From ec0ac720bfc0a981f841bf917d94cac8a2919577 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Stefan=20D=C3=B6singer?= Date: Sun, 28 Aug 2011 19:50:30 +0200 Subject: [PATCH] wined3d: Make sure that lit doesn't return NaN. --- dlls/wined3d/glsl_shader.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/dlls/wined3d/glsl_shader.c b/dlls/wined3d/glsl_shader.c index 837b7d4c0ef..7e736d889f0 100644 --- a/dlls/wined3d/glsl_shader.c +++ b/dlls/wined3d/glsl_shader.c @@ -2713,6 +2713,7 @@ static void shader_glsl_lit(const struct wined3d_shader_instruction *ins) * if(src.x > 0.0 && src.y > 0.0) dst.z = pow(src.y, power); * else dst.z = 0.0; * dst.w = 1.0; + * (where power = src.w clamped between -128 and 128) * * Obviously that has quite a few conditionals in it which we don't like. So the first step is this: * dst.x = 1.0 ... No further explanation needed @@ -2725,11 +2726,17 @@ static void shader_glsl_lit(const struct wined3d_shader_instruction *ins) * * step(0.0, x) will return 1 if src.x > 0.0, and 0 otherwise. So if y is 0 we get pow(0.0 * 1.0, power), * which sets dst.z to 0. If y > 0, but x = 0.0, we get pow(y * 0.0, power), which results in 0 too. - * if both x and y are > 0, we get pow(y * 1.0, power), as it is supposed to + * if both x and y are > 0, we get pow(y * 1.0, power), as it is supposed to. + * + * Unfortunately pow(0.0 ^ 0.0) returns NaN on most GPUs, but lit with src.y = 0 and src.w = 0 returns + * a non-NaN value in dst.z. What we return doesn't matter, as long as it is not NaN. Return 0, which is + * what all Windows HW drivers and GL_ARB_vertex_program's LIT do. */ shader_addline(ins->ctx->buffer, - "vec4(1.0, max(%s, 0.0), pow(max(0.0, %s) * step(0.0, %s), clamp(%s, -128.0, 128.0)), 1.0)%s);\n", - src0_param.param_str, src1_param.param_str, src0_param.param_str, src3_param.param_str, dst_mask); + "vec4(1.0, max(%s, 0.0), %s == 0.0 ? 0.0 : " + "pow(max(0.0, %s) * step(0.0, %s), clamp(%s, -128.0, 128.0)), 1.0)%s);\n", + src0_param.param_str, src3_param.param_str, src1_param.param_str, + src0_param.param_str, src3_param.param_str, dst_mask); } /** Process the WINED3DSIO_DST instruction in GLSL: -- 2.11.4.GIT