mesa xkeyboard-config xserver git update 25 dec 2011

1 files changed, 346 insertions, 952 deletions

diff --git a/mesalib/src/mesa/swrast/s_stencil.c b/mesalib/src/mesa/swrast/s_stencil.c
index 101ee5056..dbcbd2be0 100644
--- a/mesalib/src/mesa/swrast/s_stencil.c
+++ b/mesalib/src/mesa/swrast/s_stencil.c
@@ -26,6 +26,8 @@
 #include "main/glheader.h"
 #include "main/context.h"
 #include "main/imports.h"
+#include "main/format_pack.h"
+#include "main/format_unpack.h"
 
 #include "s_context.h"
 #include "s_depth.h"
@@ -50,193 +52,171 @@ ENDIF
 */
 
 
+
+/**
+ * Compute/return the offset of the stencil value in a pixel.
+ * For example, if the format is Z24+S8, the position of the stencil bits
+ * within the 4-byte pixel will be either 0 or 3.
+ */
+static GLint
+get_stencil_offset(gl_format format)
+{
+   const GLubyte one = 1;
+   GLubyte pixel[MAX_PIXEL_BYTES];
+   GLint bpp = _mesa_get_format_bytes(format);
+   GLint i;
+
+   assert(_mesa_get_format_bits(format, GL_STENCIL_BITS) == 8);
+   memset(pixel, 0, sizeof(pixel));
+   _mesa_pack_ubyte_stencil_row(format, 1, &one, pixel);
+
+   for (i = 0; i < bpp; i++) {
+      if (pixel[i])
+         return i;
+   }
+
+   _mesa_problem(NULL, "get_stencil_offset() failed\n");
+   return 0;
+}
+
+
+/** Clamp the stencil value to [0, 255] */
+static inline GLubyte
+clamp(GLint val)
+{
+   if (val < 0)
+      return 0;
+   else if (val > 255)
+      return 255;
+   else
+      return val;
+}
+
+
+#define STENCIL_OP(NEW_VAL)                                                 \
+   if (invmask == 0) {                                                      \
+      for (i = j = 0; i < n; i++, j += stride) {                            \
+         if (mask[i]) {                                                     \
+            GLubyte s = stencil[j];                                         \
+            (void) s;                                                       \
+            stencil[j] = (GLubyte) (NEW_VAL);                               \
+         }                                                                  \
+      }                                                                     \
+   }                                                                        \
+   else {                                                                   \
+      for (i = j = 0; i < n; i++, j += stride) {                            \
+         if (mask[i]) {                                                     \
+            GLubyte s = stencil[j];                                         \
+            stencil[j] = (GLubyte) ((invmask & s) | (wrtmask & (NEW_VAL))); \
+         }                                                                  \
+      }                                                                     \
+   }
+
+
 /**
  * Apply the given stencil operator to the array of stencil values.
  * Don't touch stencil[i] if mask[i] is zero.
- * Input:  n - size of stencil array
- *         oper - the stencil buffer operator
- *         face - 0 or 1 for front or back face operation
- *         stencil - array of stencil values
- *         mask - array [n] of flag:  1=apply operator, 0=don't apply operator
- * Output:  stencil - modified values
+ * @param n   number of stencil values
+ * @param oper  the stencil buffer operator
+ * @param face  0 or 1 for front or back face operation
+ * @param stencil  array of stencil values (in/out)
+ * @param mask  array [n] of flag:  1=apply operator, 0=don't apply operator
+ * @param stride  stride between stencil values
  */
 static void
-apply_stencil_op( const struct gl_context *ctx, GLenum oper, GLuint face,
-                  GLuint n, GLubyte stencil[], const GLubyte mask[] )
+apply_stencil_op(const struct gl_context *ctx, GLenum oper, GLuint face,
+                 GLuint n, GLubyte stencil[], const GLubyte mask[],
+                 GLint stride)
 {
    const GLubyte ref = ctx->Stencil.Ref[face];
    const GLubyte wrtmask = ctx->Stencil.WriteMask[face];
    const GLubyte invmask = (GLubyte) (~wrtmask);
-   const GLubyte stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
-   GLuint i;
+   GLuint i, j;
 
