From a7d92c3c0b0df1a5e8be3f8208868828043ab630 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Thu, 18 Aug 2016 10:57:44 +0100 Subject: [PATCH] nouveau: Fix non-1x post-scale factor with DOT3 combiner Fixes long standing bug on NV10 and NV20 where using a non-1x RGB or A post-scale with GL_DOT3_RGB or GL_DOT3_RGBA texture environment would not work. The old combiner math uses HALF_BIAS_NORMAL and HALF_BIAS_NEGATE. The GL_NV_register_combiners defines these as HALF_BIAS_NORMAL_NV max(0.0, e) - 0.5 HALF_BIAS_NEGATE_NV -max(0.0, e) + 0.5 In order to get the correct result from the dot-product, the intermediate dot-product must be multiplied by 4. This is a literal implementation of the GL_ARB_texture_env_dot3 spec. It also requires using the register combiner post-scale. As a result, the post-scale cannot be used for the post-scale set by the application. The new combiner math uses EXPAND_NORMAL and EXPAND_NEGATE. The GL_NV_register_combiners defines these as EXPAND_NORMAL_NV 2.0 * max(0.0, e) - 1.0 EXPAND_NEGATE_NV -2.0 * max(0.0, e) + 1.0 Since this fully expands the value to [-1, 1] range, the intermediate dot-product result is the desired value. This leaves the register combiner post-scale available for application use. NOTE: I have not actually tested this. Signed-off-by: Ian Romanick Acked-by: Ilia Mirkin --- src/mesa/drivers/dri/nouveau/nv10_state_frag.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/src/mesa/drivers/dri/nouveau/nv10_state_frag.c b/src/mesa/drivers/dri/nouveau/nv10_state_frag.c index c007c6c..e78eac3 100644 --- a/src/mesa/drivers/dri/nouveau/nv10_state_frag.c +++ b/src/mesa/drivers/dri/nouveau/nv10_state_frag.c @@ -135,7 +135,7 @@ get_input_source(struct combiner_state *rc, int source) /* Get the RC input mapping for the specified texture_env_combine * operand, possibly inverted or biased. */ #define INVERT 0x1 -#define HALF_BIAS 0x2 +#define NORMALIZE 0x2 static uint32_t get_input_mapping(struct combiner_state *rc, int operand, int flags) @@ -148,12 +148,12 @@ get_input_mapping(struct combiner_state *rc, int operand, int flags) map |= RC_IN_USAGE(ALPHA); if (is_negative_operand(operand) == !(flags & INVERT)) - map |= flags & HALF_BIAS ? - RC_IN_MAPPING(HALF_BIAS_NEGATE) : + map |= flags & NORMALIZE ? + RC_IN_MAPPING(EXPAND_NEGATE) : RC_IN_MAPPING(UNSIGNED_INVERT); else - map |= flags & HALF_BIAS ? - RC_IN_MAPPING(HALF_BIAS_NORMAL) : + map |= flags & NORMALIZE ? + RC_IN_MAPPING(EXPAND_NORMAL) : RC_IN_MAPPING(UNSIGNED_IDENTITY); return map; @@ -270,12 +270,10 @@ setup_combiner(struct combiner_state *rc) case GL_DOT3_RGB: case GL_DOT3_RGBA: - INPUT_ARG(rc, A, 0, HALF_BIAS); - INPUT_ARG(rc, B, 1, HALF_BIAS); + INPUT_ARG(rc, A, 0, NORMALIZE); + INPUT_ARG(rc, B, 1, NORMALIZE); - rc->out = RC_OUT_DOT_AB | RC_OUT_SCALE_4; - - assert(!rc->logscale); + rc->out = RC_OUT_DOT_AB; break; default: -- 2.7.4