Mesa (master): r600g: truncate point sampled texture coordinates

[Alex Deucher]

Module: Mesa
Branch: master
Commit: 1dc204d145dc8c0b19473a7814c201a8954b6274
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=1dc204d145dc8c0b19473a7814c201a8954b6274

Author: Alex Deucher <alexdeucher at gmail.com>
Date:   Mon Feb 28 21:52:19 2011 -0500

r600g: truncate point sampled texture coordinates

By default the hardware rounds texcoords.  However,
for point sampled textures, the expected behavior is
to truncate.  When we have point sampled textures,
set the truncate bit in the sampler.

Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=25871

Signed-off-by: Alex Deucher <alexdeucher at gmail.com>

---

 src/gallium/drivers/r600/evergreen_state.c |    6 ++++++
 src/gallium/drivers/r600/r600_state.c      |    9 ++++++++-
 2 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/src/gallium/drivers/r600/evergreen_state.c b/src/gallium/drivers/r600/evergreen_state.c
index 3efdbab..a388476 100644
--- a/src/gallium/drivers/r600/evergreen_state.c
+++ b/src/gallium/drivers/r600/evergreen_state.c
@@ -305,11 +305,16 @@ static void *evergreen_create_sampler_state(struct pipe_context *ctx,
 {
 	struct r600_pipe_state *rstate = CALLOC_STRUCT(r600_pipe_state);
 	union util_color uc;
+	uint32_t coord_trunc = 0;
 
 	if (rstate == NULL) {
 		return NULL;
 	}
 
+	if ((state->mag_img_filter == PIPE_TEX_FILTER_NEAREST) ||
+	    (state->min_img_filter == PIPE_TEX_FILTER_NEAREST))
+		coord_trunc = 1;
+
 	rstate->id = R600_PIPE_STATE_SAMPLER;
 	util_pack_color(state->border_color, PIPE_FORMAT_B8G8R8A8_UNORM, &uc);
 	r600_pipe_state_add_reg(rstate, R_03C000_SQ_TEX_SAMPLER_WORD0_0,
@@ -328,6 +333,7 @@ static void *evergreen_create_sampler_state(struct pipe_context *ctx,
 			0xFFFFFFFF, NULL);
 	r600_pipe_state_add_reg(rstate, R_03C008_SQ_TEX_SAMPLER_WORD2_0,
 				S_03C008_LOD_BIAS(S_FIXED(CLAMP(state->lod_bias, -16, 16), 8)) |
+				S_03C008_MC_COORD_TRUNCATE(coord_trunc) |
 				S_03C008_TYPE(1),
 				0xFFFFFFFF, NULL);
 
diff --git a/src/gallium/drivers/r600/r600_state.c b/src/gallium/drivers/r600/r600_state.c
index c365979..3f2af7d 100644
--- a/src/gallium/drivers/r600/r600_state.c
+++ b/src/gallium/drivers/r600/r600_state.c
@@ -358,11 +358,16 @@ static void *r600_create_sampler_state(struct pipe_context *ctx,
 {
 	struct r600_pipe_state *rstate = CALLOC_STRUCT(r600_pipe_state);
 	union util_color uc;
+	uint32_t coord_trunc = 0;
 
 	if (rstate == NULL) {
 		return NULL;
 	}
 
+	if ((state->mag_img_filter == PIPE_TEX_FILTER_NEAREST) ||
+	    (state->min_img_filter == PIPE_TEX_FILTER_NEAREST))
+		coord_trunc = 1;
+
 	rstate->id = R600_PIPE_STATE_SAMPLER;
 	util_pack_color(state->border_color, PIPE_FORMAT_B8G8R8A8_UNORM, &uc);
 	r600_pipe_state_add_reg(rstate, R_03C000_SQ_TEX_SAMPLER_WORD0_0,
@@ -379,7 +384,9 @@ static void *r600_create_sampler_state(struct pipe_context *ctx,
 			S_03C004_MIN_LOD(S_FIXED(CLAMP(state->min_lod, 0, 15), 6)) |
 			S_03C004_MAX_LOD(S_FIXED(CLAMP(state->max_lod, 0, 15), 6)) |
 			S_03C004_LOD_BIAS(S_FIXED(CLAMP(state->lod_bias, -16, 16), 6)), 0xFFFFFFFF, NULL);
-	r600_pipe_state_add_reg(rstate, R_03C008_SQ_TEX_SAMPLER_WORD2_0, S_03C008_TYPE(1), 0xFFFFFFFF, NULL);
+	r600_pipe_state_add_reg(rstate, R_03C008_SQ_TEX_SAMPLER_WORD2_0,
+				S_03C008_MC_COORD_TRUNCATE(coord_trunc) |
+				S_03C008_TYPE(1), 0xFFFFFFFF, NULL);
 	if (uc.ui) {
 		r600_pipe_state_add_reg(rstate, R_00A400_TD_PS_SAMPLER0_BORDER_RED, fui(state->border_color[0]), 0xFFFFFFFF, NULL);
 		r600_pipe_state_add_reg(rstate, R_00A404_TD_PS_SAMPLER0_BORDER_GREEN, fui(state->border_color[1]), 0xFFFFFFFF, NULL);