    switch (oper) {
-      case GL_KEEP:
-         /* do nothing */
-         break;
-      case GL_ZERO:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  stencil[i] = 0;
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  stencil[i] = (GLubyte) (stencil[i] & invmask);
-	       }
-	    }
-	 }
-	 break;
-      case GL_REPLACE:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  stencil[i] = ref;
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  GLubyte s = stencil[i];
-		  stencil[i] = (GLubyte) ((invmask & s ) | (wrtmask & ref));
-	       }
-	    }
-	 }
-	 break;
-      case GL_INCR:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  GLubyte s = stencil[i];
-		  if (s < stencilMax) {
-		     stencil[i] = (GLubyte) (s+1);
-		  }
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  /* VERIFY logic of adding 1 to a write-masked value */
-		  GLubyte s = stencil[i];
-		  if (s < stencilMax) {
-		     stencil[i] = (GLubyte) ((invmask & s) | (wrtmask & (s+1)));
-		  }
-	       }
-	    }
-	 }
-	 break;
-      case GL_DECR:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  GLubyte s = stencil[i];
-		  if (s>0) {
-		     stencil[i] = (GLubyte) (s-1);
-		  }
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  /* VERIFY logic of subtracting 1 to a write-masked value */
-		  GLubyte s = stencil[i];
-		  if (s>0) {
-		     stencil[i] = (GLubyte) ((invmask & s) | (wrtmask & (s-1)));
-		  }
-	       }
-	    }
-	 }
-	 break;
-      case GL_INCR_WRAP_EXT:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  stencil[i]++;
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte s = stencil[i];
-                  stencil[i] = (GLubyte) ((invmask & s) | (wrtmask & (s+1)));
-	       }
-	    }
-	 }
-	 break;
-      case GL_DECR_WRAP_EXT:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  stencil[i]--;
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte s = stencil[i];
-                  stencil[i] = (GLubyte) ((invmask & s) | (wrtmask & (s-1)));
-	       }
-	    }
-	 }
-	 break;
-      case GL_INVERT:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  GLubyte s = stencil[i];
-		  stencil[i] = (GLubyte) ~s;
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-		  GLubyte s = stencil[i];
-		  stencil[i] = (GLubyte) ((invmask & s) | (wrtmask & ~s));
-	       }
-	    }
-	 }
-	 break;
-      default:
-         _mesa_problem(ctx, "Bad stencil op in apply_stencil_op");
+   case GL_KEEP:
+      /* do nothing */
+      break;
+   case GL_ZERO:
+      /* replace stencil buf values with zero */
+      STENCIL_OP(0);
+      break;
+   case GL_REPLACE:
+      /* replace stencil buf values with ref value */
+      STENCIL_OP(ref);
+      break;
+   case GL_INCR:
+      /* increment stencil buf values, with clamping */
+      STENCIL_OP(clamp(s + 1));
+      break;
+   case GL_DECR:
+      /* increment stencil buf values, with clamping */
+      STENCIL_OP(clamp(s - 1));
+      break;
+   case GL_INCR_WRAP_EXT:
+      /* increment stencil buf values, without clamping */
+      STENCIL_OP(s + 1);
+      break;
+   case GL_DECR_WRAP_EXT:
+      /* increment stencil buf values, without clamping */
+      STENCIL_OP(s - 1);
+      break;
+   case GL_INVERT:
+      /* replace stencil buf values with inverted value */
+      STENCIL_OP(~s);
+      break;
+   default:
+      _mesa_problem(ctx, "Bad stencil op in apply_stencil_op");
    }
 }
 
 
 
+#define STENCIL_TEST(FUNC)                        \
+   for (i = j = 0; i < n; i++, j += stride) {     \
+      if (mask[i]) {                              \
+         s = (GLubyte) (stencil[j] & valueMask);  \
+         if (FUNC) {                              \
+            /* stencil pass */                    \
+            fail[i] = 0;                          \
+         }                                        \
+         else {                                   \
+            /* stencil fail */                    \
+            fail[i] = 1;                          \
+            mask[i] = 0;                          \
+         }                                        \
+      }                                           \
+      else {                                      \
+         fail[i] = 0;                             \
+      }                                           \
+   }
+
+
 
 /**
  * Apply stencil test to an array of stencil values (before depth buffering).
- * Input:  face - 0 or 1 for front or back-face polygons
- *         n - number of pixels in the array
- *         stencil - array of [n] stencil values
- *         mask - array [n] of flag:  0=skip the pixel, 1=stencil the pixel
- * Output:  mask - pixels which fail the stencil test will have their
- *                 mask flag set to 0.
- *          stencil - updated stencil values (where the test passed)
- * Return:  GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.
+ * For the values that fail, we'll apply the GL_STENCIL_FAIL operator to
+ * the stencil values.
+ *
+ * @param face  0 or 1 for front or back-face polygons
+ * @param n  number of pixels in the array
+ * @param stencil  array of [n] stencil values (in/out)
+ * @param mask  array [n] of flag:  0=skip the pixel, 1=stencil the pixel,
+ *              values are set to zero where the stencil test fails.
+ * @param stride  stride between stencil values
+ * @return GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.
  */
 static GLboolean
-do_stencil_test( struct gl_context *ctx, GLuint face, GLuint n, GLubyte stencil[],
-                 GLubyte mask[] )
+do_stencil_test(struct gl_context *ctx, GLuint face, GLuint n,
+                GLubyte stencil[], GLubyte mask[], GLint stride)
 {
    GLubyte fail[MAX_WIDTH];
    GLboolean allfail = GL_FALSE;
-   GLuint i;
+   GLuint i, j;
    const GLuint valueMask = ctx->Stencil.ValueMask[face];
-   const GLubyte r = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
+   const GLubyte ref = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
    GLubyte s;
 
-   ASSERT(n <= MAX_WIDTH);
-
    /*
     * Perform stencil test.  The results of this operation are stored
     * in the fail[] array:
@@ -247,140 +227,39 @@ do_stencil_test( struct gl_context *ctx, GLuint face, GLuint n, GLubyte stencil[
     *   ENDIF
     */
    switch (ctx->Stencil.Function[face]) {
-      case GL_NEVER:
-         /* never pass; always fail */
-         for (i=0;i<n;i++) {
-	    if (mask[i]) {
-	       mask[i] = 0;
-	       fail[i] = 1;
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 allfail = GL_TRUE;
-	 break;
-      case GL_LESS:
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-	       s = (GLubyte) (stencil[i] & valueMask);
-	       if (r < s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_LEQUAL:
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-	       s = (GLubyte) (stencil[i] & valueMask);
-	       if (r <= s) {
-		  /* pass */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_GREATER:
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-	       s = (GLubyte) (stencil[i] & valueMask);
-	       if (r > s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_GEQUAL:
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-	       s = (GLubyte) (stencil[i] & valueMask);
-	       if (r >= s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_EQUAL:
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-	       s = (GLubyte) (stencil[i] & valueMask);
-	       if (r == s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_NOTEQUAL:
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-	       s = (GLubyte) (stencil[i] & valueMask);
-	       if (r != s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_ALWAYS:
-	 /* always pass */
-	 for (i=0;i<n;i++) {
-	    fail[i] = 0;
-	 }
-	 break;
-      default:
-         _mesa_problem(ctx, "Bad stencil func in gl_stencil_span");
-         return 0;
+   case GL_NEVER:
+      STENCIL_TEST(0);
+      allfail = GL_TRUE;
+      break;
+   case GL_LESS:
+      STENCIL_TEST(ref < s);
+      break;
+   case GL_LEQUAL:
+      STENCIL_TEST(ref <= s);
+      break;
+   case GL_GREATER:
+      STENCIL_TEST(ref > s);
+      break;
+   case GL_GEQUAL:
+      STENCIL_TEST(ref >= s);
+      break;
+   case GL_EQUAL:
+      STENCIL_TEST(ref == s);
+      break;
+   case GL_NOTEQUAL:
+      STENCIL_TEST(ref != s);
+      break;
+   case GL_ALWAYS:
+      STENCIL_TEST(1);
+      break;
+   default:
+      _mesa_problem(ctx, "Bad stencil func in gl_stencil_span");
+      return 0;
    }
 
