static void read_depth_stencil_pixels	(	GLcontext *	ctx,
		GLint	x,
		GLint	y,
		GLsizei	width,
		GLsizei	height,
		GLenum	type,
		GLvoid *	pixels,
		const struct gl_pixelstore_attrib *	packing
	)		`[static]`

Read combined depth/stencil values. We'll have already done error checking to be sure the expected depth and stencil buffers really exist.

Definition at line 458 of file s_readpix.c.

Referenced by _swrast_ReadPixels().

{
   const GLboolean scaleOrBias
      = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
   const GLboolean stencilTransfer = ctx->Pixel.IndexShift
      || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
   struct gl_renderbuffer *depthRb, *stencilRb;

   depthRb = ctx->ReadBuffer->_DepthBuffer;
   stencilRb = ctx->ReadBuffer->_StencilBuffer;

   if (!depthRb || !stencilRb)
      return;

   depthRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
   stencilRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;

   if (depthRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
       stencilRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
       depthRb == stencilRb &&
       !scaleOrBias &&
       !stencilTransfer) {
      /* This is the ideal case.
       * Reading GL_DEPTH_STENCIL pixels from combined depth/stencil buffer.
       * Plus, no pixel transfer ops to worry about!
       */
      GLint i;
      GLint dstStride = _mesa_image_row_stride(packing, width,
                                               GL_DEPTH_STENCIL_EXT, type);
      GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
                                                       width, height,
                                                       GL_DEPTH_STENCIL_EXT,
                                                       type, 0, 0);
      for (i = 0; i < height; i++) {
         depthRb->GetRow(ctx, depthRb, width, x, y + i, dst);
         dst += dstStride;
      }
   }
   else {
      /* Reading GL_DEPTH_STENCIL pixels from separate depth/stencil buffers,
       * or we need pixel transfer.
       */
      GLint i;
      depthRb = ctx->ReadBuffer->_DepthBuffer;
      stencilRb = ctx->ReadBuffer->_StencilBuffer;

      for (i = 0; i < height; i++) {
         GLstencil stencilVals[MAX_WIDTH];

         GLuint *depthStencilDst = (GLuint *)
            _mesa_image_address2d(packing, pixels, width, height,
                                  GL_DEPTH_STENCIL_EXT, type, i, 0);

         _swrast_read_stencil_span(ctx, stencilRb, width,
                                   x, y + i, stencilVals);

         if (!scaleOrBias && !stencilTransfer
             && ctx->ReadBuffer->Visual.depthBits == 24) {
            /* ideal case */
            GLuint zVals[MAX_WIDTH]; /* 24-bit values! */
            GLint j;
            ASSERT(depthRb->DataType == GL_UNSIGNED_INT);
            /* note, we've already been clipped */
            depthRb->GetRow(ctx, depthRb, width, x, y + i, zVals);
            for (j = 0; j < width; j++) {
               depthStencilDst[j] = (zVals[j] << 8) | (stencilVals[j] & 0xff);
            }
         }
         else {
            /* general case */
            GLfloat depthVals[MAX_WIDTH];
            _swrast_read_depth_span_float(ctx, depthRb, width, x, y + i,
                                          depthVals);
            _mesa_pack_depth_stencil_span(ctx, width, depthStencilDst,
                                          depthVals, stencilVals, packing);
         }
      }
   }
}

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