168 lines
4.1 KiB
HLSL
168 lines
4.1 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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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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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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MATRIX_CONSTANTS
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END_CONSTANTS
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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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// 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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float3 ComputeLight(
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float3 lightDir,
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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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) {
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float3 L = normalize(lightDir);
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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;
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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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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(lightDir, radiance, F0, V, N, albedo, metallic, roughness);
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}
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// // directional light
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// for (int i = 0; i < 4; i++)
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// {
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// float3 lightDir = LightDirections[i];
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// float3 radiance = DirectionLightColors[i];
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// Lo += ComputeLight(lightDir, radiance, F0, V, N, albedo, metallic, roughness);
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// }
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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 fragPosition = 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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fragPosition,
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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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PixelShader = compile ps_3_0 main_ps();
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}
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}
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