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Abstracted light attenuation and direction into Light struct.

/LightweightPipelineExperimental
Felipe Lira 7 年前
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2b8e4ba4
共有 2 个文件被更改，包括 190 次插入 和 186 次删除
  1. 345
      ScriptableRenderPipeline/LightweightPipeline/LWRP/ShaderLibrary/Lighting.hlsl
  2. 31
      ScriptableRenderPipeline/LightweightPipeline/LWRP/ShaderLibrary/Shadows.hlsl

345
ScriptableRenderPipeline/LightweightPipeline/LWRP/ShaderLibrary/Lighting.hlsl
查看文件


///////////////////////////////////////////////////////////////////////////////
// Light Helpers //
///////////////////////////////////////////////////////////////////////////////
// Abstraction over Light input constants
half subtractiveModeBakedOcclusion;
half3 distanceAttenuation;
half4 distanceAttenuation;
LightInput GetMainLight()
// Abstraction over Light shading data.
struct Light
{
half3 direction;
half3 color;
half attenuation;
half realtimeAttenuation;
};
///////////////////////////////////////////////////////////////////////////////
// Attenuation Functions /
///////////////////////////////////////////////////////////////////////////////
half CookieAttenuation(float3 worldPos)
{
#ifdef _MAIN_LIGHT_COOKIE
#ifdef _MAIN_LIGHT_DIRECTIONAL
float2 cookieUV = mul(_WorldToLight, float4(worldPos, 1.0)).xy;
return SAMPLE_TEXTURE2D(_MainLightCookie, sampler_MainLightCookie, cookieUV).a;
#elif defined(_MAIN_LIGHT_SPOT)
float4 projPos = mul(_WorldToLight, float4(worldPos, 1.0));
float2 cookieUV = projPos.xy / projPos.w + 0.5;
return SAMPLE_TEXTURE2D(_MainLightCookie, sampler_MainLightCookie, cookieUV).a;
#endif // POINT LIGHT cookie not supported
#endif
return 1;
}
// Matches Unity Vanila attenuation
// Attenuation smoothly decreases to light range.
half DistanceAttenuation(half distanceSqr, half3 distanceAttenuation)
{
// We use a shared distance attenuation for additional directional and puctual lights
// for directional lights attenuation will be 1
half quadFalloff = distanceAttenuation.x;
half denom = distanceSqr * quadFalloff + 1.0;
half lightAtten = 1.0 / denom;
// We need to smoothly fade attenuation to light range. We start fading linearly at 80% of light range
// Therefore:
// fadeDistance = (0.8 * 0.8 * lightRangeSq)
// smoothFactor = (lightRangeSqr - distanceSqr) / (lightRangeSqr - fadeDistance)
// We can rewrite that to fit a MAD by doing
// distanceSqr * (1.0 / (fadeDistanceSqr - lightRangeSqr)) + (-lightRangeSqr / (fadeDistanceSqr - lightRangeSqr)
// distanceSqr * distanceAttenuation.y + distanceAttenuation.z
half smoothFactor = saturate(distanceSqr * distanceAttenuation.y + distanceAttenuation.z);
return lightAtten * smoothFactor;
}
half SpotAttenuation(half3 spotDirection, half3 lightDirection, half4 spotAttenuation)
{
// Spot Attenuation with a linear falloff can be defined as
// (SdotL - cosOuterAngle) / (cosInnerAngle - cosOuterAngle)
// This can be rewritten as
// invAngleRange = 1.0 / (cosInnerAngle - cosOuterAngle)
// SdotL * invAngleRange + (-cosOuterAngle * invAngleRange)
// SdotL * spotAttenuation.x + spotAttenuation.y
// If we precompute the terms in a MAD instruction
half SdotL = dot(spotDirection, lightDirection);
half atten = saturate(SdotL * spotAttenuation.x + spotAttenuation.y);
return atten * atten;
}
half4 GetLightDirectionAndRealtimeAttenuation(LightInput lightInput, float3 positionWS)
