Adds more fog component tests.

src/shaders/fog_vec4_unset.vs.cg

@@ -6,6 +6,7 @@ struct vIn {
 struct vOut {
   float4 pos : POSITION;
   float4 col0 : COLOR0;
+  float4 fog : FOG;
 };
 
 vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, uniform float4x4 projection_matrix,

src/shaders/fog_vec4_w.vs.cg

@@ -26,7 +26,10 @@ vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, un
   result.pos = pos;
   result.col0 = I.diffuse;
 
-  result.fog.w = fog_values.w;
+  // Note: Compiler warnings about unused components are expected, this is intentionally part of the test.
+  // Force all the correct components of fog_values to be referenced via `clamp`. Failure to do this results in
+  // Cg generating code that copies the entire vector, causing values to be set erroneously.
+  result.fog.w = clamp(fog_values.w, 0.0f, 1.0f);
 
   return result;
 }

src/shaders/fog_vec4_wx.vs.cg

@@ -26,8 +26,11 @@ vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, un
   result.pos = pos;
   result.col0 = I.diffuse;
 
-  result.fog.w = fog_values.w;
-  result.fog.x = fog_values.x;
+  // Note: Compiler warnings about unused components are expected, this is intentionally part of the test.
+  // Force all the correct components of fog_values to be referenced via `clamp`. Failure to do this results in
+  // Cg generating code that copies the entire vector, causing values to be set erroneously.
+  result.fog.w = clamp(fog_values.w, 0.0f, 1.0f);
+  result.fog.x = clamp(fog_values.x, 0.0f, 1.0f);
 
   return result;
 }

src/shaders/fog_vec4_wy.vs.cg

@@ -26,8 +26,11 @@ vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, un
   result.pos = pos;
   result.col0 = I.diffuse;
 
-  result.fog.w = fog_values.w;
-  result.fog.y = fog_values.y;
+  // Note: Compiler warnings about unused components are expected, this is intentionally part of the test.
+  // Force all the correct components of fog_values to be referenced via `clamp`. Failure to do this results in
+  // Cg generating code that copies the entire vector, causing values to be set erroneously.
+  result.fog.w = clamp(fog_values.w, 0.0f, 1.0f);
+  result.fog.y = clamp(fog_values.y, 0.0f, 1.0f);
 
   return result;
 }

src/shaders/fog_vec4_wzyx.vs.cg

@@ -26,10 +26,13 @@ vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, un
   result.pos = pos;
   result.col0 = I.diffuse;
 
-  result.fog.w = fog_values.w;
-  result.fog.z = fog_values.z;
-  result.fog.y = fog_values.y;
-  result.fog.x = fog_values.x;
+  // Note: Compiler warnings about unused components are expected, this is intentionally part of the test.
+  // Force all the correct components of fog_values to be referenced via `clamp`. Failure to do this results in
+  // Cg generating code that copies the entire vector, causing values to be set erroneously.
+  result.fog.w = clamp(fog_values.w, 0.0f, 1.0f);
+  result.fog.z = clamp(fog_values.z, 0.0f, 1.0f);
+  result.fog.y = clamp(fog_values.y, 0.0f, 1.0f);
+  result.fog.x = clamp(fog_values.x, 0.0f, 1.0f);
 
   return result;
 }

src/shaders/fog_vec4_x.vs.cg

@@ -26,7 +26,10 @@ vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, un
   result.pos = pos;
   result.col0 = I.diffuse;
 
-  result.fog.x = fog_values.x;
+  // Note: Compiler warnings about unused components are expected, this is intentionally part of the test.
+  // Force all the correct components of fog_values to be referenced via `clamp`. Failure to do this results in
+  // Cg generating code that copies the entire vector, causing values to be set erroneously.
+  result.fog.x = clamp(fog_values.x, 0.0f, 1.0f);
 
   return result;
 }

src/shaders/fog_vec4_xyzw.vs.cg

@@ -26,10 +26,13 @@ vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, un
   result.pos = pos;
   result.col0 = I.diffuse;
 
