static void
feedback_tri( struct draw_stage *stage, struct prim_header *prim )
{
   struct feedback_stage *fs = feedback_stage(stage);
   struct draw_context *draw = stage->draw;
   _mesa_feedback_token(fs->ctx, (GLfloat) GL_POLYGON_TOKEN);
   _mesa_feedback_token(fs->ctx, (GLfloat) 3); /* three vertices */
   feedback_vertex(fs->ctx, draw, prim->v[0]);
   feedback_vertex(fs->ctx, draw, prim->v[1]);
   feedback_vertex(fs->ctx, draw, prim->v[2]);
}
示例#2
0
文件: feedback.c 项目: soreau/mesa
void GLAPIENTRY
_mesa_PassThrough( GLfloat token )
{
    GET_CURRENT_CONTEXT(ctx);

    if (ctx->RenderMode==GL_FEEDBACK) {
        FLUSH_VERTICES(ctx, 0);
        _mesa_feedback_token( ctx, (GLfloat) (GLint) GL_PASS_THROUGH_TOKEN );
        _mesa_feedback_token( ctx, token );
    }
}
static void
feedback_line( struct draw_stage *stage, struct prim_header *prim )
{
   struct feedback_stage *fs = feedback_stage(stage);
   struct draw_context *draw = stage->draw;
   if (fs->reset_stipple_counter) {
      _mesa_feedback_token(fs->ctx, (GLfloat) GL_LINE_RESET_TOKEN);
      fs->reset_stipple_counter = GL_FALSE;
   }
   else {
      _mesa_feedback_token(fs->ctx, (GLfloat) GL_LINE_TOKEN);
   }
   feedback_vertex(fs->ctx, draw, prim->v[0]);
   feedback_vertex(fs->ctx, draw, prim->v[1]);
}
static void
feedback_point( struct draw_stage *stage, struct prim_header *prim )
{
   struct feedback_stage *fs = feedback_stage(stage);
   struct draw_context *draw = stage->draw;
   _mesa_feedback_token(fs->ctx, (GLfloat) GL_POINT_TOKEN);
   feedback_vertex(fs->ctx, draw, prim->v[0]);
}
示例#5
0
/*
 * Put triangle in feedback buffer.
 */
void
_swrast_feedback_triangle(struct gl_context *ctx, const SWvertex *v0,
                          const SWvertex *v1, const SWvertex *v2)
{
   if (!_swrast_culltriangle(ctx, v0, v1, v2)) {
      _mesa_feedback_token(ctx, (GLfloat) (GLint) GL_POLYGON_TOKEN);
      _mesa_feedback_token(ctx, (GLfloat) 3); /* three vertices */

      if (ctx->Light.ShadeModel == GL_SMOOTH) {
         feedback_vertex(ctx, v0, v0);
         feedback_vertex(ctx, v1, v1);
         feedback_vertex(ctx, v2, v2);
      }
      else {
         feedback_vertex(ctx, v0, v2);
         feedback_vertex(ctx, v1, v2);
         feedback_vertex(ctx, v2, v2);
      }
   }
}
示例#6
0
void
_swrast_feedback_line(struct gl_context *ctx, const SWvertex *v0,
                      const SWvertex *v1)
{
   GLenum token = GL_LINE_TOKEN;
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   if (swrast->StippleCounter == 0)
      token = GL_LINE_RESET_TOKEN;

   _mesa_feedback_token(ctx, (GLfloat) (GLint) token);

   if (ctx->Light.ShadeModel == GL_SMOOTH) {
      feedback_vertex(ctx, v0, v0);
      feedback_vertex(ctx, v1, v1);
   }
   else {
      feedback_vertex(ctx, v0, v1);
      feedback_vertex(ctx, v1, v1);
   }

