mesa: fix glGetFramebufferAttachmentParameteriv w/ on-demand FRONT_BACK alloc

This fixes 66 CTS tests on st/mesa.

Cc: 12.0 <mesa-stable@lists.freedesktop.org>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index 2c01526d16791c36104cde26d375b7765d037bca..09da6b70d878f6340bffdd54432afb0a2338a98b 100644 (file)
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -303,9 +303,21 @@ _mesa_get_fb0_attachment(struct gl_context *ctx, struct gl_framebuffer *fb,
 
    switch (attachment) {
    case GL_FRONT_LEFT:
-      return &fb->Attachment[BUFFER_FRONT_LEFT];
+      /* Front buffers can be allocated on the first use, but
+       * glGetFramebufferAttachmentParameteriv must work even if that
+       * allocation hasn't happened yet. In such case, use the back buffer,
+       * which should be the same.
+       */
+      if (fb->Attachment[BUFFER_FRONT_LEFT].Type == GL_NONE)
+         return &fb->Attachment[BUFFER_BACK_LEFT];
+      else
+         return &fb->Attachment[BUFFER_FRONT_LEFT];
    case GL_FRONT_RIGHT:
-      return &fb->Attachment[BUFFER_FRONT_RIGHT];
+      /* Same as above. */
+      if (fb->Attachment[BUFFER_FRONT_RIGHT].Type == GL_NONE)
+         return &fb->Attachment[BUFFER_BACK_RIGHT];
+      else
+         return &fb->Attachment[BUFFER_FRONT_RIGHT];
    case GL_BACK_LEFT:
       return &fb->Attachment[BUFFER_BACK_LEFT];
    case GL_BACK_RIGHT: