+ | New file for volumetric

shaders/compute.glsl

@@ -80,6 +80,8 @@ struct hitInfo
 #include "shaders/random.glsl"
 #include "shaders/intersect.glsl"
 #include "shaders/scatter.glsl"
+#include "shaders/light.glsl"
+#include "shaders/volumetric.glsl"
 
 Ray	portalRay(Ray ray, hitInfo hit)
 {
@@ -139,68 +141,6 @@ hitInfo	traceRay(Ray ray)
 	return (hit);
 }
 
-float sampleHG(float g, inout uint rng_state)
-{
-    if (abs(g) < 0.001)
-        return 2.0 * randomValue(rng_state) - 1.0;
-        
-    float sqr_term = (1.0 - g * g) / (1.0 + g - 2.0 * g * randomValue(rng_state));
-    return (1.0 + g * g - sqr_term * sqr_term) / (2.0 * g);
-}
-
-vec3 sampleDirection(vec3 forward, float cos_theta, inout uint rng_state)
-{
-    float phi = 2.0 * M_PI * randomValue(rng_state);
-    float sin_theta = sqrt(max(0.0, 1.0 - cos_theta * cos_theta));
-    
-    vec3 dir;
-    dir.x = sin_theta * cos(phi);
-    dir.y = sin_theta * sin(phi);
-    dir.z = cos_theta;
-    
-    vec3 up = abs(forward.z) < 0.999 ? vec3(0, 0, 1) : vec3(1, 0, 0);
-    vec3 right = normalize(cross(up, forward));
-    up = cross(forward, right);
-    
-    return normalize(
-        dir.x * right +
-        dir.y * up +
-        dir.z * forward
-    );
-}
-
-vec3	sampleLights(vec3 position)
-{
-	vec3 light = vec3(0.0);
-
-	for (int i = 0; i < u_objectsNum; i++)
-	{
-		GPUObject obj = objects[i];
-		GPUMaterial mat = materials[obj.mat_index];
-
-		if (obj.type == 0 && mat.emission > 0.0)
-		{
-			vec3 light_dir = normalize(obj.position - position);
-			float light_dist = length(obj.position - position);
-
-			Ray shadow_ray = Ray(position + light_dir * 0.01, light_dir);
-			hitInfo shadow_hit = traceRay(shadow_ray);
-
-			if (shadow_hit.obj_index == i)
-				light += mat.emission * mat.color / (light_dist);
-		}
-	}
-
-	return (light);
-}
-
-struct VolumeProperties {
-    vec3 sigma_a;    // absorption coefficient
-    vec3 sigma_s;    // scattering coefficient
-    vec3 sigma_t;    // extinction coefficient
-    float g;         // phase function parameter
-};
-
 vec3    pathtrace(Ray ray, inout uint rng_state)
 {
 	vec3	color = vec3(1.0);
@@ -218,23 +158,10 @@ vec3    pathtrace(Ray ray, inout uint rng_state)
 	{
 		hitInfo hit = traceRay(ray);
 
-		float t_scatter = -log(randomValue(rng_state)) / volume.sigma_t.x;
+		float t_scatter = 0.0;
-        float t_surface = hit.t;
+		if (atmosScatter(volume, hit, t_scatter, rng_state))
-
-		if (t_scatter < t_surface && volume.sigma_t.x > 0.0)
         {
-            vec3 scatter_pos = ray.origin + ray.direction * t_scatter;
+			calculateVolumetricLight(t_scatter, volume, ray, color, light, transmittance, rng_state);
-            
-            transmittance *= exp(-volume.sigma_t * t_scatter);
-            color *= volume.sigma_s / volume.sigma_t;
-            
-            light += transmittance * color * sampleLights(scatter_pos);
-            
-            float cos_theta = sampleHG(volume.g, rng_state);
-            vec3 new_dir = sampleDirection(ray.direction, cos_theta, rng_state);
-            
-            ray.origin = scatter_pos;
-            ray.direction = new_dir;
             continue;
         }
 
@@ -245,7 +172,7 @@ vec3    pathtrace(Ray ray, inout uint rng_state)
 			break;
 		}
 
-		transmittance *= exp(-volume.sigma_t * t_surface);
+		transmittance *= exp(-volume.sigma_t * hit.t);
 
 		GPUObject obj = objects[hit.obj_index];
 		GPUMaterial mat = materials[obj.mat_index];
@@ -257,9 +184,7 @@ vec3    pathtrace(Ray ray, inout uint rng_state)
         color /= p;
 		//
 
-		color *= mat.color;
+		calculateLightColor(color, light, mat, hit);
-		light += mat.emission * mat.color;
-		// light += sampleLights(hit.position);
 		
 		if (mat.emission > 0.0)
 			break;

