Consolidate lighting calculations
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Anthony
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c722d80503
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8a5c9a6445
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@ -94,6 +94,11 @@ struct TransformInfo
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static TransformInfo View; // Vertex transformed to viewspace
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static TransformInfo Projection; // Vertex transformed to projection space
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static const int LIGHT_TYPE_NONE = 0;
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static const int LIGHT_TYPE_POINT = 1;
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static const int LIGHT_TYPE_SPOT = 2;
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static const int LIGHT_TYPE_DIRECTIONAL = 3;
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// Final lighting output
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struct LightingOutput
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{
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@ -101,155 +106,71 @@ struct LightingOutput
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TwoSidedColor Specular;
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};
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TwoSidedColor DoSpecular(const float3 toLightVN, const float3 toViewerVN, const float2 powers, const float4 lightSpecular)
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{
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TwoSidedColor Specular;
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Specular.Front = Specular.Back = float3(0, 0, 0);
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// Specular
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// Note : if (state.Modes.SpecularEnable) no longer required because when disabled, CPU sets all lightSpecular.rgb inputs to 0
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{
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// Blinn-Phong
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// https://learnopengl.com/Advanced-Lighting/Advanced-Lighting
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const float3 halfway = normalize(toViewerVN + toLightVN);
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const float NdotH = dot(View.Normal, halfway);
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const float3 frontSpecular = pow(abs(NdotH), powers[0]) * lightSpecular.rgb;
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const float3 backSpecular = pow(abs(NdotH), powers[1]) * lightSpecular.rgb;
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if (NdotH >= 0)
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Specular.Front = frontSpecular;
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else
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Specular.Back = backSpecular;
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}
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return Specular;
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}
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// useful reference https://drivers.amd.com/misc/samples/dx9/FixedFuncShader.pdf
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LightingOutput DoPointLight(const Light l, const float3 toViewerVN, const float2 powers)
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LightingOutput DoLight(const Light l, const float3 toViewerN, const float2 powers)
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{
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LightingOutput o;
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o.Diffuse.Front = o.Diffuse.Back = float3(0, 0, 0);
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o.Specular.Front = o.Specular.Back = float3(0, 0, 0);
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// Diffuse
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const float3 toLightV = l.PositionV - View.Position.xyz;
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const float lightDist = length(toLightV);
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const float3 toLightVN = normalize(toLightV);
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const float3 toLight = l.PositionV - View.Position.xyz;
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const float3 toLightN = normalize(toLight);
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float attenuation = 1;
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float spotIntensity = 1;
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// A(Constant) + A(Linear) * dist + A(Exp) * dist^2
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float attenuation =
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1 / (l.Attenuation[0]
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+ l.Attenuation[1] * lightDist
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+ l.Attenuation[2] * lightDist * lightDist);
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if (l.Type == LIGHT_TYPE_SPOT) {
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// Spotlight factors
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// https://docs.microsoft.com/en-us/windows/win32/direct3d9/light-types
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float3 toVertexN = -toLightN;
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float cosAlpha = dot(l.DirectionVN, toVertexN);
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// I = ( cos(a) - cos(phi/2) ) / ( cos(theta/2) - cos(phi/2) )
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float spotBase = saturate((cosAlpha - l.CosHalfPhi) / l.SpotIntensityDivisor);
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float spotIntensity = pow(spotBase, l.Falloff);
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}
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// Range cutoff
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if (lightDist > l.Range)
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attenuation = 0;
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if (l.Type == LIGHT_TYPE_POINT || l.Type == LIGHT_TYPE_SPOT) {
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float lightDist = length(toLight);
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const float NdotL = dot(View.Normal, toLightVN);
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const float3 lightDiffuse = abs(NdotL) * attenuation * l.Diffuse.rgb;
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// A(Constant) + A(Linear) * dist + A(Exp) * dist^2
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attenuation =
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1 / (l.Attenuation[0]
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+ l.Attenuation[1] * lightDist
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+ l.Attenuation[2] * lightDist * lightDist);
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if (NdotL >= 0)
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o.Diffuse.Front = lightDiffuse;
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else
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o.Diffuse.Back = lightDiffuse;
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// Range cutoff
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if (lightDist > l.Range)
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attenuation = 0;
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}
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// Specular
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o.Specular = DoSpecular(toLightVN, toViewerVN, powers, l.Specular);
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o.Specular.Front *= attenuation;
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o.Specular.Back *= attenuation;
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// Diffuse lighting calculation
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const float NdotLFront = dot(View.Normal, toLightN);
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const float NdotLBack = dot(-View.Normal, toLightN);
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o.Diffuse.Front = max(NdotLFront, 0) * l.Diffuse.rgb * attenuation * spotIntensity;
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o.Diffuse.Back = max(NdotLBack, 0) * l.Diffuse.rgb * attenuation * spotIntensity;
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// Specular lighting calculation
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// Note : if (state.Modes.SpecularEnable) no longer required because when disabled, CPU sets all lightSpecular.rgb inputs to 0
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// Blinn-Phong
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// https://learnopengl.com/Advanced-Lighting/Advanced-Lighting
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const float3 halfway = normalize(toViewerN + toLightN);
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const float NdotHFront = dot(View.Normal, halfway);
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const float NdotHBack = dot(-View.Normal, halfway);
