pixman mesa git update 1 Mar 2011

1 files changed, 561 insertions, 560 deletions

diff --git a/mesalib/src/mesa/state_tracker/st_cb_readpixels.c b/mesalib/src/mesa/state_tracker/st_cb_readpixels.c
index 570873916..f8da2a4d1 100644
--- a/mesalib/src/mesa/state_tracker/st_cb_readpixels.c
+++ b/mesalib/src/mesa/state_tracker/st_cb_readpixels.c
@@ -1,560 +1,561 @@
-/**************************************************************************

- * 

- * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.

- * 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, sub license, 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 (including the

- * next paragraph) 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 NON-INFRINGEMENT.

- * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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.

- * 

- **************************************************************************/

-

-

-/**

- * glReadPixels interface to pipe

- *

- * \author Brian Paul

- */

-

-

-#include "main/imports.h"

-#include "main/bufferobj.h"

-#include "main/context.h"

-#include "main/image.h"

-#include "main/pack.h"

-

-#include "pipe/p_context.h"

-#include "pipe/p_defines.h"

-#include "util/u_format.h"

-#include "util/u_inlines.h"

-#include "util/u_tile.h"

-

-#include "st_debug.h"

-#include "st_context.h"

-#include "st_atom.h"

-#include "st_cb_bitmap.h"

-#include "st_cb_readpixels.h"

-#include "st_cb_fbo.h"

-

-/**

- * Special case for reading stencil buffer.

- * For color/depth we use get_tile().  For stencil, map the stencil buffer.

- */

-void

-st_read_stencil_pixels(struct gl_context *ctx, GLint x, GLint y,

-                       GLsizei width, GLsizei height,

-                       GLenum format, GLenum type,

-                       const struct gl_pixelstore_attrib *packing,

-                       GLvoid *pixels)

-{

-   struct gl_framebuffer *fb = ctx->ReadBuffer;

-   struct pipe_context *pipe = st_context(ctx)->pipe;

-   struct st_renderbuffer *strb = st_renderbuffer(fb->_StencilBuffer);

-   struct pipe_transfer *pt;

-   ubyte *stmap;

-   GLint j;

-

-   if (strb->Base.Wrapped) {

-      strb = st_renderbuffer(strb->Base.Wrapped);

-   }

-

-   if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP) {

-      y = ctx->DrawBuffer->Height - y - height;

-   }

-

-   /* Create a read transfer from the renderbuffer's texture */

-

-   pt = pipe_get_transfer(pipe, strb->texture,

-                          0, 0,

-                          PIPE_TRANSFER_READ,

-                          x, y, width, height);

-

-   /* map the stencil buffer */

-   stmap = pipe_transfer_map(pipe, pt);

-

-   /* width should never be > MAX_WIDTH since we did clipping earlier */

-   ASSERT(width <= MAX_WIDTH);

-

-   /* process image row by row */

-   for (j = 0; j < height; j++) {

-      GLvoid *dest;

-      GLstencil sValues[MAX_WIDTH];

-      GLfloat zValues[MAX_WIDTH];

-      GLint srcY;

-

-      if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP) {

-         srcY = height - j - 1;

-      }

-      else {

-         srcY = j;

-      }

-

-      /* get stencil (and Z) values */

-      switch (pt->resource->format) {

-      case PIPE_FORMAT_S8_USCALED:

-         {

-            const ubyte *src = stmap + srcY * pt->stride;

-            memcpy(sValues, src, width);

-         }

-         break;

-      case PIPE_FORMAT_Z24_UNORM_S8_USCALED:

-         if (format == GL_DEPTH_STENCIL) {

-            const uint *src = (uint *) (stmap + srcY * pt->stride);

-            const GLfloat scale = 1.0f / (0xffffff);

-            GLint k;

-            for (k = 0; k < width; k++) {

-               sValues[k] = src[k] >> 24;

-               zValues[k] = (src[k] & 0xffffff) * scale;

-            }

-         }

-         else {

-            const uint *src = (uint *) (stmap + srcY * pt->stride);

-            GLint k;

-            for (k = 0; k < width; k++) {

-               sValues[k] = src[k] >> 24;

-            }

-         }

-         break;

-      case PIPE_FORMAT_S8_USCALED_Z24_UNORM:

-         if (format == GL_DEPTH_STENCIL) {

-            const uint *src = (uint *) (stmap + srcY * pt->stride);

-            const GLfloat scale = 1.0f / (0xffffff);

-            GLint k;

-            for (k = 0; k < width; k++) {

-               sValues[k] = src[k] & 0xff;

-               zValues[k] = (src[k] >> 8) * scale;

-            }

-         }

-         else {

-            const uint *src = (uint *) (stmap + srcY * pt->stride);

-            GLint k;

-            for (k = 0; k < width; k++) {

-               sValues[k] = src[k] & 0xff;

-            }

-         }

-         break;

-      default:

-         assert(0);

-      }

-

-      /* store */

-      dest = _mesa_image_address2d(packing, pixels, width, height,

-                                   format, type, j, 0);

-      if (format == GL_DEPTH_STENCIL) {

-         _mesa_pack_depth_stencil_span(ctx, width, dest,

-                                       zValues, sValues, packing);

-      }

-      else {

-         _mesa_pack_stencil_span(ctx, width, type, dest, sValues, packing);

-      }

-   }

-

-   /* unmap the stencil buffer */

-   pipe_transfer_unmap(pipe, pt);

-   pipe->transfer_destroy(pipe, pt);

-}

-

-

-/**

- * Return renderbuffer to use for reading color pixels for glRead/CopyPixel

- * commands.