{
half4 directionAndAttenuation;
float3 posToLightVec = lightInput.position.xyz - positionWS * lightInput.position.w;
float distanceSqr = max(dot(posToLightVec, posToLightVec), 0.001);
directionAndAttenuation.xyz = half3(posToLightVec * rsqrt(distanceSqr));
directionAndAttenuation.w = DistanceAttenuation(distanceSqr, lightInput.distanceAttenuation.xyz);
directionAndAttenuation.w *= SpotAttenuation(lightInput.spotDirection.xyz, directionAndAttenuation.xyz, lightInput.spotAttenuation);
return directionAndAttenuation;
}
half4 GetMainLightDirectionAndRealtimeAttenuation(LightInput lightInput, float3 positionWS)
{
half4 directionAndAttenuation;
#if defined(_MAIN_LIGHT_DIRECTIONAL)
directionAndAttenuation = half4(lightInput.position.xyz, 1.0);
#else
directionAndAttenuation = GetLightDirectionAndRealtimeAttenuation(lightInput, positionWS);
#endif
// Cookies and shadows are only computed for main light
directionAndAttenuation.w *= CookieAttenuation(positionWS);
directionAndAttenuation.w *= RealtimeShadowAttenuation(positionWS);
return directionAndAttenuation;
}
Light GetMainLight(half3 positionWS)
LightInput light;
light.position = _MainLightPosition;
light.color = _MainLightColor.rgb;
light.subtractiveModeBakedOcclusion = _MainLightDistanceAttenuation.w;
light.distanceAttenuation = _MainLightDistanceAttenuation.xyz;
light.spotDirection = _MainLightSpotDir;
light.spotAttenuation = _MainLightSpotAttenuation;
LightInput lightInput;
lightInput.position = _MainLightPosition;
lightInput.color = _MainLightColor.rgb;
lightInput.distanceAttenuation = _MainLightDistanceAttenuation;
lightInput.spotDirection = _MainLightSpotDir;
lightInput.spotAttenuation = _MainLightSpotAttenuation;
half4 directionAndRealtimeAttenuation = GetMainLightDirectionAndRealtimeAttenuation(lightInput, positionWS);
Light light;
light.direction = directionAndRealtimeAttenuation.xyz;
light.realtimeAttenuation = directionAndRealtimeAttenuation.w;
light.attenuation = MixRealtimeAndBakedOcclusion(light.realtimeAttenuation, lightInput.distanceAttenuation.w);
light.color = lightInput.color;
LightInput GetLight(int i)
Light GetLight(int i, half3 positionWS)
LightInput light;
LightInput lightInput;
light.position = _AdditionalLightPosition[lightIndex];
light.color = _AdditionalLightColor[lightIndex].rgb;
light.subtractiveModeBakedOcclusion = _AdditionalLightDistanceAttenuation[lightIndex].w;
light.distanceAttenuation = _AdditionalLightDistanceAttenuation[lightIndex].xyz;
light.spotDirection = _AdditionalLightSpotDir[lightIndex];
light.spotAttenuation = _AdditionalLightSpotAttenuation[lightIndex];
lightInput.position = _AdditionalLightPosition[lightIndex];
lightInput.color = _AdditionalLightColor[lightIndex].rgb;
lightInput.distanceAttenuation = _AdditionalLightDistanceAttenuation[lightIndex];
lightInput.spotDirection = _AdditionalLightSpotDir[lightIndex];
lightInput.spotAttenuation = _AdditionalLightSpotAttenuation[lightIndex];
half4 directionAndRealtimeAttenuation = GetLightDirectionAndRealtimeAttenuation(lightInput, positionWS);
Light light;
light.direction = directionAndRealtimeAttenuation.xyz;
light.realtimeAttenuation = directionAndRealtimeAttenuation.w;
light.attenuation = MixRealtimeAndBakedOcclusion(light.realtimeAttenuation, lightInput.distanceAttenuation.w);
light.color = lightInput.color;
return light;
}

