160 lines
3.9 KiB
HLSL
160 lines
3.9 KiB
HLSL
#include "Macros.fxh" //from FNA
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static const float PI = 3.141592653589793;
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// Transformation Matrices
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float4x4 World;
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float4x4 View;
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float4x4 Projection;
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float4x4 WorldViewProjection;
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float4x3 WorldInverseTranspose;
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// Samplers
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DECLARE_TEXTURE(BaseColorTexture, 0);
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DECLARE_TEXTURE(NormalTexture, 1);
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DECLARE_TEXTURE(EmissionTexture, 2);
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DECLARE_TEXTURE(OcclusionTexture, 3);
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DECLARE_TEXTURE(MetallicRoughnessTexture, 4);
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DECLARE_CUBEMAP(EnvDiffuseTexture, 8);
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DECLARE_TEXTURE(BrdfLutTexture, 9);
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DECLARE_CUBEMAP(EnvSpecularTexture, 10);
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// Light Info
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float3 LightPositions[4];
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float3 LightColors[4];
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// PBR Values
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float3 Albedo;
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float Metallic;
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float Roughness;
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float AO;
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float3 EyePosition;
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struct VertexShaderInput
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{
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float4 Position : POSITION;
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float3 Normal : NORMAL;
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float2 TexCoord : TEXCOORD0;
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};
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struct PixelShaderInput
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{
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float4 Position : SV_POSITION;
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float2 TexCoord : TEXCOORD0;
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float3 PositionWS : TEXCOORD1;
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float3 NormalWS : TEXCOORD2;
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};
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PixelShaderInput main_vs(VertexShaderInput input)
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{
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PixelShaderInput output;
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output.PositionWS = mul(input.Position, World).xyz;
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output.TexCoord = input.TexCoord;
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output.NormalWS = normalize(mul(WorldInverseTranspose, input.Normal));
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output.Position = mul(input.Position, WorldViewProjection);
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return output;
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}
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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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// The case where we have no texture maps for any PBR data
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float4 None(PixelShaderInput input) : SV_TARGET
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{
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float3 N = normalize(input.NormalWS);
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float3 V = normalize(EyePosition - input.PositionWS);
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float3 Lo = float3(0.0, 0.0, 0.0);
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for (int i = 0; i < 4; i++)
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{
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float3 lightDir = LightPositions[i] - input.PositionWS;
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float3 L = normalize(lightDir);
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float3 H = normalize(V + L);
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float distance = length(lightDir);
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float attenuation = 1.0 / (distance * distance);
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float3 radiance = LightColors[i] * attenuation;
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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 F = FresnelSchlick(max(dot(H, V), 0.0), F0);
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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 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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Lo += (kD * Albedo / PI + specular) * radiance * NdotL;
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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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Technique PBR
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{
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Pass Pass1
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{
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VertexShader = compile vs_3_0 main_vs();
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PixelShader = compile ps_3_0 None();
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}
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}
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