304 lines
8.0 KiB
HLSL
304 lines
8.0 KiB
HLSL
#include "Macros.fxh" //from FNA
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static const float PI = 3.141592653589793;
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static const int MAX_POINT_LIGHTS = 64;
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static const int NUM_SHADOW_CASCADES = 4;
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DECLARE_TEXTURE(gPosition, 0);
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DECLARE_TEXTURE(gAlbedo, 1);
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DECLARE_TEXTURE(gNormal, 2);
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DECLARE_TEXTURE(gMetallicRoughness, 3);
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DECLARE_TEXTURE(shadowMapOne, 4);
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DECLARE_TEXTURE(shadowMapTwo, 5);
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DECLARE_TEXTURE(shadowMapThree, 6);
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DECLARE_TEXTURE(shadowMapFour, 7);
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BEGIN_CONSTANTS
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float3 EyePosition _ps(c0) _cb(c0);
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float3 PointLightPositions[MAX_POINT_LIGHTS] _ps(c1) _cb(c1);
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float3 PointLightColors[MAX_POINT_LIGHTS] _ps(c65) _cb(c65);
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float3 DirectionalLightDirection _ps(c129) _cb(c129);
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float3 DirectionalLightColor _ps(c130) _cb(c130);
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float CascadeFarPlanes[NUM_SHADOW_CASCADES] _ps(c131) _cb(c131);
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MATRIX_CONSTANTS
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float4x4 LightSpaceMatrixOne _ps(c135) _cb(c135);
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float4x4 LightSpaceMatrixTwo _ps(c139) _cb(c139);
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float4x4 LightSpaceMatrixThree _ps(c143) _cb(c143);
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float4x4 LightSpaceMatrixFour _ps(c147) _cb(c147);
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// used to select shadow cascade
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float4x4 ViewMatrix _ps(c151) _cb(c151);
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END_CONSTANTS
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struct VertexInput
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{
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float4 Position : POSITION;
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float2 TexCoord : TEXCOORD;
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};
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struct PixelInput
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{
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float4 Position : SV_POSITION;
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float2 TexCoord : TEXCOORD0;
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};
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PixelInput main_vs(VertexInput input)
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{
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PixelInput output;
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output.Position = input.Position;
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output.TexCoord = input.TexCoord;
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return output;
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}
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// Pixel Shader
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float3 FresnelSchlick(float cosTheta, float3 F0)
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{
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return F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
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}
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float DistributionGGX(float3 N, float3 H, float roughness)
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{
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float a = roughness * roughness;
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float a2 = a * a;
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float NdotH = max(dot(N, H), 0.0);
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float NdotH2 = NdotH * NdotH;
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float num = a2;
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float denom = (NdotH2 * (a2 - 1.0) + 1.0);
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denom = PI * denom * denom;
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return num / denom;
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}
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float GeometrySchlickGGX(float NdotV, float roughness)
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{
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float r = (roughness + 1.0);
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float k = (r * r) / 8.0;
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float num = NdotV;
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float denom = NdotV * (1.0 - k) + k;
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return num / denom;
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}
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float GeometrySmith(float3 N, float3 V, float3 L, float roughness)
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{
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float NdotV = max(dot(N, V), 0.0);
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float NdotL = max(dot(N, L), 0.0);
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float ggx2 = GeometrySchlickGGX(NdotV, roughness);
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float ggx1 = GeometrySchlickGGX(NdotL, roughness);
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return ggx1 * ggx2;
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}
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float ComputeShadow(float3 positionWorldSpace, float3 N, float L)
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{
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float bias = 0.005 * tan(acos(dot(N, L)));
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bias = clamp(bias, 0, 0.01);
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float4 positionCameraSpace = mul(float4(positionWorldSpace, 1.0), ViewMatrix);
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int shadowCascadeIndex = 0; // 0 is closest
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for (int i = 0; i < NUM_SHADOW_CASCADES; i++)
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{
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if (abs(positionCameraSpace.z) < CascadeFarPlanes[i])
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{
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shadowCascadeIndex = i;
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break;
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}
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}
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float4x4 lightSpaceMatrix;
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if (shadowCascadeIndex == 0)
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{
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lightSpaceMatrix = LightSpaceMatrixOne;
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}
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else if (shadowCascadeIndex == 1)
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{
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lightSpaceMatrix = LightSpaceMatrixTwo;
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}
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else if (shadowCascadeIndex == 2)
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{
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lightSpaceMatrix = LightSpaceMatrixThree;
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}
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else
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{
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lightSpaceMatrix = LightSpaceMatrixFour;
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}
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float4 positionLightSpace = mul(float4(positionWorldSpace, 1.0), lightSpaceMatrix);
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// maps to [-1, 1]
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float3 projectionCoords = positionLightSpace.xyz / positionLightSpace.w;
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// maps to [0, 1]
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projectionCoords.x = (projectionCoords.x * 0.5) + 0.5;
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projectionCoords.y = (projectionCoords.y * 0.5) + 0.5;
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projectionCoords.y *= -1;
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// in XNA clip z is 0 to 1 already
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float inc = 1.0 / 1024.0;
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float shadowFactor = 0;
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for (int row = -1; row <= 1; row++)
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{
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for (int col = -1; col <= 1; col++)
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{
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float closestDepth;
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if (shadowCascadeIndex == 0)
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{
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closestDepth = SAMPLE_TEXTURE(shadowMapOne, projectionCoords.xy + float2(row, col) * inc).r;
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}
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else if (shadowCascadeIndex == 1)
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{
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closestDepth = SAMPLE_TEXTURE(shadowMapTwo, projectionCoords.xy + float2(row, col) * inc).r;
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}
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else if (shadowCascadeIndex == 2)
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{
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closestDepth = SAMPLE_TEXTURE(shadowMapThree, projectionCoords.xy + float2(row, col) * inc).r;
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}
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else
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{
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closestDepth = SAMPLE_TEXTURE(shadowMapFour, projectionCoords.xy + float2(row, col) * inc).r;
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}
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shadowFactor += projectionCoords.z - bias > closestDepth ? 1.0 : 0.0;
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}
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}
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shadowFactor /= 9.0;
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if (projectionCoords.z > 1.0)
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{
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shadowFactor = 1.0;
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}
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return shadowFactor;
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// float currentDepth = projectionCoords.z;
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// if (currentDepth > 1.0)
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// {
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// return 0.0;
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// }
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// if (currentDepth - bias > closestDepth)
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// {
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// return 1.0;
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// }
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// else
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// {
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// return 0.0;
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// }
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}
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float3 ComputeLight(
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float3 L,
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float3 radiance,
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float3 F0,
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float3 V,
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float3 N,
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float3 albedo,
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float metallic,
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float roughness,
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float shadow
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) {
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float3 H = normalize(V + L);
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float NDF = DistributionGGX(N, H, roughness);
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float G = GeometrySmith(N, V, L, roughness);
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float3 F = FresnelSchlick(max(dot(H, V), 0.0), F0);
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float3 numerator = NDF * G * F;
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float denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0);
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float3 specular = numerator / max(denominator, 0.001);
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float3 kS = F;
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float3 kD = float3(1.0, 1.0, 1.0) - kS;
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kD *= 1.0 - metallic;
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float NdotL = max(dot(N, L), 0.0);
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return (kD * albedo / PI + specular) * radiance * NdotL * shadow;
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}
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float4 ComputeColor(
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float3 worldPosition,
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float3 worldNormal,
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float3 albedo,
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float metallic,
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float roughness
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) {
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float3 V = normalize(EyePosition - worldPosition);
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float3 N = normalize(worldNormal);
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float3 F0 = float3(0.04, 0.04, 0.04);
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F0 = lerp(F0, albedo, metallic);
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float3 Lo = float3(0.0, 0.0, 0.0);
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// point light
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for (int i = 0; i < MAX_POINT_LIGHTS; i++)
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{
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float3 lightDir = PointLightPositions[i] - worldPosition;
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float3 L = normalize(lightDir);
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float distance = length(lightDir);
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float attenuation = 1.0 / (distance * distance);
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float3 radiance = PointLightColors[i] * attenuation;
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Lo += ComputeLight(L, radiance, F0, V, N, albedo, metallic, roughness, 1.0);
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}
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// directional light
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float3 L = normalize(DirectionalLightDirection);
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float3 radiance = DirectionalLightColor;
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float shadow = ComputeShadow(worldPosition, N, L);
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Lo += ComputeLight(L, radiance, F0, V, N, albedo, metallic, roughness, (1.0 - shadow));
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float3 ambient = float3(0.03, 0.03, 0.03) * albedo; // * AO;
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float3 color = ambient + Lo;
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color = color / (color + float3(1.0, 1.0, 1.0));
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float exposureConstant = 1.0 / 2.2;
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color = pow(color, float3(exposureConstant, exposureConstant, exposureConstant));
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return float4(color, 1.0);
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}
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float4 main_ps(PixelInput input) : SV_TARGET0
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{
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float3 worldPosition = SAMPLE_TEXTURE(gPosition, input.TexCoord).rgb;
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float3 normal = SAMPLE_TEXTURE(gNormal, input.TexCoord).xyz;
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float3 albedo = SAMPLE_TEXTURE(gAlbedo, input.TexCoord).rgb;
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float2 metallicRoughness = SAMPLE_TEXTURE(gMetallicRoughness, input.TexCoord).rg;
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return ComputeColor(
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worldPosition,
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normal,
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albedo,
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metallicRoughness.r,
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metallicRoughness.g
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);
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}
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Technique DeferredPBR
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{
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Pass
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{
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VertexShader = compile vs_3_0 main_vs();
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PixelShader = compile ps_3_0 main_ps();
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}
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}
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