   swrast->StippleCounter++;
}
示例#7
0
void
_swrast_feedback_point(struct gl_context *ctx, const SWvertex *v)
{
   _mesa_feedback_token(ctx, (GLfloat) (GLint) GL_POINT_TOKEN);
   feedback_vertex(ctx, v, v);
}
示例#8
0
文件: feedback.c 项目: soreau/mesa
/**
 * Put a vertex into the feedback buffer.
 */
void
_mesa_feedback_vertex(struct gl_context *ctx,
                      const GLfloat win[4],
                      const GLfloat color[4],
                      const GLfloat texcoord[4])
{
    _mesa_feedback_token( ctx, win[0] );
    _mesa_feedback_token( ctx, win[1] );
    if (ctx->Feedback._Mask & FB_3D) {
        _mesa_feedback_token( ctx, win[2] );
    }
    if (ctx->Feedback._Mask & FB_4D) {
        _mesa_feedback_token( ctx, win[3] );
    }
    if (ctx->Feedback._Mask & FB_COLOR) {
        _mesa_feedback_token( ctx, color[0] );
        _mesa_feedback_token( ctx, color[1] );
        _mesa_feedback_token( ctx, color[2] );
        _mesa_feedback_token( ctx, color[3] );
    }
    if (ctx->Feedback._Mask & FB_TEXTURE) {
        _mesa_feedback_token( ctx, texcoord[0] );
        _mesa_feedback_token( ctx, texcoord[1] );
        _mesa_feedback_token( ctx, texcoord[2] );
        _mesa_feedback_token( ctx, texcoord[3] );
    }
}
示例#9
0
/*
 * Execute glDrawPixels
 */
static void GLAPIENTRY
_mesa_DrawPixels( GLsizei width, GLsizei height,
                  GLenum format, GLenum type, const GLvoid *pixels )
{
   GLenum err;
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glDrawPixels(%d, %d, %s, %s, %p) // to %s at %d, %d\n",
                  width, height,
                  _mesa_lookup_enum_by_nr(format),
                  _mesa_lookup_enum_by_nr(type),
                  pixels,
                  _mesa_lookup_enum_by_nr(ctx->DrawBuffer->ColorDrawBuffer[0]),
                  IROUND(ctx->Current.RasterPos[0]),
                  IROUND(ctx->Current.RasterPos[1]));


   if (width < 0 || height < 0) {
      _mesa_error( ctx, GL_INVALID_VALUE, "glDrawPixels(width or height < 0)" );
      return;
   }

   /* We're not using the current vertex program, and the driver may install
    * its own.  Note: this may dirty some state.
    */
   _mesa_set_vp_override(ctx, GL_TRUE);

   /* Note: this call does state validation */
   if (!_mesa_valid_to_render(ctx, "glDrawPixels")) {
      goto end;      /* the error code was recorded */
   }

   /* GL 3.0 introduced a new restriction on glDrawPixels() over what was in
    * GL_EXT_texture_integer.  From section 3.7.4 ("Rasterization of Pixel
    * Rectangles) on page 151 of the GL 3.0 specification:
    *
    *     "If format contains integer components, as shown in table 3.6, an
    *      INVALID OPERATION error is generated."
    *
    * Since DrawPixels rendering would be merely undefined if not an error (due
    * to a lack of defined mapping from integer data to gl_Color fragment shader
    * input), NVIDIA's implementation also just returns this error despite
    * exposing GL_EXT_texture_integer, just return an error regardless.
    */
   if (_mesa_is_enum_format_integer(format)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawPixels(integer format)");
      goto end;
   }

   err = _mesa_error_check_format_and_type(ctx, format, type);
   if (err != GL_NO_ERROR) {
      _mesa_error(ctx, err, "glDrawPixels(invalid format %s and/or type %s)",
                  _mesa_lookup_enum_by_nr(format),
                  _mesa_lookup_enum_by_nr(type));
      goto end;
   }

   /* do special format-related checks */
   switch (format) {
   case GL_STENCIL_INDEX:
   case GL_DEPTH_COMPONENT:
   case GL_DEPTH_STENCIL_EXT:
      /* these buffers must exist */
      if (!_mesa_dest_buffer_exists(ctx, format)) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                     "glDrawPixels(missing deest buffer)");
         goto end;
      }
      break;
   case GL_COLOR_INDEX:
      if (ctx->PixelMaps.ItoR.Size == 0 ||
          ctx->PixelMaps.ItoG.Size == 0 ||
          ctx->PixelMaps.ItoB.Size == 0) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                "glDrawPixels(drawing color index pixels into RGB buffer)");
         goto end;
      }
      break;
   default:
      /* for color formats it's not an error if the destination color
       * buffer doesn't exist.
       */
      break;
   }

   if (ctx->RasterDiscard) {
      goto end;
   }

   if (!ctx->Current.RasterPosValid) {
      goto end;  /* no-op, not an error */
   }