    if (ctx->Stencil.FailFunc[face] != GL_KEEP) {
-      apply_stencil_op( ctx, ctx->Stencil.FailFunc[face], face, n, stencil, fail );
+      apply_stencil_op(ctx, ctx->Stencil.FailFunc[face], face, n, stencil,
+                       fail, stride);
    }
 
    return !allfail;
@@ -406,54 +285,100 @@ compute_pass_fail_masks(GLuint n, const GLubyte origMask[],
 
 
 /**
- * Apply stencil and depth testing to the span of pixels.
- * Both software and hardware stencil buffers are acceptable.
- * Input:  n - number of pixels in the span
- *         x, y - location of leftmost pixel in span
- *         z - array [n] of z values
- *         mask - array [n] of flags  (1=test this pixel, 0=skip the pixel)
- * Output:  mask - array [n] of flags (1=stencil and depth test passed)
- * Return: GL_FALSE - all fragments failed the testing
- *         GL_TRUE - one or more fragments passed the testing
- *
+ * Get 8-bit stencil values from random locations in the stencil buffer.
  */
-static GLboolean
-stencil_and_ztest_span(struct gl_context *ctx, SWspan *span, GLuint face)
+static void
+get_s8_values(struct gl_context *ctx, struct gl_renderbuffer *rb,
+              GLuint count, const GLint x[], const GLint y[],
+              GLubyte stencil[])
 {
-   struct gl_framebuffer *fb = ctx->DrawBuffer;
-   struct gl_renderbuffer *rb = fb->_StencilBuffer;
-   GLubyte stencilRow[MAX_WIDTH];
-   GLubyte *stencil;
-   const GLuint n = span->end;
-   const GLint x = span->x;
-   const GLint y = span->y;
-   GLubyte *mask = span->array->mask;
+   const GLint w = rb->Width, h = rb->Height;
+   const GLubyte *map = (const GLubyte *) rb->Data;
+   GLuint i;
 
-   ASSERT((span->arrayMask & SPAN_XY) == 0);
-   ASSERT(ctx->Stencil.Enabled);
-   ASSERT(n <= MAX_WIDTH);
-#ifdef DEBUG
-   if (ctx->Depth.Test) {
-      ASSERT(span->arrayMask & SPAN_Z);
+   if (rb->Format == MESA_FORMAT_S8) {
+      const GLuint rowStride = rb->RowStride;
+      for (i = 0; i < count; i++) {
+         if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) {
+            stencil[i] = *(map + y[i] * rowStride + x[i]);
+         }
+      }
+   }
+   else {
+      const GLuint bpp = _mesa_get_format_bytes(rb->Format);
+      const GLuint rowStride = rb->RowStride * bpp;
+      for (i = 0; i < count; i++) {
+         if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) {
+            const GLubyte *src = map + y[i] * rowStride + x[i] * bpp;
+            _mesa_unpack_ubyte_stencil_row(rb->Format, 1, src, &stencil[i]);
+         }
+      }
    }
-#endif
+}
+
+
+/**
+ * Put 8-bit stencil values at random locations into the stencil buffer.
+ */
+static void
+put_s8_values(struct gl_context *ctx, struct gl_renderbuffer *rb,
+              GLuint count, const GLint x[], const GLint y[],
+              const GLubyte stencil[])
+{
+   const GLint w = rb->Width, h = rb->Height;
+   GLuint i;
 
-   stencil = (GLubyte *) rb->GetPointer(ctx, rb, x, y);
-   if (!stencil) {
-      rb->GetRow(ctx, rb, n, x, y, stencilRow);
-      stencil = stencilRow;
+   for (i = 0; i < count; i++) {
+      if (x[i] >= 0 && y[i] >= 0 && x[i] < w && y[i] < h) {
+         GLubyte *dst = _swrast_pixel_address(rb, x[i], y[i]);
+         _mesa_pack_ubyte_stencil_row(rb->Format, 1, &stencil[i], dst);
+      }
+   }
+}
+
+
+/**
+ * /return GL_TRUE = one or more fragments passed,
+ * GL_FALSE = all fragments failed.
+ */
+GLboolean
+_swrast_stencil_and_ztest_span(struct gl_context *ctx, SWspan *span)
+{
+   struct gl_framebuffer *fb = ctx->DrawBuffer;
+   struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
+   const GLint stencilOffset = get_stencil_offset(rb->Format);
+   const GLint stencilStride = _mesa_get_format_bytes(rb->Format);
+   const GLuint face = (span->facing == 0) ? 0 : ctx->Stencil._BackFace;
+   const GLuint count = span->end;
+   GLubyte *mask = span->array->mask;
+   GLubyte stencilTemp[MAX_WIDTH];
+   GLubyte *stencilBuf;
+
+   if (span->arrayMask & SPAN_XY) {
+      /* read stencil values from random locations */
+      get_s8_values(ctx, rb, count, span->array->x, span->array->y,
+                    stencilTemp);
+      stencilBuf = stencilTemp;
+   }
+   else {
+      /* Processing a horizontal run of pixels.  Since stencil is always
+       * 8 bits for all MESA_FORMATs, we just need to use the right offset
+       * and stride to access them.
+       */
+      stencilBuf = _swrast_pixel_address(rb, span->x, span->y) + stencilOffset;
    }
 