return _GlossyEnvironmentColor.rgb * occlusion;
}
half3 SubtractDirectMainLightFromLightmap(Light mainLight, half3 normalWS, half3 bakedGI)
{
#if defined(_MAIN_LIGHT_DIRECTIONAL) && defined(_MIXED_LIGHTING_SUBTRACTIVE) && defined(LIGHTMAP_ON) && defined(_SHADOWS_ENABLED)
// Let's try to make realtime shadows work on a surface, which already contains
// baked lighting and shadowing from the main sun light.
// Summary:
// 1) Calculate possible value in the shadow by subtracting estimated light contribution from the places occluded by realtime shadow:
// a) preserves other baked lights and light bounces
// b) eliminates shadows on the geometry facing away from the light
// 2) Clamp against user defined ShadowColor.
// 3) Pick original lightmap value, if it is the darkest one.
// 1) Gives good estimate of illumination as if light would've been shadowed during the bake.
// Preserves bounce and other baked lights
// No shadows on the geometry facing away from the light
half shadowStrength = _ShadowData.x;
half NdotL = saturate(dot(mainLight.direction, normalWS));
half3 lambert = mainLight.color * NdotL;
half3 estimatedLightContributionMaskedByInverseOfShadow = lambert * (1.0 - mainLight.realtimeAttenuation);
half3 subtractedLightmap = bakedGI - estimatedLightContributionMaskedByInverseOfShadow;
// 2) Allows user to define overall ambient of the scene and control situation when realtime shadow becomes too dark.
half3 realtimeShadow = max(subtractedLightmap, _SubtractiveShadowColor.xyz);
realtimeShadow = lerp(bakedGI, realtimeShadow, shadowStrength);
// 3) Pick darkest color
return min(bakedGI, realtimeShadow);
#endif
return bakedGI;
}
///////////////////////////////////////////////////////////////////////////////
// BRDF Functions //
///////////////////////////////////////////////////////////////////////////////