   if (ctx->RenderMode == GL_RENDER) {
      if (width > 0 && height > 0) {
         /* Round, to satisfy conformance tests (matches SGI's OpenGL) */
         GLint x = IROUND(ctx->Current.RasterPos[0]);
         GLint y = IROUND(ctx->Current.RasterPos[1]);

         if (_mesa_is_bufferobj(ctx->Unpack.BufferObj)) {
            /* unpack from PBO */
            if (!_mesa_validate_pbo_access(2, &ctx->Unpack, width, height,
                                           1, format, type, INT_MAX, pixels)) {
               _mesa_error(ctx, GL_INVALID_OPERATION,
                           "glDrawPixels(invalid PBO access)");
               goto end;
            }
            if (_mesa_bufferobj_mapped(ctx->Unpack.BufferObj)) {
               /* buffer is mapped - that's an error */
               _mesa_error(ctx, GL_INVALID_OPERATION,
                           "glDrawPixels(PBO is mapped)");
               goto end;
            }
         }

         ctx->Driver.DrawPixels(ctx, x, y, width, height, format, type,
                                &ctx->Unpack, pixels);
      }
   }
   else if (ctx->RenderMode == GL_FEEDBACK) {
      /* Feedback the current raster pos info */
      FLUSH_CURRENT( ctx, 0 );
      _mesa_feedback_token( ctx, (GLfloat) (GLint) GL_DRAW_PIXEL_TOKEN );
      _mesa_feedback_vertex( ctx,
                             ctx->Current.RasterPos,
                             ctx->Current.RasterColor,
                             ctx->Current.RasterTexCoords[0] );
   }
   else {
      ASSERT(ctx->RenderMode == GL_SELECT);
      /* Do nothing.  See OpenGL Spec, Appendix B, Corollary 6. */
   }

end:
   _mesa_set_vp_override(ctx, GL_FALSE);

   if (MESA_DEBUG_FLAGS & DEBUG_ALWAYS_FLUSH) {
      _mesa_flush(ctx);
   }
}
示例#10
0
static void GLAPIENTRY
_mesa_Bitmap( GLsizei width, GLsizei height,
              GLfloat xorig, GLfloat yorig, GLfloat xmove, GLfloat ymove,
              const GLubyte *bitmap )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);

   if (width < 0 || height < 0) {
      _mesa_error( ctx, GL_INVALID_VALUE, "glBitmap(width or height < 0)" );
      return;
   }

   if (!ctx->Current.RasterPosValid) {
      return;    /* do nothing */
   }

   /* Note: this call does state validation */
   if (!_mesa_valid_to_render(ctx, "glBitmap")) {
      /* the error code was recorded */
      return;
   }

   if (ctx->RasterDiscard)
      return;

   if (ctx->RenderMode == GL_RENDER) {
      /* Truncate, to satisfy conformance tests (matches SGI's OpenGL). */
      if (width > 0 && height > 0) {
         const GLfloat epsilon = 0.0001F;
         GLint x = IFLOOR(ctx->Current.RasterPos[0] + epsilon - xorig);
         GLint y = IFLOOR(ctx->Current.RasterPos[1] + epsilon - yorig);

         if (_mesa_is_bufferobj(ctx->Unpack.BufferObj)) {
            /* unpack from PBO */
            if (!_mesa_validate_pbo_access(2, &ctx->Unpack, width, height,
                                           1, GL_COLOR_INDEX, GL_BITMAP,
                                           INT_MAX, (const GLvoid *) bitmap)) {
               _mesa_error(ctx, GL_INVALID_OPERATION,
                           "glBitmap(invalid PBO access)");
               return;
            }
            if (_mesa_bufferobj_mapped(ctx->Unpack.BufferObj)) {
               /* buffer is mapped - that's an error */
               _mesa_error(ctx, GL_INVALID_OPERATION,
                           "glBitmap(PBO is mapped)");
               return;
            }
         }

         ctx->Driver.Bitmap( ctx, x, y, width, height, &ctx->Unpack, bitmap );
      }
   }
#if _HAVE_FULL_GL
   else if (ctx->RenderMode == GL_FEEDBACK) {
      FLUSH_CURRENT(ctx, 0);
      _mesa_feedback_token( ctx, (GLfloat) (GLint) GL_BITMAP_TOKEN );
      _mesa_feedback_vertex( ctx,
                             ctx->Current.RasterPos,
                             ctx->Current.RasterColor,
                             ctx->Current.RasterTexCoords[0] );
   }
   else {
      ASSERT(ctx->RenderMode == GL_SELECT);
      /* Do nothing.  See OpenGL Spec, Appendix B, Corollary 6. */
   }
#endif