- */

-struct st_renderbuffer *

-st_get_color_read_renderbuffer(struct gl_context *ctx)

-{

-   struct gl_framebuffer *fb = ctx->ReadBuffer;

-   struct st_renderbuffer *strb =

-      st_renderbuffer(fb->_ColorReadBuffer);

-

-   return strb;

-}

-

-

-/**

- * Try to do glReadPixels in a fast manner for common cases.

- * \return GL_TRUE for success, GL_FALSE for failure

- */

-static GLboolean

-st_fast_readpixels(struct gl_context *ctx, struct st_renderbuffer *strb,

-                   GLint x, GLint y, GLsizei width, GLsizei height,

-                   GLenum format, GLenum type,

-                   const struct gl_pixelstore_attrib *pack,

-                   GLvoid *dest)

-{

-   enum combination {

-      A8R8G8B8_UNORM_TO_RGBA_UBYTE,

-      A8R8G8B8_UNORM_TO_RGB_UBYTE,

-      A8R8G8B8_UNORM_TO_BGRA_UINT

-   } combo;

-

-   if (ctx->_ImageTransferState)

-      return GL_FALSE;

-

-   if (strb->format == PIPE_FORMAT_B8G8R8A8_UNORM &&

-       format == GL_RGBA && type == GL_UNSIGNED_BYTE) {

-      combo = A8R8G8B8_UNORM_TO_RGBA_UBYTE;

-   }

-   else if (strb->format == PIPE_FORMAT_B8G8R8A8_UNORM &&

-            format == GL_RGB && type == GL_UNSIGNED_BYTE) {

-      combo = A8R8G8B8_UNORM_TO_RGB_UBYTE;

-   }

-   else if (strb->format == PIPE_FORMAT_B8G8R8A8_UNORM &&

-            format == GL_BGRA && type == GL_UNSIGNED_INT_8_8_8_8_REV) {

-      combo = A8R8G8B8_UNORM_TO_BGRA_UINT;

-   }

-   else {

-      return GL_FALSE;

-   }

-

-   /*printf("st_fast_readpixels combo %d\n", (GLint) combo);*/

-

-   {

-      struct pipe_context *pipe = st_context(ctx)->pipe;

-      struct pipe_transfer *trans;

-      const GLubyte *map;

-      GLubyte *dst;

-      GLint row, col, dy, dstStride;

-

-      if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {

-         /* convert GL Y to Gallium Y */

-         y = strb->texture->height0 - y - height;

-      }

-

-      trans = pipe_get_transfer(pipe, strb->texture,

-                                0, 0,

-                                PIPE_TRANSFER_READ,

-                                x, y, width, height);

-      if (!trans) {

-         return GL_FALSE;

-      }

-

-      map = pipe_transfer_map(pipe, trans);

-      if (!map) {

-         pipe->transfer_destroy(pipe, trans);

-         return GL_FALSE;

-      }

-

-      /* We always write to the user/dest buffer from low addr to high addr

-       * but the read order depends on renderbuffer orientation

-       */

-      if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {

-         /* read source rows from bottom to top */

-         y = height - 1;

-         dy = -1;

-      }

-      else {

-         /* read source rows from top to bottom */

-         y = 0;

-         dy = 1;

-      }

-

-      dst = _mesa_image_address2d(pack, dest, width, height,

-                                  format, type, 0, 0);

-      dstStride = _mesa_image_row_stride(pack, width, format, type);

-

-      switch (combo) {

-      case A8R8G8B8_UNORM_TO_RGBA_UBYTE:

-         for (row = 0; row < height; row++) {

-            const GLubyte *src = map + y * trans->stride;

-            for (col = 0; col < width; col++) {

-               GLuint pixel = ((GLuint *) src)[col];

-               dst[col*4+0] = (pixel >> 16) & 0xff;

-               dst[col*4+1] = (pixel >>  8) & 0xff;

-               dst[col*4+2] = (pixel >>  0) & 0xff;

-               dst[col*4+3] = (pixel >> 24) & 0xff;

-            }

-            dst += dstStride;

-            y += dy;

-         }

-         break;

-      case A8R8G8B8_UNORM_TO_RGB_UBYTE:

-         for (row = 0; row < height; row++) {

-            const GLubyte *src = map + y * trans->stride;

