+   }
+   else {
+      _mesa_problem(NULL, "bad format in do_row()");
+   }
+}
+
+
+/*
+ * These functions generate a 1/2-size mipmap image from a source image.
+ * Texture borders are handled by copying or averaging the source image's
+ * border texels, depending on the scale-down factor.
+ */
+
+static void
+make_1d_mipmap(GLenum datatype, GLuint comps, GLint border,
+               GLint srcWidth, const GLubyte *srcPtr,
+               GLint dstWidth, GLubyte *dstPtr)
+{
+   const GLint bpt = bytes_per_pixel(datatype, comps);
+   const GLubyte *src;
+   GLubyte *dst;
+
+   /* skip the border pixel, if any */
+   src = srcPtr + border * bpt;
+   dst = dstPtr + border * bpt;
+
+   /* we just duplicate the input row, kind of hack, saves code */
+   do_row(datatype, comps, srcWidth - 2 * border, src, src,
+          dstWidth - 2 * border, dst);
+
+   if (border) {
+      /* copy left-most pixel from source */
+      MEMCPY(dstPtr, srcPtr, bpt);
+      /* copy right-most pixel from source */
+      MEMCPY(dstPtr + (dstWidth - 1) * bpt,
+             srcPtr + (srcWidth - 1) * bpt,
+             bpt);
+   }
+}
+
+
+static void
+make_2d_mipmap(GLenum datatype, GLuint comps, GLint border,
+               GLint srcWidth, GLint srcHeight,
+	       const GLubyte *srcPtr, GLint srcRowStride,
+               GLint dstWidth, GLint dstHeight,
+	       GLubyte *dstPtr, GLint dstRowStride)
+{
+   const GLint bpt = bytes_per_pixel(datatype, comps);
+   const GLint srcWidthNB = srcWidth - 2 * border;  /* sizes w/out border */
+   const GLint dstWidthNB = dstWidth - 2 * border;
+   const GLint dstHeightNB = dstHeight - 2 * border;
+   const GLint srcRowBytes = bpt * srcRowStride;
+   const GLint dstRowBytes = bpt * dstRowStride;
+   const GLubyte *srcA, *srcB;
+   GLubyte *dst;
+   GLint row;
+
+   /* Compute src and dst pointers, skipping any border */
+   srcA = srcPtr + border * ((srcWidth + 1) * bpt);
+   if (srcHeight > 1) 
+      srcB = srcA + srcRowBytes;
+   else
+      srcB = srcA;
+   dst = dstPtr + border * ((dstWidth + 1) * bpt);
+
+   for (row = 0; row < dstHeightNB; row++) {
+      do_row(datatype, comps, srcWidthNB, srcA, srcB,
+             dstWidthNB, dst);
+      srcA += 2 * srcRowBytes;
+      srcB += 2 * srcRowBytes;
+      dst += dstRowBytes;
+   }
+
+   /* This is ugly but probably won't be used much */
+   if (border > 0) {
+      /* fill in dest border */
+      /* lower-left border pixel */
+      MEMCPY(dstPtr, srcPtr, bpt);
+      /* lower-right border pixel */
+      MEMCPY(dstPtr + (dstWidth - 1) * bpt,
+             srcPtr + (srcWidth - 1) * bpt, bpt);
+      /* upper-left border pixel */
+      MEMCPY(dstPtr + dstWidth * (dstHeight - 1) * bpt,
+             srcPtr + srcWidth * (srcHeight - 1) * bpt, bpt);
+      /* upper-right border pixel */
+      MEMCPY(dstPtr + (dstWidth * dstHeight - 1) * bpt,
+             srcPtr + (srcWidth * srcHeight - 1) * bpt, bpt);
+      /* lower border */
+      do_row(datatype, comps, srcWidthNB,
+             srcPtr + bpt,
+             srcPtr + bpt,
+             dstWidthNB, dstPtr + bpt);
+      /* upper border */
+      do_row(datatype, comps, srcWidthNB,
+             srcPtr + (srcWidth * (srcHeight - 1) + 1) * bpt,
+             srcPtr + (srcWidth * (srcHeight - 1) + 1) * bpt,
+             dstWidthNB,
+             dstPtr + (dstWidth * (dstHeight - 1) + 1) * bpt);
+      /* left and right borders */
+      if (srcHeight == dstHeight) {
+         /* copy border pixel from src to dst */
+         for (row = 1; row < srcHeight; row++) {
+            MEMCPY(dstPtr + dstWidth * row * bpt,
+                   srcPtr + srcWidth * row * bpt, bpt);
+            MEMCPY(dstPtr + (dstWidth * row + dstWidth - 1) * bpt,
+                   srcPtr + (srcWidth * row + srcWidth - 1) * bpt, bpt);
+         }
+      }
+      else {
+         /* average two src pixels each dest pixel */
+         for (row = 0; row < dstHeightNB; row += 2) {
+            do_row(datatype, comps, 1,
+                   srcPtr + (srcWidth * (row * 2 + 1)) * bpt,
+                   srcPtr + (srcWidth * (row * 2 + 2)) * bpt,
