mesa: Ignore blits to/from missing buffers

The EXT_framebuffer_object spec (and later specs) say:

     "If a buffer is specified in <mask> and does not exist in both
     the read and draw framebuffers, the corresponding bit is silently
     ignored."

Check for color, depth, and stencil that the source and destination
FBOs have the specified buffers.  If the buffer is missing, remove the
bit from the blit request mask and continue.

Fixes the crash in piglit test 'fbo-missing-attachment-blit from', and
fixes 'fbo-missing-attachment-blit es2 from'.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=37739
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
NOTE: This is a candidate for the stable branches.

diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index d4400709aefaed4a1ab5d889fd84bae2240e24e5..2230b2623367f54ec451b2dea0b2d299882f3e42 100644 (file)
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -2429,6 +2429,17 @@ _mesa_BlitFramebufferEXT(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
    if (mask & GL_COLOR_BUFFER_BIT) {
       colorReadRb = readFb->_ColorReadBuffer;
       colorDrawRb = drawFb->_ColorDrawBuffers[0];
+
+      /* From the EXT_framebuffer_object spec:
+       *
+       *     "If a buffer is specified in <mask> and does not exist in both
+       *     the read and draw framebuffers, the corresponding bit is silently
+       *     ignored."
+       */
+      if ((colorReadRb == NULL) || (colorDrawRb == NULL)) {
+        colorReadRb = colorDrawRb = NULL;
+        mask &= ~GL_COLOR_BUFFER_BIT;
+      }
    }
    else {
       colorReadRb = colorDrawRb = NULL;
@@ -2437,10 +2448,19 @@ _mesa_BlitFramebufferEXT(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
    if (mask & GL_STENCIL_BUFFER_BIT) {
       struct gl_renderbuffer *readRb = readFb->_StencilBuffer;
       struct gl_renderbuffer *drawRb = drawFb->_StencilBuffer;
-      if (!readRb ||
-          !drawRb ||
-          _mesa_get_format_bits(readRb->Format, GL_STENCIL_BITS) != 
-          _mesa_get_format_bits(drawRb->Format, GL_STENCIL_BITS)) {
+
+      /* From the EXT_framebuffer_object spec:
+       *
+       *     "If a buffer is specified in <mask> and does not exist in both
+       *     the read and draw framebuffers, the corresponding bit is silently
+       *     ignored."
+       */
+      if ((readRb == NULL) || (drawRb == NULL)) {
+        readRb = drawRb = NULL;
+        mask &= ~GL_STENCIL_BUFFER_BIT;
+      }
+      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 size mismatch)");
          return;
@@ -2450,10 +2470,19 @@ _mesa_BlitFramebufferEXT(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
    if (mask & GL_DEPTH_BUFFER_BIT) {
       struct gl_renderbuffer *readRb = readFb->_DepthBuffer;
       struct gl_renderbuffer *drawRb = drawFb->_DepthBuffer;
-      if (!readRb ||
-          !drawRb ||
-          _mesa_get_format_bits(readRb->Format, GL_DEPTH_BITS) != 
-          _mesa_get_format_bits(drawRb->Format, GL_DEPTH_BITS)) {
+
+      /* From the EXT_framebuffer_object spec:
+       *
+       *     "If a buffer is specified in <mask> and does not exist in both
+       *     the read and draw framebuffers, the corresponding bit is silently
+       *     ignored."
+       */
+      if ((readRb == NULL) || (drawRb == NULL)) {
+        readRb = drawRb = NULL;
+        mask &= ~GL_DEPTH_BUFFER_BIT;
+      }
+      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 size mismatch)");
          return;