-            for (col = 0; col < width; col++) {

-               GLuint pixel = ((GLuint *) src)[col];

-               dst[col*3+0] = (pixel >> 16) & 0xff;

-               dst[col*3+1] = (pixel >>  8) & 0xff;

-               dst[col*3+2] = (pixel >>  0) & 0xff;

-            }

-            dst += dstStride;

-            y += dy;

-         }

-         break;

-      case A8R8G8B8_UNORM_TO_BGRA_UINT:

-         for (row = 0; row < height; row++) {

-            const GLubyte *src = map + y * trans->stride;

-            memcpy(dst, src, 4 * width);

-            dst += dstStride;

-            y += dy;

-         }

-         break;

-      default:

-         ; /* nothing */

-      }

-

-      pipe_transfer_unmap(pipe, trans);

-      pipe->transfer_destroy(pipe, trans);

-   }

-

-   return GL_TRUE;

-}

-

-

-/**

- * Do glReadPixels by getting rows from the framebuffer transfer with

- * get_tile().  Convert to requested format/type with Mesa image routines.

- * Image transfer ops are done in software too.

- */

-static void

-st_readpixels(struct gl_context *ctx, GLint x, GLint y, GLsizei width, GLsizei height,

-              GLenum format, GLenum type,

-              const struct gl_pixelstore_attrib *pack,

-              GLvoid *dest)

-{

-   struct st_context *st = st_context(ctx);

-   struct pipe_context *pipe = st->pipe;

-   GLfloat (*temp)[4];

-   const GLbitfield transferOps = ctx->_ImageTransferState;

-   GLsizei i, j;

-   GLint yStep, dfStride;

-   GLfloat *df;

-   struct st_renderbuffer *strb;

-   struct gl_pixelstore_attrib clippedPacking = *pack;

-   struct pipe_transfer *trans;

-   enum pipe_format pformat;

-

-   assert(ctx->ReadBuffer->Width > 0);

-

-   st_validate_state(st);

-

-   /* Do all needed clipping here, so that we can forget about it later */

-   if (!_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {

-      /* The ReadPixels transfer is totally outside the window bounds */

-      return;

-   }

-

-   st_flush_bitmap_cache(st);

-

-   dest = _mesa_map_pbo_dest(ctx, &clippedPacking, dest);

-   if (!dest)

-      return;

-

-   if (format == GL_STENCIL_INDEX ||

-       format == GL_DEPTH_STENCIL) {

-      st_read_stencil_pixels(ctx, x, y, width, height,

-                             format, type, pack, dest);

-      return;

-   }

-   else if (format == GL_DEPTH_COMPONENT) {

-      strb = st_renderbuffer(ctx->ReadBuffer->_DepthBuffer);

-      if (strb->Base.Wrapped) {

-         strb = st_renderbuffer(strb->Base.Wrapped);

-      }

-   }

-   else {

-      /* Read color buffer */

-      strb = st_get_color_read_renderbuffer(ctx);

-   }

-

-   if (!strb)

-      return;

-

-   /* try a fast-path readpixels before anything else */

-   if (st_fast_readpixels(ctx, strb, x, y, width, height,

-                          format, type, pack, dest)) {

-      /* success! */

-      _mesa_unmap_pbo_dest(ctx, &clippedPacking);

-      return;

-   }

-

-   /* allocate temp pixel row buffer */

-   temp = (GLfloat (*)[4]) malloc(4 * width * sizeof(GLfloat));

-   if (!temp) {

-      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");

-      return;

-   }

-

-   if (format == GL_RGBA && type == GL_FLOAT) {

-      /* write tile(row) directly into user's buffer */

-      df = (GLfloat *) _mesa_image_address2d(&clippedPacking, dest, width,

-                                             height, format, type, 0, 0);

-      dfStride = width * 4;

-   }

-   else {

-      /* write tile(row) into temp row buffer */

-      df = (GLfloat *) temp;

-      dfStride = 0;

-   }

-

-   if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {

-      /* convert GL Y to Gallium Y */

-      y = strb->Base.Height - y - height;

-   }

-

-   /* Create a read transfer from the renderbuffer's texture */

-   trans = pipe_get_transfer(pipe, strb->texture,

-                             0, 0,

-                             PIPE_TRANSFER_READ,

-                             x, y, width, height);

-

-   /* determine bottom-to-top vs. top-to-bottom order */

-   if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {

-      y = height - 1;

-      yStep = -1;

-   }

-   else {

-      y = 0;

-      yStep = 1;

-   }

-

-   /* possibly convert sRGB format to linear RGB format */

-   pformat = util_format_linear(trans->resource->format);

-

-   if (ST_DEBUG & DEBUG_FALLBACK)

-      debug_printf("%s: fallback processing\n", __FUNCTION__);

-

-   /*

-    * Copy pixels from pipe_transfer to user memory

-    */

-   {

-      /* dest of first pixel in client memory */

-      GLubyte *dst = _mesa_image_address2d(&clippedPacking, dest, width,

-                                           height, format, type, 0, 0);