+                   1, dstPtr + (dstWidth * row + 1) * bpt);
+            do_row(datatype, comps, 1,
+                   srcPtr + (srcWidth * (row * 2 + 1) + srcWidth - 1) * bpt,
+                   srcPtr + (srcWidth * (row * 2 + 2) + srcWidth - 1) * bpt,
+                   1, dstPtr + (dstWidth * row + 1 + dstWidth - 1) * bpt);
+         }
+      }
+   }
+}
+
+
+static void
+make_3d_mipmap(GLenum datatype, GLuint comps, GLint border,
+               GLint srcWidth, GLint srcHeight, GLint srcDepth,
+               const GLubyte *srcPtr, GLint srcRowStride,
+               GLint dstWidth, GLint dstHeight, GLint dstDepth,
+               GLubyte *dstPtr, GLint dstRowStride)
+{
+   const GLint bpt = bytes_per_pixel(datatype, comps);
+   const GLint srcWidthNB = srcWidth - 2 * border;  /* sizes w/out border */
+   const GLint srcDepthNB = srcDepth - 2 * border;
+   const GLint dstWidthNB = dstWidth - 2 * border;
+   const GLint dstHeightNB = dstHeight - 2 * border;
+   const GLint dstDepthNB = dstDepth - 2 * border;
+   GLint img, row;
+   GLint bytesPerSrcImage, bytesPerDstImage;
+   GLint bytesPerSrcRow, bytesPerDstRow;
+   GLint srcImageOffset, srcRowOffset;
+
+   (void) srcDepthNB; /* silence warnings */
+
+
+   bytesPerSrcImage = srcWidth * srcHeight * bpt;
+   bytesPerDstImage = dstWidth * dstHeight * bpt;
+
+   bytesPerSrcRow = srcWidth * bpt;
+   bytesPerDstRow = dstWidth * bpt;
+
+   /* Offset between adjacent src images to be averaged together */
+   srcImageOffset = (srcDepth == dstDepth) ? 0 : bytesPerSrcImage;
+
+   /* Offset between adjacent src rows to be averaged together */
+   srcRowOffset = (srcHeight == dstHeight) ? 0 : srcWidth * bpt;
+
+   /*
+    * Need to average together up to 8 src pixels for each dest pixel.
+    * Break that down into 3 operations:
+    *   1. take two rows from source image and average them together.
+    *   2. take two rows from next source image and average them together.
+    *   3. take the two averaged rows and average them for the final dst row.
+    */
+
+   /*
+   _mesa_printf("mip3d %d x %d x %d  ->  %d x %d x %d\n",
+          srcWidth, srcHeight, srcDepth, dstWidth, dstHeight, dstDepth);
+   */
+
+   for (img = 0; img < dstDepthNB; img++) {
+      /* first source image pointer, skipping border */
+      const GLubyte *imgSrcA = srcPtr
+         + (bytesPerSrcImage + bytesPerSrcRow + border) * bpt * border
+         + img * (bytesPerSrcImage + srcImageOffset);
+      /* second source image pointer, skipping border */
+      const GLubyte *imgSrcB = imgSrcA + srcImageOffset;
+      /* address of the dest image, skipping border */
+      GLubyte *imgDst = dstPtr
+         + (bytesPerDstImage + bytesPerDstRow + border) * bpt * border
+         + img * bytesPerDstImage;
+
+      /* setup the four source row pointers and the dest row pointer */
+      const GLubyte *srcImgARowA = imgSrcA;
+      const GLubyte *srcImgARowB = imgSrcA + srcRowOffset;
+      const GLubyte *srcImgBRowA = imgSrcB;
+      const GLubyte *srcImgBRowB = imgSrcB + srcRowOffset;
+      GLubyte *dstImgRow = imgDst;
+
+      for (row = 0; row < dstHeightNB; row++) {
+         do_row_3D(datatype, comps, srcWidthNB, 
+                   srcImgARowA, srcImgARowB,
+                   srcImgBRowA, srcImgBRowB,
+                   dstWidthNB, dstImgRow);
+
+         /* advance to next rows */
+         srcImgARowA += bytesPerSrcRow + srcRowOffset;
+         srcImgARowB += bytesPerSrcRow + srcRowOffset;
+         srcImgBRowA += bytesPerSrcRow + srcRowOffset;
+         srcImgBRowB += bytesPerSrcRow + srcRowOffset;
+         dstImgRow += bytesPerDstRow;
+      }
+   }
+
+
+   /* Luckily we can leverage the make_2d_mipmap() function here! */
+   if (border > 0) {
+      /* do front border image */
+      make_2d_mipmap(datatype, comps, 1, srcWidth, srcHeight, srcPtr, srcRowStride,
+                     dstWidth, dstHeight, dstPtr, dstRowStride);
+      /* do back border image */
+      make_2d_mipmap(datatype, comps, 1, srcWidth, srcHeight,
+                     srcPtr + bytesPerSrcImage * (srcDepth - 1), srcRowStride,