-  result.fog.x = fog_values.x;
-  result.fog.y = fog_values.y;
-  result.fog.z = fog_values.z;
-  result.fog.w = fog_values.w;
+  // Note: Compiler warnings about unused components are expected, this is intentionally part of the test.
+  // Force all the correct components of fog_values to be referenced via `clamp`. Failure to do this results in
+  // Cg generating code that copies the entire vector, causing values to be set erroneously.
+  result.fog.x = clamp(fog_values.x, 0.0f, 1.0f);
+  result.fog.y = clamp(fog_values.y, 0.0f, 1.0f);
+  result.fog.z = clamp(fog_values.z, 0.0f, 1.0f);
+  result.fog.w = clamp(fog_values.w, 0.0f, 1.0f);
 
   return result;
 }

src/shaders/fog_vec4_y.vs.cg

@@ -6,13 +6,14 @@ struct vIn {
 struct vOut {
   float4 pos : POSITION;
   float4 col0 : COLOR0;
+  float4 col1 : COLOR1;
   // cg expects this to be a single value, but will generate the correct code to manipulate a vector anyway.
   // Certain games (e.g., NFS Underground) treat oFog as a vec4, and that behavior is tested here.
   float4 fog : FOG;
 };
 
 vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, uniform float4x4 projection_matrix,
-          uniform float4 fog_values) {
+          uniform float4 fog_values, uniform float4 clamp_values, uniform float y_value_hack) {
   vOut result;
 
   // Transform position and normal
@@ -26,7 +27,18 @@ vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, un
   result.pos = pos;
   result.col0 = I.diffuse;
 
-  result.fog.y = fog_values.y;
+  // Note: Compiler warnings about unused components are expected, this is intentionally part of the test.
+  // Force all the correct components of fog_values to be referenced via `clamp`. Failure to do this results in
+  // Cg generating code that copies the entire vector, causing values to be set erroneously.
+
+  // Unfortunately in the Y case, the clamp generates
+  //   MAX(oFog,y, R0.x, c[109]);
+  // which ends up using c[109].x instead of c[109].y (c[109] = [1.0, 0.0, ...]) forcing y to always be 1.0.
+  // To work around this, the y_value is passed in through an additional uniform.
+  // Unfortunately we still need to use fog_values so it keeps its place in the transform constants, so it is assigned
+  // to specular output.
+  result.col1.r = clamp(fog_values.y, clamp_values.x, clamp_values.y);
+  result.fog.y = y_value_hack;
 
   return result;
 }

src/shaders/fog_vec4_z.vs.cg

@@ -26,7 +26,10 @@ vOut main(vIn I, uniform float4x4 model_matrix, uniform float4x4 view_matrix, un
   result.pos = pos;
   result.col0 = I.diffuse;
 
-  result.fog.z = fog_values.z;
+  // Note: Compiler warnings about unused components are expected, this is intentionally part of the test.
+  // Force all the correct components of fog_values to be referenced via `clamp`. Failure to do this results in
+  // Cg generating code that copies the entire vector, causing values to be set erroneously.
+  result.fog.z = clamp(fog_values.z, 0.0f, 1.0f);
 
   return result;
 }

src/tests/fog_tests.cpp

@@ -327,16 +327,19 @@ static constexpr uint32_t kFogVec4Z[] = {
 
 // clang format off
 static const FogVec4CoordTests::TestConfig kFogWTests[] = {
-    {"None", DEF_SHADER(kFogVec4Unset), {0.0f, 0.0f, 0.0f, 0.0f}},
+    // None just carries over the last set value.
+    //    {"None", DEF_SHADER(kFogVec4Unset), {0.0f, 0.0f, 0.0f, 0.0f}},
 
