sampling in random hemisphere

src/shaders/raycasting.cginc

@@ -55,7 +55,7 @@ HitResult castBricks(vec3 origin, vec3 start, vec3 dir, vec3 incAxis, uint addr)
 *   origin: Camera position
 *   dir: Ray coming from camera position going through currently drawn pixel
 */
-HitResult castNodes(Ray ray)
+HitResult castNodes(Ray ray, uint maxSteps)
 {
     // Round input pos to nearest voxel
     vec3 pos = floor(ray.origin);
@@ -70,7 +70,7 @@ HitResult castNodes(Ray ray)
     vec3 incAxis = vec3(0,0,0);
 
     // Iterate
-    for(int i=0;i<110;i++)
+    for(int i=0;i<maxSteps;i++)
     {
         // Get node
         uint node = texelFetch(_NodesTexture, ivec3(pos), 0).r;

src/shaders/shader.frag

@@ -37,30 +37,55 @@ float random(float s) {
     return fract(sin(seed++ + s)*43758.5453123); 
 }
 
-void main() 
+vec3 randomHemisphere(vec3 dir)
 {
-    // Black by default
-    out_color = vec4(0,0,0,1);
+    vec3 uu = normalize(cross(dir, vec3(0.0,1.0,1.0)));
+    vec3 vv = cross(uu, dir);
+	
+    vec2 rv2 = vec2(random(1), random(2));
 
+	float ra = sqrt(rv2.y);
+	float rx = ra*cos(6.2831*rv2.x); 
+	float ry = ra*sin(6.2831*rv2.x);
+	float rz = sqrt(1.0-rv2.y);
+	vec3  rr = vec3(rx*uu + ry*vv + rz*dir );
+
+    return normalize(rr);
+}
+
+vec3 solve()
+{
     // Calculate ray direction
     vec3 view_dir = (_ProjMatrixInv * vec4(vert_uv, 0, 1)).xyz;
     vec3 rayDir = normalize(_ViewMatrix * vec4(view_dir,0)).xyz;
     Ray primaryRay = Ray(_CamPos, rayDir);
 
     // Raycast
-    HitResult primary = castNodes(primaryRay);
+    HitResult primary = castNodes(primaryRay, 100);
     if(primary.data > 0)
     {
-        out_color = vec4(applyLighting(primary.pos, primaryRay.dir, primary.normal, primary.data), 1.0);
+        vec3 color = applyLighting(primary.pos, primaryRay.dir, primary.normal, primary.data);
+        vec3 hitPos = primary.pos-primaryRay.dir*0.000001;
 
-        Ray shadowRay =  Ray(primary.pos-primaryRay.dir*0.000001, _SunDir);
-        HitResult shadow = castNodes(shadowRay);
-        if(shadow.data > 0) out_color *= 0.1;
-    }
-    else
-    {
-        float up = clamp(dot(primaryRay.dir, vec3(0, 1, 0)) + 0.1, 0, 1);
-        vec3 sky = vec3(0.176, 0.592, 0.901) * up;
-        out_color = vec4(sky, 1.0);
+        // Shadow ray
+        Ray shadowRay = Ray(hitPos, _SunDir);
+        HitResult shadow = castNodes(shadowRay, 50);
+        if(shadow.data > 0) color *= 0.1;
+
+        // Secondary ray
+        Ray secondRay = Ray(hitPos, randomHemisphere(primary.normal));
+        HitResult second = castNodes(secondRay, 25);
+        if(second.data > 0) color += getAlbedo(second.data) * 0.8;
+
+        return color;
     }
+
+    float up = clamp(dot(primaryRay.dir, vec3(0, 1, 0)) + 0.1, 0, 1);
+    return vec3(0.176, 0.592, 0.901) * up;
+}
+
+void main() 
+{
+    seed = 420 * vert_uv.x + 1337 * vert_uv.y + _Time * 1234;
+    out_color = vec4(solve(), 1);
 }

src/shaders/shading.cginc

@@ -1,18 +1,25 @@
+/*
+*   Returns material albedo for given voxel
+*/
+vec3 getAlbedo(uint data)
+{
+    return _Materials[data-1].albedo.rgb;
+}
+
 /*
     point: Hit point
     view: View vector (camera ray)
     normal: Normal vector
 */
-vec3 applyLighting(vec3 hitPoint, vec3 view, vec3 normal, uint brick)
+vec3 applyLighting(vec3 hitPoint, vec3 view, vec3 normal, uint data)
 {
     // Lighting
-    vec3 light_color = vec3(1.0, 1.0, 1.0);
+    vec3 light_color = vec3(1);
 
     vec3 ambient = light_color * 0.1;
     vec3 diffuse = light_color * max(1.0-dot(normal, _SunDir), 0.0);
     vec3 specular = light_color * pow(max(dot(view, reflect(_SunDir, normal)), 0.0), 32);
 
     // Combine colors
-    vec3 object_color = _Materials[brick-1].albedo.rgb;//vec3(0.0, 0.1, 0.5);
-    return (ambient + diffuse + specular) * object_color;
+    return (ambient + diffuse + specular) * getAlbedo(data);
 }