+                     dstWidth, dstHeight,
+                     dstPtr + bytesPerDstImage * (dstDepth - 1), dstRowStride);
+      /* do four remaining border edges that span the image slices */
+      if (srcDepth == dstDepth) {
+         /* just copy border pixels from src to dst */
+         for (img = 0; img < dstDepthNB; img++) {
+            const GLubyte *src;
+            GLubyte *dst;
+
+            /* do border along [img][row=0][col=0] */
+            src = srcPtr + (img + 1) * bytesPerSrcImage;
+            dst = dstPtr + (img + 1) * bytesPerDstImage;
+            MEMCPY(dst, src, bpt);
+
+            /* do border along [img][row=dstHeight-1][col=0] */
+            src = srcPtr + (img * 2 + 1) * bytesPerSrcImage
+                         + (srcHeight - 1) * bytesPerSrcRow;
+            dst = dstPtr + (img + 1) * bytesPerDstImage
+                         + (dstHeight - 1) * bytesPerDstRow;
+            MEMCPY(dst, src, bpt);
+
+            /* do border along [img][row=0][col=dstWidth-1] */
+            src = srcPtr + (img * 2 + 1) * bytesPerSrcImage
+                         + (srcWidth - 1) * bpt;
+            dst = dstPtr + (img + 1) * bytesPerDstImage
+                         + (dstWidth - 1) * bpt;
+            MEMCPY(dst, src, bpt);
+
+            /* do border along [img][row=dstHeight-1][col=dstWidth-1] */
+            src = srcPtr + (img * 2 + 1) * bytesPerSrcImage
+                         + (bytesPerSrcImage - bpt);
+            dst = dstPtr + (img + 1) * bytesPerDstImage
+                         + (bytesPerDstImage - bpt);
+            MEMCPY(dst, src, bpt);
+         }
+      }
+      else {
+         /* average border pixels from adjacent src image pairs */
+         ASSERT(srcDepthNB == 2 * dstDepthNB);
+         for (img = 0; img < dstDepthNB; img++) {
+            const GLubyte *src;
+            GLubyte *dst;
+
+            /* do border along [img][row=0][col=0] */
+            src = srcPtr + (img * 2 + 1) * bytesPerSrcImage;
+            dst = dstPtr + (img + 1) * bytesPerDstImage;
+            do_row(datatype, comps, 1, src, src + srcImageOffset, 1, dst);
+
+            /* do border along [img][row=dstHeight-1][col=0] */
+            src = srcPtr + (img * 2 + 1) * bytesPerSrcImage
+                         + (srcHeight - 1) * bytesPerSrcRow;
+            dst = dstPtr + (img + 1) * bytesPerDstImage
+                         + (dstHeight - 1) * bytesPerDstRow;
+            do_row(datatype, comps, 1, src, src + srcImageOffset, 1, dst);
+
+            /* do border along [img][row=0][col=dstWidth-1] */
+            src = srcPtr + (img * 2 + 1) * bytesPerSrcImage
+                         + (srcWidth - 1) * bpt;
+            dst = dstPtr + (img + 1) * bytesPerDstImage
+                         + (dstWidth - 1) * bpt;
+            do_row(datatype, comps, 1, src, src + srcImageOffset, 1, dst);
+
+            /* do border along [img][row=dstHeight-1][col=dstWidth-1] */
+            src = srcPtr + (img * 2 + 1) * bytesPerSrcImage
+                         + (bytesPerSrcImage - bpt);
+            dst = dstPtr + (img + 1) * bytesPerDstImage
+                         + (bytesPerDstImage - bpt);
+            do_row(datatype, comps, 1, src, src + srcImageOffset, 1, dst);
+         }
+      }
+   }
+}
+
+
+static void
+make_1d_stack_mipmap(GLenum datatype, GLuint comps, GLint border,
+                     GLint srcWidth, const GLubyte *srcPtr, GLuint srcRowStride,
+                     GLint dstWidth, GLint dstHeight,
+		     GLubyte *dstPtr, GLuint dstRowStride )
+{
+   const GLint bpt = bytes_per_pixel(datatype, comps);
+   const GLint srcWidthNB = srcWidth - 2 * border;  /* sizes w/out border */
+   const GLint dstWidthNB = dstWidth - 2 * border;
+   const GLint dstHeightNB = dstHeight - 2 * border;
+   const GLint srcRowBytes = bpt * srcRowStride;
+   const GLint dstRowBytes = bpt * dstRowStride;
+   const GLubyte *src;
+   GLubyte *dst;
+   GLint row;
+
+   /* Compute src and dst pointers, skipping any border */
+   src = srcPtr + border * ((srcWidth + 1) * bpt);
+   dst = dstPtr + border * ((dstWidth + 1) * bpt);
