i965: Simplify the remaining clear logic by relying on the meta clear.

The GLSL clear path doesn't need any buffer presence checks, since
those are already handled in the normal drawing path code.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Chad Versace <chad.versace@linux.intel.com>

src/mesa/drivers/dri/i965/brw_clear.c

@@ -1,7 +1,7 @@
 /**************************************************************************
  *
  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
- * Copyright 2009 Intel Corporation.
+ * Copyright 2009, 2012 Intel Corporation.
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
@@ -81,11 +81,6 @@ static void
 intelClear(struct gl_context *ctx, GLbitfield mask)
 {
    struct intel_context *intel = intel_context(ctx);
-   GLbitfield tri_mask = 0;
-   GLbitfield swrast_mask = 0;
-   struct gl_framebuffer *fb = ctx->DrawBuffer;
-   struct intel_renderbuffer *irb;
-   int i;
 
    if (!_mesa_check_conditional_render(ctx))
       return;
@@ -94,52 +89,21 @@ intelClear(struct gl_context *ctx, GLbitfield mask)
       intel->front_buffer_dirty = true;
    }
 
-   if (0)
-      fprintf(stderr, "%s\n", __FUNCTION__);
-
-   /* Get SW clears out of the way: Anything without an intel_renderbuffer */
-   for (i = 0; i < BUFFER_COUNT; i++) {
-      if (!(mask & (1 << i)))
-	 continue;
-
-      irb = intel_get_renderbuffer(fb, i);
-      if (unlikely(!irb)) {
-	 swrast_mask |= (1 << i);
-	 mask &= ~(1 << i);
-      }
-   }
-   if (unlikely(swrast_mask)) {
-      debug_mask("swrast", swrast_mask);
-      _swrast_Clear(ctx, swrast_mask);
-   }
-
-   tri_mask |= (mask & BUFFER_BITS_COLOR);
-
-   /* Make sure we have up to date buffers before we start looking at
-    * the tiling bits to determine how to clear. */
-   intel_prepare_render(intel);
-
-   /* HW stencil */
-   if (mask & BUFFER_BIT_STENCIL) {
-      const struct intel_region *stencilRegion
-         = intel_get_rb_region(fb, BUFFER_STENCIL);
-      if (stencilRegion) {
-	 tri_mask |= BUFFER_BIT_STENCIL;
-      }
-   }
-
-   /* HW depth */
-   if (mask & BUFFER_BIT_DEPTH) {
-      tri_mask |= BUFFER_BIT_DEPTH;
-   }
-
-   /* Anything left, just use tris */
-   tri_mask |= mask;
+   GLbitfield tri_mask = mask & (BUFFER_BITS_COLOR |
+				 BUFFER_BIT_STENCIL |
+				 BUFFER_BIT_DEPTH);
 
    if (tri_mask) {
       debug_mask("tri", tri_mask);
+      mask &= ~tri_mask;
       _mesa_meta_glsl_Clear(&intel->ctx, tri_mask);
    }
+
+   /* Any strange buffers get passed off to swrast */
+   if (mask) {
+      debug_mask("swrast", mask);
+      _swrast_Clear(ctx, mask);
+   }
 }