    /*
     * Apply the stencil test to the fragments.
     * failMask[i] is 1 if the stencil test failed.
     */
-   if (do_stencil_test( ctx, face, n, stencil, mask ) == GL_FALSE) {
+   if (!do_stencil_test(ctx, face, count, stencilBuf, mask, stencilStride)) {
       /* all fragments failed the stencil test, we're done. */
       span->writeAll = GL_FALSE;
-      if (!rb->GetPointer(ctx, rb, 0, 0)) {
-         /* put updated stencil values into buffer */
-         rb->PutRow(ctx, rb, n, x, y, stencil, NULL);
+      if (span->arrayMask & SPAN_XY) {
+         /* need to write the updated stencil values back to the buffer */
+         put_s8_values(ctx, rb, count, span->array->x, span->array->y,
+                       stencilTemp);
       }
       return GL_FALSE;
    }
@@ -463,11 +388,12 @@ stencil_and_ztest_span(struct gl_context *ctx, SWspan *span, GLuint face)
     * and apply Zpass and Zfail stencil ops.
     */
    if (ctx->Depth.Test == GL_FALSE ||
-       ctx->DrawBuffer->_DepthBuffer == NULL) {
+       ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer == NULL) {
       /*
        * No depth buffer, just apply zpass stencil function to active pixels.
        */
-      apply_stencil_op( ctx, ctx->Stencil.ZPassFunc[face], face, n, stencil, mask );
+      apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face, count,
+                       stencilBuf, mask, stencilStride);
    }
    else {
       /*
@@ -476,29 +402,28 @@ stencil_and_ztest_span(struct gl_context *ctx, SWspan *span, GLuint face)
       GLubyte passMask[MAX_WIDTH], failMask[MAX_WIDTH], origMask[MAX_WIDTH];
 
       /* save the current mask bits */
-      memcpy(origMask, mask, n * sizeof(GLubyte));
+      memcpy(origMask, mask, count * sizeof(GLubyte));
 
       /* apply the depth test */
       _swrast_depth_test_span(ctx, span);
 
-      compute_pass_fail_masks(n, origMask, mask, passMask, failMask);
+      compute_pass_fail_masks(count, origMask, mask, passMask, failMask);
 
       /* apply the pass and fail operations */
       if (ctx->Stencil.ZFailFunc[face] != GL_KEEP) {
-         apply_stencil_op( ctx, ctx->Stencil.ZFailFunc[face], face,
-                           n, stencil, failMask );
+         apply_stencil_op(ctx, ctx->Stencil.ZFailFunc[face], face,
+                          count, stencilBuf, failMask, stencilStride);
       }
       if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
-         apply_stencil_op( ctx, ctx->Stencil.ZPassFunc[face], face,
-                           n, stencil, passMask );
+         apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face,
+                          count, stencilBuf, passMask, stencilStride);
       }
    }
 
-   /*
-    * Write updated stencil values back into hardware stencil buffer.
-    */
-   if (!rb->GetPointer(ctx, rb, 0, 0)) {
-      rb->PutRow(ctx, rb, n, x, y, stencil, NULL);
+   /* Write updated stencil values back into hardware stencil buffer */
+   if (span->arrayMask & SPAN_XY) {
+      put_s8_values(ctx, rb, count, span->array->x, span->array->y,
+                    stencilBuf);
    }
    
    span->writeAll = GL_FALSE;
@@ -508,530 +433,6 @@ stencil_and_ztest_span(struct gl_context *ctx, SWspan *span, GLuint face)
 
 
 