shaders/light.glsl

@@ -0,0 +1,53 @@
+
+vec3 GetEnvironmentLight(Ray ray)
+{
+	vec3 sun_pos = vec3(-1., 1.0, 0.);
+	float SunFocus = 1.5;
+	float SunIntensity = 0.5;
+
+	vec3 GroundColour = vec3(0.5, 0.5, 0.5);
+	vec3 SkyColourHorizon = vec3(135 / 255.0f, 206 / 255.0f, 235 / 255.0f);
+	vec3 SkyColourZenith = SkyColourHorizon / 2.0;
+
+	float skyGradientT = pow(smoothstep(0.0, 0.4, ray.direction.y), 0.35);
+	float groundToSkyT = smoothstep(-0.01, 0.0, ray.direction.y);
+	vec3 skyGradient = mix(SkyColourHorizon, SkyColourZenith, skyGradientT);
+	float sun = pow(max(0, dot(ray.direction, sun_pos.xyz)), SunFocus) * SunIntensity;
+	// Combine ground, sky, and sun
+	vec3 composite = mix(GroundColour, skyGradient, groundToSkyT) + sun * int(groundToSkyT >= 1);
+	return composite;
+}
+
+hitInfo	traceRay(Ray ray);
+
+vec3	sampleLights(vec3 position)
+{
+	vec3 light = vec3(0.0);
+
+	for (int i = 0; i < u_objectsNum; i++)
+	{
+		GPUObject obj = objects[i];
+		GPUMaterial mat = materials[obj.mat_index];
+
+		if (obj.type == 0 && mat.emission > 0.0)
+		{
+			vec3 light_dir = normalize(obj.position - position);
+			float light_dist = length(obj.position - position);
+
+			Ray shadow_ray = Ray(position + light_dir * 0.01, light_dir);
+			hitInfo shadow_hit = traceRay(shadow_ray);
+
+			if (shadow_hit.obj_index == i)
+				light += mat.emission * mat.color / (light_dist);
+		}
+	}
+
+	return (light);
+}
+
+void    calculateLightColor(inout vec3 color, inout vec3 light, GPUMaterial mat, hitInfo hit)
+{
+    color *= mat.color;
+    light += mat.emission * mat.color;
+    // light += sampleLights(hit.position);
+}

shaders/random.glsl

@@ -35,22 +35,3 @@ vec3 randomHemisphereDirection(vec3 normal, inout uint rng_state)
 	vec3 direction = randomDirection(rng_state);
 	return (direction * sign(dot(normal, direction)));
 }
-
-vec3 GetEnvironmentLight(Ray ray)
-{
-	vec3 sun_pos = vec3(-1., 1.0, 0.);
-	float SunFocus = 1.5;
-	float SunIntensity = 0.5;
-
-	vec3 GroundColour = vec3(0.5, 0.5, 0.5);
-	vec3 SkyColourHorizon = vec3(135 / 255.0f, 206 / 255.0f, 235 / 255.0f);
-	vec3 SkyColourZenith = SkyColourHorizon / 2.0;
-
-	float skyGradientT = pow(smoothstep(0.0, 0.4, ray.direction.y), 0.35);
-	float groundToSkyT = smoothstep(-0.01, 0.0, ray.direction.y);
-	vec3 skyGradient = mix(SkyColourHorizon, SkyColourZenith, skyGradientT);
-	float sun = pow(max(0, dot(ray.direction, sun_pos.xyz)), SunFocus) * SunIntensity;
-	// Combine ground, sky, and sun
-	vec3 composite = mix(GroundColour, skyGradient, groundToSkyT) + sun * int(groundToSkyT >= 1);
-	return composite;
-}

shaders/volumetric.glsl

@@ -0,0 +1,60 @@
+
+struct VolumeProperties {
+    vec3 sigma_a;    // absorption coefficient
+    vec3 sigma_s;    // scattering coefficient
+    vec3 sigma_t;    // extinction coefficient
+    float g;         // phase function parameter
+};
+
+float sampleHG(float g, inout uint rng_state)
+{
+    if (abs(g) < 0.001)
+        return 2.0 * randomValue(rng_state) - 1.0;
+        
+    float sqr_term = (1.0 - g * g) / (1.0 + g - 2.0 * g * randomValue(rng_state));
+    return (1.0 + g * g - sqr_term * sqr_term) / (2.0 * g);
+}
+
+vec3 sampleDirection(vec3 forward, float cos_theta, inout uint rng_state)
+{
+    float phi = 2.0 * M_PI * randomValue(rng_state);
+    float sin_theta = sqrt(max(0.0, 1.0 - cos_theta * cos_theta));
+    
+    vec3 dir;
+    dir.x = sin_theta * cos(phi);
+    dir.y = sin_theta * sin(phi);
+    dir.z = cos_theta;
+    
+    vec3 up = abs(forward.z) < 0.999 ? vec3(0, 0, 1) : vec3(1, 0, 0);
+    vec3 right = normalize(cross(up, forward));
+    up = cross(forward, right);
+    
+    return normalize(
+        dir.x * right +
+        dir.y * up +
+        dir.z * forward
+    );
+}
+
+bool atmosScatter(VolumeProperties volume, hitInfo hit, inout float t_scatter, inout uint rng_state)
+{
+    t_scatter = -log(randomValue(rng_state)) / volume.sigma_t.x;
+
+    return (t_scatter < hit.t && volume.sigma_t.x > 0.0);
+}
+
+void calculateVolumetricLight(float t_scatter, VolumeProperties volume, inout Ray ray, inout vec3 color, inout vec3 light, inout vec3 transmittance, inout uint rng_state)
+{
+    vec3 scatter_pos = ray.origin + ray.direction * t_scatter;
+            
+    transmittance *= exp(-volume.sigma_t * t_scatter);
+    color *= volume.sigma_s / volume.sigma_t;
+    
+    light += transmittance * color * sampleLights(scatter_pos);
+    
+    float cos_theta = sampleHG(volume.g, rng_state);
+    vec3 new_dir = sampleDirection(ray.direction, cos_theta, rng_state);
+    
+    ray.origin = scatter_pos;
+    ray.direction = new_dir;
+}