Kav/Effects/HLSL/DeferredPBREffect.fx

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