-      /* dest row stride */

-      const GLint dstStride = _mesa_image_row_stride(&clippedPacking, width,

-                                                     format, type);

-

-      if (pformat == PIPE_FORMAT_Z24_UNORM_S8_USCALED ||

-          pformat == PIPE_FORMAT_Z24X8_UNORM) {

-         if (format == GL_DEPTH_COMPONENT) {

-            for (i = 0; i < height; i++) {

-               GLuint ztemp[MAX_WIDTH];

-               GLfloat zfloat[MAX_WIDTH];

-               const double scale = 1.0 / ((1 << 24) - 1);

-               pipe_get_tile_raw(pipe, trans, 0, y, width, 1, ztemp, 0);

-               y += yStep;

-               for (j = 0; j < width; j++) {

-                  zfloat[j] = (float) (scale * (ztemp[j] & 0xffffff));

-               }

-               _mesa_pack_depth_span(ctx, width, dst, type,

-                                     zfloat, &clippedPacking);

-               dst += dstStride;

-            }

-         }

-         else {

-            /* XXX: unreachable code -- should be before st_read_stencil_pixels */

-            assert(format == GL_DEPTH_STENCIL_EXT);

-            for (i = 0; i < height; i++) {

-               GLuint *zshort = (GLuint *)dst;

-               pipe_get_tile_raw(pipe, trans, 0, y, width, 1, dst, 0);

-               y += yStep;

-               /* Reverse into 24/8 */

-               for (j = 0; j < width; j++) {

-                  zshort[j] = (zshort[j] << 8) | (zshort[j] >> 24);

-               }

-               dst += dstStride;

-            }

-         }

-      }

-      else if (pformat == PIPE_FORMAT_S8_USCALED_Z24_UNORM ||

-               pformat == PIPE_FORMAT_X8Z24_UNORM) {

-         if (format == GL_DEPTH_COMPONENT) {

-            for (i = 0; i < height; i++) {

-               GLuint ztemp[MAX_WIDTH];

-               GLfloat zfloat[MAX_WIDTH];

-               const double scale = 1.0 / ((1 << 24) - 1);

-               pipe_get_tile_raw(pipe, trans, 0, y, width, 1, ztemp, 0);

-               y += yStep;

-               for (j = 0; j < width; j++) {

-                  zfloat[j] = (float) (scale * ((ztemp[j] >> 8) & 0xffffff));

-               }

-               _mesa_pack_depth_span(ctx, width, dst, type,

-                                     zfloat, &clippedPacking);

-               dst += dstStride;

-            }

-         }

-         else {

-            /* XXX: unreachable code -- should be before st_read_stencil_pixels */

-            assert(format == GL_DEPTH_STENCIL_EXT);

-            for (i = 0; i < height; i++) {

-               pipe_get_tile_raw(pipe, trans, 0, y, width, 1, dst, 0);

-               y += yStep;

-               dst += dstStride;

-            }

-         }

-      }

-      else if (pformat == PIPE_FORMAT_Z16_UNORM) {

-         for (i = 0; i < height; i++) {

-            GLushort ztemp[MAX_WIDTH];

-            GLfloat zfloat[MAX_WIDTH];

-            const double scale = 1.0 / 0xffff;

-            pipe_get_tile_raw(pipe, trans, 0, y, width, 1, ztemp, 0);

-            y += yStep;

-            for (j = 0; j < width; j++) {

-               zfloat[j] = (float) (scale * ztemp[j]);

-            }

-            _mesa_pack_depth_span(ctx, width, dst, type,

-                                  zfloat, &clippedPacking);

-            dst += dstStride;

-         }

-      }

-      else if (pformat == PIPE_FORMAT_Z32_UNORM) {

-         for (i = 0; i < height; i++) {

-            GLuint ztemp[MAX_WIDTH];

-            GLfloat zfloat[MAX_WIDTH];

-            const double scale = 1.0 / 0xffffffff;

-            pipe_get_tile_raw(pipe, trans, 0, y, width, 1, ztemp, 0);

-            y += yStep;

-            for (j = 0; j < width; j++) {

-               zfloat[j] = (float) (scale * ztemp[j]);

-            }

-            _mesa_pack_depth_span(ctx, width, dst, type,

-                                  zfloat, &clippedPacking);

-            dst += dstStride;

-         }

-      }

-      else {

-         /* RGBA format */

-         /* Do a row at a time to flip image data vertically */

-         for (i = 0; i < height; i++) {

-            pipe_get_tile_rgba_format(pipe, trans, 0, y, width, 1,

-                                      pformat, df);

-            y += yStep;

-            df += dfStride;

-            if (!dfStride) {

-               _mesa_pack_rgba_span_float(ctx, width, temp, format, type, dst,

-                                          &clippedPacking, transferOps);

-               dst += dstStride;

-            }

-         }

-      }

-   }

-

-   free(temp);

-

-   pipe->transfer_destroy(pipe, trans);

