269 lines
12 KiB
GLSL
269 lines
12 KiB
GLSL
#version 450
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const int MAX_LIGHTS = 4;
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const float PI = 3.14159265359;
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const int kCascadeRes = 1024; // CSM 级联图边长（与引擎 SceneTypes.h 同步）
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struct Light {
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vec4 color; // rgb = 颜色，a = 强度
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vec4 direction; // 方向光：xyz = 方向（已归一）
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vec4 position; // 点光：xyz = 世界位置
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vec4 params; // x = 类型(0=方向,1=点)，y = 衰减半径
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};
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layout(location = 0) in vec2 fragUV;
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layout(location = 1) in vec3 fragNormal;
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layout(location = 2) in vec3 fragWorldPos;
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layout(location = 3) in float fragViewDepth;
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layout(location = 4) in vec2 fragVelocity;
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layout(location = 5) in vec3 fragTangent;
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layout(location = 0) out vec4 outColor;
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layout(location = 1) out vec2 outVelocity; // TAA velocity 附件
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layout(set = 0, binding = 0) uniform UniformBufferObject {
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mat4 view;
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mat4 proj;
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mat4 lightSpace[3]; // CSM 各级联光空间 VP
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vec4 cascadeSplits; // xyz = 级联 0..2 远边界（视图深度）
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vec4 ambientColor;
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Light lights[MAX_LIGHTS];
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mat4 projNoJitter;
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mat4 prevView;
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mat4 prevProj;
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vec4 cameraPos;
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} ubo;
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// 材质纹理槽（binding = Material::Slot）
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layout(set = 1, binding = 0) uniform sampler2D albedoMap;
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layout(set = 1, binding = 1) uniform sampler2D normalMap;
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layout(set = 1, binding = 2) uniform sampler2D metallicRoughnessMap; // G=粗糙度 B=金属度
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layout(set = 1, binding = 3) uniform sampler2D emissiveMap;
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layout(set = 1, binding = 4) uniform sampler2D aoMap; // 环境光遮蔽（R 通道）
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layout(set = 1, binding = 5) uniform sampler2D roughnessMap; // 独立粗糙度图（R 通道，specular 工作流）
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layout(set = 1, binding = 6) uniform MaterialParams {
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vec4 factors; // x = metallic 因子，y = roughness 因子，z = 独立粗糙度图开关，w = MASK 镂空开关
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vec4 baseColor; // glTF baseColorFactor：rgb 调色 albedo，a = BLEND 透明度
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vec4 surface; // x = ior（F0 换算），y = transmission（不透明段恒 0 语义），z = 自发光强度，w = 体积厚度
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vec4 misc; // x = unlit（KHR_materials_unlit，1 = 早退直出 albedo）
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vec4 emissiveFactor; // 自发光颜色（rgb × emissiveMap × surface.z；黑 = 不发光）
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vec4 uvA[6]; // 每槽 UV 线性变换（KHR_texture_transform，v-up 空间）(a11,a12,a21,a22)，槽序 = binding
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vec4 uvT[6]; // 每槽 UV 平移 (tx, ty, 0, 0)
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} matParams;
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// 每槽 UV 变换：uv' = A·uv + t（identity 时退化为直通）。slot 必须
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// 字面量调用点（编译期展开索引）；6 = Material::kSlotCount
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vec2 ApplyUv(int slot, vec2 uv) {
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vec4 a = matParams.uvA[slot];
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vec4 t = matParams.uvT[slot];
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return vec2(a.x * uv.x + a.y * uv.y + t.x,
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a.z * uv.x + a.w * uv.y + t.y);
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}
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// CSM 阴影（sampler2DShadow：单次采样 = 硬件 2×2 深度比较 PCF）
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layout(set = 2, binding = 0) uniform sampler2DShadow shadowMap0; // CSM 级联 0（最近）
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layout(set = 2, binding = 1) uniform sampler2DShadow shadowMap1; // 级联 1
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layout(set = 2, binding = 2) uniform sampler2DShadow shadowMap2; // 级联 2（最远）
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layout(set = 2, binding = 3) uniform samplerCube irradianceMap; // 漫反射环境光（IBL 阶段②）
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layout(set = 2, binding = 4) uniform samplerCube prefilteredMap; // 镜面环境（mip 分 roughness，阶段③）
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layout(set = 2, binding = 5) uniform sampler2D brdfLut; // BRDF 积分表 (NdotV, roughness) → (scale, bias)
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// 第 0 盏方向光（KeyLight）的 CSM 阴影因子。
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// 级联按视图深度选择；3×3 纹素偏移采样（每 tap 硬件 2×2 PCF，
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// 等效 36 次比较）→ 软阴影边缘；采样器 clamp-to-border 白色：
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// 光视锥外自动 1.0（无阴影），省出界分支
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float ShadowFactor(vec3 N, float viewDepth) {
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// 阴影总开关（ubo.cascadeSplits.w 由 CPU 每帧写入）：关闭即全亮，
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// 配合 ShadowPass 空转（深度图无内容也读不到这里）
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if (ubo.cascadeSplits.w < 0.5) return 1.0;
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int cascade = 2;
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for (int i = 0; i < 3; ++i) {
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if (viewDepth < ubo.cascadeSplits[i]) { cascade = i; break; }
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}
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vec4 ls = ubo.lightSpace[cascade] * vec4(fragWorldPos, 1.0);
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vec3 proj = ls.xyz / ls.w;
