From 318bb080b04c961141a962d440d0e1296f8adda6 Mon Sep 17 00:00:00 2001 From: Roland Scheidegger Date: Fri, 8 Oct 2010 21:06:04 +0200 Subject: [PATCH] gallivm: more linear tex wrap mode calculation simplification Rearrange order of operations a bit to make some clamps easier. All calculations should be equivalent. Note there seems to be some inconsistency in the clamp to edge case wrt normalized/non-normalized coords, could potentially simplify this too. --- .../auxiliary/gallivm/lp_bld_sample_soa.c | 21 ++++++++----------- 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c index 29adb579288..242e8d3d50d 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_sample_soa.c @@ -291,6 +291,8 @@ lp_build_sample_wrap_linear(struct lp_build_sample_context *bld, coord = lp_build_mul(coord_bld, coord, length_f); coord = lp_build_sub(coord_bld, coord, half); } + /* XXX this is odd normalized ranges from -0.5 to length-0.5 after denorm + but non-normalized ranges from to 0.5 to length-0.5 after clamp */ else { LLVMValueRef min, max; /* clamp to [0.5, length - 0.5] */ @@ -309,16 +311,15 @@ lp_build_sample_wrap_linear(struct lp_build_sample_context *bld, case PIPE_TEX_WRAP_CLAMP_TO_BORDER: { - LLVMValueRef min, max; + LLVMValueRef min; if (bld->static_state->normalized_coords) { /* scale coord to length */ coord = lp_build_mul(coord_bld, coord, length_f); } - /* clamp to [-0.5, length + 0.5] */ - min = lp_build_const_vec(coord_bld->type, -0.5F); - max = lp_build_sub(coord_bld, length_f, min); - coord = lp_build_clamp(coord_bld, coord, min, max); + /* was: clamp to [-0.5, length + 0.5], then sub 0.5 */ coord = lp_build_sub(coord_bld, coord, half); + min = lp_build_const_vec(coord_bld->type, -1.0F); + coord = lp_build_clamp(coord_bld, coord, min, length_f); /* convert to int, compute lerp weight */ lp_build_ifloor_fract(coord_bld, coord, &coord0, &weight); coord1 = lp_build_add(int_coord_bld, coord0, int_coord_bld->one); @@ -388,8 +389,6 @@ lp_build_sample_wrap_linear(struct lp_build_sample_context *bld, case PIPE_TEX_WRAP_MIRROR_CLAMP_TO_BORDER: { - LLVMValueRef min, max; - coord = lp_build_abs(coord_bld, coord); if (bld->static_state->normalized_coords) { @@ -397,12 +396,10 @@ lp_build_sample_wrap_linear(struct lp_build_sample_context *bld, coord = lp_build_mul(coord_bld, coord, length_f); } - /* clamp to [-0.5, length + 0.5] */ - min = lp_build_negate(coord_bld, half); - max = lp_build_sub(coord_bld, length_f, min); - coord = lp_build_clamp(coord_bld, coord, min, max); - + /* was: clamp to [-0.5, length + 0.5] then sub 0.5 */ + /* skip -0.5 clamp (always positive), do sub first */ coord = lp_build_sub(coord_bld, coord, half); + coord = lp_build_min(coord_bld, coord, length_f); /* convert to int, compute lerp weight */ lp_build_ifloor_fract(coord_bld, coord, &coord0, &weight); -- 2.30.2