-

-   _mesa_unmap_pbo_dest(ctx, &clippedPacking);

-}

-

-

-void st_init_readpixels_functions(struct dd_function_table *functions)

-{

-   functions->ReadPixels = st_readpixels;

-}

+/**************************************************************************
+ * 
+ * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
+ * 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, sub license, 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 (including the
+ * next paragraph) 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 NON-INFRINGEMENT.
+ * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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.
+ * 
+ **************************************************************************/
+
+
+/**
+ * glReadPixels interface to pipe
+ *
+ * \author Brian Paul
+ */
+
+
+#include "main/imports.h"
+#include "main/bufferobj.h"
+#include "main/context.h"
+#include "main/image.h"
+#include "main/pack.h"
+#include "main/pbo.h"
+
+#include "pipe/p_context.h"
+#include "pipe/p_defines.h"
+#include "util/u_format.h"
+#include "util/u_inlines.h"
+#include "util/u_tile.h"
+
+#include "st_debug.h"
+#include "st_context.h"
+#include "st_atom.h"
+#include "st_cb_bitmap.h"
+#include "st_cb_readpixels.h"
+#include "st_cb_fbo.h"
+
+/**
+ * Special case for reading stencil buffer.
+ * For color/depth we use get_tile().  For stencil, map the stencil buffer.
+ */
+void
+st_read_stencil_pixels(struct gl_context *ctx, GLint x, GLint y,
+                       GLsizei width, GLsizei height,
+                       GLenum format, GLenum type,
+                       const struct gl_pixelstore_attrib *packing,
+                       GLvoid *pixels)
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct pipe_context *pipe = st_context(ctx)->pipe;
+   struct st_renderbuffer *strb = st_renderbuffer(fb->_StencilBuffer);
+   struct pipe_transfer *pt;
+   ubyte *stmap;
+   GLint j;
+
+   if (strb->Base.Wrapped) {
+      strb = st_renderbuffer(strb->Base.Wrapped);
+   }
+
+   if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP) {
+      y = ctx->DrawBuffer->Height - y - height;
+   }
+
+   /* Create a read transfer from the renderbuffer's texture */
+
+   pt = pipe_get_transfer(pipe, strb->texture,
+                          0, 0,
+                          PIPE_TRANSFER_READ,
+                          x, y, width, height);
+
+   /* map the stencil buffer */
+   stmap = pipe_transfer_map(pipe, pt);
+
+   /* width should never be > MAX_WIDTH since we did clipping earlier */
+   ASSERT(width <= MAX_WIDTH);
+
+   /* process image row by row */
+   for (j = 0; j < height; j++) {
+      GLvoid *dest;
+      GLstencil sValues[MAX_WIDTH];
+      GLfloat zValues[MAX_WIDTH];
+      GLint srcY;
+
+      if (st_fb_orientation(ctx->DrawBuffer) == Y_0_TOP) {
+         srcY = height - j - 1;
+      }
+      else {
+         srcY = j;
+      }
+
+      /* get stencil (and Z) values */
+      switch (pt->resource->format) {
+      case PIPE_FORMAT_S8_USCALED:
+         {
+            const ubyte *src = stmap + srcY * pt->stride;
+            memcpy(sValues, src, width);
+         }
+         break;
+      case PIPE_FORMAT_Z24_UNORM_S8_USCALED:
+         if (format == GL_DEPTH_STENCIL) {
+            const uint *src = (uint *) (stmap + srcY * pt->stride);
+            const GLfloat scale = 1.0f / (0xffffff);
+            GLint k;
+            for (k = 0; k < width; k++) {
+               sValues[k] = src[k] >> 24;
+               zValues[k] = (src[k] & 0xffffff) * scale;
+            }
+         }
+         else {
+            const uint *src = (uint *) (stmap + srcY * pt->stride);
+            GLint k;
+            for (k = 0; k < width; k++) {
+               sValues[k] = src[k] >> 24;
+            }
+         }
+         break;
+      case PIPE_FORMAT_S8_USCALED_Z24_UNORM:
+         if (format == GL_DEPTH_STENCIL) {
+            const uint *src = (uint *) (stmap + srcY * pt->stride);
+            const GLfloat scale = 1.0f / (0xffffff);
+            GLint k;
+            for (k = 0; k < width; k++) {
+               sValues[k] = src[k] & 0xff;
+               zValues[k] = (src[k] >> 8) * scale;
+            }
+         }
+         else {
+            const uint *src = (uint *) (stmap + srcY * pt->stride);
+            GLint k;
+            for (k = 0; k < width; k++) {
+               sValues[k] = src[k] & 0xff;
+            }
+         }
+         break;
+      default:
+         assert(0);
+      }
+
+      /* store */
