i965: Implement glBlendBarrier.

This is a no-op if the platform supports coherent framebuffer fetch,
-- If it doesn't we just need to flush the render cache and invalidate
the texture cache in order for previous rendering to be visible to
framebuffer fetch.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/mesa/drivers/dri/i965/brw_program.c b/src/mesa/drivers/dri/i965/brw_program.c
index 0e55c7ba18e9bf2478134daf4b35bed85e5c5fc4..9d32dd3c3ff02466ae313edd333dc1b9da7888c3 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_program.c
+++ b/src/mesa/drivers/dri/i965/brw_program.c
@@ -310,6 +310,25 @@ brw_memory_barrier(struct gl_context *ctx, GLbitfield barriers)
    brw_emit_pipe_control_flush(brw, bits);
 }
 
+static void
+brw_blend_barrier(struct gl_context *ctx)
+{
+   struct brw_context *brw = brw_context(ctx);
+
+   if (!ctx->Extensions.MESA_shader_framebuffer_fetch) {
+      if (brw->gen >= 6) {
+         brw_emit_pipe_control_flush(brw,
+                                     PIPE_CONTROL_RENDER_TARGET_FLUSH |
+                                     PIPE_CONTROL_CS_STALL);
+         brw_emit_pipe_control_flush(brw,
+                                     PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE);
+      } else {
+         brw_emit_pipe_control_flush(brw,
+                                     PIPE_CONTROL_RENDER_TARGET_FLUSH);
+      }
+   }
+}
+
 void
 brw_add_texrect_params(struct gl_program *prog)
 {
@@ -379,6 +398,7 @@ void brwInitFragProgFuncs( struct dd_function_table *functions )
    functions->LinkShader = brw_link_shader;
 
    functions->MemoryBarrier = brw_memory_barrier;
+   functions->BlendBarrier = brw_blend_barrier;
 }
 
 struct shader_times {