137 lines
No EOL
3.4 KiB
Text
137 lines
No EOL
3.4 KiB
Text
/* Copyright (c) 2025, Sascha Willems
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*
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* SPDX-License-Identifier: MIT
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*
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*/
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struct VSInput
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{
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float3 Pos;
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float3 Normal;
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};
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struct VSOutput
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{
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float4 Pos : SV_POSITION;
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float3 WorldPos;
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float3 Normal;
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};
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struct UBO
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{
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float4x4 projection;
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float4x4 model;
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float4x4 view;
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float3 camPos;
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};
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ConstantBuffer<UBO> ubo;
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// Inline uniform block
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struct UniformInline {
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float roughness;
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float metallic;
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float r;
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float g;
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float b;
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float ambient;
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};
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[[vk::binding(0,1)]] ConstantBuffer<UniformInline> material;
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#define PI 3.14159265359
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#define MATERIALCOLOR float3(material.r, material.g, material.b)
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// Normal Distribution function --------------------------------------
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float D_GGX(float dotNH, float roughness)
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{
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float alpha = roughness * roughness;
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float alpha2 = alpha * alpha;
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float denom = dotNH * dotNH * (alpha2 - 1.0) + 1.0;
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return (alpha2)/(PI * denom*denom);
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}
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// Geometric Shadowing function --------------------------------------
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float G_SchlicksmithGGX(float dotNL, float dotNV, 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 GL = dotNL / (dotNL * (1.0 - k) + k);
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float GV = dotNV / (dotNV * (1.0 - k) + k);
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return GL * GV;
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}
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// Fresnel function ----------------------------------------------------
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float3 F_Schlick(float cosTheta, float metallic)
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{
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float3 F0 = lerp(float3(0.04, 0.04, 0.04), MATERIALCOLOR, metallic); // * material.specular
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float3 F = F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
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return F;
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}
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// Specular BRDF composition --------------------------------------------
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float3 BRDF(float3 L, float3 V, float3 N, float metallic, float roughness)
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{
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// Precalculate vectors and dot products
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float3 H = normalize (V + L);
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float dotNV = clamp(dot(N, V), 0.0, 1.0);
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float dotNL = clamp(dot(N, L), 0.0, 1.0);
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float dotLH = clamp(dot(L, H), 0.0, 1.0);
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float dotNH = clamp(dot(N, H), 0.0, 1.0);
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// Light color fixed
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float3 lightColor = float3(1.0, 1.0, 1.0);
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float3 color = float3(0.0, 0.0, 0.0);
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if (dotNL > 0.0)
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{
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float rroughness = max(0.05, roughness);
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// D = Normal distribution (Distribution of the microfacets)
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float D = D_GGX(dotNH, rroughness);
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// G = Geometric shadowing term (Microfacets shadowing)
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float G = G_SchlicksmithGGX(dotNL, dotNV, rroughness);
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// F = Fresnel factor (Reflectance depending on angle of incidence)
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float3 F = F_Schlick(dotNV, metallic);
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float3 spec = D * F * G / (4.0 * dotNL * dotNV);
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color += spec * dotNL * lightColor;
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}
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return color;
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}
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[shader("vertex")]
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VSOutput vertexMain(VSInput input, uniform float3 objPos)
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{
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VSOutput output;
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float3 locPos = mul(ubo.model, float4(input.Pos, 1.0)).xyz;
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output.WorldPos = locPos + objPos;
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output.Normal = mul((float4x3)ubo.model, input.Normal).xyz;
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output.Pos = mul(ubo.projection, mul(ubo.view, float4(output.WorldPos, 1.0)));
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return output;
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}
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[shader("fragment")]
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float4 fragmentMain(VSOutput input)
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{
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float3 N = normalize(input.Normal);
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float3 V = normalize(ubo.camPos - input.WorldPos);
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float roughness = material.roughness;
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// Specular contribution
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float3 lightPos = float3(0.0f, 0.0f, 10.0f);
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float3 Lo = float3(0.0, 0.0, 0.0);
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float3 L = normalize(lightPos.xyz - input.WorldPos);
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Lo += BRDF(L, V, N, material.metallic, roughness);
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// Combine with ambient
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float3 color = MATERIALCOLOR * material.ambient;
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color += Lo;
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// Gamma correct
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color = pow(color, float3(0.4545, 0.4545, 0.4545));
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return float4(color, 1.0);
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} |