}
///////////////////////////////////////////////////////////////////////////////
// Attenuation Functions /
///////////////////////////////////////////////////////////////////////////////
half CookieAttenuation(float3 worldPos)
{
#ifdef _MAIN_LIGHT_COOKIE
#ifdef _MAIN_LIGHT_DIRECTIONAL
float2 cookieUV = mul(_WorldToLight, float4(worldPos, 1.0)).xy;
return SAMPLE_TEXTURE2D(_MainLightCookie, sampler_MainLightCookie, cookieUV).a;
#elif defined(_MAIN_LIGHT_SPOT)
float4 projPos = mul(_WorldToLight, float4(worldPos, 1.0));
float2 cookieUV = projPos.xy / projPos.w + 0.5;
return SAMPLE_TEXTURE2D(_MainLightCookie, sampler_MainLightCookie, cookieUV).a;
#endif // POINT LIGHT cookie not supported
#endif
return 1;
}
// Matches Unity Vanila attenuation
// Attenuation smoothly decreases to light range.
half DistanceAttenuation(half distanceSqr, half3 distanceAttenuation)
{
// We use a shared distance attenuation for additional directional and puctual lights
// for directional lights attenuation will be 1
half quadFalloff = distanceAttenuation.x;
half denom = distanceSqr * quadFalloff + 1.0;
half lightAtten = 1.0 / denom;
// We need to smoothly fade attenuation to light range. We start fading linearly at 80% of light range
// Therefore:
// fadeDistance = (0.8 * 0.8 * lightRangeSq)
// smoothFactor = (lightRangeSqr - distanceSqr) / (lightRangeSqr - fadeDistance)
// We can rewrite that to fit a MAD by doing
// distanceSqr * (1.0 / (fadeDistanceSqr - lightRangeSqr)) + (-lightRangeSqr / (fadeDistanceSqr - lightRangeSqr)
// distanceSqr * distanceAttenuation.y + distanceAttenuation.z
half smoothFactor = saturate(distanceSqr * distanceAttenuation.y + distanceAttenuation.z);
return lightAtten * smoothFactor;
}
half SpotAttenuation(half3 spotDirection, half3 lightDirection, half4 spotAttenuation)
{
// Spot Attenuation with a linear falloff can be defined as
// (SdotL - cosOuterAngle) / (cosInnerAngle - cosOuterAngle)
// This can be rewritten as
// invAngleRange = 1.0 / (cosInnerAngle - cosOuterAngle)
// SdotL * invAngleRange + (-cosOuterAngle * invAngleRange)
// SdotL * spotAttenuation.x + spotAttenuation.y
// If we precompute the terms in a MAD instruction
half SdotL = dot(spotDirection, lightDirection);
half atten = saturate(SdotL * spotAttenuation.x + spotAttenuation.y);
return atten * atten;
}
inline half GetLightDirectionAndRealtimeAttenuation(LightInput lightInput, float3 positionWS, out half3 lightDirection)
{
float3 posToLightVec = lightInput.position.xyz - positionWS * lightInput.position.w;
float distanceSqr = max(dot(posToLightVec, posToLightVec), 0.001);
// normalized light dir
lightDirection = half3(posToLightVec * rsqrt(distanceSqr));
half lightAtten = DistanceAttenuation(distanceSqr, lightInput.distanceAttenuation);
lightAtten *= SpotAttenuation(lightInput.spotDirection.xyz, lightDirection, lightInput.spotAttenuation);
return lightAtten;
}
inline half GetMainLightDirectionAndRealtimeAttenuation(LightInput lightInput, float3 positionWS, out half3 lightDirection)
{
#if defined(_MAIN_LIGHT_DIRECTIONAL)
// Light pos holds normalized light dir
lightDirection = lightInput.position.xyz;
half attenuation = 1.0;
#else
half attenuation = GetLightDirectionAndRealtimeAttenuation(lightInput, positionWS, lightDirection);
#endif
// Cookies and shadows are only computed for main light
attenuation *= CookieAttenuation(positionWS);
attenuation *= RealtimeShadowAttenuation(positionWS);
return attenuation;
}
///////////////////////////////////////////////////////////////////////////////
// Lighting Functions //
///////////////////////////////////////////////////////////////////////////////
half3 LightingLambert(half3 lightColor, half3 lightDir, half3 normal)

return EnvironmentBRDF(brdfData, indirectDiffuse, indirectSpecular, fresnelTerm);
}
half3 ShadeLight(BRDFData brdfData, half3 lightColor, half3 lightDirectionWS, half lightAttenuation, half3 normalWS, half3 positionWS, half3 viewDirectionWS)
half3 ShadeLight(BRDFData brdfData, half3 lightColor, half3 lightDirectionWS, half lightAttenuation, half3 normalWS, half3 viewDirectionWS)
{
half NdotL = saturate(dot(normalWS, lightDirectionWS));
half3 radiance = lightColor * (lightAttenuation * NdotL);

half3 ShadeLight(BRDFData brdfData, LightInput light, half3 normalWS, half3 positionWS, half3 viewDirectionWS)
{
half3 lightDirectionWS;
half lightAttenuation = GetLightDirectionAndRealtimeAttenuation(light, positionWS, /*out*/ lightDirectionWS);
lightAttenuation = MixRealtimeAndBakedOcclusion(lightAttenuation, light.subtractiveModeBakedOcclusion);
return ShadeLight(brdfData, light.color, lightDirectionWS, lightAttenuation, normalWS, positionWS, viewDirectionWS);
}
half3 ShadeMainLight(BRDFData brdfData, half3 normalWS, half3 positionWS, half3 viewDirectionWS)
half3 ShadeLight(BRDFData brdfData, Light light, half3 normalWS, half3 viewDirectionWS)
LightInput mainLight = GetMainLight();
half3 lightDirectionWS;
half lightAttenuation = GetMainLightDirectionAndRealtimeAttenuation(mainLight, positionWS, /*out*/ lightDirectionWS);
lightAttenuation = MixRealtimeAndBakedOcclusion(lightAttenuation, mainLight.subtractiveModeBakedOcclusion);
return ShadeLight(brdfData, mainLight.color, lightDirectionWS, lightAttenuation, normalWS, positionWS, viewDirectionWS);
return ShadeLight(brdfData, light.color, light.direction, light.attenuation, normalWS, viewDirectionWS);
}
half3 VertexLighting(float3 positionWS, half3 normalWS)

