1 files changed, 28 insertions, 13 deletions
diff --git a/src/mesa/main/framebuffer.c b/src/mesa/main/framebuffer.c
index 1fd31a53211..c9b30d32528 100644
--- a/src/mesa/main/framebuffer.c
+++ b/src/mesa/main/framebuffer.c
@@ -65,7 +65,9 @@ compute_depth_max(struct gl_framebuffer *fb)
       fb->_DepthMax = 0xffffffff;
    }
    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
-   fb->_MRD = 1.0;  /* Minimum resolvable depth value, for polygon offset */
+
+   /* Minimum resolvable depth value, for polygon offset */
+   fb->_MRD = 1.0 / fb->_DepthMaxF;
 }
 
 
@@ -652,6 +654,27 @@ update_color_read_buffer(GLcontext *ctx, struct gl_framebuffer *fb)
 }
 
 
+static void
+update_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb)
+{
+   /* Completeness only matters for user-created framebuffers */
+   if (fb->Name != 0) {
+      /* XXX: EXT_framebuffer_blit:
+         framebuffer must still be complete wrt read/draw? */
+      _mesa_test_framebuffer_completeness(ctx, fb);
+      _mesa_update_framebuffer_visual(fb);
+   }
+
+   /* update_color_draw/read_buffers not needed for
+      read/draw only fb, but shouldn't hurt ??? */
+   update_color_draw_buffers(ctx, fb);
+   update_color_read_buffer(ctx, fb);
+   _mesa_update_depth_buffer(ctx, fb, BUFFER_DEPTH);
+   _mesa_update_stencil_buffer(ctx, fb, BUFFER_STENCIL);
+
+   compute_depth_max(fb);
+}
+
 /**
  * Update state related to the current draw/read framebuffers.
  * Specifically, update these framebuffer fields:
@@ -669,19 +692,11 @@ void
 _mesa_update_framebuffer(GLcontext *ctx)
 {
    struct gl_framebuffer *fb = ctx->DrawBuffer;
+   struct gl_framebuffer *fbread = ctx->ReadBuffer;
 
-   /* Completeness only matters for user-created framebuffers */
-   if (fb->Name != 0) {
-      _mesa_test_framebuffer_completeness(ctx, fb);
-      _mesa_update_framebuffer_visual(fb);
-   }
-
-   update_color_draw_buffers(ctx, fb);
-   update_color_read_buffer(ctx, fb);
-   _mesa_update_depth_buffer(ctx, fb, BUFFER_DEPTH);
-   _mesa_update_stencil_buffer(ctx, fb, BUFFER_STENCIL);
-
-   compute_depth_max(fb);
+   update_framebuffer(ctx, fb);
+   if (fbread != fb)
+      update_framebuffer(ctx, fbread);
 }