<URP>/ShaderLibrary/RealtimeLights.hlsl full source
#ifndef UNIVERSAL_REALTIME_LIGHTS_INCLUDED
#define UNIVERSAL_REALTIME_LIGHTS_INCLUDED
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/AmbientOcclusion.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/LightCookie/LightCookie.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Clustering.hlsl"
// Abstraction over Light shading data.
struct Light
{
half3 direction;
half3 color;
float distanceAttenuation; // full-float precision required on some platforms
half shadowAttenuation;
uint layerMask;
};
#if USE_CLUSTER_LIGHT_LOOP && defined(LIGHTMAP_ON) && defined(LIGHTMAP_SHADOW_MIXING)
#define CLUSTER_LIGHT_LOOP_SUBTRACTIVE_LIGHT_CHECK if (_AdditionalLightsColor[lightIndex].a > 0.0h) continue;
#else
#define CLUSTER_LIGHT_LOOP_SUBTRACTIVE_LIGHT_CHECK
#endif
#if defined(UNITY_PLATFORM_META_QUEST) && META_QUEST_LIGHTUNROLL
#define UNROLL_ONELIGHT [unroll(1)]
#else
#define UNROLL_ONELIGHT
#endif
#if USE_CLUSTER_LIGHT_LOOP
#define LIGHT_LOOP_BEGIN(lightCount) { \
uint lightIndex; \
ClusterIterator _urp_internal_clusterIterator = ClusterInit(inputData.normalizedScreenSpaceUV, inputData.positionWS, 0); \
[loop] while (ClusterNext(_urp_internal_clusterIterator, lightIndex)) { \
lightIndex += URP_FP_DIRECTIONAL_LIGHTS_COUNT; \
CLUSTER_LIGHT_LOOP_SUBTRACTIVE_LIGHT_CHECK
#define LIGHT_LOOP_END } }
#else
#define LIGHT_LOOP_BEGIN(lightCount) \
UNROLL_ONELIGHT \
for (uint lightIndex = 0u; lightIndex < lightCount; ++lightIndex) {
#define LIGHT_LOOP_END }
#endif
///////////////////////////////////////////////////////////////////////////////
// Attenuation Functions /
///////////////////////////////////////////////////////////////////////////////
// Matches Unity Vanilla HINT_NICE_QUALITY attenuation
// Attenuation smoothly decreases to light range.
float DistanceAttenuation(float distanceSqr, half2 distanceAttenuation)
{
// We use a shared distance attenuation for additional directional and puctual lights
// for directional lights attenuation will be 1
float lightAtten = rcp(distanceSqr);
float2 distanceAttenuationFloat = float2(distanceAttenuation);
// Use the smoothing factor also used in the Unity lightmapper.
half factor = half(distanceSqr * distanceAttenuationFloat.x);
half smoothFactor = saturate(half(1.0) - factor * factor);
smoothFactor = smoothFactor * smoothFactor;
return lightAtten * smoothFactor;
}
half AngleAttenuation(half3 spotDirection, half3 lightDirection, half2 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;
}
///////////////////////////////////////////////////////////////////////////////
// Light Abstraction //
///////////////////////////////////////////////////////////////////////////////
Light GetMainLight()
{
Light light;
light.direction = half3(_MainLightPosition.xyz);
#if USE_CLUSTER_LIGHT_LOOP
#if defined(LIGHTMAP_ON) && defined(LIGHTMAP_SHADOW_MIXING)
light.distanceAttenuation = _MainLightColor.a;
#else
light.distanceAttenuation = 1.0;
#endif
#else
light.distanceAttenuation = unity_LightData.z; // unity_LightData.z is 1 when not culled by the culling mask, otherwise 0.
