i965: define, use BRW_MAX_DRAW_BUFFERS

i965 might support more than 4 color draw buffers.  But if not, this protects
from breakage if the Mesa limit is raised.

3 files changed, 8 insertions, 4 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index c300c33adc..48685c087b 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -105,6 +105,7 @@ GLboolean brwCreateContext( const __GLcontextModes *mesaVis,
 
    TNL_CONTEXT(ctx)->Driver.RunPipeline = _tnl_run_pipeline;
 
+   ctx->Const.MaxDrawBuffers = BRW_MAX_DRAW_BUFFERS;
    ctx->Const.MaxTextureImageUnits = BRW_MAX_TEX_UNIT;
    ctx->Const.MaxTextureCoordUnits = 8; /* Mesa limit */
    ctx->Const.MaxTextureUnits = MIN2(ctx->Const.MaxTextureCoordUnits,
diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 7834569761..59f9475b5a 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -252,20 +252,23 @@ struct brw_vs_ouput_sizes {
 /** Number of texture sampler units */
 #define BRW_MAX_TEX_UNIT 16
 
+/** Max number of render targets in a shader */
+#define BRW_MAX_DRAW_BUFFERS 4
+
 /**
  * Size of our surface binding table for the WM.
  * This contains pointers to the drawing surfaces and current texture
  * objects and shader constant buffers (+2).
  */
-#define BRW_WM_MAX_SURF (MAX_DRAW_BUFFERS + BRW_MAX_TEX_UNIT + 1)
+#define BRW_WM_MAX_SURF (BRW_MAX_DRAW_BUFFERS + BRW_MAX_TEX_UNIT + 1)
 
 /**
  * Helpers to convert drawing buffers, textures and constant buffers
  * to surface binding table indexes, for WM.
  */
 #define SURF_INDEX_DRAW(d)           (d)
-#define SURF_INDEX_FRAG_CONST_BUFFER (MAX_DRAW_BUFFERS) 
-#define SURF_INDEX_TEXTURE(t)        (MAX_DRAW_BUFFERS + 1 + (t))
+#define SURF_INDEX_FRAG_CONST_BUFFER (BRW_MAX_DRAW_BUFFERS) 
+#define SURF_INDEX_TEXTURE(t)        (BRW_MAX_DRAW_BUFFERS + 1 + (t))
 
 /**
  * Size of surface binding table for the VS.
diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
index 73ae06eea1..3b2c6a25be 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
@@ -709,7 +709,7 @@ static void prepare_wm_surfaces(struct brw_context *brw )
    }
 
    old_nr_surfaces = brw->wm.nr_surfaces;
-   brw->wm.nr_surfaces = MAX_DRAW_BUFFERS;
+   brw->wm.nr_surfaces = BRW_MAX_DRAW_BUFFERS;
 
    if (brw->wm.surf_bo[SURF_INDEX_FRAG_CONST_BUFFER] != NULL)
        brw->wm.nr_surfaces = SURF_INDEX_FRAG_CONST_BUFFER + 1;