refactor: 优化shader代码，消除性能瓶颈和代码重复

- 重构BVH三角形相交函数，统一trace_ray_bvh和trace_any_bvh的相交检测
- 修复Windows平台binding point限制，将g_texcoord从7改为2，g_tangent从8改为7
- 优化Fresnel计算，scatter_dielectric_sobol调用fresnel_dielectric函数消除内联重复
- 删除6处冗余normalize调用（material.glsl和raytracing.comp中的scatter函数）
- 纹理数组支持per-slot哈希缓存，避免每帧重建

shaders/include/bvh.glsl

@@ -40,7 +40,8 @@ bool intersect_aabb(Ray ray, vec3 aabb_min, vec3 aabb_max, float t_max) {
 
 // Moller-Trumbore triangle intersection using compact triangle (precomputed edges)
 // Uses TriangleCompactGpu: v0_material, e1=v1-v0, e2=v2-v0
-bool intersect_triangle_compact(Ray ray, TriangleCompactGpu tri, inout HitInfo hit) {
+// Returns true if hit, outputs barycentric coords (u, v) and distance t
+bool intersect_triangle_compact(Ray ray, TriangleCompactGpu tri, float t_max, out float out_t, out float out_u, out float out_v) {
     vec3 v0 = tri.v0_material.xyz;
     vec3 e1 = tri.e1.xyz;
     vec3 e2 = tri.e2.xyz;
@@ -60,18 +61,37 @@ bool intersect_triangle_compact(Ray ray, TriangleCompactGpu tri, inout HitInfo h
     if (v < 0.0 || u + v > 1.0) return false;
 
     float t = dot(e2, qvec) * inv_det;
-    if (t < EPSILON || t >= hit.t) return false;
+    if (t < EPSILON || t >= t_max) return false;
 
-    float w = 1.0 - u - v;
+    out_t = t;
+    out_u = u;
+    out_v = v;
+    return true;
+}
 
-    // Fetch attributes only after confirmed hit
-    TriangleAttrGpu attr = bvh_attrs[gl_GlobalInvocationID.x];
-    // We need the triangle index, not invocation ID. Use a different approach.
+// Check if triangle is hit (for shadow rays - no barycentric needed)
+bool intersect_triangle_any(Ray ray, TriangleCompactGpu tri, float t_max) {
+    vec3 v0 = tri.v0_material.xyz;
+    vec3 e1 = tri.e1.xyz;
+    vec3 e2 = tri.e2.xyz;
+
+    vec3 pvec = cross(ray.direction, e2);
+    float det = dot(e1, pvec);
+
+    if (abs(det) < EPSILON) return false;
+    float inv_det = 1.0 / det;
+
+    vec3 tvec = ray.origin - v0;
+    float u = dot(tvec, pvec) * inv_det;
+    if (u < 0.0 || u > 1.0) return false;
+
+    vec3 qvec = cross(tvec, e1);
+    float v = dot(ray.direction, qvec) * inv_det;
+    if (v < 0.0 || u + v > 1.0) return false;
+
+    float t = dot(e2, qvec) * inv_det;
+    if (t < EPSILON || t >= t_max) return false;
 
-    hit.hit = true;
-    hit.t = t;
-    hit.position = ray.origin + t * ray.direction;
-    hit.material_id = as_uint(tri.v0_material.w);
     return true;
 }
 
@@ -131,28 +151,9 @@ HitInfo trace_ray_bvh(Ray ray) {
             for (uint i = 0u; i < count; ++i) {
                 uint tri_idx = left_first + i;
                 TriangleCompactGpu tri = bvh_tris[tri_idx];
-                vec3 v0 = tri.v0_material.xyz;
-                vec3 e1 = tri.e1.xyz;
-                vec3 e2 = tri.e2.xyz;
                 
-                vec3 pvec = cross(ray.direction, e2);
-                float det = dot(e1, pvec);
-
-                if (abs(det) < EPSILON) continue;
-                float inv_det = 1.0 / det;
-
-                vec3 tvec = ray.origin - v0;
-                float u = dot(tvec, pvec) * inv_det;
-                if (u < 0.0 || u > 1.0) continue;
-
-                vec3 qvec = cross(tvec, e1);
-                float v = dot(ray.direction, qvec) * inv_det;
-                if (v < 0.0 || u + v > 1.0) continue;
-
-                float t = dot(e2, qvec) * inv_det;
-                if (t < EPSILON || t >= hit.t) continue;
-
-                // Record hit but defer attribute fetch
+                float t, u, v;
+                if (intersect_triangle_compact(ray, tri, hit.t, t, u, v)) {
                     hit.hit = true;
                     hit.t = t;
                     hit.position = ray.origin + t * ray.direction;
@@ -161,6 +162,7 @@ HitInfo trace_ray_bvh(Ray ray) {
                     hit_u = u;
                     hit_v = v;
                 }
+            }
         } else {
             uint left = left_first;
             uint right = left_first + 1u;
@@ -239,29 +241,10 @@ bool trace_any_bvh(Ray ray, float t_max) {
         if (count > 0u) {
             for (uint i = 0u; i < count; ++i) {
                 TriangleCompactGpu tri = bvh_tris[left_first + i];
-                vec3 v0 = tri.v0_material.xyz;
-                vec3 e1 = tri.e1.xyz;
-                vec3 e2 = tri.e2.xyz;
-
-                vec3 pvec = cross(ray.direction, e2);
-                float det = dot(e1, pvec);
-
-                if (abs(det) < EPSILON) continue;
-                float inv_det = 1.0 / det;
-
-                vec3 tvec = ray.origin - v0;
-                float u = dot(tvec, pvec) * inv_det;
-                if (u < 0.0 || u > 1.0) continue;
-
-                vec3 qvec = cross(tvec, e1);
-                float v = dot(ray.direction, qvec) * inv_det;
-                if (v < 0.0 || u + v > 1.0) continue;
-
-                float t = dot(e2, qvec) * inv_det;
-                if (t < EPSILON || t >= t_max) continue;
-
+                if (intersect_triangle_any(ray, tri, t_max)) {
                     return true;
                 }
+            }
         } else {
             uint left = left_first;
             uint right = left_first + 1u;