+
+   for (row = 0; row < dstHeightNB; row++) {
+      do_row(datatype, comps, srcWidthNB, src, src,
+             dstWidthNB, dst);
+      src += srcRowBytes;
+      dst += dstRowBytes;
+   }
+
+   if (border) {
+      /* copy left-most pixel from source */
+      MEMCPY(dstPtr, srcPtr, bpt);
+      /* copy right-most pixel from source */
+      MEMCPY(dstPtr + (dstWidth - 1) * bpt,
+             srcPtr + (srcWidth - 1) * bpt,
+             bpt);
+   }
+}
+
+
+/**
+ * \bug
+ * There is quite a bit of refactoring that could be done with this function
+ * and \c make_2d_mipmap.
+ */
+static void
+make_2d_stack_mipmap(GLenum datatype, GLuint comps, GLint border,
+                     GLint srcWidth, GLint srcHeight,
+		     const GLubyte *srcPtr, GLint srcRowStride,
+                     GLint dstWidth, GLint dstHeight, GLint dstDepth,
+                     GLubyte *dstPtr, GLint dstRowStride)
+{
+   const GLint bpt = bytes_per_pixel(datatype, comps);
+   const GLint srcWidthNB = srcWidth - 2 * border;  /* sizes w/out border */
+   const GLint dstWidthNB = dstWidth - 2 * border;
+   const GLint dstHeightNB = dstHeight - 2 * border;
+   const GLint dstDepthNB = dstDepth - 2 * border;
+   const GLint srcRowBytes = bpt * srcRowStride;
+   const GLint dstRowBytes = bpt * dstRowStride;
+   const GLubyte *srcA, *srcB;
+   GLubyte *dst;
+   GLint layer;
+   GLint row;
+
+   /* Compute src and dst pointers, skipping any border */
+   srcA = srcPtr + border * ((srcWidth + 1) * bpt);
+   if (srcHeight > 1) 
+      srcB = srcA + srcRowBytes;
+   else
+      srcB = srcA;
+   dst = dstPtr + border * ((dstWidth + 1) * bpt);
+
+   for (layer = 0; layer < dstDepthNB; layer++) {
+      for (row = 0; row < dstHeightNB; row++) {
+         do_row(datatype, comps, srcWidthNB, srcA, srcB,
+                dstWidthNB, dst);
+         srcA += 2 * srcRowBytes;
+         srcB += 2 * srcRowBytes;
+         dst += dstRowBytes;
+      }
+
+      /* This is ugly but probably won't be used much */
+      if (border > 0) {
+         /* fill in dest border */
+         /* lower-left border pixel */
+         MEMCPY(dstPtr, srcPtr, bpt);
+         /* lower-right border pixel */
+         MEMCPY(dstPtr + (dstWidth - 1) * bpt,
+                srcPtr + (srcWidth - 1) * bpt, bpt);
+         /* upper-left border pixel */
+         MEMCPY(dstPtr + dstWidth * (dstHeight - 1) * bpt,
+                srcPtr + srcWidth * (srcHeight - 1) * bpt, bpt);
+         /* upper-right border pixel */
+         MEMCPY(dstPtr + (dstWidth * dstHeight - 1) * bpt,
+                srcPtr + (srcWidth * srcHeight - 1) * bpt, bpt);
+         /* lower border */
+         do_row(datatype, comps, srcWidthNB,
+                srcPtr + bpt,
+                srcPtr + bpt,
+                dstWidthNB, dstPtr + bpt);
+         /* upper border */
+         do_row(datatype, comps, srcWidthNB,
+                srcPtr + (srcWidth * (srcHeight - 1) + 1) * bpt,
+                srcPtr + (srcWidth * (srcHeight - 1) + 1) * bpt,
+                dstWidthNB,
+                dstPtr + (dstWidth * (dstHeight - 1) + 1) * bpt);
+         /* left and right borders */
+         if (srcHeight == dstHeight) {
+            /* copy border pixel from src to dst */
+            for (row = 1; row < srcHeight; row++) {
+               MEMCPY(dstPtr + dstWidth * row * bpt,
+                      srcPtr + srcWidth * row * bpt, bpt);
+               MEMCPY(dstPtr + (dstWidth * row + dstWidth - 1) * bpt,
+                      srcPtr + (srcWidth * row + srcWidth - 1) * bpt, bpt);
+            }
+         }
+         else {
+            /* average two src pixels each dest pixel */
+            for (row = 0; row < dstHeightNB; row += 2) {
+               do_row(datatype, comps, 1,
+                      srcPtr + (srcWidth * (row * 2 + 1)) * bpt,
+                      srcPtr + (srcWidth * (row * 2 + 2)) * bpt,
+                      1, dstPtr + (dstWidth * row + 1) * bpt);
+               do_row(datatype, comps, 1,
+                      srcPtr + (srcWidth * (row * 2 + 1) + srcWidth - 1) * bpt,