+      dest = _mesa_image_address2d(packing, pixels, width, height,
+                                   format, type, j, 0);
+      if (format == GL_DEPTH_STENCIL) {
+         _mesa_pack_depth_stencil_span(ctx, width, dest,
+                                       zValues, sValues, packing);
+      }
+      else {
+         _mesa_pack_stencil_span(ctx, width, type, dest, sValues, packing);
+      }
+   }
+
+   /* unmap the stencil buffer */
+   pipe_transfer_unmap(pipe, pt);
+   pipe->transfer_destroy(pipe, pt);
+}
+
+
+/**
+ * Return renderbuffer to use for reading color pixels for glRead/CopyPixel
+ * commands.
+ */
+struct st_renderbuffer *
+st_get_color_read_renderbuffer(struct gl_context *ctx)
+{
+   struct gl_framebuffer *fb = ctx->ReadBuffer;
+   struct st_renderbuffer *strb =
+      st_renderbuffer(fb->_ColorReadBuffer);
+
+   return strb;
+}
+
+
+/**
+ * Try to do glReadPixels in a fast manner for common cases.
+ * \return GL_TRUE for success, GL_FALSE for failure
+ */
+static GLboolean
+st_fast_readpixels(struct gl_context *ctx, struct st_renderbuffer *strb,
+                   GLint x, GLint y, GLsizei width, GLsizei height,
+                   GLenum format, GLenum type,
+                   const struct gl_pixelstore_attrib *pack,
+                   GLvoid *dest)
+{
+   enum combination {
+      A8R8G8B8_UNORM_TO_RGBA_UBYTE,
+      A8R8G8B8_UNORM_TO_RGB_UBYTE,
+      A8R8G8B8_UNORM_TO_BGRA_UINT
+   } combo;
+
+   if (ctx->_ImageTransferState)
+      return GL_FALSE;
+
+   if (strb->format == PIPE_FORMAT_B8G8R8A8_UNORM &&
+       format == GL_RGBA && type == GL_UNSIGNED_BYTE) {
+      combo = A8R8G8B8_UNORM_TO_RGBA_UBYTE;
+   }
+   else if (strb->format == PIPE_FORMAT_B8G8R8A8_UNORM &&
+            format == GL_RGB && type == GL_UNSIGNED_BYTE) {
+      combo = A8R8G8B8_UNORM_TO_RGB_UBYTE;
+   }
+   else if (strb->format == PIPE_FORMAT_B8G8R8A8_UNORM &&
+            format == GL_BGRA && type == GL_UNSIGNED_INT_8_8_8_8_REV) {
+      combo = A8R8G8B8_UNORM_TO_BGRA_UINT;
+   }
+   else {
+      return GL_FALSE;
+   }
+
+   /*printf("st_fast_readpixels combo %d\n", (GLint) combo);*/
+
+   {
+      struct pipe_context *pipe = st_context(ctx)->pipe;
+      struct pipe_transfer *trans;
+      const GLubyte *map;
+      GLubyte *dst;
+      GLint row, col, dy, dstStride;
+
+      if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
+         /* convert GL Y to Gallium Y */
+         y = strb->texture->height0 - y - height;
+      }
+
+      trans = pipe_get_transfer(pipe, strb->texture,
+                                0, 0,
+                                PIPE_TRANSFER_READ,
+                                x, y, width, height);
+      if (!trans) {
+         return GL_FALSE;
+      }
+
+      map = pipe_transfer_map(pipe, trans);
+      if (!map) {
+         pipe->transfer_destroy(pipe, trans);
+         return GL_FALSE;
+      }
+
+      /* We always write to the user/dest buffer from low addr to high addr
+       * but the read order depends on renderbuffer orientation
+       */
+      if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
+         /* read source rows from bottom to top */
+         y = height - 1;
+         dy = -1;
+      }
+      else {
+         /* read source rows from top to bottom */
+         y = 0;
+         dy = 1;
+      }
+
+      dst = _mesa_image_address2d(pack, dest, width, height,
+                                  format, type, 0, 0);
+      dstStride = _mesa_image_row_stride(pack, width, format, type);
+
+      switch (combo) {
+      case A8R8G8B8_UNORM_TO_RGBA_UBYTE:
+         for (row = 0; row < height; row++) {
+            const GLubyte *src = map + y * trans->stride;
+            for (col = 0; col < width; col++) {
+               GLuint pixel = ((GLuint *) src)[col];
+               dst[col*4+0] = (pixel >> 16) & 0xff;
+               dst[col*4+1] = (pixel >>  8) & 0xff;
+               dst[col*4+2] = (pixel >>  0) & 0xff;
+               dst[col*4+3] = (pixel >> 24) & 0xff;
+            }
+            dst += dstStride;
+            y += dy;
+         }
+         break;
+      case A8R8G8B8_UNORM_TO_RGB_UBYTE:
+         for (row = 0; row < height; row++) {
+            const GLubyte *src = map + y * trans->stride;
+            for (col = 0; col < width; col++) {
+               GLuint pixel = ((GLuint *) src)[col];
+               dst[col*3+0] = (pixel >> 16) & 0xff;
+               dst[col*3+1] = (pixel >>  8) & 0xff;
+               dst[col*3+2] = (pixel >>  0) & 0xff;
+            }