-    {"W", DEF_SHADER(kFogVec4W), {0.0f, 0.0f, 0.0f, 0.0f}},
-    {"W", DEF_SHADER(kFogVec4W), {0.0f, 0.0f, 0.0f, 1.0f}},
+    {"W", DEF_SHADER(kFogVec4W), {0.0f, 0.25f, 0.0f, 0.0f}},
+    {"W", DEF_SHADER(kFogVec4W), {0.5f, 0.5f, 0.0f, 0.0f}},
+    {"W", DEF_SHADER(kFogVec4W), {1.0f, 0.0f, 0.0f, 0.5f}},
+    {"W", DEF_SHADER(kFogVec4W), {0.3f, 0.3f, 0.3f, 1.0f}},
 
     {"WX", DEF_SHADER(kFogVec4WX), {0.25f, 0.0f, 0.0f, 0.5f}},
     {"WX", DEF_SHADER(kFogVec4WX), {0.65f, 0.0f, 0.0f, 0.0f}},
 
-    {"WY", DEF_SHADER(kFogVec4WY), {0.0f, 0.0f, 0.25f, 0.75f}},
-    {"WY", DEF_SHADER(kFogVec4WY), {0.0f, 0.0f, 0.75f, 0.25f}},
+    {"WY", DEF_SHADER(kFogVec4WY), {1.0f, 0.0f, 1.00f, 0.75f}},
+    {"WY", DEF_SHADER(kFogVec4WY), {0.0f, 0.75f, 0.75f, 0.25f}},
 
     {"WZYX", DEF_SHADER(kFogVec4WZYX), {0.25f, 0.5f, 0.75f, 1.0f}},
     {"WZYX", DEF_SHADER(kFogVec4WZYX), {1.0f, 0.75f, 0.5f, 0.25f}},
@@ -347,9 +350,11 @@ static const FogVec4CoordTests::TestConfig kFogWTests[] = {
     {"XYZW", DEF_SHADER(kFogVec4XYZW), {1.0f, 0.25f, 0.75f, 0.5f}},
     {"XYZW", DEF_SHADER(kFogVec4XYZW), {0.0f, 0.33f, 0.66f, 0.9f}},
 
-    {"Y", DEF_SHADER(kFogVec4Y), {0.0f, 4.0f, 0.0f, 0.0f}},
-    {"Y", DEF_SHADER(kFogVec4Y), {0.0f, 6.0f, 0.0f, 0.0f}},
+    {"Y", DEF_SHADER(kFogVec4Y), {0.0f, 0.0f, 0.0f, 0.0f}},
+    {"Y", DEF_SHADER(kFogVec4Y), {0.0f, 0.1f, 0.0f, 0.0f}},
+    {"Y", DEF_SHADER(kFogVec4Y), {0.0f, 0.6f, 0.0f, 0.0f}},
 
+    {"Z", DEF_SHADER(kFogVec4Z), {0.0f, 0.0f, 0.0f, 0.0f}},
     {"Z", DEF_SHADER(kFogVec4Z), {0.0f, 0.0f, 0.2f, 0.0f}},
     {"Z", DEF_SHADER(kFogVec4Z), {0.0f, 0.0f, 0.8f, 0.0f}},
 };
@@ -392,6 +397,10 @@ void FogVec4CoordTests::Test(const TestConfig& config) {
   auto shader = host_.GetShaderProgram();
   shader->SetShaderOverride(config.shader, config.shader_size);
   shader->SetUniformF(12, config.fog[0], config.fog[1], config.fog[2], config.fog[3]);
+  // const c[13] = 1 0
+  shader->SetUniformF(13, 1.0f, 0.0f);
+  // Hack for bug in Cg/vpcompiler wrt. clamp on the y-value. See fog_vec4_y.vs.cg.
+  shader->SetUniformF(14, config.fog[1]);
   host_.SetShaderProgram(shader);
 
   static constexpr uint32_t kBackgroundColor = 0xFF303030;