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HelloVulkan/shaders/simple_shader_translucent.frag
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atdunbg 5d88ed2057 Improve PBR quality: mip chains, anisotropic filtering, baseColorFactor
Root causes behind blurry/unphysical materials (4K pocket watch render
mushy, glass fully opaque, watch hands unreadable):

- Textures loaded via stbi had a single mip level: 4096x4096 albedo/MR
  maps sampled with no LOD -> minification aliasing turned fine detail
  (watch hands) into noise. Generate a full blit-based mip chain with
  per-level layout transitions.
- samplerAnisotropy was never enabled on the device and every sampler
  was created with anisotropy disabled: grazing-angle surfaces (watch
  face, ground) collapsed into a blur. Enable the device feature and
  16x anisotropic filtering on material texture samplers.
- glTF baseColorFactor was ignored: the glass material (alphaMode
  BLEND, no baseColor texture, baseColorFactor.a = 0.3) fell back to
  the default white texture with alpha = 1 and rendered fully opaque.
  MaterialParams gains a baseColor vec4 (rgb tints albedo, a scales
  the blend alpha) threaded through both PBR shaders.
- alphaMode MASK was treated as opaque: add a factors.w switch that
  performs an alpha cutout test in the opaque shader.
- Fix material cache key dropping factors.z (separate-roughness
  switch); it now encodes the full factors and baseColor vectors.
2026-10-05 12:01:07 +08:00

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#version 450
const int MAX_LIGHTS = 4;
const float PI = 3.14159265359;
const int kCascadeRes = 1024; // CSM 级联图边长(与引擎 SceneTypes.h 同步)
struct Light {
vec4 color; // rgb = 颜色,a = 强度
vec4 direction; // 方向光:xyz = 方向(已归一)
vec4 position; // 点光:xyz = 世界位置
vec4 params; // x = 类型(0=方向,1=点),y = 衰减半径
};
layout(location = 0) in vec2 fragUV;
layout(location = 1) in vec3 fragNormal;
layout(location = 2) in vec3 fragWorldPos;
layout(location = 3) in float fragViewDepth;
layout(location = 4) in vec2 fragVelocity;
layout(location = 5) in vec3 fragTangent;
layout(location = 0) out vec4 outColor;
layout(location = 1) out vec2 outVelocity; // TAA velocity 附件
layout(set = 0, binding = 0) uniform UniformBufferObject {
mat4 view;
mat4 proj;
mat4 lightSpace[3]; // CSM 各级联光空间 VP
vec4 cascadeSplits; // xyz = 级联 0..2 远边界(视图深度)
vec4 ambientColor;
Light lights[MAX_LIGHTS];
mat4 projNoJitter;
mat4 prevView;
mat4 prevProj;
vec4 cameraPos;
} ubo;
// 材质纹理槽(binding = Material::Slot)
layout(set = 1, binding = 0) uniform sampler2D albedoMap;
layout(set = 1, binding = 1) uniform sampler2D normalMap;
layout(set = 1, binding = 2) uniform sampler2D metallicRoughnessMap; // G=粗糙度 B=金属度
layout(set = 1, binding = 3) uniform sampler2D emissiveMap;
layout(set = 1, binding = 4) uniform sampler2D aoMap; // 环境光遮蔽(R 通道)
layout(set = 1, binding = 5) uniform sampler2D roughnessMap; // 独立粗糙度图(R 通道,specular 工作流)
layout(set = 1, binding = 6) uniform MaterialParams {
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
vec4 baseColor; // glTF baseColorFactor:rgb 调色 albedo,a = BLEND 透明度
} matParams;
// CSM 阴影(sampler2DShadow:单次采样 = 硬件 2×2 深度比较 PCF)
