Specular lighting works differently on flat-shaded polys

Also lower multIndex values for smooth-shaded specular, more accurate to real hardware

Src/Graphics/New3D/Model.h

@@ -149,6 +149,7 @@ struct Mesh
 
 	// lighting
 	bool fixedShading	= false;
+	bool smoothShading	= false;
 	bool lighting		= false;
 	bool specular		= false;
 	float shininess		= 0;

Src/Graphics/New3D/New3D.cpp

@@ -1246,6 +1246,7 @@ void CNew3D::SetMeshValues(SortingMesh *currentMesh, PolyHeader &ph)
 	currentMesh->fogIntensity	= ph.LightModifier();
 	currentMesh->translatorMap	= ph.TranslatorMap();
 	currentMesh->noLosReturn	= ph.NoLosReturn();
+	currentMesh->smoothShading	= ph.SmoothShading();
 
 	if (currentMesh->textured) {
 

Src/Graphics/New3D/R3DShader.cpp

@@ -31,6 +31,7 @@ void R3DShader::Start()
 	m_noLosReturn		= false;
 	m_textureInverted	= false;
 	m_fixedShading		= false;
+	m_smoothShading		= false;
 	m_translatorMap		= false;
 	m_modelScale		= 1.0f;
 	m_nodeAlpha			= 1.0f;
@@ -132,6 +133,7 @@ bool R3DShader::LoadShader(const char* vertexShader, const char* fragmentShader)
 	m_locSpecularValue		= glGetUniformLocation(m_shaderProgram, "specularValue");
 	m_locSpecularEnabled	= glGetUniformLocation(m_shaderProgram, "specularEnabled");
 	m_locFixedShading		= glGetUniformLocation(m_shaderProgram, "fixedShading");
+	m_locSmoothShading		= glGetUniformLocation(m_shaderProgram, "smoothShading");
 	m_locTranslatorMap		= glGetUniformLocation(m_shaderProgram, "translatorMap");
 
 	m_locSpotEllipse		= glGetUniformLocation(m_shaderProgram, "spotEllipse");
@@ -294,6 +296,11 @@ void R3DShader::SetMeshUniforms(const Mesh* m)
 		m_fixedShading = m->fixedShading;
 	}
 
+	if (m_dirtyMesh || m->smoothShading != m_smoothShading) {
+		glUniform1i(m_locSmoothShading, m->smoothShading);
+		m_smoothShading = m->smoothShading;
+	}
+
 	if (m_dirtyMesh || m->translatorMap != m_translatorMap) {
 		glUniform1i(m_locTranslatorMap, m->translatorMap);
 		m_translatorMap = m->translatorMap;

Src/Graphics/New3D/R3DShader.h

@@ -67,6 +67,7 @@ private:
 	float	m_specularValue;
 	bool	m_specularEnabled;
 	bool	m_fixedShading;
+	bool	m_smoothShading;
 	bool	m_translatorMap;
 	bool	m_polyAlpha;
 	int		m_texturePage;
@@ -109,6 +110,7 @@ private:
 	GLint m_locSpecularValue;
 	GLint m_locSpecularEnabled;
 	GLint m_locFixedShading;
+	GLint m_locSmoothShading;
 
 	GLint m_locSpotEllipse;
 	GLint m_locSpotRange;

Src/Graphics/New3D/R3DShaderQuads.h

@@ -216,6 +216,7 @@ uniform float	fogStart;
 uniform float	fogAttenuation;
 uniform float	fogAmbient;
 uniform bool	fixedShading;
+uniform bool	smoothShading;
 uniform int		hardwareStep;
 uniform int		colourLayer;
 uniform bool	polyAlpha;
@@ -464,20 +465,27 @@ void main()
 		// for now assume fixed shading doesn't work with specular
 		if (specularEnabled) {
 
-			float exponent, NdotL, specularFactor;
+			float specularFactor;
-			vec4 biasIndex, expIndex, multIndex;
 
-			// Always clamp floor to zero, we don't want deep black areas
+			if (smoothShading)
-			NdotL = max(0.0,sunFactor);
+			{
+				// Always clamp floor to zero
+				float NdotL = max(0.0, sunFactor);
 
-			expIndex = vec4(8.0, 16.0, 32.0, 64.0);
+				vec4 expIndex = vec4(8.0, 16.0, 32.0, 64.0);
-			multIndex = vec4(2.0, 2.0, 3.0, 4.0);
+				vec4 multIndex = vec4(1.6, 1.6, 2.4, 3.2);
-			biasIndex = vec4(0.95, 0.95, 1.05, 1.0);
+				float exponent = expIndex[int(shininess)];
-			exponent = expIndex[int(shininess)] / biasIndex[int(shininess)];
 			
 				specularFactor = pow(NdotL, exponent);
 				specularFactor *= multIndex[int(shininess)];
-			specularFactor *= biasIndex[int(shininess)];
+			}
+			else
+			{
+				// flat shaded polys use Phong reflection model (R dot V) without any exponent or multiplier
+				// V = (0.0, 0.0, 1.0) is used by Model 3 as a fast approximation, so R dot V = R.z
+				vec3 R = reflect(-sunVector, fsViewNormal);
+				specularFactor = max(0.0, R.z);
+			}
 			
 			specularFactor *= specularValue;
 			specularFactor *= lighting[1].x;

Src/Graphics/New3D/R3DShaderTriangles.h

@@ -104,6 +104,7 @@ uniform float	fogStart;
 uniform float	fogAttenuation;
 uniform float	fogAmbient;
 uniform bool	fixedShading;
+uniform bool	smoothShading;
 uniform int		hardwareStep;
 uniform int		colourLayer;
 uniform bool	polyAlpha;
@@ -235,20 +236,27 @@ void main()
 		// for now assume fixed shading doesn't work with specular
 		if (specularEnabled) {
 
-			float exponent, NdotL, specularFactor;
+			float specularFactor;
-			vec4 biasIndex, expIndex, multIndex;
 
-			// Always clamp floor to zero, we don't want deep black areas
+			if (smoothShading)
-			NdotL = max(0.0,sunFactor);
+			{
+				// Always clamp floor to zero
+				float NdotL = max(0.0, sunFactor);
 
-			expIndex = vec4(8.0, 16.0, 32.0, 64.0);
+				vec4 expIndex = vec4(8.0, 16.0, 32.0, 64.0);
-			multIndex = vec4(2.0, 2.0, 3.0, 4.0);
+				vec4 multIndex = vec4(1.6, 1.6, 2.4, 3.2);
-			biasIndex = vec4(0.95, 0.95, 1.05, 1.0);
+				float exponent = expIndex[int(shininess)];
-			exponent = expIndex[int(shininess)] / biasIndex[int(shininess)];
 			
 				specularFactor = pow(NdotL, exponent);
 				specularFactor *= multIndex[int(shininess)];
-			specularFactor *= biasIndex[int(shininess)];
+			}
+			else
+			{
+				// flat shaded polys use Phong reflection model (R dot V) without any exponent or multiplier
+				// V = (0.0, 0.0, 1.0) is used by Model 3 as a fast approximation, so R dot V = R.z
+				vec3 R = reflect(-sunVector, fsViewNormal);
+				specularFactor = max(0.0, R.z);
+			}
 			
 			specularFactor *= specularValue;
 			specularFactor *= lighting[1].x;