+            dst += dstStride;
+            y += dy;
+         }
+         break;
+      case A8R8G8B8_UNORM_TO_BGRA_UINT:
+         for (row = 0; row < height; row++) {
+            const GLubyte *src = map + y * trans->stride;
+            memcpy(dst, src, 4 * width);
+            dst += dstStride;
+            y += dy;
+         }
+         break;
+      default:
+         ; /* nothing */
+      }
+
+      pipe_transfer_unmap(pipe, trans);
+      pipe->transfer_destroy(pipe, trans);
+   }
+
+   return GL_TRUE;
+}
+
+
+/**
+ * Do glReadPixels by getting rows from the framebuffer transfer with
+ * get_tile().  Convert to requested format/type with Mesa image routines.
+ * Image transfer ops are done in software too.
+ */
+static void
+st_readpixels(struct gl_context *ctx, GLint x, GLint y, GLsizei width, GLsizei height,
+              GLenum format, GLenum type,
+              const struct gl_pixelstore_attrib *pack,
+              GLvoid *dest)
+{
+   struct st_context *st = st_context(ctx);
+   struct pipe_context *pipe = st->pipe;
+   GLfloat (*temp)[4];
+   const GLbitfield transferOps = ctx->_ImageTransferState;
+   GLsizei i, j;
+   GLint yStep, dfStride;
+   GLfloat *df;
+   struct st_renderbuffer *strb;
+   struct gl_pixelstore_attrib clippedPacking = *pack;
+   struct pipe_transfer *trans;
+   enum pipe_format pformat;
+
+   assert(ctx->ReadBuffer->Width > 0);
+
+   st_validate_state(st);
+
+   /* Do all needed clipping here, so that we can forget about it later */
+   if (!_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
+      /* The ReadPixels transfer is totally outside the window bounds */
+      return;
+   }
+
+   st_flush_bitmap_cache(st);
+
+   dest = _mesa_map_pbo_dest(ctx, &clippedPacking, dest);
+   if (!dest)
+      return;
+
+   if (format == GL_STENCIL_INDEX ||
+       format == GL_DEPTH_STENCIL) {
+      st_read_stencil_pixels(ctx, x, y, width, height,
+                             format, type, pack, dest);
+      return;
+   }
+   else if (format == GL_DEPTH_COMPONENT) {
+      strb = st_renderbuffer(ctx->ReadBuffer->_DepthBuffer);
+      if (strb->Base.Wrapped) {
+         strb = st_renderbuffer(strb->Base.Wrapped);
+      }
+   }
+   else {
+      /* Read color buffer */
+      strb = st_get_color_read_renderbuffer(ctx);
+   }
+
+   if (!strb)
+      return;
+
+   /* try a fast-path readpixels before anything else */
+   if (st_fast_readpixels(ctx, strb, x, y, width, height,
+                          format, type, pack, dest)) {
+      /* success! */
+      _mesa_unmap_pbo_dest(ctx, &clippedPacking);
+      return;
+   }
+
+   /* allocate temp pixel row buffer */
+   temp = (GLfloat (*)[4]) malloc(4 * width * sizeof(GLfloat));
+   if (!temp) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
+      return;
+   }
+
+   if (format == GL_RGBA && type == GL_FLOAT) {
+      /* write tile(row) directly into user's buffer */
+      df = (GLfloat *) _mesa_image_address2d(&clippedPacking, dest, width,
+                                             height, format, type, 0, 0);
+      dfStride = width * 4;
+   }
+   else {
+      /* write tile(row) into temp row buffer */
+      df = (GLfloat *) temp;
+      dfStride = 0;
+   }
+
+   if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
+      /* convert GL Y to Gallium Y */
+      y = strb->Base.Height - y - height;
+   }
+
+   /* Create a read transfer from the renderbuffer's texture */
+   trans = pipe_get_transfer(pipe, strb->texture,
+                             0, 0,
+                             PIPE_TRANSFER_READ,
+                             x, y, width, height);
+
+   /* determine bottom-to-top vs. top-to-bottom order */
+   if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
+      y = height - 1;
+      yStep = -1;
+   }
+   else {
+      y = 0;
+      yStep = 1;
+   }
+
+   /* possibly convert sRGB format to linear RGB format */
+   pformat = util_format_linear(trans->resource->format);
+
+   if (ST_DEBUG & DEBUG_FALLBACK)
+      debug_printf("%s: fallback processing\n", __FUNCTION__);
+
+   /*
+    * Copy pixels from pipe_transfer to user memory
+    */
+   {
+      /* dest of first pixel in client memory */
+      GLubyte *dst = _mesa_image_address2d(&clippedPacking, dest, width,
+                                           height, format, type, 0, 0);
+      /* dest row stride */
+      const GLint dstStride = _mesa_image_row_stride(&clippedPacking, width,
+                                                     format, type);
+