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vec2 uv = proj.xy * 0.5 + 0.5;
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vec3 L = normalize(-ubo.lights[0].direction.xyz);
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float bias = max(0.004 * (1.0 - dot(N, L)), 0.0012);
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float texel = 1.0 / float(kCascadeRes); // 与引擎 kCascadeRes 同步
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float shadow = 0.0;
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for (int y = -1; y <= 1; ++y) {
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for (int x = -1; x <= 1; ++x) {
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float lit;
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if (cascade == 0)
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lit = texture(shadowMap0, vec3(uv + vec2(x, y) * texel,
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proj.z - bias));
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else if (cascade == 1)
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lit = texture(shadowMap1, vec3(uv + vec2(x, y) * texel,
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proj.z - bias));
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else
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lit = texture(shadowMap2, vec3(uv + vec2(x, y) * texel,
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proj.z - bias));
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shadow += mix(0.3, 1.0, lit); // 影中保留 0.3 环境感
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}
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}
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return shadow / 9.0;
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}
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// 法线贴图 → 世界空间法线（TBN 构建）。
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// 无切线数据（零向量）或平法线贴图时退回几何法线。
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vec3 MappedNormal(vec3 geomN, vec3 T, vec2 uv) {
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if (dot(T, T) < 1e-4) return geomN;
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vec3 N = geomN;
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vec3 nT = normalize(T - N * dot(N, T)); // 正交化
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vec3 B = cross(N, nT);
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vec3 sampled = texture(normalMap, uv).xyz * 2.0 - 1.0;
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if (dot(sampled, sampled) < 1e-4) return geomN;
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return normalize(nT * sampled.x + B * sampled.y + N * sampled.z);
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}
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// ---- Cook-Torrance BRDF 各项 ----
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float DistributionGGX(float NdotH, float roughness) {
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float a = roughness * roughness;
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float a2 = a * a;
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float d = NdotH * NdotH * (a2 - 1.0) + 1.0;
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return a2 / (PI * d * d);
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}
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float GeometrySmith(float NdotV, float NdotL, float roughness) {
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float r = roughness + 1.0;
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float k = (r * r) / 8.0; // 解析光源用此 k（IBL 才用 IBL 版本）
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float gv = NdotV / (NdotV * (1.0 - k) + k);
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float gl = NdotL / (NdotL * (1.0 - k) + k);
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return gv * gl;
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}
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vec3 FresnelSchlick(float cosTheta, vec3 F0) {
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return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
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}
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// 粗糙度感知的 Fresnel（IBL 用）：粗糙表面掠射边缘的 F 上升更平缓
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vec3 FresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness) {
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vec3 Fmax = max(vec3(1.0 - roughness), F0);
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return F0 + (Fmax - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
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}
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void main() {
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vec4 albedoTex = texture(albedoMap, ApplyUv(0, fragUV));
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// alphaMode=MASK 镂空（表针/栅栏等硬边贴图）：低于阈值的纹素直接丢弃
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if (matParams.factors.w > 0.5 && albedoTex.a < 0.5) discard;
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vec3 albedo = albedoTex.rgb * matParams.baseColor.rgb;
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// KHR_materials_unlit：无光照语义（文字标签/示意图），albedo 直出
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if (matParams.misc.x > 0.5) {
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outColor = vec4(albedo, albedoTex.a * matParams.baseColor.a);
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outVelocity = fragVelocity;
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return;
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}
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vec4 mr = texture(metallicRoughnessMap, ApplyUv(2, fragUV));
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// 粗糙度源按 factors.z 切换：glTF 合图工作流读 MR.g；
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// FBX/OBJ specular 工作流（z=1）换用独立粗糙度图 R 通道
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float roughness = clamp(mix(mr.g, texture(roughnessMap, ApplyUv(5, fragUV)).r,
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matParams.factors.z) * matParams.factors.y,
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0.045, 1.0);
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float metallic = clamp(mr.b * matParams.factors.x, 0.0, 1.0);
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// 自发光强度（KHR_materials_emissive_strength，缺省 1）；
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// emissiveFactor = 颜色因子（无贴图时发光的入口——兜底贴图恒黑）
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vec3 emissive = texture(emissiveMap, ApplyUv(3, fragUV)).rgb
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* matParams.emissiveFactor.rgb * matParams.surface.z;
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vec3 N = MappedNormal(normalize(fragNormal), fragTangent, ApplyUv(1, fragUV));
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vec3 V = normalize(ubo.cameraPos.xyz - fragWorldPos);
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// 双面法线：cull 关闭 + glTF doubleSided=true，背面片元（表壳后盖/