   /* update raster position */
   ctx->Current.RasterPos[0] += xmove;
   ctx->Current.RasterPos[1] += ymove;

   if (MESA_DEBUG_FLAGS & DEBUG_ALWAYS_FLUSH) {
      _mesa_flush(ctx);
   }
}
示例#11
0
static void GLAPIENTRY
_mesa_CopyPixels( GLint srcx, GLint srcy, GLsizei width, GLsizei height,
                  GLenum type )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx,
                  "glCopyPixels(%d, %d, %d, %d, %s) // from %s to %s at %d, %d\n",
                  srcx, srcy, width, height,
                  _mesa_lookup_enum_by_nr(type),
                  _mesa_lookup_enum_by_nr(ctx->ReadBuffer->ColorReadBuffer),
                  _mesa_lookup_enum_by_nr(ctx->DrawBuffer->ColorDrawBuffer[0]),
                  IROUND(ctx->Current.RasterPos[0]),
                  IROUND(ctx->Current.RasterPos[1]));

   if (width < 0 || height < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glCopyPixels(width or height < 0)");
      return;
   }

   /* Note: more detailed 'type' checking is done by the
    * _mesa_source/dest_buffer_exists() calls below.  That's where we
    * check if the stencil buffer exists, etc.
    */
   if (type != GL_COLOR &&
       type != GL_DEPTH &&
       type != GL_STENCIL &&
       type != GL_DEPTH_STENCIL) {
      _mesa_error(ctx, GL_INVALID_ENUM, "glCopyPixels(type=%s)",
                  _mesa_lookup_enum_by_nr(type));
      return;
   }

   /* We're not using the current vertex program, and the driver may install
    * it's own.  Note: this may dirty some state.
    */
   _mesa_set_vp_override(ctx, GL_TRUE);

   /* Note: this call does state validation */
   if (!_mesa_valid_to_render(ctx, "glCopyPixels")) {
      goto end;      /* the error code was recorded */
   }

   /* Check read buffer's status (draw buffer was already checked) */
   if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
      _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
                  "glCopyPixels(incomplete framebuffer)" );
      goto end;
   }

   if (_mesa_is_user_fbo(ctx->ReadBuffer) &&
       ctx->ReadBuffer->Visual.samples > 0) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
		  "glCopyPixels(multisample FBO)");
      goto end;
   }

   if (!_mesa_source_buffer_exists(ctx, type) ||
       !_mesa_dest_buffer_exists(ctx, type)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glCopyPixels(missing source or dest buffer)");
      goto end;
   }

   if (ctx->RasterDiscard) {
      goto end;
   }

   if (!ctx->Current.RasterPosValid || width == 0 || height == 0) {
      goto end; /* no-op, not an error */
   }

   if (ctx->RenderMode == GL_RENDER) {
      /* Round to satisfy conformance tests (matches SGI's OpenGL) */
      if (width > 0 && height > 0) {
         GLint destx = IROUND(ctx->Current.RasterPos[0]);
         GLint desty = IROUND(ctx->Current.RasterPos[1]);
         ctx->Driver.CopyPixels( ctx, srcx, srcy, width, height, destx, desty,
                                 type );
      }
   }
   else if (ctx->RenderMode == GL_FEEDBACK) {
      FLUSH_CURRENT( ctx, 0 );
      _mesa_feedback_token( ctx, (GLfloat) (GLint) GL_COPY_PIXEL_TOKEN );
      _mesa_feedback_vertex( ctx, 
                             ctx->Current.RasterPos,
                             ctx->Current.RasterColor,
                             ctx->Current.RasterTexCoords[0] );
   }
   else {
      ASSERT(ctx->RenderMode == GL_SELECT);
      /* Do nothing.  See OpenGL Spec, Appendix B, Corollary 6. */
   }

end:
   _mesa_set_vp_override(ctx, GL_FALSE);

   if (MESA_DEBUG_FLAGS & DEBUG_ALWAYS_FLUSH) {
      _mesa_flush(ctx);
   }
}
示例#12
0
/*
 * Execute glDrawPixels
 */
static void GLAPIENTRY
_mesa_DrawPixels( GLsizei width, GLsizei height,
                  GLenum format, GLenum type, const GLvoid *pixels )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);

   if (width < 0 || height < 0) {
      _mesa_error( ctx, GL_INVALID_VALUE, "glDrawPixels(width or height < 0" );
      return;
   }