int vertexLightEnd = min(_AdditionalLightCount.y, unity_LightIndicesOffsetAndCount.y);
for (int lightIter = vertexLightStart; lightIter < vertexLightEnd; ++lightIter)
{
LightInput light = GetLight(lightIter);
Light light = GetLight(lightIter, positionWS);
half3 lightDirection;
half atten = GetLightDirectionAndRealtimeAttenuation(light, positionWS, lightDirection);
half3 lightColor = light.color * atten;
vertexLightColor += LightingLambert(lightColor, lightDirection, normalWS);
half3 lightColor = light.color * light.realtimeAttenuation;
vertexLightColor += LightingLambert(lightColor, light.direction, normalWS);
}
#endif

BRDFData brdfData;
InitializeBRDFData(albedo, metallic, specular, smoothness, alpha, brdfData);
Light mainLight = GetMainLight(positionWS);
bakedGI = SubtractDirectMainLightFromLightmap(mainLight, normalWS, bakedGI);
color += ShadeMainLight(brdfData, normalWS, positionWS, viewDirectionWS);
color += ShadeLight(brdfData, mainLight, normalWS, viewDirectionWS);
for (int lightIter = 0; lightIter < pixelLightCount; ++lightIter)
for (int i = 0; i < pixelLightCount; ++i)
LightInput light = GetLight(lightIter);
color += ShadeLight(brdfData, light, normalWS, positionWS, viewDirectionWS);
Light light = GetLight(i, positionWS);
color += ShadeLight(brdfData, light, normalWS, viewDirectionWS);
}
#endif

{
half3 lightDirection;
LightInput mainLight = GetMainLight();
half realtimeMainLightAtten = GetMainLightDirectionAndRealtimeAttenuation(mainLight, positionWS, lightDirection);
half3 NdotL = saturate(dot(normalWS, lightDirection));
Light mainLight = GetMainLight(positionWS);
half3 NdotL = saturate(dot(normalWS, mainLight.direction));
half3 indirectDiffuse = bakedGI;
half mainLightAtten = MixRealtimeAndBakedOcclusion(realtimeMainLightAtten, mainLight.subtractiveModeBakedOcclusion);
half3 diffuseColor = lambert * mainLightAtten + indirectDiffuse;
half3 indirectDiffuse = SubtractDirectMainLightFromLightmap(mainLight, normalWS, bakedGI);
half3 diffuseColor = lambert * mainLight.attenuation + indirectDiffuse;
for (int lightIter = 0; lightIter < pixelLightCount; ++lightIter)
for (int i = 0; i < pixelLightCount; ++i)
LightInput light = GetLight(lightIter);
half lightAttenuation = GetLightDirectionAndRealtimeAttenuation(light, positionWS, lightDirection);
lightAttenuation = MixRealtimeAndBakedOcclusion(lightAttenuation, light.subtractiveModeBakedOcclusion);
half3 attenuatedLightColor = light.color * lightAttenuation;
Light light = GetLight(i, positionWS);
half3 attenuatedLightColor = light.color * light.attenuation;
diffuseColor += LightingLambert(attenuatedLightColor, lightDirection, normalWS);
}
#endif

