pbr

Author: Aaron Ma

examples/50_custom_renderer/render.comp

@@ -97,15 +97,15 @@ vec3 get_obb_normal(vec3 ro, vec3 rd, uint id, float t) {
     return normalize(rotate_vector(n, tf.quat));
 }
 
-bool trace_shadow(vec3 ro, vec3 rd, float max_t) {
+bool trace_shadow_fast(vec3 ro, vec3 rd, float max_t, int max_steps) {
     float t_min, t_max; if (!intersect_aabb(ro, rd, vec3(WORLD_MIN), vec3(WORLD_MAX), t_min, t_max)) return false;
     t_min = max(t_min, 0.0); t_max = min(t_max, max_t);
     vec3 cell_p = (ro + rd * (t_min + 0.001) - WORLD_MIN) / CELL_SIZE;
     ivec3 cell = clamp(ivec3(floor(cell_p)), ivec3(0), ivec3(127));
     vec3 step = sign(rd), t_delta = abs(CELL_SIZE / rd), t_max_step;
     for(int i=0; i<3; ++i) t_max_step[i] = t_min + (rd[i]>0.0?floor(cell_p[i])+1.0-cell_p[i]:cell_p[i]-floor(cell_p[i])) * t_delta[i];
     uint64_t cached_mask = 0; ivec3 last_brick = ivec3(-1);
-    for (int i = 0; i < 24; ++i) {
+    for (int i = 0; i < max_steps; ++i) {
         ivec3 brick_p = cell >> 2;
         if (brick_p != last_brick) {
             cached_mask = all_bitmasks[pc.bitmask_id].bitmasks[brick_p.x + (brick_p.y << 5) + (brick_p.z << 10)];
@@ -161,16 +161,24 @@ float trace_ao(vec3 ro, vec3 n) {
     }
     return 1.0;
 }
+vec3 get_sky(vec3 rd) {
+    vec3 L = normalize(vec3(0.5, 1.0, 0.3));
+    float sun = pow(max(dot(rd, L), 0.0), 128.0);
+    vec3 sky = mix(vec3(0.1, 0.2, 0.4), vec3(0.4, 0.6, 0.9), max(rd.y, 0.0));
+    return sky + vec3(1.0, 0.8, 0.5) * sun * 5.0; // Bright sun disk
+}
 
 void main() {
     uvec2 pixel = gl_GlobalInvocationID.xy;
     if (pixel.x >= uint(pc.res.x) || pixel.y >= uint(pc.res.y)) return;
-    
+    uint seed = hash(pixel.x + pixel.y * uint(pc.res.x)); 
     vec2 uv = (vec2(pixel) / pc.res) * 2.0 - 1.0; uv.x *= pc.res.x / pc.res.y;
     vec3 rd = normalize(pc.cam_dir.xyz + pc.cam_right.xyz * uv.x + pc.cam_up.xyz * uv.y), ro = pc.cam_pos.xyz;
-    float t_min, t_max; vec3 color = vec3(0.005, 0.005, 0.01) + rd.y * 0.02;
+    float t_min, t_max; vec3 color = get_sky(rd);
+
     if (intersect_aabb(ro, rd, vec3(WORLD_MIN), vec3(WORLD_MAX), t_min, t_max)) {
         t_min = max(t_min, 0.0);
+
         vec3 cell_p = (ro + rd * (t_min + 0.0001) - WORLD_MIN) / CELL_SIZE;
         ivec3 cell = clamp(ivec3(floor(cell_p)), ivec3(0), ivec3(127));
         vec3 step = sign(rd), t_delta = abs(CELL_SIZE / rd), t_max_step;
@@ -210,10 +218,19 @@ void main() {
             Material mat = all_mats[pc.mat_id].mats[hit_id]; vec3 L = normalize(vec3(0.5, 1.0, 0.3));
             float diff = max(dot(hit_n, L), 0.0);
             float ao = trace_ao(ro + rd * hit_t + hit_n * 0.01, hit_n);
-            color = mat.base_color.rgb * (diff * 0.8 + 0.2 * ao);
+
+            vec3 sky_color = get_sky(hit_n);
+            color = mat.base_color.rgb * (diff * 1.5 + sky_color * 0.2 * ao);
             if (mat.emissive > 0.0) color += mat.base_color.rgb * mat.emissive;
-            if (pc.use_shadows == 1 && diff > 0.0) if (trace_shadow(ro + rd * hit_t + hit_n * 0.002, L, 20.0)) color *= 0.4;
+            if (pc.use_shadows == 1 && diff > 0.0) {
+                if (trace_shadow_fast(ro + rd * hit_t + hit_n * 0.01, L, 20.0, 48)) color *= 0.6;
+            }
         }
     }
+
+    // ACES Tonemapping
+    const float a = 2.51, b = 0.03, c = 2.43, d = 0.59, e = 0.14;
+    color = clamp((color * (a * color + b)) / (color * (c * color + d) + e), 0.0, 1.0);
+    
     imageStore(all_images[pc.img_id], ivec2(pixel), vec4(color, 1.0));
 }