#endif
light.shadowAttenuation = 1.0;
light.color = _MainLightColor.rgb;
light.layerMask = _MainLightLayerMask;
return light;
}
Light GetMainLight(float4 shadowCoord)
{
Light light = GetMainLight();
light.shadowAttenuation = MainLightRealtimeShadow(shadowCoord);
return light;
}
Light GetMainLight(float4 shadowCoord, float3 positionWS, half4 shadowMask)
{
Light light = GetMainLight();
light.shadowAttenuation = MainLightShadow(shadowCoord, positionWS, shadowMask, _MainLightOcclusionProbes);
#if defined(_LIGHT_COOKIES)
real3 cookieColor = SampleMainLightCookie(positionWS);
light.color *= cookieColor;
#endif
return light;
}
Light GetMainLight(InputData inputData, half4 shadowMask, AmbientOcclusionFactor aoFactor)
{
Light light = GetMainLight(inputData.shadowCoord, inputData.positionWS, shadowMask);
#if defined(_SCREEN_SPACE_OCCLUSION) && !defined(_SURFACE_TYPE_TRANSPARENT)
if (IsLightingFeatureEnabled(DEBUGLIGHTINGFEATUREFLAGS_AMBIENT_OCCLUSION))
{
light.color *= aoFactor.directAmbientOcclusion;
}
#endif
return light;
}
// Fills a light struct given a perObjectLightIndex
Light GetAdditionalPerObjectLight(int perObjectLightIndex, float3 positionWS)
{
// Abstraction over Light input constants
#if USE_STRUCTURED_BUFFER_FOR_LIGHT_DATA
float4 lightPositionWS = _AdditionalLightsBuffer[perObjectLightIndex].position;
half3 color = _AdditionalLightsBuffer[perObjectLightIndex].color.rgb;
half4 distanceAndSpotAttenuation = _AdditionalLightsBuffer[perObjectLightIndex].attenuation;
half4 spotDirection = _AdditionalLightsBuffer[perObjectLightIndex].spotDirection;
uint lightLayerMask = _AdditionalLightsBuffer[perObjectLightIndex].layerMask;
#else
float4 lightPositionWS = _AdditionalLightsPosition[perObjectLightIndex];
half3 color = _AdditionalLightsColor[perObjectLightIndex].rgb;
half4 distanceAndSpotAttenuation = _AdditionalLightsAttenuation[perObjectLightIndex];
half4 spotDirection = _AdditionalLightsSpotDir[perObjectLightIndex];
uint lightLayerMask = asuint(_AdditionalLightsLayerMasks[perObjectLightIndex]);
#endif
// Directional lights store direction in lightPosition.xyz and have .w set to 0.0.
// This way the following code will work for both directional and punctual lights.
float3 lightVector = lightPositionWS.xyz - positionWS * lightPositionWS.w;
float distanceSqr = max(dot(lightVector, lightVector), HALF_MIN);
half3 lightDirection = half3(lightVector * rsqrt(distanceSqr));
// full-float precision required on some platforms
#if (META_QUEST_NO_SPOTLIGHTS_LIGHT_LOOP)
float attenuation = DistanceAttenuation(distanceSqr, distanceAndSpotAttenuation.xy);
#else
float attenuation = DistanceAttenuation(distanceSqr, distanceAndSpotAttenuation.xy) * AngleAttenuation(spotDirection.xyz, lightDirection, distanceAndSpotAttenuation.zw);
#endif
Light light;
light.direction = lightDirection;
light.distanceAttenuation = attenuation;
light.shadowAttenuation = 1.0; // This value can later be overridden in GetAdditionalLight(uint i, float3 positionWS, half4 shadowMask)
light.color = color;
light.layerMask = lightLayerMask;
return light;
}
uint GetPerObjectLightIndexOffset()
{
#if USE_STRUCTURED_BUFFER_FOR_LIGHT_DATA
return uint(unity_LightData.x);
#else
return 0;
#endif
}
// Returns a per-object index given a loop index.
// This abstract the underlying data implementation for storing lights/light indices
int GetPerObjectLightIndex(uint index)
{
/////////////////////////////////////////////////////////////////////////////////////////////
// Structured Buffer Path /
// /
// Lights and light indices are stored in StructuredBuffer. We can just index them. /
// Currently all non-mobile platforms take this path :( /
// There are limitation in mobile GPUs to use SSBO (performance / no vertex shader support) /
/////////////////////////////////////////////////////////////////////////////////////////////
#if USE_STRUCTURED_BUFFER_FOR_LIGHT_DATA
uint offset = uint(unity_LightData.x);
return _AdditionalLightsIndices[offset + index];
/////////////////////////////////////////////////////////////////////////////////////////////
// UBO path /
// /
// We store 8 light indices in half4 unity_LightIndices[2]; /
// Due to memory alignment unity doesn't support int[] or float[] /
// Even trying to reinterpret cast the unity_LightIndices to float[] won't work /
// it will cast to float4[] and create extra register pressure. :( /
/////////////////////////////////////////////////////////////////////////////////////////////
#else
// since index is uint shader compiler will implement
// div & mod as bitfield ops (shift and mask).
// TODO: Can we index a float4? Currently compiler is
// replacing unity_LightIndicesX[i] with a dp4 with identity matrix.
// u_xlat16_40 = dot(unity_LightIndices[int(u_xlatu13)], ImmCB_0_0_0[u_xlati1]);
// This increases both arithmetic and register pressure.
//
// NOTE: min16float4 bug workaround.
// Take the "vec4" part into float4 tmp variable in order to force float4 math.
// It appears indexing half4 as min16float4 on DX11 can fail. (dp4 {min16f})
float4 tmp = unity_LightIndices[index / 4];
return int(tmp[index % 4]);
#endif
}
// Fills a light struct given a loop i index. This will convert the i
// index to a perObjectLightIndex
Light GetAdditionalLight(uint i, float3 positionWS)
{
#if USE_CLUSTER_LIGHT_LOOP
int lightIndex = i;
#else
int lightIndex = GetPerObjectLightIndex(i);
#endif
return GetAdditionalPerObjectLight(lightIndex, positionWS);
}
Light GetAdditionalLight(uint i, float3 positionWS, half4 shadowMask)
{
#if USE_CLUSTER_LIGHT_LOOP
int lightIndex = i;
#else
int lightIndex = GetPerObjectLightIndex(i);
#endif
Light light = GetAdditionalPerObjectLight(lightIndex, positionWS);
#if USE_STRUCTURED_BUFFER_FOR_LIGHT_DATA
half4 occlusionProbeChannels = _AdditionalLightsBuffer[lightIndex].occlusionProbeChannels;
#else
half4 occlusionProbeChannels = _AdditionalLightsOcclusionProbes[lightIndex];
#endif
light.shadowAttenuation = AdditionalLightShadow(lightIndex, positionWS, light.direction, shadowMask, occlusionProbeChannels);
#if defined(_LIGHT_COOKIES)
real3 cookieColor = SampleAdditionalLightCookie(lightIndex, positionWS);
light.color *= cookieColor;
#endif
return light;
}
Light GetAdditionalLight(uint i, InputData inputData, half4 shadowMask, AmbientOcclusionFactor aoFactor)
{
Light light = GetAdditionalLight(i, inputData.positionWS, shadowMask);
#if defined(_SCREEN_SPACE_OCCLUSION) && !defined(_SURFACE_TYPE_TRANSPARENT)
if (IsLightingFeatureEnabled(DEBUGLIGHTINGFEATUREFLAGS_AMBIENT_OCCLUSION))
{
light.color *= aoFactor.directAmbientOcclusion;
}
#endif
return light;
}
int GetAdditionalLightsCount()
{
#if USE_CLUSTER_LIGHT_LOOP
// Counting the number of lights in clustered requires traversing the bit list, and is not needed up front.
return 0;
#else
// TODO: we need to expose in SRP api an ability for the pipeline cap the amount of lights
// in the culling. This way we could do the loop branch with an uniform
// This would be helpful to support baking exceeding lights in SH as well
return int(min(_AdditionalLightsCount.x, unity_LightData.y));
#endif
}
half4 CalculateShadowMask(InputData inputData)
{
// To ensure backward compatibility we have to avoid using shadowMask input, as it is not present in older shaders
#if defined(SHADOWS_SHADOWMASK) && defined(LIGHTMAP_ON)
half4 shadowMask = inputData.shadowMask; // Shadowmask was sampled from lightmap
#elif !defined(LIGHTMAP_ON) && (defined(PROBE_VOLUMES_L1) || defined(PROBE_VOLUMES_L2))
half4 shadowMask = inputData.shadowMask; // Shadowmask (probe occlusion) was sampled from APV
#elif !defined (LIGHTMAP_ON)
half4 shadowMask = unity_ProbesOcclusion; // Sample shadowmask (probe occlusion) from legacy probes
#else
half4 shadowMask = half4(1, 1, 1, 1); // Fallback shadowmask, fully unoccluded
#endif
return shadowMask;
}
#endif