layout(set = 2, binding = 0) uniform sampler2DShadow shadowMap0; // CSM 级联 0(最近)
layout(set = 2, binding = 1) uniform sampler2DShadow shadowMap1; // 级联 1
layout(set = 2, binding = 2) uniform sampler2DShadow shadowMap2; // 级联 2(最远)
layout(set = 2, binding = 3) uniform samplerCube irradianceMap; // 漫反射环境光(IBL 阶段②)
layout(set = 2, binding = 4) uniform samplerCube prefilteredMap; // 镜面环境(mip 分 roughness,阶段③)
layout(set = 2, binding = 5) uniform sampler2D brdfLut; // BRDF 积分表 (NdotV, roughness) → (scale, bias)
// 第 0 盏方向光(KeyLight)的 CSM 阴影因子。
// 级联按视图深度选择;3×3 纹素偏移采样(每 tap 硬件 2×2 PCF,
// 等效 36 次比较)→ 软阴影边缘;采样器 clamp-to-border 白色:
// 光视锥外自动 1.0(无阴影),省出界分支
float ShadowFactor(vec3 N, float viewDepth) {
// 阴影总开关(ubo.cascadeSplits.w 由 CPU 每帧写入):关闭即全亮,
// 配合 ShadowPass 空转(深度图无内容也读不到这里)
if (ubo.cascadeSplits.w < 0.5) return 1.0;
int cascade = 2;
for (int i = 0; i < 3; ++i) {
if (viewDepth < ubo.cascadeSplits[i]) { cascade = i; break; }
}
vec4 ls = ubo.lightSpace[cascade] * vec4(fragWorldPos, 1.0);
vec3 proj = ls.xyz / ls.w;
vec2 uv = proj.xy * 0.5 + 0.5;
vec3 L = normalize(-ubo.lights[0].direction.xyz);
float bias = max(0.004 * (1.0 - dot(N, L)), 0.0012);
float texel = 1.0 / float(kCascadeRes); // 与引擎 kCascadeRes 同步
float shadow = 0.0;
for (int y = -1; y <= 1; ++y) {
for (int x = -1; x <= 1; ++x) {
float lit;
if (cascade == 0)
lit = texture(shadowMap0, vec3(uv + vec2(x, y) * texel,
proj.z - bias));
else if (cascade == 1)
lit = texture(shadowMap1, vec3(uv + vec2(x, y) * texel,
proj.z - bias));
else
lit = texture(shadowMap2, vec3(uv + vec2(x, y) * texel,
proj.z - bias));
shadow += mix(0.3, 1.0, lit); // 影中保留 0.3 环境感
}
}
return shadow / 9.0;
}
// 法线贴图 → 世界空间法线(TBN 构建)。
// 无切线数据(零向量)或平法线贴图时退回几何法线。
vec3 MappedNormal(vec3 geomN, vec3 T, vec2 uv) {
if (dot(T, T) < 1e-4) return geomN;
vec3 N = geomN;
vec3 nT = normalize(T - N * dot(N, T)); // 正交化
vec3 B = cross(N, nT);
vec3 sampled = texture(normalMap, uv).xyz * 2.0 - 1.0;
if (dot(sampled, sampled) < 1e-4) return geomN;
return normalize(nT * sampled.x + B * sampled.y + N * sampled.z);
}
// ---- Cook-Torrance BRDF 各项 ----
float DistributionGGX(float NdotH, float roughness) {
float a = roughness * roughness;
float a2 = a * a;
float d = NdotH * NdotH * (a2 - 1.0) + 1.0;
return a2 / (PI * d * d);
}
float GeometrySmith(float NdotV, float NdotL, float roughness) {
float r = roughness + 1.0;
float k = (r * r) / 8.0; // 解析光源用此 k(IBL 才用 IBL 版本)
float gv = NdotV / (NdotV * (1.0 - k) + k);
float gl = NdotL / (NdotL * (1.0 - k) + k);
return gv * gl;
}
vec3 FresnelSchlick(float cosTheta, vec3 F0) {
return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
}
// 粗糙度感知的 Fresnel(IBL 用):粗糙表面掠射边缘的 F 上升更平缓
vec3 FresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness) {
vec3 Fmax = max(vec3(1.0 - roughness), F0);
return F0 + (Fmax - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
}
void main() {
vec4 albedoTex = texture(albedoMap, fragUV);
vec3 albedo = albedoTex.rgb * matParams.baseColor.rgb;
vec4 mr = texture(metallicRoughnessMap, fragUV);
// 粗糙度源按 factors.z 切换:glTF 合图工作流读 MR.g;
// FBX/OBJ specular 工作流(z=1)换用独立粗糙度图 R 通道
float roughness = clamp(mix(mr.g, texture(roughnessMap, fragUV).r,
matParams.factors.z) * matParams.factors.y,
