mesa: Skip partial InvalidateFramebuffer of packed depth/stencil.

One of the CTS cases tries to invalidate just stencil of packed
depth/stencil, and we incorrectly lost the depth contents.

Fixes dEQP-GLES3.functional.fbo.invalidate.whole.unbind_read_stencil
Fixes: 0c42b5f3cb90 ("mesa: wire up InvalidateFramebuffer")
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

(cherry picked from commit db2ae51121067b66d4ee8313ba7f74cecb201a03)

1 files changed, 23 insertions, 0 deletions

diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
index 8290ea94dfc..87c33be7854 100644
--- a/src/mesa/main/fbobject.c
+++ b/src/mesa/main/fbobject.c
@@ -4691,6 +4691,29 @@ discard_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb,
       if (!att)
          continue;
 
+      /* If we're asked to invalidate just depth or just stencil, but the
+       * attachment is packed depth/stencil, then we can only use
+       * Driver.DiscardFramebuffer if the attachments list includes both depth
+       * and stencil and they both point at the same renderbuffer.
+       */
+      if ((attachments[i] == GL_DEPTH_ATTACHMENT ||
+           attachments[i] == GL_STENCIL_ATTACHMENT) &&
+          (!att->Renderbuffer ||
+           att->Renderbuffer->_BaseFormat == GL_DEPTH_STENCIL)) {
+         GLenum other_format = (attachments[i] == GL_DEPTH_ATTACHMENT ?
+                                GL_STENCIL_ATTACHMENT : GL_DEPTH_ATTACHMENT);
+         bool has_both = false;
+         for (int j = 0; j < numAttachments; j++) {
+            if (attachments[j] == other_format)
+               has_both = true;
+            break;
+         }
+
+         if (fb->Attachment[BUFFER_DEPTH].Renderbuffer !=
+             fb->Attachment[BUFFER_STENCIL].Renderbuffer || !has_both)
+            continue;
+      }
+
       ctx->Driver.DiscardFramebuffer(ctx, fb, att);
    }
 }