Hi,
GL_ARB_provoking_vertex states that quads are not required to abide
the provoking vertex convention, and the actual hardware and/or driver
behavior can be queried with
GL_QUADS_FOLLOW_PROVOKING_VERTEX_CONVENTION.
I'd like to add a new PIPE_CAP_* to query for this capability in
Gallium, as it appears R3xx-R5xx hardware doesn't support the first
vertex convention for quads and I'd like the driver to behave
correctly. Fortunately, other primitive types are supported.
I decided to use the name "quads follow flatshade_first convention"
instead of "provoking vertex convention" because the actual state
variable in pipe_rasterizer_state is called flatshade_first.
The attached patch:
- adds PIPE_CAP_QUADS_FOLLOW_FLATSHADE_FIRST_CONVENTION
- adds the query in the Mesa state tracker
- and updates softpipe and llvmpipe to return 1 when this cap is
queried, and r300g to explicitly return 0
Please review/push.
Cheers.
Marek
From bbf279f81e03a6872507cbf533b382748c4ae015 Mon Sep 17 00:00:00 2001
From: =?utf-8?q?Marek=20Ol=C5=A1=C3=A1k?= <mar...@gmail.com>
Date: Fri, 18 Dec 2009 05:10:27 +0100
Subject: [PATCH] gallium: add PIPE_CAP_QUADS_FOLLOW_FLATSHADE_FIRST_CONVENTION
---
src/gallium/drivers/llvmpipe/lp_screen.c | 2 ++
src/gallium/drivers/r300/r300_screen.c | 2 ++
src/gallium/drivers/softpipe/sp_screen.c | 2 ++
src/gallium/include/pipe/p_defines.h | 1 +
src/mesa/state_tracker/st_extensions.c | 4 ++++
5 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/src/gallium/drivers/llvmpipe/lp_screen.c b/src/gallium/drivers/llvmpipe/lp_screen.c
index 9b47415..fa786f9 100644
--- a/src/gallium/drivers/llvmpipe/lp_screen.c
+++ b/src/gallium/drivers/llvmpipe/lp_screen.c
@@ -110,6 +110,8 @@ llvmpipe_get_param(struct pipe_screen *screen, int param)
return 1;
case PIPE_CAP_BLEND_EQUATION_SEPARATE:
return 1;
+ case PIPE_CAP_QUADS_FOLLOW_FLATSHADE_FIRST_CONVENTION:
+ return 1;
default:
return 0;
}
diff --git a/src/gallium/drivers/r300/r300_screen.c b/src/gallium/drivers/r300/r300_screen.c
index c2ea9b6..0b75ecf 100644
--- a/src/gallium/drivers/r300/r300_screen.c
+++ b/src/gallium/drivers/r300/r300_screen.c
@@ -138,6 +138,8 @@ static int r300_get_param(struct pipe_screen* pscreen, int param)
return 0;
case PIPE_CAP_BLEND_EQUATION_SEPARATE:
return 1;
+ case PIPE_CAP_QUADS_FOLLOW_FLATSHADE_FIRST_CONVENTION:
+ return 0;
default:
debug_printf("r300: Implementation error: Bad param %d\n",
param);
diff --git a/src/gallium/drivers/softpipe/sp_screen.c b/src/gallium/drivers/softpipe/sp_screen.c
index bd3532d..510150b 100644
--- a/src/gallium/drivers/softpipe/sp_screen.c
+++ b/src/gallium/drivers/softpipe/sp_screen.c
@@ -91,6 +91,8 @@ softpipe_get_param(struct pipe_screen *screen, int param)
return 1;
case PIPE_CAP_BLEND_EQUATION_SEPARATE:
return 1;
+ case PIPE_CAP_QUADS_FOLLOW_FLATSHADE_FIRST_CONVENTION:
+ return 1;
default:
return 0;
}
diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index fe1390d..6a37893 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -393,6 +393,7 @@ enum pipe_transfer_usage {
#define PIPE_CAP_MAX_PREDICATE_REGISTERS 30
#define PIPE_CAP_MAX_COMBINED_SAMPLERS 31 /*< Maximum texture image units accessible from vertex
and fragment shaders combined */
+#define PIPE_CAP_QUADS_FOLLOW_FLATSHADE_FIRST_CONVENTION 32
/**
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index ef3cbc5..db3380b 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -125,6 +125,10 @@ void st_init_limits(struct st_context *st)
= CLAMP(screen->get_param(screen, PIPE_CAP_MAX_RENDER_TARGETS),
1, MAX_DRAW_BUFFERS);
+ c->QuadsFollowProvokingVertexConvention
+ = CLAMP(screen->get_param(screen, PIPE_CAP_QUADS_FOLLOW_FLATSHADE_FIRST_CONVENTION),
+ 0, 1);
+
/* Is TGSI_OPCODE_CONT supported? */
/* XXX separate query for early function return? */
st->ctx->Shader.EmitContReturn =
--
1.6.3.3
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