   /* We're not using the current vertex program, and the driver may install
    * it's own.
    */
   _mesa_set_vp_override(ctx, GL_TRUE);

   if (ctx->NewState) {
      _mesa_update_state(ctx);
   }

   if (!valid_fragment_program(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glDrawPixels (invalid fragment program)");
      goto end;
   }

   if (_mesa_error_check_format_type(ctx, format, type, GL_TRUE)) {
      /* the error was already recorded */
      goto end;
   }

   if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
      _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
                  "glDrawPixels(incomplete framebuffer)" );
      goto end;
   }

   if (!ctx->Current.RasterPosValid) {
      goto end; /* no-op, not an error */
   }

   if (ctx->RenderMode == GL_RENDER) {
      if (width > 0 && height > 0) {
         /* Round, to satisfy conformance tests (matches SGI's OpenGL) */
         GLint x = IROUND(ctx->Current.RasterPos[0]);
         GLint y = IROUND(ctx->Current.RasterPos[1]);

         if (ctx->Unpack.BufferObj->Name) {
            /* unpack from PBO */
            if (!_mesa_validate_pbo_access(2, &ctx->Unpack, width, height, 1,
                                           format, type, pixels)) {
               _mesa_error(ctx, GL_INVALID_OPERATION,
                           "glDrawPixels(invalid PBO access)");
               goto end;
            }
            if (_mesa_bufferobj_mapped(ctx->Unpack.BufferObj)) {
               /* buffer is mapped - that's an error */
               _mesa_error(ctx, GL_INVALID_OPERATION,
                           "glDrawPixels(PBO is mapped)");
               goto end;
            }
         }

         ctx->Driver.DrawPixels(ctx, x, y, width, height, format, type,
                                &ctx->Unpack, pixels);
      }
   }
   else if (ctx->RenderMode == GL_FEEDBACK) {
      /* Feedback the current raster pos info */
      FLUSH_CURRENT( ctx, 0 );
      _mesa_feedback_token( ctx, (GLfloat) (GLint) GL_DRAW_PIXEL_TOKEN );
      _mesa_feedback_vertex( ctx,
                             ctx->Current.RasterPos,
                             ctx->Current.RasterColor,
                             ctx->Current.RasterIndex,
                             ctx->Current.RasterTexCoords[0] );
   }
   else {
      ASSERT(ctx->RenderMode == GL_SELECT);
      /* Do nothing.  See OpenGL Spec, Appendix B, Corollary 6. */
   }

end:
   _mesa_set_vp_override(ctx, GL_FALSE);
}
示例#13
0
static void GLAPIENTRY
_mesa_Bitmap( GLsizei width, GLsizei height,
              GLfloat xorig, GLfloat yorig, GLfloat xmove, GLfloat ymove,
              const GLubyte *bitmap )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);

   if (width < 0 || height < 0) {
      _mesa_error( ctx, GL_INVALID_VALUE, "glBitmap(width or height < 0)" );
      return;
   }

   if (!ctx->Current.RasterPosValid) {
      return;    /* do nothing */
   }

   if (ctx->NewState) {
      _mesa_update_state(ctx);
   }

   if (!valid_fragment_program(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glBitmap (invalid fragment program)");
      return;
   }

   if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
      _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
                  "glBitmap(incomplete framebuffer)");
      return;
   }

   if (ctx->RenderMode == GL_RENDER) {
      /* Truncate, to satisfy conformance tests (matches SGI's OpenGL). */
      if (width > 0 && height > 0) {
         const GLfloat epsilon = 0.0001F;
         GLint x = IFLOOR(ctx->Current.RasterPos[0] + epsilon - xorig);
         GLint y = IFLOOR(ctx->Current.RasterPos[1] + epsilon - yorig);