+                      srcPtr + (srcWidth * (row * 2 + 2) + srcWidth - 1) * bpt,
+                      1, dstPtr + (dstWidth * row + 1 + dstWidth - 1) * bpt);
+            }
+         }
+      }
+   }
+}
+
+
+/**
+ * Down-sample a texture image to produce the next lower mipmap level.
+ * \param comps  components per texel (1, 2, 3 or 4)
+ * \param srcRowStride  stride between source rows, in texels
+ * \param dstRowStride  stride between destination rows, in texels
+ */
+void
+_mesa_generate_mipmap_level(GLenum target,
+                            GLenum datatype, GLuint comps,
+                            GLint border,
+                            GLint srcWidth, GLint srcHeight, GLint srcDepth,
+                            const GLubyte *srcData,
+                            GLint srcRowStride,
+                            GLint dstWidth, GLint dstHeight, GLint dstDepth,
+                            GLubyte *dstData,
+                            GLint dstRowStride)
+{
+   /*
+    * We use simple 2x2 averaging to compute the next mipmap level.
+    */
+   switch (target) {
+   case GL_TEXTURE_1D:
+      make_1d_mipmap(datatype, comps, border,
+                     srcWidth, srcData,
+                     dstWidth, dstData);
+      break;
+   case GL_TEXTURE_2D:
+   case GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB:
+   case GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB:
+   case GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB:
+   case GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB:
+   case GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB:
+   case GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB:
+      make_2d_mipmap(datatype, comps, border,
+                     srcWidth, srcHeight, srcData, srcRowStride,
+                     dstWidth, dstHeight, dstData, dstRowStride);
+      break;
+   case GL_TEXTURE_3D:
+      make_3d_mipmap(datatype, comps, border,
+                     srcWidth, srcHeight, srcDepth,
+                     srcData, srcRowStride,
+                     dstWidth, dstHeight, dstDepth,
+                     dstData, dstRowStride);
+      break;
+   case GL_TEXTURE_1D_ARRAY_EXT:
+      make_1d_stack_mipmap(datatype, comps, border,
+                           srcWidth, srcData, srcRowStride,
+                           dstWidth, dstHeight,
+                           dstData, dstRowStride);
+      break;
+   case GL_TEXTURE_2D_ARRAY_EXT:
+      make_2d_stack_mipmap(datatype, comps, border,
+                           srcWidth, srcHeight,
+                           srcData, srcRowStride,
+                           dstWidth, dstHeight,
+                           dstDepth, dstData, dstRowStride);
+      break;
+   case GL_TEXTURE_RECTANGLE_NV:
+      /* no mipmaps, do nothing */
+      break;
+   default:
+      _mesa_problem(NULL, "bad dimensions in _mesa_generate_mipmaps");
+      return;
+   }
+}
+
+
+/**
+ * compute next (level+1) image size
+ * \return GL_FALSE if no smaller size can be generated (eg. src is 1x1x1 size)
+ */
+static GLboolean
+next_mipmap_level_size(GLenum target, GLint border,
+                       GLint srcWidth, GLint srcHeight, GLint srcDepth,
+                       GLint *dstWidth, GLint *dstHeight, GLint *dstDepth)
+{
+   if (srcWidth - 2 * border > 1) {
+      *dstWidth = (srcWidth - 2 * border) / 2 + 2 * border;
+   }
+   else {
+      *dstWidth = srcWidth; /* can't go smaller */
+   }
+
+   if ((srcHeight - 2 * border > 1) && 
+       (target != GL_TEXTURE_1D_ARRAY_EXT)) {
+      *dstHeight = (srcHeight - 2 * border) / 2 + 2 * border;
+   }
+   else {
+      *dstHeight = srcHeight; /* can't go smaller */
+   }
+
+   if ((srcDepth - 2 * border > 1) &&
+       (target != GL_TEXTURE_2D_ARRAY_EXT)) {
+      *dstDepth = (srcDepth - 2 * border) / 2 + 2 * border;
+   }
+   else {
+      *dstDepth = srcDepth; /* can't go smaller */
+   }
+
+   if (*dstWidth == srcWidth &&
+       *dstHeight == srcHeight &&
+       *dstDepth == srcDepth) {
+      return GL_FALSE;
+   }
+   else {
+      return GL_TRUE;
+   }
+}
+
+
+
+
+/**
+ * Automatic mipmap generation.
