[Mesa-dev] [PATCH] Revert "mesa: check depth, stencil formats (not depths) in glBlitFramebuffer"

[Chad Versace]

This reverts commit 3f1fab06844f696de44d9a56e83ff62e8ea576bd.

This loosens the format validation in glBlitFramebuffer. When blitting
depth bits, don't require an exact match between the depth formats; only
require that the two formats have the same number of depth bits. Ditto for
stencil.

Fixes Piglit fbo/fbo-blit-d24s8 on Intel drivers with separate stencil
enabled.

The problem was that, on Intel drivers with separate stencil, the default
framebuffer has separate depth and stencil buffers with formats X8_Z24 and
S8. The test attempts to blit the depth bits from a S8_Z24 buffer into the
default framebuffer.

Between S8_Z24 buffers, the EXT_framebuffer_blit spec allows
glBlitFramebuffer to blit the depth and stencil bits separately. So I see
no reason to prevent blitting the depth bits between X8_Z24 and S8_Z24 or
the stencil bits between S8 and S8_Z24.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44665
Note: This is a candidate for the 8.0 branch.
CC: Brian Paul <brianp at wmware.com>
Reported-by: Xunx Fang <xunx.fang at intel.com>
Signed-off-by: Chad Versace <chad.versace at linux.intel.com>
---
 src/mesa/main/fbobject.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index 0524959..9a5e780 100644
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -2709,9 +2709,10 @@ _mesa_BlitFramebufferEXT(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
       if ((readRb == NULL) || (drawRb == NULL)) {
 	 mask &= ~GL_STENCIL_BUFFER_BIT;
       }
-      else if (readRb->Format != drawRb->Format) {
+      else if (_mesa_get_format_bits(readRb->Format, GL_STENCIL_BITS) !=
+	       _mesa_get_format_bits(drawRb->Format, GL_STENCIL_BITS)) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
-                     "glBlitFramebufferEXT(stencil buffer format mismatch)");
+                     "glBlitFramebufferEXT(stencil buffer size mismatch)");
          return;
       }
    }
@@ -2731,9 +2732,10 @@ _mesa_BlitFramebufferEXT(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
       if ((readRb == NULL) || (drawRb == NULL)) {
 	 mask &= ~GL_DEPTH_BUFFER_BIT;
       }
-      else if (readRb->Format != drawRb->Format) {
+      else if (_mesa_get_format_bits(readRb->Format, GL_DEPTH_BITS) !=
+	       _mesa_get_format_bits(drawRb->Format, GL_DEPTH_BITS)) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
-                     "glBlitFramebufferEXT(depth buffer format mismatch)");
+                     "glBlitFramebufferEXT(depth buffer size mismatch)");
          return;
       }
    }
-- 
1.7.7.4