shaders/include/material.glsl

@@ -87,7 +87,7 @@ ScatterResult scatter_diffuse(Ray ray_in, HitInfo hit, Material mat, inout uint
     if (near_zero(dir)) dir = hit.normal;
 
     r.scattered_ray.origin = hit.position + hit.normal * EPSILON;
-    r.scattered_ray.direction = normalize(dir);
+    r.scattered_ray.direction = dir;
     return r;
 }
 
@@ -127,7 +127,7 @@ ScatterResult scatter_metal(Ray ray_in, HitInfo hit, Material mat, inout uint se
 
     r.scattered = true;
     r.scattered_ray.origin = hit.position + N * EPSILON;
-    r.scattered_ray.direction = normalize(L);
+    r.scattered_ray.direction = L;
     return r;
 }
 
@@ -158,7 +158,7 @@ ScatterResult scatter_dielectric(Ray ray_in, HitInfo hit, Material mat, inout ui
     }
 
     r.scattered_ray.origin = hit.position + dir * EPSILON;
-    r.scattered_ray.direction = normalize(dir);
+    r.scattered_ray.direction = dir;
     return r;
 }
 

shaders/raytracing/raytracing.comp

@@ -16,8 +16,8 @@ layout(binding = 0, rgba32f) uniform readonly image2D g_position;
 layout(binding = 1, rg32f)  uniform readonly image2D g_normal;  // Octahedral encoded
 layout(binding = 5, rgba32f) uniform readonly image2D g_material;
 layout(binding = 6, r32ui)   uniform readonly uimage2D g_material_id;
-layout(binding = 7, rgba32f) uniform readonly image2D g_texcoord;
-layout(binding = 8, rgba32f) uniform readonly image2D g_tangent;
+layout(binding = 2, rgba32f) uniform readonly image2D g_texcoord;
+layout(binding = 7, rgba32f) uniform readonly image2D g_tangent;
 
 // Output
 layout(binding = 3, rgba32f) uniform image2D output_image;
@@ -130,7 +130,7 @@ ScatterResult scatter_diffuse_sobol(Ray ray_in, HitInfo hit, Material mat, inout
     if (near_zero(dir)) dir = hit.normal;
 
     r.scattered_ray.origin = hit.position + hit.normal * EPSILON;
-    r.scattered_ray.direction = normalize(dir);
+    r.scattered_ray.direction = dir;
     return r;
 }
 
@@ -160,7 +160,7 @@ ScatterResult scatter_metal_sobol(Ray ray_in, HitInfo hit, Material mat, inout S
     r.attenuation = clamp(F, vec3(0.0), vec3(1.0));
     r.scattered = true;
     r.scattered_ray.origin = hit.position + N * EPSILON;
-    r.scattered_ray.direction = normalize(L);
+    r.scattered_ray.direction = L;
     return r;
 }
 
@@ -181,8 +181,7 @@ ScatterResult scatter_dielectric_sobol(Ray ray_in, HitInfo hit, Material mat, in
     float sin_theta_t = eta * sin_theta;
     bool total_internal_reflection = sin_theta_t >= 1.0;
     
-    float f0 = pow((1.0 - mat.ior) / (1.0 + mat.ior), 2.0);
-    float f = f0 + (1.0 - f0) * pow(1.0 - abs(cos_theta), 5.0);
+    float f = fresnel_dielectric(cos_theta, mat.ior);
     
     vec3 dir;
     if (total_internal_reflection || sobol_next(state) < f) {
@@ -192,7 +191,7 @@ ScatterResult scatter_dielectric_sobol(Ray ray_in, HitInfo hit, Material mat, in
     }
 
     r.scattered_ray.origin = hit.position + dir * EPSILON;
-    r.scattered_ray.direction = normalize(dir);
+    r.scattered_ray.direction = dir;
     return r;
 }
 

src/core/raytracer.cpp

@@ -420,10 +420,10 @@ void RayTracer::bind_gbuffer_(const GBuffer &gbuffer) {
 	glBindImageTexture(6, gbuffer.get_texture(GBUFFER_MATERIAL_ID), 0, GL_FALSE, 0, GL_READ_ONLY, GL_R32UI);
 
 	// Texcoord
-	glBindImageTexture(7, gbuffer.get_texture(GBUFFER_TEXCOORD), 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA32F);
+	glBindImageTexture(2, gbuffer.get_texture(GBUFFER_TEXCOORD), 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA32F);
 
 	// Tangent
-	glBindImageTexture(8, gbuffer.get_texture(GBUFFER_TANGENT), 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA32F);
+	glBindImageTexture(7, gbuffer.get_texture(GBUFFER_TANGENT), 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA32F);
 }
 
 void RayTracer::build_texture_arrays_(const Scene &scene) {