i965: glClearBuffer() should only clear a single buffer.

glClearBuffer() is currently clearing all active draw color buffers (all
buffers that have not been set to GL_NONE when calling glDrawBuffers) instead
of only clearing the one it receives as parameter. Altough brw_clear()
receives a bit mask indicating the color buffers that should be cleared,
this mask is ignored when calling brw_blorp_clear_color().

This was breaking the 'fbo-drawbuffers-none glClearBuffer' piglit test.

The patch provides the bit mask to brw_blorp_clear_color() so it can limit
clearing to the color buffers present in the mask.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76832
Reviewed-by: Eric Anholt <[email protected]>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_blorp_clear.cpp b/src/mesa/drivers/dri/i965/brw_blorp_clear.cpp
index 851af8cadb8..0b13bf1331b 100644
--- a/src/mesa/drivers/dri/i965/brw_blorp_clear.cpp
+++ b/src/mesa/drivers/dri/i965/brw_blorp_clear.cpp
@@ -567,12 +567,16 @@ do_single_blorp_clear(struct brw_context *brw, struct gl_framebuffer *fb,
 extern "C" {
 bool
 brw_blorp_clear_color(struct brw_context *brw, struct gl_framebuffer *fb,
-                      bool partial_clear)
+                      GLbitfield mask, bool partial_clear)
 {
    for (unsigned buf = 0; buf < fb->_NumColorDrawBuffers; buf++) {
       struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[buf];
       struct intel_renderbuffer *irb = intel_renderbuffer(rb);
 
+      /* Only clear the buffers present in the provided mask */
+      if (((1 << fb->_ColorDrawBufferIndexes[buf]) & mask) == 0)
+         continue;
+
       /* If this is an ES2 context or GL_ARB_ES2_compatibility is supported,
        * the framebuffer can be complete with some attachments missing.  In
        * this case the _ColorDrawBuffers pointer will be NULL.