[PATCH 1/5] wined3d: Do not clamp fog in the VS.

[Elizabeth Figura]

From: Elizabeth Figura

NVidia and WARP clamp before interpolation in the oFog case; AMD clamps only
after interpolation (which we also do).

On the other hand, test_fog() proves that clamping should not be done before
interpolation in the FFP case, for any driver.

In order to emulate an FFP vertex shader with a real compiled shader, we need to
avoid clamping before interpolation, choosing the AMD behaviour here.
---
 dlls/wined3d/glsl_shader.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/wined3d/glsl_shader.c b/dlls/wined3d/glsl_shader.c
index 7bf9a5a9679..6c9f308b9f8 100644
--- a/dlls/wined3d/glsl_shader.c
+++ b/dlls/wined3d/glsl_shader.c
@@ -7366,7 +7366,7 @@ static GLuint shader_glsl_generate_vs3_rasterizer_input_setup(struct shader_glsl
             }
             else if (shader_match_semantic(semantic_name, WINED3D_DECL_USAGE_FOG))
             {
-                shader_addline(buffer, "%s = clamp(outputs[%u].%c, 0.0, 1.0);\n",
+                shader_addline(buffer, "%s = outputs[%u].%c;\n",
                         legacy_syntax ? "gl_FogFragCoord" : "ffp_varying_fogcoord",
                         output->register_idx, reg_mask[1]);
             }