+ * This is the fallback/default function for ctx->Driver.GenerateMipmap().
+ * Generate a complete set of mipmaps from texObj's BaseLevel image.
+ * Stop at texObj's MaxLevel or when we get to the 1x1 texture.
+ * For cube maps, target will be one of
+ * GL_TEXTURE_CUBE_MAP_POSITIVE/NEGATIVE_X/Y/Z; never GL_TEXTURE_CUBE_MAP.
+ */
+void
+_mesa_generate_mipmap(GLcontext *ctx, GLenum target,
+                      struct gl_texture_object *texObj)
+{
+   const struct gl_texture_image *srcImage;
+   const struct gl_texture_format *convertFormat;
+   const GLubyte *srcData = NULL;
+   GLubyte *dstData = NULL;
+   GLint level, maxLevels;
+   GLenum datatype;
+   GLuint comps;
+
+   ASSERT(texObj);
+   /* XXX choose cube map face here??? */
+   srcImage = texObj->Image[0][texObj->BaseLevel];
+   ASSERT(srcImage);
+
+   maxLevels = _mesa_max_texture_levels(ctx, texObj->Target);
+   ASSERT(maxLevels > 0);  /* bad target */
+
+   /* Find convertFormat - the format that do_row() will process */
+   if (srcImage->IsCompressed) {
+      /* setup for compressed textures */
+      GLuint row;
+      GLint  components, size;
+      GLchan *dst;
+
+      assert(texObj->Target == GL_TEXTURE_2D ||
+             texObj->Target == GL_TEXTURE_CUBE_MAP_ARB);
+
+      if (srcImage->_BaseFormat == GL_RGB) {
+         convertFormat = &_mesa_texformat_rgb;
+         components = 3;
+      }
+      else if (srcImage->_BaseFormat == GL_RGBA) {
+         convertFormat = &_mesa_texformat_rgba;
+         components = 4;
+      }
+      else {
+         _mesa_problem(ctx, "bad srcImage->_BaseFormat in _mesa_generate_mipmaps");
+         return;
+      }
+
+      /* allocate storage for uncompressed GL_RGB or GL_RGBA images */
+      size = _mesa_bytes_per_pixel(srcImage->_BaseFormat, CHAN_TYPE)
+         * srcImage->Width * srcImage->Height * srcImage->Depth + 20;
+      /* 20 extra bytes, just be safe when calling last FetchTexel */
+      srcData = (GLubyte *) _mesa_malloc(size);
+      if (!srcData) {
+         _mesa_error(ctx, GL_OUT_OF_MEMORY, "generate mipmaps");
+         return;
+      }
+      dstData = (GLubyte *) _mesa_malloc(size / 2);  /* 1/4 would probably be OK */
+      if (!dstData) {
+         _mesa_error(ctx, GL_OUT_OF_MEMORY, "generate mipmaps");
+         _mesa_free((void *) srcData);
+         return;
+      }
+
+      /* decompress base image here */
+      dst = (GLchan *) srcData;
+      for (row = 0; row < srcImage->Height; row++) {
+         GLuint col;
+         for (col = 0; col < srcImage->Width; col++) {
+            srcImage->FetchTexelc(srcImage, col, row, 0, dst);
+            dst += components;
+         }
+      }
+   }
+   else {
+      /* uncompressed */
+      convertFormat = srcImage->TexFormat;
+   }
+
+   _mesa_format_to_type_and_comps(convertFormat, &datatype, &comps);
+
+   for (level = texObj->BaseLevel; level < texObj->MaxLevel
+           && level < maxLevels - 1; level++) {
+      /* generate image[level+1] from image[level] */
+      const struct gl_texture_image *srcImage;
+      struct gl_texture_image *dstImage;
+      GLint srcWidth, srcHeight, srcDepth;
+      GLint dstWidth, dstHeight, dstDepth;
+      GLint border, bytesPerTexel;
+      GLboolean nextLevel;
+
+      /* get src image parameters */
+      srcImage = _mesa_select_tex_image(ctx, texObj, target, level);
+      ASSERT(srcImage);
+      srcWidth = srcImage->Width;
+      srcHeight = srcImage->Height;
+      srcDepth = srcImage->Depth;
+      border = srcImage->Border;
+
+      nextLevel = next_mipmap_level_size(target, border,
+                                         srcWidth, srcHeight, srcDepth,
+                                         &dstWidth, &dstHeight, &dstDepth);
+      if (!nextLevel) {
+         /* all done */
+         if (srcImage->IsCompressed) {
+            _mesa_free((void *) srcData);
+            _mesa_free(dstData);
+         }
+         return;
+      }
+
