[Mesa-dev] [RFC PATCH 01/10] i965: allow 8 user clip planes on CTG+

[Chris Forbes]

There's no need to use a clip flag for NEGW on these gens, so
no reason we can't just enable 8 planes.

V2: Bump (and document!) MAX_VERTS in the clip code.

Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
---
 src/mesa/drivers/dri/i965/brw_clip.h     | 6 +++++-
 src/mesa/drivers/dri/i965/brw_clip_tri.c | 4 ++--
 src/mesa/drivers/dri/i965/brw_context.c  | 2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_clip.h b/src/mesa/drivers/dri/i965/brw_clip.h
index 2b02f85..671d3a9 100644
--- a/src/mesa/drivers/dri/i965/brw_clip.h
+++ b/src/mesa/drivers/dri/i965/brw_clip.h
@@ -36,7 +36,11 @@
 #include "brw_context.h"
 #include "brw_eu.h"
 
-#define MAX_VERTS (3+6+6)	
+/* Initial 3 verts, plus at most 6 additional verts from intersections
+ * with fixed planes, plus at most 8 additional verts from intersections
+ * with user clip planes
+ */
+#define MAX_VERTS (3+6+8)
 
 /* Note that if unfilled primitives are being emitted, we have to fix
  * up polygon offset and flatshading at this point:
diff --git a/src/mesa/drivers/dri/i965/brw_clip_tri.c b/src/mesa/drivers/dri/i965/brw_clip_tri.c
index 19179c1..b37c8c9 100644
--- a/src/mesa/drivers/dri/i965/brw_clip_tri.c
+++ b/src/mesa/drivers/dri/i965/brw_clip_tri.c
@@ -273,9 +273,9 @@ void brw_clip_tri( struct brw_clip_compile *c )
    brw_MOV(p, get_addr_reg(freelist_ptr), brw_address(c->reg.vertex[3]) );
 
    /* Set the initial vertex source mask: The first 6 planes are the bounds
-    * of the view volume; the next 6 planes are the user clipping planes.
+    * of the view volume; the next 8 planes are the user clipping planes.
     */
-   brw_MOV(p, c->reg.vertex_src_mask, brw_imm_ud(0xfc0));
+   brw_MOV(p, c->reg.vertex_src_mask, brw_imm_ud(0x3fc0));
 
    brw_DO(p, BRW_EXECUTE_1);
    {
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 1669a23..f7d3b71 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -190,7 +190,7 @@ brw_initialize_context_constants(struct brw_context *brw)
    ctx->Const.MaxPointSizeAA = 255.0;
    ctx->Const.PointSizeGranularity = 1.0;
 
-   if (brw->gen >= 6)
+   if (brw->gen >= 5 || brw->is_g4x)
       ctx->Const.MaxClipPlanes = 8;
 
    ctx->Const.VertexProgram.MaxNativeInstructions = 16 * 1024;
-- 
1.8.3.4