         if (ctx->Unpack.BufferObj->Name) {
            /* unpack from PBO */
            if (!_mesa_validate_pbo_access(2, &ctx->Unpack, width, height, 1,
                                           GL_COLOR_INDEX, GL_BITMAP,
                                           (GLvoid *) bitmap)) {
               _mesa_error(ctx, GL_INVALID_OPERATION,
                           "glBitmap(invalid PBO access)");
               return;
            }
            if (_mesa_bufferobj_mapped(ctx->Unpack.BufferObj)) {
               /* buffer is mapped - that's an error */
               _mesa_error(ctx, GL_INVALID_OPERATION,
                           "glBitmap(PBO is mapped)");
               return;
            }
         }

         ctx->Driver.Bitmap( ctx, x, y, width, height, &ctx->Unpack, bitmap );
      }
   }
#if _HAVE_FULL_GL
   else if (ctx->RenderMode == GL_FEEDBACK) {
      FLUSH_CURRENT(ctx, 0);
      _mesa_feedback_token( ctx, (GLfloat) (GLint) GL_BITMAP_TOKEN );
      _mesa_feedback_vertex( ctx,
                             ctx->Current.RasterPos,
                             ctx->Current.RasterColor,
                             ctx->Current.RasterIndex, 
                             ctx->Current.RasterTexCoords[0] );
   }
   else {
      ASSERT(ctx->RenderMode == GL_SELECT);
      /* Do nothing.  See OpenGL Spec, Appendix B, Corollary 6. */
   }
#endif

   /* update raster position */
   ctx->Current.RasterPos[0] += xmove;
   ctx->Current.RasterPos[1] += ymove;
}
示例#14
0
static void GLAPIENTRY
_mesa_CopyPixels( GLint srcx, GLint srcy, GLsizei width, GLsizei height,
                  GLenum type )
{
   GET_CURRENT_CONTEXT(ctx);
   ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);

   if (width < 0 || height < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glCopyPixels(width or height < 0)");
      return;
   }

   /* Note: more detailed 'type' checking is done by the
    * _mesa_source/dest_buffer_exists() calls below.  That's where we
    * check if the stencil buffer exists, etc.
    */
   if (type != GL_COLOR &&
       type != GL_DEPTH &&
       type != GL_STENCIL &&
       type != GL_DEPTH_STENCIL) {
      _mesa_error(ctx, GL_INVALID_ENUM, "glCopyPixels(type=%s)",
                  _mesa_lookup_enum_by_nr(type));
      return;
   }

   /* We're not using the current vertex program, and the driver may install
    * it's own.
    */
   _mesa_set_vp_override(ctx, GL_TRUE);

   if (ctx->NewState) {
      _mesa_update_state(ctx);
   }

   if (!valid_fragment_program(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glCopyPixels (invalid fragment program)");
      goto end;
   }

   if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT ||
       ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
      _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
                  "glCopyPixels(incomplete framebuffer)" );
      goto end;
   }

   if (!_mesa_source_buffer_exists(ctx, type) ||
       !_mesa_dest_buffer_exists(ctx, type)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glCopyPixels(missing source or dest buffer)");
      goto end;
   }

   if (!ctx->Current.RasterPosValid || width ==0 || height == 0) {
      goto end; /* no-op, not an error */
   }

   if (ctx->RenderMode == GL_RENDER) {
      /* Round to satisfy conformance tests (matches SGI's OpenGL) */
      if (width > 0 && height > 0) {
         GLint destx = IROUND(ctx->Current.RasterPos[0]);
         GLint desty = IROUND(ctx->Current.RasterPos[1]);
         ctx->Driver.CopyPixels( ctx, srcx, srcy, width, height, destx, desty,
                                 type );
      }
   }
   else if (ctx->RenderMode == GL_FEEDBACK) {
      FLUSH_CURRENT( ctx, 0 );
      _mesa_feedback_token( ctx, (GLfloat) (GLint) GL_COPY_PIXEL_TOKEN );
      _mesa_feedback_vertex( ctx, 
                             ctx->Current.RasterPos,
                             ctx->Current.RasterColor,
                             ctx->Current.RasterIndex,
                             ctx->Current.RasterTexCoords[0] );
   }
   else {
      ASSERT(ctx->RenderMode == GL_SELECT);
      /* Do nothing.  See OpenGL Spec, Appendix B, Corollary 6. */
   }

end:
   _mesa_set_vp_override(ctx, GL_FALSE);
}