+      /* get dest gl_texture_image */
+      dstImage = _mesa_get_tex_image(ctx, texObj, target, level + 1);
+      if (!dstImage) {
+         _mesa_error(ctx, GL_OUT_OF_MEMORY, "generating mipmaps");
+         return;
+      }
+
+      /* Free old image data */
+      if (dstImage->Data)
+         ctx->Driver.FreeTexImageData(ctx, dstImage);
+
+      /* initialize new image */
+      _mesa_init_teximage_fields(ctx, target, dstImage, dstWidth, dstHeight,
+                                 dstDepth, border, srcImage->InternalFormat);
+      dstImage->DriverData = NULL;
+      dstImage->TexFormat = srcImage->TexFormat;
+      dstImage->FetchTexelc = srcImage->FetchTexelc;
+      dstImage->FetchTexelf = srcImage->FetchTexelf;
+      dstImage->IsCompressed = srcImage->IsCompressed;
+      if (dstImage->IsCompressed) {
+         dstImage->CompressedSize
+            = ctx->Driver.CompressedTextureSize(ctx, dstImage->Width,
+                                              dstImage->Height,
+                                              dstImage->Depth,
+                                              dstImage->TexFormat->MesaFormat);
+         ASSERT(dstImage->CompressedSize > 0);
+      }
+
+      ASSERT(dstImage->TexFormat);
+      ASSERT(dstImage->FetchTexelc);
+      ASSERT(dstImage->FetchTexelf);
+
+      /* Alloc new teximage data buffer.
+       * Setup src and dest data pointers.
+       */
+      if (dstImage->IsCompressed) {
+         dstImage->Data = _mesa_alloc_texmemory(dstImage->CompressedSize);
+         if (!dstImage->Data) {
+            _mesa_error(ctx, GL_OUT_OF_MEMORY, "generating mipmaps");
+            return;
+         }
+         /* srcData and dstData are already set */
+         ASSERT(srcData);
+         ASSERT(dstData);
+      }
+      else {
+         bytesPerTexel = dstImage->TexFormat->TexelBytes;
+         ASSERT(dstWidth * dstHeight * dstDepth * bytesPerTexel > 0);
+         dstImage->Data = _mesa_alloc_texmemory(dstWidth * dstHeight
+                                                * dstDepth * bytesPerTexel);
+         if (!dstImage->Data) {
+            _mesa_error(ctx, GL_OUT_OF_MEMORY, "generating mipmaps");
+            return;
+         }
+         srcData = (const GLubyte *) srcImage->Data;
+         dstData = (GLubyte *) dstImage->Data;
+      }
+
+      _mesa_generate_mipmap_level(target, datatype, comps, border,
+                                  srcWidth, srcHeight, srcDepth, 
+                                  srcData, srcImage->RowStride,
+                                  dstWidth, dstHeight, dstDepth, 
+                                  dstData, dstImage->RowStride);
+
+
+      if (dstImage->IsCompressed) {
+         GLubyte *temp;
+         /* compress image from dstData into dstImage->Data */
+         const GLenum srcFormat = convertFormat->BaseFormat;
+         GLint dstRowStride
+            = _mesa_compressed_row_stride(dstImage->TexFormat->MesaFormat, dstWidth);
+         ASSERT(srcFormat == GL_RGB || srcFormat == GL_RGBA);
+         dstImage->TexFormat->StoreImage(ctx, 2, dstImage->_BaseFormat,
+                                         dstImage->TexFormat,
+                                         dstImage->Data,
+                                         0, 0, 0, /* dstX/Y/Zoffset */
+                                         dstRowStride, 0, /* strides */
+                                         dstWidth, dstHeight, 1, /* size */
+                                         srcFormat, CHAN_TYPE,
+                                         dstData, /* src data, actually */
+                                         &ctx->DefaultPacking);
+         /* swap src and dest pointers */
+         temp = (GLubyte *) srcData;
+         srcData = dstData;
+         dstData = temp;
+      }
+
+   } /* loop over mipmap levels */
+}
+
+
+/**
+ * Helper function for drivers which need to rescale texture images to
+ * certain aspect ratios.