{
half3 lightDirection;
LightInput mainLight = GetMainLight();
half realtimeMainLightAtten = GetMainLightDirectionAndRealtimeAttenuation(mainLight, positionWS, lightDirection);
half3 NdotL = saturate(dot(normalWS, lightDirection));
Light mainLight = GetMainLight(positionWS);
half3 NdotL = saturate(dot(normalWS, mainLight.direction));
half3 indirectDiffuse = bakedGI;
half mainLightAtten = MixRealtimeAndBakedOcclusion(realtimeMainLightAtten, mainLight.subtractiveModeBakedOcclusion);
half3 diffuseColor = lambert * mainLightAtten + indirectDiffuse;
half3 specularColor = LightingSpecular(mainLight.color * mainLightAtten, lightDirection, normalWS, viewDirectionWS, specularGloss, shininess);
half3 indirectDiffuse = SubtractDirectMainLightFromLightmap(mainLight, normalWS, bakedGI);
half3 diffuseColor = lambert * mainLight.attenuation + indirectDiffuse;
half3 specularColor = LightingSpecular(mainLight.color * mainLight.attenuation, mainLight.direction, normalWS, viewDirectionWS, specularGloss, shininess);
for (int lightIter = 0; lightIter < pixelLightCount; ++lightIter)
for (int i = 0; i < pixelLightCount; ++i)
LightInput light = GetLight(lightIter);
half lightAttenuation = GetLightDirectionAndRealtimeAttenuation(light, positionWS, lightDirection);
lightAttenuation = MixRealtimeAndBakedOcclusion(lightAttenuation, light.subtractiveModeBakedOcclusion);
half3 attenuatedLightColor = light.color * lightAttenuation;
diffuseColor += LightingLambert(attenuatedLightColor, lightDirection, normalWS);
specularColor += LightingSpecular(attenuatedLightColor, lightDirection, normalWS, viewDirectionWS, specularGloss, shininess);
Light light = GetLight(i, positionWS);
half3 attenuatedLightColor = light.color * light.attenuation;
diffuseColor += LightingLambert(attenuatedLightColor, light.direction, normalWS);
specularColor += LightingSpecular(attenuatedLightColor, light.direction, normalWS, viewDirectionWS, specularGloss, shininess);
}
#endif

31
ScriptableRenderPipeline/LightweightPipeline/LWRP/ShaderLibrary/Shadows.hlsl
查看文件


return realtimeAttenuation;
}
inline half3 SubtractDirectMainLightFromLightmap(half3 bakedGI, half attenuation, half3 lambert)
{
#if defined(_MIXED_LIGHTING_SUBTRACTIVE) && defined(LIGHTMAP_ON) && defined(_SHADOWS_ENABLED)
// Let's try to make realtime shadows work on a surface, which already contains
// baked lighting and shadowing from the main sun light.
// Summary:
// 1) Calculate possible value in the shadow by subtracting estimated light contribution from the places occluded by realtime shadow:
// a) preserves other baked lights and light bounces
// b) eliminates shadows on the geometry facing away from the light
// 2) Clamp against user defined ShadowColor.
// 3) Pick original lightmap value, if it is the darkest one.
// 1) Gives good estimate of illumination as if light would've been shadowed during the bake.
// Preserves bounce and other baked lights
// No shadows on the geometry facing away from the light
half shadowStrength = _ShadowData.x;
half3 estimatedLightContributionMaskedByInverseOfShadow = lambert * (1.0 - attenuation);
half3 subtractedLightmap = bakedGI - estimatedLightContributionMaskedByInverseOfShadow;
// 2) Allows user to define overall ambient of the scene and control situation when realtime shadow becomes too dark.
half3 realtimeShadow = max(subtractedLightmap, _SubtractiveShadowColor.xyz);
realtimeShadow = lerp(bakedGI, realtimeShadow, shadowStrength);
// 3) Pick darkest color
return min(bakedGI, realtimeShadow);
#endif
return bakedGI;
}
#endif
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