0.045, 1.0);
float metallic = clamp(mr.b * matParams.factors.x, 0.0, 1.0);
vec3 emissive = texture(emissiveMap, fragUV).rgb;
vec3 N = MappedNormal(normalize(fragNormal), fragTangent, fragUV);
vec3 V = normalize(ubo.cameraPos.xyz - fragWorldPos);
float NdotV = max(dot(N, V), 1e-4);
vec3 F0 = mix(vec3(0.04), albedo, metallic); // 电介质基准反射率 4%
vec3 Lo = vec3(0.0);
float shade0 = 1.0f; // 第 0 盏光的阴影因子(环境光同步衰减用)
for (int i = 0; i < MAX_LIGHTS; ++i) {
// 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
vec3 L;
float atten = 1.0;
if (ubo.lights[i].params.x > 0.5) {
vec3 toLight = ubo.lights[i].position.xyz - fragWorldPos;
float d = length(toLight);
if (d >= ubo.lights[i].params.y) continue;
L = toLight / d;
float a = clamp(1.0 - (d * d) /
(ubo.lights[i].params.y * ubo.lights[i].params.y),
0.0, 1.0);
atten = a * a;
} else {
L = normalize(-ubo.lights[i].direction.xyz);
}
vec3 radiance = ubo.lights[i].color.rgb * ubo.lights[i].color.a * atten;
float NdotL = max(dot(N, L), 0.0);
if (NdotL <= 0.0) continue;
// Cook-Torrance 镜面项
vec3 H = normalize(V + L);
float NdotH = max(dot(N, H), 0.0);
float NdotH2 = max(dot(H, V), 0.0);
float D = DistributionGGX(NdotH, roughness);
float G = GeometrySmith(NdotV, NdotL, roughness);
vec3 F = FresnelSchlick(NdotH2, F0);
vec3 kS = F;
vec3 kD = (1.0 - kS) * (1.0 - metallic); // 金属不参与漫反射
vec3 specular = (D * G * F) /
max(4.0 * NdotV * NdotL, 1e-4);
// 阴影只来自第 0 盏方向光(CSM)
float shade = (i == 0 && ubo.lights[0].params.x < 0.5)
? ShadowFactor(N, fragViewDepth) : 1.0;
if (i == 0) shade0 = shade;
// 漫反射影中保留 0.3(间接光近似);镜面项是"光源的镜面像",
// 光源被遮挡即完全消失——按 shade 重映射(0.3→0,1.0→1)。
// 否则掠射角下 spec(HDR 8)×0.3 仍是白块,影子比天空还亮
float shadeSpec = max((shade - 0.3f) / 0.7f, 0.0f);
Lo += (kD * albedo / PI) * radiance * NdotL * shade
+ specular * radiance * NdotL * shadeSpec;
}
// 环境光:IBL split-sum(阶段②③)。
// 漫反射:N 采样 irradiance cube(半球 Lambert 预卷积)
// 镜面:R 采样 pre-filtered cube(mip = roughness 分级)
// × BRDF LUT 查表得 F 缩放/偏置
// ambientColor = 用户可调强度/色调乘子
vec3 F_amb = FresnelSchlickRoughness(NdotV, F0, roughness);
vec3 kD_amb = (1.0 - F_amb) * (1.0 - metallic);
vec3 irradiance = texture(irradianceMap, N).rgb;
float ao = texture(aoMap, fragUV).r;
vec3 diffuse = kD_amb * irradiance * albedo * ao;
vec3 R = reflect(-V, N);
const float kMaxPrefilterMip = 4.0; // 与 Cubemap::kPrefilterMips - 1 同步
vec3 prefilteredColor = textureLod(prefilteredMap, R,
roughness * kMaxPrefilterMip).rgb;
vec2 envBRDF = texture(brdfLut, vec2(NdotV, roughness)).rg;
vec3 specular = prefilteredColor * (F_amb * envBRDF.x + envBRDF.y);
vec3 ambient = (diffuse + specular) * ubo.ambientColor.rgb
* mix(0.4, 1.0, shade0); // 阴影区环境同步衰减(简化遮蔽)
// alpha = albedo 贴图覆盖率 × baseColorFactor.a(glTF alphaMode=BLEND
// 混合源;玻璃类无 baseColor 贴图材质的透明度全靠 factor.a)。
// 预乘在 tonemap 段完成。
outColor = vec4(ambient + Lo + emissive, albedoTex.a * matParams.baseColor.a);
outVelocity = fragVelocity;
// 深度语义:真实深度测试 + 真实写入(depthWrite 状态保持 TRUE——
// 绕开 NVIDIA shader-object "depthWrite=FALSE 下绘制" 的灾难病态)。
// 早期版本在此写 gl_FragDepth=1.0 模拟"只测不写",但深度比较符是
// eLess:片元自身的 1.0 对清屏值 1.0 与不透明深度(更小)永远测试
// 失败,透明队列一个像素都出不来(Transparent 调试视图实锤)。
// 透明段是帧内最后一个 pass 且深度每帧清空,真实写入无副作用;
// back-to-front 排序下近面后画恒通过,混合顺序仍由排序保证。
}