+ * Nearest filtering only (for broken hardware that can't support
+ * all aspect ratios).  This can be made a lot faster, but I don't
+ * really care enough...
+ */
+void
+_mesa_rescale_teximage2d(GLuint bytesPerPixel,
+			 GLuint srcStrideInPixels,
+			 GLuint dstRowStride,
+			 GLint srcWidth, GLint srcHeight,
+			 GLint dstWidth, GLint dstHeight,
+			 const GLvoid *srcImage, GLvoid *dstImage)
+{
+   GLint row, col;
+
+#define INNER_LOOP( TYPE, HOP, WOP )					\
+   for ( row = 0 ; row < dstHeight ; row++ ) {				\
+      GLint srcRow = row HOP hScale;					\
+      for ( col = 0 ; col < dstWidth ; col++ ) {			\
+	 GLint srcCol = col WOP wScale;					\
+	 dst[col] = src[srcRow * srcStrideInPixels + srcCol];		\
+      }									\
+      dst = (TYPE *) ((GLubyte *) dst + dstRowStride);			\
+   }									\
+
+#define RESCALE_IMAGE( TYPE )						\
+do {									\
+   const TYPE *src = (const TYPE *)srcImage;				\
+   TYPE *dst = (TYPE *)dstImage;					\
+									\
+   if ( srcHeight < dstHeight ) {					\
+      const GLint hScale = dstHeight / srcHeight;			\
+      if ( srcWidth < dstWidth ) {					\
+	 const GLint wScale = dstWidth / srcWidth;			\
+	 INNER_LOOP( TYPE, /, / );					\
+      }									\
+      else {								\
+	 const GLint wScale = srcWidth / dstWidth;			\
+	 INNER_LOOP( TYPE, /, * );					\
+      }									\
+   }									\
+   else {								\
+      const GLint hScale = srcHeight / dstHeight;			\
+      if ( srcWidth < dstWidth ) {					\
+	 const GLint wScale = dstWidth / srcWidth;			\
+	 INNER_LOOP( TYPE, *, / );					\
+      }									\
+      else {								\
+	 const GLint wScale = srcWidth / dstWidth;			\
+	 INNER_LOOP( TYPE, *, * );					\
+      }									\
+   }									\
+} while (0)
+
+   switch ( bytesPerPixel ) {
+   case 4:
+      RESCALE_IMAGE( GLuint );
+      break;
+
+   case 2:
+      RESCALE_IMAGE( GLushort );
+      break;
+
+   case 1:
+      RESCALE_IMAGE( GLubyte );
+      break;
+   default:
+      _mesa_problem(NULL,"unexpected bytes/pixel in _mesa_rescale_teximage2d");
+   }
+}
+
+
+/**
+ * Upscale an image by replication, not (typical) stretching.
+ * We use this when the image width or height is less than a
+ * certain size (4, 8) and we need to upscale an image.
+ */
+void
+_mesa_upscale_teximage2d(GLsizei inWidth, GLsizei inHeight,
+                         GLsizei outWidth, GLsizei outHeight,
+                         GLint comps, const GLchan *src, GLint srcRowStride,
+                         GLchan *dest )
+{
+   GLint i, j, k;
+
+   ASSERT(outWidth >= inWidth);
+   ASSERT(outHeight >= inHeight);
+#if 0
+   ASSERT(inWidth == 1 || inWidth == 2 || inHeight == 1 || inHeight == 2);
+   ASSERT((outWidth & 3) == 0);
+   ASSERT((outHeight & 3) == 0);
+#endif
+
+   for (i = 0; i < outHeight; i++) {
+      const GLint ii = i % inHeight;
+      for (j = 0; j < outWidth; j++) {
+         const GLint jj = j % inWidth;
+         for (k = 0; k < comps; k++) {
+            dest[(i * outWidth + j) * comps + k]
+               = src[ii * srcRowStride + jj * comps + k];
+         }
+      }
+   }
+}
+