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// 内壁等从背面看到的表面）几何法线背向相机，NdotL≤0 → 直接光全灭、
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// IBL 采错半球 = 纯黑壳（three.js DoubleSide 对背面自动翻法线，
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// 这里对齐该语义；与 translucent shader 的翻转同款）
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if (dot(N, V) < 0.0) N = -N;
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float NdotV = max(dot(N, V), 1e-4);
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// F0 按折射率换算（KHR_materials_ior）：((ior-1)/(ior+1))²；
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// glTF 缺省 ior=1.5 → 0.04，与旧固定值一致
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float ior = max(matParams.surface.x, 1.0);
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vec3 F0 = mix(vec3((ior - 1.0) / (ior + 1.0)
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* (ior - 1.0) / (ior + 1.0)),
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albedo, metallic); // 电介质 F0 / 金属 albedo
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vec3 Lo = vec3(0.0);
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float shade0 = 1.0f; // 第 0 盏光的阴影因子（环境光同步衰减用）
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for (int i = 0; i < MAX_LIGHTS; ++i) {
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// 按类型分支：方向光无衰减；点光方向指向光源 + 平方距离衰减
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vec3 L;
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float atten = 1.0;
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if (ubo.lights[i].params.x > 0.5) {
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vec3 toLight = ubo.lights[i].position.xyz - fragWorldPos;
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float d = length(toLight);
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if (d >= ubo.lights[i].params.y) continue;
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L = toLight / d;
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float a = clamp(1.0 - (d * d) /
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(ubo.lights[i].params.y * ubo.lights[i].params.y),
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0.0, 1.0);
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atten = a * a;
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} else {
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L = normalize(-ubo.lights[i].direction.xyz);
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}
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vec3 radiance = ubo.lights[i].color.rgb * ubo.lights[i].color.a * atten;
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float NdotL = max(dot(N, L), 0.0);
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if (NdotL <= 0.0) continue;
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// Cook-Torrance 镜面项
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vec3 H = normalize(V + L);
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float NdotH = max(dot(N, H), 0.0);
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float NdotH2 = max(dot(H, V), 0.0);
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float D = DistributionGGX(NdotH, roughness);
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float G = GeometrySmith(NdotV, NdotL, roughness);
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vec3 F = FresnelSchlick(NdotH2, F0);
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vec3 kS = F;
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vec3 kD = (1.0 - kS) * (1.0 - metallic); // 金属不参与漫反射
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vec3 specular = (D * G * F) /
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max(4.0 * NdotV * NdotL, 1e-4);
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// 阴影只来自第 0 盏方向光（CSM）
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float shade = (i == 0 && ubo.lights[0].params.x < 0.5)
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? ShadowFactor(N, fragViewDepth) : 1.0;
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if (i == 0) shade0 = shade;
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// 漫反射影中保留 0.3（间接光近似）；镜面项是"光源的镜面像"，
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// 光源被遮挡即完全消失——按 shade 重映射（0.3→0，1.0→1）。
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// 否则掠射角下 spec(HDR 8)×0.3 仍是白块，影子比天空还亮
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float shadeSpec = max((shade - 0.3f) / 0.7f, 0.0f);
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Lo += (kD * albedo / PI) * radiance * NdotL * shade
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+ specular * radiance * NdotL * shadeSpec;
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}
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// 环境光：IBL split-sum（阶段②③）。
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// 漫反射：N 采样 irradiance cube（半球 Lambert 预卷积）
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// 镜面：R 采样 pre-filtered cube（mip = roughness 分级）
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// × BRDF LUT 查表得 F 缩放/偏置
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// ambientColor = 用户可调强度/色调乘子
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vec3 F_amb = FresnelSchlickRoughness(NdotV, F0, roughness);
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vec3 kD_amb = (1.0 - F_amb) * (1.0 - metallic);
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vec3 irradiance = texture(irradianceMap, N).rgb;
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float ao = texture(aoMap, ApplyUv(4, fragUV)).r;
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vec3 diffuse = kD_amb * irradiance * albedo * ao;
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vec3 R = reflect(-V, N);
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const float kMaxPrefilterMip = 4.0; // 与 Cubemap::kPrefilterMips - 1 同步
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vec3 prefilteredColor = textureLod(prefilteredMap, R,
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roughness * kMaxPrefilterMip).rgb;
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vec2 envBRDF = texture(brdfLut, vec2(NdotV, roughness)).rg;
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vec3 specular = prefilteredColor * (F_amb * envBRDF.x + envBRDF.y);
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vec3 ambient = (diffuse + specular) * ubo.ambientColor.rgb
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* mix(0.4, 1.0, shade0); // 阴影区环境同步衰减（简化遮蔽）
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// alpha = albedo 贴图覆盖率 × baseColorFactor.a（glTF alphaMode=BLEND
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// 混合源）；不透明资产两者恒 1 行为不变。预乘在 tonemap 段完成。
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outColor = vec4(ambient + Lo + emissive, albedoTex.a * matParams.baseColor.a);
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// ==== DEBUG B1: 纯 albedo 直出（验证贴图绑定/UV 采样）====
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// outColor = vec4(albedo, 1.0);
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outVelocity = fragVelocity;
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}
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