-/*
- * Return the address of a stencil buffer value given the window coords:
- */
-#define STENCIL_ADDRESS(X, Y)  (stencilStart + (Y) * stride + (X))
-
-
-
-/**
- * Apply the given stencil operator for each pixel in the array whose
- * mask flag is set.
- * \note  This is for software stencil buffers only.
- * Input:  n - number of pixels in the span
- *         x, y - array of [n] pixels
- *         operator - the stencil buffer operator
- *         mask - array [n] of flag:  1=apply operator, 0=don't apply operator
- */
-static void
-apply_stencil_op_to_pixels( struct gl_context *ctx,
-                            GLuint n, const GLint x[], const GLint y[],
-                            GLenum oper, GLuint face, const GLubyte mask[] )
-{
-   struct gl_framebuffer *fb = ctx->DrawBuffer;
-   struct gl_renderbuffer *rb = fb->_StencilBuffer;
-   const GLubyte stencilMax = (1 << fb->Visual.stencilBits) - 1;
-   const GLubyte ref = ctx->Stencil.Ref[face];
-   const GLubyte wrtmask = ctx->Stencil.WriteMask[face];
-   const GLubyte invmask = (GLubyte) (~wrtmask);
-   GLuint i;
-   GLubyte *stencilStart = (GLubyte *) rb->Data;
-   const GLuint stride = rb->Width;
-
-   ASSERT(rb->GetPointer(ctx, rb, 0, 0));
-
-   switch (oper) {
-      case GL_KEEP:
-         /* do nothing */
-         break;
-      case GL_ZERO:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-                  *sptr = 0;
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-		  *sptr = (GLubyte) (invmask & *sptr);
-	       }
-	    }
-	 }
-	 break;
-      case GL_REPLACE:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-                  *sptr = ref;
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-		  *sptr = (GLubyte) ((invmask & *sptr ) | (wrtmask & ref));
-	       }
-	    }
-	 }
-	 break;
-      case GL_INCR:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-		  if (*sptr < stencilMax) {
-		     *sptr = (GLubyte) (*sptr + 1);
-		  }
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-		  if (*sptr < stencilMax) {
-		     *sptr = (GLubyte) ((invmask & *sptr) | (wrtmask & (*sptr+1)));
-		  }
-	       }
-	    }
-	 }
-	 break;
-      case GL_DECR:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-		  if (*sptr>0) {
-		     *sptr = (GLubyte) (*sptr - 1);
-		  }
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-		  if (*sptr>0) {
-		     *sptr = (GLubyte) ((invmask & *sptr) | (wrtmask & (*sptr-1)));
-		  }
-	       }
-	    }
-	 }
-	 break;
-      case GL_INCR_WRAP_EXT:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-                  *sptr = (GLubyte) (*sptr + 1);
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-                  *sptr = (GLubyte) ((invmask & *sptr) | (wrtmask & (*sptr+1)));
-	       }
-	    }
-	 }
-	 break;
-      case GL_DECR_WRAP_EXT:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-                  *sptr = (GLubyte) (*sptr - 1);
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-                  *sptr = (GLubyte) ((invmask & *sptr) | (wrtmask & (*sptr-1)));
-	       }
-	    }
-	 }
-	 break;
-      case GL_INVERT:
-	 if (invmask==0) {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-                  *sptr = (GLubyte) (~*sptr);
-	       }
-	    }
-	 }
-	 else {
-	    for (i=0;i<n;i++) {
-	       if (mask[i]) {
-                  GLubyte *sptr = STENCIL_ADDRESS( x[i], y[i] );
-                  *sptr = (GLubyte) ((invmask & *sptr) | (wrtmask & ~*sptr));
-	       }
-	    }
-	 }
-	 break;
-      default:
-         _mesa_problem(ctx, "Bad stencilop in apply_stencil_op_to_pixels");
-   }
-}
-
-
-
-/**
- * Apply stencil test to an array of pixels before depth buffering.
- *
- * \note Used for software stencil buffer only.
- * Input:  n - number of pixels in the span
- *         x, y - array of [n] pixels to stencil
- *         mask - array [n] of flag:  0=skip the pixel, 1=stencil the pixel
- * Output:  mask - pixels which fail the stencil test will have their
- *                 mask flag set to 0.
- * \return  GL_FALSE = all pixels failed, GL_TRUE = zero or more pixels passed.
- */
-static GLboolean
-stencil_test_pixels( struct gl_context *ctx, GLuint face, GLuint n,
-                     const GLint x[], const GLint y[], GLubyte mask[] )
-{
-   const struct gl_framebuffer *fb = ctx->DrawBuffer;
-   struct gl_renderbuffer *rb = fb->_StencilBuffer;
-   GLubyte fail[MAX_WIDTH];
-   GLubyte r, s;
-   GLuint i;
-   GLboolean allfail = GL_FALSE;
-   const GLuint valueMask = ctx->Stencil.ValueMask[face];
-   const GLubyte *stencilStart = (GLubyte *) rb->Data;
-   const GLuint stride = rb->Width;
-
-   ASSERT(rb->GetPointer(ctx, rb, 0, 0));
-
-   /*
-    * Perform stencil test.  The results of this operation are stored
-    * in the fail[] array:
-    *   IF fail[i] is non-zero THEN
-    *       the stencil fail operator is to be applied
-    *   ELSE
-    *       the stencil fail operator is not to be applied
-    *   ENDIF
-    */
-
-   switch (ctx->Stencil.Function[face]) {
-      case GL_NEVER:
-         /* always fail */
-         for (i=0;i<n;i++) {
-	    if (mask[i]) {
-	       mask[i] = 0;
-	       fail[i] = 1;
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 allfail = GL_TRUE;
-	 break;
-      case GL_LESS:
-	 r = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-               const GLubyte *sptr = STENCIL_ADDRESS(x[i],y[i]);
-	       s = (GLubyte) (*sptr & valueMask);
-	       if (r < s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_LEQUAL:
-	 r = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-               const GLubyte *sptr = STENCIL_ADDRESS(x[i],y[i]);
-	       s = (GLubyte) (*sptr & valueMask);
-	       if (r <= s) {
-		  /* pass */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_GREATER:
-	 r = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-               const GLubyte *sptr = STENCIL_ADDRESS(x[i],y[i]);
-	       s = (GLubyte) (*sptr & valueMask);
-	       if (r > s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_GEQUAL:
-	 r = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-               const GLubyte *sptr = STENCIL_ADDRESS(x[i],y[i]);
-	       s = (GLubyte) (*sptr & valueMask);
-	       if (r >= s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_EQUAL:
-	 r = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-               const GLubyte *sptr = STENCIL_ADDRESS(x[i],y[i]);
-	       s = (GLubyte) (*sptr & valueMask);
-	       if (r == s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_NOTEQUAL:
-	 r = (GLubyte) (ctx->Stencil.Ref[face] & valueMask);
-	 for (i=0;i<n;i++) {
-	    if (mask[i]) {
-               const GLubyte *sptr = STENCIL_ADDRESS(x[i],y[i]);
-	       s = (GLubyte) (*sptr & valueMask);
-	       if (r != s) {
-		  /* passed */
-		  fail[i] = 0;
-	       }
-	       else {
-		  fail[i] = 1;
-		  mask[i] = 0;
-	       }
-	    }
-	    else {
-	       fail[i] = 0;
-	    }
-	 }
-	 break;
-      case GL_ALWAYS:
-	 /* always pass */
-	 for (i=0;i<n;i++) {
-	    fail[i] = 0;
-	 }
-	 break;
-      default:
-         _mesa_problem(ctx, "Bad stencil func in gl_stencil_pixels");
-         return 0;
-   }
-
-   if (ctx->Stencil.FailFunc[face] != GL_KEEP) {
-      apply_stencil_op_to_pixels( ctx, n, x, y, ctx->Stencil.FailFunc[face],
-                                  face, fail );
-   }
-
-   return !allfail;
-}
-
-
-
-
-/**
- * Apply stencil and depth testing to an array of pixels.
- * This is used both for software and hardware stencil buffers.
- *
- * The comments in this function are a bit sparse but the code is
- * almost identical to stencil_and_ztest_span(), which is well
- * commented.
- *
- * Input:  n - number of pixels in the array
- *         x, y - array of [n] pixel positions
- *         z - array [n] of z values
- *         mask - array [n] of flags  (1=test this pixel, 0=skip the pixel)
- * Output: mask - array [n] of flags (1=stencil and depth test passed)
- * Return: GL_FALSE - all fragments failed the testing
- *         GL_TRUE - one or more fragments passed the testing
- */
-static GLboolean
-stencil_and_ztest_pixels( struct gl_context *ctx, SWspan *span, GLuint face )
-{
-   GLubyte passMask[MAX_WIDTH], failMask[MAX_WIDTH], origMask[MAX_WIDTH];
-   struct gl_framebuffer *fb = ctx->DrawBuffer;
-   struct gl_renderbuffer *rb = fb->_StencilBuffer;
-   const GLuint n = span->end;
-   const GLint *x = span->array->x;
-   const GLint *y = span->array->y;
-   GLubyte *mask = span->array->mask;
-
-   ASSERT(span->arrayMask & SPAN_XY);
-   ASSERT(ctx->Stencil.Enabled);
-   ASSERT(n <= MAX_WIDTH);
-
-   if (!rb->GetPointer(ctx, rb, 0, 0)) {
-      /* No direct access */
-      GLubyte stencil[MAX_WIDTH];
-
-      ASSERT(rb->DataType == GL_UNSIGNED_BYTE);
-      _swrast_get_values(ctx, rb, n, x, y, stencil, sizeof(GLubyte));
-
-      memcpy(origMask, mask, n * sizeof(GLubyte));          
-
-      (void) do_stencil_test(ctx, face, n, stencil, mask);
-
-      if (ctx->Depth.Test == GL_FALSE) {
-         apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face,
-                          n, stencil, mask);
-      }
-      else {
-         GLubyte tmpMask[MAX_WIDTH]; 
-         memcpy(tmpMask, mask, n * sizeof(GLubyte));
-
-         _swrast_depth_test_span(ctx, span);
-
-         compute_pass_fail_masks(n, tmpMask, mask, passMask, failMask);
-
-         if (ctx->Stencil.ZFailFunc[face] != GL_KEEP) {
-            apply_stencil_op(ctx, ctx->Stencil.ZFailFunc[face], face,
-                             n, stencil, failMask);
-         }
-         if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
-            apply_stencil_op(ctx, ctx->Stencil.ZPassFunc[face], face,
-                             n, stencil, passMask);
-         }
-      }
-
-      /* Write updated stencil values into hardware stencil buffer */
-      rb->PutValues(ctx, rb, n, x, y, stencil, origMask);
-
-      return GL_TRUE;
-   }
-   else {
-      /* Direct access to stencil buffer */
-
-      if (stencil_test_pixels(ctx, face, n, x, y, mask) == GL_FALSE) {
-         /* all fragments failed the stencil test, we're done. */
-         return GL_FALSE;
-      }
-
-      if (ctx->Depth.Test==GL_FALSE) {
-         apply_stencil_op_to_pixels(ctx, n, x, y,
-                                    ctx->Stencil.ZPassFunc[face], face, mask);
-      }
-      else {
-         memcpy(origMask, mask, n * sizeof(GLubyte));
-
-         _swrast_depth_test_span(ctx, span);
-
-         compute_pass_fail_masks(n, origMask, mask, passMask, failMask);
-
-         if (ctx->Stencil.ZFailFunc[face] != GL_KEEP) {
-            apply_stencil_op_to_pixels(ctx, n, x, y,
-                                       ctx->Stencil.ZFailFunc[face],
-                                       face, failMask);
-         }
-         if (ctx->Stencil.ZPassFunc[face] != GL_KEEP) {
-            apply_stencil_op_to_pixels(ctx, n, x, y,
-                                       ctx->Stencil.ZPassFunc[face],
-                                       face, passMask);
-         }
-      }
-
-      return GL_TRUE;  /* one or more fragments passed both tests */
-   }
-}
-
-
-/**
- * /return GL_TRUE = one or more fragments passed,
- * GL_FALSE = all fragments failed.
- */
-GLboolean
-_swrast_stencil_and_ztest_span(struct gl_context *ctx, SWspan *span)
-{
-   const GLuint face = (span->facing == 0) ? 0 : ctx->Stencil._BackFace;
-
-   if (span->arrayMask & SPAN_XY)
-      return stencil_and_ztest_pixels(ctx, span, face);
-   else
-      return stencil_and_ztest_span(ctx, span, face);
-}
-
-
-#if 0
-GLuint
-clip_span(GLuint bufferWidth, GLuint bufferHeight,
-          GLint x, GLint y, GLuint *count)
-{
-   GLuint n = *count;
-   GLuint skipPixels = 0;
-
-   if (y < 0 || y >= bufferHeight || x + n <= 0 || x >= bufferWidth) {
-      /* totally out of bounds */
-      n = 0;
-   }
-   else {
-      /* left clip */
-      if (x < 0) {
-         skipPixels = -x;
-         x = 0;
-         n -= skipPixels;
-      }
-      /* right clip */
-      if (x + n > bufferWidth) {
-         GLint dx = x + n - bufferWidth;
-         n -= dx;
-      }
-   }
-
-   *count = n;
-
-   return skipPixels;
-}
-#endif
-
 
