summaryrefslogtreecommitdiffstats
path: root/src/mesa/drivers/dri/i965/brw_vs.h
diff options
context:
space:
mode:
authorPaul Berry <stereotype441@gmail.com>2013-02-16 05:59:34 -0800
committerPaul Berry <stereotype441@gmail.com>2013-02-20 13:48:45 -0800
commit54d9c8a04a3d79da9a73f4b30d1c30874e05dc58 (patch)
tree0fb7150cc4ec84129222bac97ee5c059c56124e5 /src/mesa/drivers/dri/i965/brw_vs.h
parent8b586322e71d5ad0ce95d0fbcbfeb4df13f65040 (diff)
downloadexternal_mesa3d-54d9c8a04a3d79da9a73f4b30d1c30874e05dc58.zip
external_mesa3d-54d9c8a04a3d79da9a73f4b30d1c30874e05dc58.tar.gz
external_mesa3d-54d9c8a04a3d79da9a73f4b30d1c30874e05dc58.tar.bz2
i965: Consign COORD_REPLACE VS hacks to Pre-Gen6.
Pre-Gen6, the SF thread requires exact matching between VS output slots (aka VUE slots) and FS input slots, even when the corresponding VS output slot is unused due to being overwritten by point coordinate replacement (glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE)). As a result, we have a special hack in the VS to ensure when any texture coordinate is subject to point coordinate replacement, it is always allocated space in the VUE, even if it isn't written to by the VS. This hack isn't needed from Gen6 onwards, since SF (Gen7: SBE) swizzling has the ability to insert the point coordinate into gl_TexCoord[] without needing a corresponding unused VUE slot. Note that no modification of SF setup code is required for this patch--get_attr_override() already does the right thing. However, we make a slight comment change to clarify why this works. In addition to eliminating unnecessary VS recompiles and saving precious URB space on Gen6+, this will save us the trouble of having to adjust this hack when we implement geometry shaders. Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Diffstat (limited to 'src/mesa/drivers/dri/i965/brw_vs.h')
-rw-r--r--src/mesa/drivers/dri/i965/brw_vs.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_vs.h b/src/mesa/drivers/dri/i965/brw_vs.h
index 75c8a5f..caa8f7c 100644
--- a/src/mesa/drivers/dri/i965/brw_vs.h
+++ b/src/mesa/drivers/dri/i965/brw_vs.h
@@ -86,7 +86,17 @@ struct brw_vs_prog_key {
GLuint userclip_planes_enabled_gen_4_5:MAX_CLIP_PLANES;
GLuint copy_edgeflag:1;
+
+ /**
+ * For pre-Gen6 hardware, a bitfield indicating which texture coordinates
+ * are going to be replaced with point coordinates (as a consequence of a
+ * call to glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE)). Because
+ * our SF thread requires exact matching between VS outputs and FS inputs,
+ * these texture coordinates will need to be unconditionally included in
+ * the VUE, even if they aren't written by the vertex shader.
+ */
GLuint point_coord_replace:8;
+
GLuint clamp_vertex_color:1;
struct brw_sampler_prog_key_data tex;