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o.Specular.Front = pow(max(NdotHFront, 0), powers[0]) * l.Specular.rgb * attenuation * spotIntensity;
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o.Specular.Back = pow(max(NdotHBack, 0), powers[1]) * l.Specular.rgb * attenuation * spotIntensity;
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return o;
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}
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LightingOutput DoSpotLight(const Light l, const float3 toViewerVN, const float2 powers)
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{
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LightingOutput o;
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o.Diffuse.Front = o.Diffuse.Back = float3(0, 0, 0);
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o.Specular.Front = o.Specular.Back = float3(0, 0, 0);
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// Diffuse
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const float3 toLightV = l.PositionV - View.Position.xyz;
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const float lightDist = length(toLightV);
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const float3 toLightVN = normalize(toLightV);
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const float3 toVertexVN = -toLightVN;
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// https://docs.microsoft.com/en-us/windows/win32/direct3d9/light-types
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const float cosAlpha = dot(l.DirectionVN, toVertexVN);
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// I = ( cos(a) - cos(phi/2) ) / ( cos(theta/2) - cos(phi/2) )
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const float spotBase = saturate((cosAlpha - l.CosHalfPhi) / l.SpotIntensityDivisor);
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const float spotIntensity = pow(spotBase, l.Falloff);
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// A(Constant) + A(Linear) * dist + A(Exp) * dist^2
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float attenuation =
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1 / (l.Attenuation[0]
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+ l.Attenuation[1] * lightDist
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+ l.Attenuation[2] * lightDist * lightDist);
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// Range cutoff
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if (lightDist > l.Range)
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attenuation = 0;
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const float NdotL = dot(View.Normal, toLightVN);
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const float3 lightDiffuse = abs(NdotL) * attenuation * l.Diffuse.rgb * spotIntensity;
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if (NdotL >= 0)
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o.Diffuse.Front = lightDiffuse;
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else
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o.Diffuse.Back = lightDiffuse;
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// Specular
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o.Specular = DoSpecular(toLightVN, toViewerVN, powers, l.Specular);
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o.Specular.Front *= attenuation;
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o.Specular.Back *= attenuation;
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return o;
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}
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LightingOutput DoDirectionalLight(const Light l, const float3 toViewerVN, const float2 powers)
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{
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LightingOutput o;
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o.Diffuse.Front = o.Diffuse.Back = float3(0, 0, 0);
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o.Specular.Front = o.Specular.Back = float3(0, 0, 0);
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// Diffuse
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// Intensity from N . L
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const float3 toLightVN = -l.DirectionVN;
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const float NdotL = dot(View.Normal, toLightVN);
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const float3 lightDiffuse = abs(NdotL * l.Diffuse.rgb);
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// Apply light contribution to front or back face
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// as the case may be
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if (NdotL >= 0)
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o.Diffuse.Front = lightDiffuse;
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else
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o.Diffuse.Back = lightDiffuse;
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// Specular
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o.Specular = DoSpecular(toLightVN, toViewerVN, powers, l.Specular);
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return o;
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}
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LightingOutput CalcLighting(const float2 powers)
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{
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static const int LIGHT_TYPE_NONE = 0;
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static const int LIGHT_TYPE_POINT = 1;
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static const int LIGHT_TYPE_SPOT = 2;
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static const int LIGHT_TYPE_DIRECTIONAL = 3;
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LightingOutput totalLightOutput;
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totalLightOutput.Diffuse.Front = float3(0, 0, 0);
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totalLightOutput.Diffuse.Back = float3(0, 0, 0);
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totalLightOutput.Specular.Front = float3(0, 0, 0);
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totalLightOutput.Specular.Back = float3(0, 0, 0);
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const float3 toViewerVN = state.Modes.LocalViewer
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const float3 toViewerN = state.Modes.LocalViewer
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? float3(0, 0, -1) // Strip sample
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: normalize(-View.Position.xyz); // DoA3 character select
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@ -258,19 +179,14 @@ LightingOutput CalcLighting(const float2 powers)
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const Light currentLight = state.Lights[i];
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LightingOutput currentLightOutput;
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if(currentLight.Type == LIGHT_TYPE_POINT)
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currentLightOutput = DoPointLight(currentLight, toViewerVN, powers);
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else if(currentLight.Type == LIGHT_TYPE_SPOT)
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currentLightOutput = DoSpotLight(currentLight, toViewerVN, powers);
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else if (currentLight.Type == LIGHT_TYPE_DIRECTIONAL)
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currentLightOutput = DoDirectionalLight(currentLight, toViewerVN, powers);
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else
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continue;
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if (currentLight.Type != LIGHT_TYPE_NONE) {
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currentLightOutput = DoLight(currentLight, toViewerN, powers);
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totalLightOutput.Diffuse.Front += currentLightOutput.Diffuse.Front;
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totalLightOutput.Diffuse.Back += currentLightOutput.Diffuse.Back;
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totalLightOutput.Specular.Front += currentLightOutput.Specular.Front;
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totalLightOutput.Specular.Back += currentLightOutput.Specular.Back;
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totalLightOutput.Diffuse.Front += currentLightOutput.Diffuse.Front;
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totalLightOutput.Diffuse.Back += currentLightOutput.Diffuse.Back;
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totalLightOutput.Specular.Front += currentLightOutput.Specular.Front;
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totalLightOutput.Specular.Back += currentLightOutput.Specular.Back;
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}
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}
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return totalLightOutput;
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