 /**
  * Return a span of stencil values from the stencil buffer.
@@ -1044,6 +445,8 @@ void
 _swrast_read_stencil_span(struct gl_context *ctx, struct gl_renderbuffer *rb,
                           GLint n, GLint x, GLint y, GLubyte stencil[])
 {
+   GLubyte *src;
+
    if (y < 0 || y >= (GLint) rb->Height ||
        x + n <= 0 || x >= (GLint) rb->Width) {
       /* span is completely outside framebuffer */
@@ -1064,7 +467,8 @@ _swrast_read_stencil_span(struct gl_context *ctx, struct gl_renderbuffer *rb,
       return;
    }
 
-   rb->GetRow(ctx, rb, n, x, y, stencil);
+   src = _swrast_pixel_address(rb, x, y);
+   _mesa_unpack_ubyte_stencil_row(rb->Format, n, src, stencil);
 }
 
 
@@ -1082,9 +486,10 @@ _swrast_write_stencil_span(struct gl_context *ctx, GLint n, GLint x, GLint y,
                            const GLubyte stencil[] )
 {
    struct gl_framebuffer *fb = ctx->DrawBuffer;
-   struct gl_renderbuffer *rb = fb->_StencilBuffer;
+   struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
    const GLuint stencilMax = (1 << fb->Visual.stencilBits) - 1;
    const GLuint stencilMask = ctx->Stencil.WriteMask[0];
+   GLubyte *stencilBuf;
 
    if (y < 0 || y >= (GLint) rb->Height ||
        x + n <= 0 || x >= (GLint) rb->Width) {
@@ -1105,140 +510,129 @@ _swrast_write_stencil_span(struct gl_context *ctx, GLint n, GLint x, GLint y,
       return;
    }
 
+   stencilBuf = _swrast_pixel_address(rb, x, y);
+
    if ((stencilMask & stencilMax) != stencilMax) {
       /* need to apply writemask */
       GLubyte destVals[MAX_WIDTH], newVals[MAX_WIDTH];
       GLint i;
-      rb->GetRow(ctx, rb, n, x, y, destVals);
+
+      _mesa_unpack_ubyte_stencil_row(rb->Format, n, stencilBuf, destVals);
       for (i = 0; i < n; i++) {
          newVals[i]
             = (stencil[i] & stencilMask) | (destVals[i] & ~stencilMask);
       }
-      rb->PutRow(ctx, rb, n, x, y, newVals, NULL);
+      _mesa_pack_ubyte_stencil_row(rb->Format, n, newVals, stencilBuf);
    }
    else {
-      rb->PutRow(ctx, rb, n, x, y, stencil, NULL);
+      _mesa_pack_ubyte_stencil_row(rb->Format, n, stencil, stencilBuf);
    }
 }
 
 
 
 /**
- * Clear the stencil buffer.
+ * Clear the stencil buffer.  If the buffer is a combined
+ * depth+stencil buffer, only the stencil bits will be touched.
  */
 void
-_swrast_clear_stencil_buffer( struct gl_context *ctx, struct gl_renderbuffer *rb )
+_swrast_clear_stencil_buffer(struct gl_context *ctx)
 {
+   struct gl_renderbuffer *rb =
+      ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
    const GLubyte stencilBits = ctx->DrawBuffer->Visual.stencilBits;
-   const GLuint mask = ctx->Stencil.WriteMask[0];
-   const GLuint invMask = ~mask;
-   const GLuint clearVal = (ctx->Stencil.Clear & mask);
+   const GLuint writeMask = ctx->Stencil.WriteMask[0];
    const GLuint stencilMax = (1 << stencilBits) - 1;
    GLint x, y, width, height;
+   GLubyte *map;
+   GLint rowStride, i, j;
+   GLbitfield mapMode;
 
-   if (!rb || mask == 0)
+   if (!rb || writeMask == 0)
       return;
 
-   ASSERT(rb->DataType == GL_UNSIGNED_BYTE ||
-          rb->DataType == GL_UNSIGNED_SHORT);
-
-   ASSERT(rb->_BaseFormat == GL_STENCIL_INDEX);
-
    /* compute region to clear */
    x = ctx->DrawBuffer->_Xmin;
    y = ctx->DrawBuffer->_Ymin;
    width  = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
    height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
 
