Clamp vertex lighting before interpolation

Fixes a regression in which pass lighting was clamped after being passed
to fragment shader. For correct FFP emulation, we need to clamp the result
in vertex shader. When clamping after interpolation, negative lights in
particular have a much more drastic effect.

files/shaders/groundcover_fragment.glsl

@@ -73,12 +73,7 @@ void main()
     vec3 diffuseLight, ambientLight;
     doLighting(passViewPos, normalize(viewNormal), shadowing, diffuseLight, ambientLight);
     lighting = diffuseLight + ambientLight;
-#endif
-
-#if @clamp
-    lighting = clamp(lighting, vec3(0.0), vec3(1.0));
-#else
-    lighting = max(lighting, 0.0);
+    clampLightingResult(lighting);
 #endif
 
     gl_FragData[0].xyz *= lighting;

files/shaders/groundcover_vertex.glsl

@@ -165,6 +165,7 @@ void main(void)
     vec3 diffuseLight, ambientLight;
     doLighting(viewPos.xyz, viewNormal, diffuseLight, ambientLight, shadowDiffuseLighting);
     passLighting = diffuseLight + ambientLight;
+    clampLightingResult(passLighting);
 #endif
 
 #if (@shadows_enabled)

files/shaders/lighting_util.glsl

@@ -129,3 +129,12 @@ vec4 lcalcSpecular(int lightIndex)
     return @getLight[lightIndex].specular;
 #endif
 }
+
+void clampLightingResult(inout vec3 lighting)
+{
+#if @clamp
+    lighting = clamp(lighting, vec3(0.0), vec3(1.0));
+#else
+    lighting = max(lighting, 0.0);
+#endif
+}

files/shaders/nv_default_fragment.glsl

@@ -78,11 +78,7 @@ void main()
 #endif
     vec3 lighting = diffuseColor.xyz * diffuseLight + getAmbientColor().xyz * ambientLight + emission;
 
-#if @clamp
-    lighting = clamp(lighting, vec3(0.0), vec3(1.0));
-#else
-    lighting = max(lighting, 0.0);
-#endif
+    clampLightingResult(lighting);
 
     gl_FragData[0].xyz *= lighting;
 

files/shaders/objects_fragment.glsl

@@ -176,12 +176,7 @@ void main()
     doLighting(passViewPos, normalize(viewNormal), shadowing, diffuseLight, ambientLight);
     vec3 emission = getEmissionColor().xyz * emissiveMult;
     lighting = diffuseColor.xyz * diffuseLight + getAmbientColor().xyz * ambientLight + emission;
-#endif
-
-#if @clamp
-    lighting = clamp(lighting, vec3(0.0), vec3(1.0));
-#else
-    lighting = max(lighting, 0.0);
+    clampLightingResult(lighting);
 #endif
 
     gl_FragData[0].xyz *= lighting;

files/shaders/objects_vertex.glsl

@@ -125,6 +125,7 @@ void main(void)
     doLighting(viewPos.xyz, viewNormal, diffuseLight, ambientLight, shadowDiffuseLighting);
     vec3 emission = getEmissionColor().xyz * emissiveMult;
     passLighting = getDiffuseColor().xyz * diffuseLight + getAmbientColor().xyz * ambientLight + emission;
+    clampLightingResult(passLighting);
     shadowDiffuseLighting *= getDiffuseColor().xyz;
 #endif
 

files/shaders/terrain_fragment.glsl

@@ -87,12 +87,7 @@ void main()
     vec3 diffuseLight, ambientLight;
     doLighting(passViewPos, normalize(viewNormal), shadowing, diffuseLight, ambientLight);
     lighting = diffuseColor.xyz * diffuseLight + getAmbientColor().xyz * ambientLight + getEmissionColor().xyz;
-#endif
-
-#if @clamp
-    lighting = clamp(lighting, vec3(0.0), vec3(1.0));
-#else
-    lighting = max(lighting, 0.0);
+    clampLightingResult(lighting);
 #endif
 
     gl_FragData[0].xyz *= lighting;

files/shaders/terrain_vertex.glsl

@@ -47,6 +47,7 @@ void main(void)
     vec3 diffuseLight, ambientLight;
     doLighting(viewPos.xyz, viewNormal, diffuseLight, ambientLight, shadowDiffuseLighting);
     passLighting = getDiffuseColor().xyz * diffuseLight + getAmbientColor().xyz * ambientLight + getEmissionColor().xyz;
+    clampLightingResult(passLighting);
     shadowDiffuseLighting *= getDiffuseColor().xyz;
 #endif