+      if (pformat == PIPE_FORMAT_Z24_UNORM_S8_USCALED ||
+          pformat == PIPE_FORMAT_Z24X8_UNORM) {
+         if (format == GL_DEPTH_COMPONENT) {
+            for (i = 0; i < height; i++) {
+               GLuint ztemp[MAX_WIDTH];
+               GLfloat zfloat[MAX_WIDTH];
+               const double scale = 1.0 / ((1 << 24) - 1);
+               pipe_get_tile_raw(pipe, trans, 0, y, width, 1, ztemp, 0);
+               y += yStep;
+               for (j = 0; j < width; j++) {
+                  zfloat[j] = (float) (scale * (ztemp[j] & 0xffffff));
+               }
+               _mesa_pack_depth_span(ctx, width, dst, type,
+                                     zfloat, &clippedPacking);
+               dst += dstStride;
+            }
+         }
+         else {
+            /* XXX: unreachable code -- should be before st_read_stencil_pixels */
+            assert(format == GL_DEPTH_STENCIL_EXT);
+            for (i = 0; i < height; i++) {
+               GLuint *zshort = (GLuint *)dst;
+               pipe_get_tile_raw(pipe, trans, 0, y, width, 1, dst, 0);
+               y += yStep;
+               /* Reverse into 24/8 */
+               for (j = 0; j < width; j++) {
+                  zshort[j] = (zshort[j] << 8) | (zshort[j] >> 24);
+               }
+               dst += dstStride;
+            }
+         }
+      }
+      else if (pformat == PIPE_FORMAT_S8_USCALED_Z24_UNORM ||
+               pformat == PIPE_FORMAT_X8Z24_UNORM) {
+         if (format == GL_DEPTH_COMPONENT) {
+            for (i = 0; i < height; i++) {
+               GLuint ztemp[MAX_WIDTH];
+               GLfloat zfloat[MAX_WIDTH];
+               const double scale = 1.0 / ((1 << 24) - 1);
+               pipe_get_tile_raw(pipe, trans, 0, y, width, 1, ztemp, 0);
+               y += yStep;
+               for (j = 0; j < width; j++) {
+                  zfloat[j] = (float) (scale * ((ztemp[j] >> 8) & 0xffffff));
+               }
+               _mesa_pack_depth_span(ctx, width, dst, type,
+                                     zfloat, &clippedPacking);
+               dst += dstStride;
+            }
+         }
+         else {
+            /* XXX: unreachable code -- should be before st_read_stencil_pixels */
+            assert(format == GL_DEPTH_STENCIL_EXT);
+            for (i = 0; i < height; i++) {
+               pipe_get_tile_raw(pipe, trans, 0, y, width, 1, dst, 0);
+               y += yStep;
+               dst += dstStride;
+            }
+         }
+      }
+      else if (pformat == PIPE_FORMAT_Z16_UNORM) {
+         for (i = 0; i < height; i++) {
+            GLushort ztemp[MAX_WIDTH];
+            GLfloat zfloat[MAX_WIDTH];
+            const double scale = 1.0 / 0xffff;
+            pipe_get_tile_raw(pipe, trans, 0, y, width, 1, ztemp, 0);
+            y += yStep;
+            for (j = 0; j < width; j++) {
+               zfloat[j] = (float) (scale * ztemp[j]);
+            }
+            _mesa_pack_depth_span(ctx, width, dst, type,
+                                  zfloat, &clippedPacking);
+            dst += dstStride;
+         }
+      }
+      else if (pformat == PIPE_FORMAT_Z32_UNORM) {
+         for (i = 0; i < height; i++) {
+            GLuint ztemp[MAX_WIDTH];
+            GLfloat zfloat[MAX_WIDTH];
+            const double scale = 1.0 / 0xffffffff;
+            pipe_get_tile_raw(pipe, trans, 0, y, width, 1, ztemp, 0);
+            y += yStep;
+            for (j = 0; j < width; j++) {
+               zfloat[j] = (float) (scale * ztemp[j]);
+            }
+            _mesa_pack_depth_span(ctx, width, dst, type,
+                                  zfloat, &clippedPacking);
+            dst += dstStride;
+         }
+      }
+      else {
+         /* RGBA format */
+         /* Do a row at a time to flip image data vertically */
+         for (i = 0; i < height; i++) {
+            pipe_get_tile_rgba_format(pipe, trans, 0, y, width, 1,
+                                      pformat, df);
+            y += yStep;
+            df += dfStride;
+            if (!dfStride) {
+               _mesa_pack_rgba_span_float(ctx, width, temp, format, type, dst,
+                                          &clippedPacking, transferOps);
+               dst += dstStride;
+            }
+         }
+      }
+   }
+
+   free(temp);
+
+   pipe->transfer_destroy(pipe, trans);
+
+   _mesa_unmap_pbo_dest(ctx, &clippedPacking);
+}
+
+
+void st_init_readpixels_functions(struct dd_function_table *functions)
+{
+   functions->ReadPixels = st_readpixels;
+}