-   if (rb->GetPointer(ctx, rb, 0, 0)) {
-      /* Direct buffer access */
-      if ((mask & stencilMax) != stencilMax) {
-         /* need to mask the clear */
-         if (rb->DataType == GL_UNSIGNED_BYTE) {
-            GLint i, j;
-            for (i = 0; i < height; i++) {
-               GLubyte *stencil = (GLubyte*) rb->GetPointer(ctx, rb, x, y + i);
-               for (j = 0; j < width; j++) {
-                  stencil[j] = (stencil[j] & invMask) | clearVal;
-               }
-            }
-         }
-         else {
-            GLint i, j;
+   mapMode = GL_MAP_WRITE_BIT;
+   if ((writeMask & stencilMax) != stencilMax) {
+      /* need to mask stencil values */
+      mapMode |= GL_MAP_READ_BIT;
+   }
+   else if (_mesa_get_format_bits(rb->Format, GL_DEPTH_BITS) > 0) {
+      /* combined depth+stencil, need to mask Z values */
+      mapMode |= GL_MAP_READ_BIT;
+   }
+
+   ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height,
+                               mapMode, &map, &rowStride);
+   if (!map) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glClear(stencil)");
+      return;
+   }
+
+   switch (rb->Format) {
+   case MESA_FORMAT_S8:
+      {
+         GLubyte clear = ctx->Stencil.Clear & writeMask & 0xff;
+         GLubyte mask = (~writeMask) & 0xff;
+         if (mask != 0) {
+            /* masked clear */
             for (i = 0; i < height; i++) {
-               GLushort *stencil = (GLushort*) rb->GetPointer(ctx, rb, x, y + i);
+               GLubyte *row = map;
                for (j = 0; j < width; j++) {
-                  stencil[j] = (stencil[j] & invMask) | clearVal;
+                  row[j] = (row[j] & mask) | clear;
                }
+               map += rowStride;
             }
          }
-      }
-      else {
-         /* no bit masking */
-         if (width == (GLint) rb->Width && rb->DataType == GL_UNSIGNED_BYTE) {
-            /* optimized case */
-            /* Note: bottom-to-top raster assumed! */
-            GLubyte *stencil = (GLubyte *) rb->GetPointer(ctx, rb, x, y);
-            GLuint len = width * height * sizeof(GLubyte);
-            memset(stencil, clearVal, len);
+         else if (rowStride == width) {
+            /* clear whole buffer */
+            memset(map, clear, width * height);
          }
          else {
-            /* general case */
-            GLint i;
+            /* clear scissored */
             for (i = 0; i < height; i++) {
-               GLvoid *stencil = rb->GetPointer(ctx, rb, x, y + i);
-               if (rb->DataType == GL_UNSIGNED_BYTE) {
-                  memset(stencil, clearVal, width);
-               }
-               else {
-                  _mesa_memset16((short unsigned int*) stencil, clearVal, width);
-               }
+               memset(map, clear, width);
+               map += rowStride;
             }
          }
       }
-   }
-   else {
-      /* no direct access */
-      if ((mask & stencilMax) != stencilMax) {
-         /* need to mask the clear */
-         if (rb->DataType == GL_UNSIGNED_BYTE) {
-            GLint i, j;
-            for (i = 0; i < height; i++) {
-               GLubyte stencil[MAX_WIDTH];
-               rb->GetRow(ctx, rb, width, x, y + i, stencil);
-               for (j = 0; j < width; j++) {
-                  stencil[j] = (stencil[j] & invMask) | clearVal;
-               }
-               rb->PutRow(ctx, rb, width, x, y + i, stencil, NULL);
-            }
-         }
-         else {
-            GLint i, j;
-            for (i = 0; i < height; i++) {
-               GLushort stencil[MAX_WIDTH];
-               rb->GetRow(ctx, rb, width, x, y + i, stencil);
-               for (j = 0; j < width; j++) {
-                  stencil[j] = (stencil[j] & invMask) | clearVal;
-               }
-               rb->PutRow(ctx, rb, width, x, y + i, stencil, NULL);
+      break;
+   case MESA_FORMAT_S8_Z24:
+      {
+         GLuint clear = (ctx->Stencil.Clear & writeMask & 0xff) << 24;
+         GLuint mask = (((~writeMask) & 0xff) << 24) | 0xffffff;
+         for (i = 0; i < height; i++) {
+            GLuint *row = (GLuint *) map;
+            for (j = 0; j < width; j++) {
+               row[j] = (row[j] & mask) | clear;
             }
+            map += rowStride;
          }
       }
-      else {
-         /* no bit masking */
-         const GLubyte clear8 = (GLubyte) clearVal;
-         const GLushort clear16 = (GLushort) clearVal;
-         const void *clear;
-         GLint i;
-         if (rb->DataType == GL_UNSIGNED_BYTE) {
-            clear = &clear8;
-         }
-         else {
-            clear = &clear16;
-         }
+      break;
+   case MESA_FORMAT_Z24_S8:
+      {
+         GLuint clear = ctx->Stencil.Clear & writeMask & 0xff;
+         GLuint mask = 0xffffff00 | ((~writeMask) & 0xff);
          for (i = 0; i < height; i++) {
-            rb->PutMonoRow(ctx, rb, width, x, y + i, clear, NULL);
+            GLuint *row = (GLuint *) map;
+            for (j = 0; j < width; j++) {
+               row[j] = (row[j] & mask) | clear;
+            }
+            map += rowStride;
          }
       }
+      break;
+   default:
+      _mesa_problem(ctx, "Unexpected stencil buffer format %s"
+                    " in _swrast_clear_stencil_buffer()",
+                    _mesa_get_format_name(rb->Format));
    }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, rb);
 }