+ | Better random

includes/RT/Object.hpp

@@ -20,7 +20,7 @@ typedef struct s_Material
 	glm::vec3	color;
 	float		emission;
 	float		roughness;
-	float		specular;
+	float		metallic;
 }				Material;
 
 class Object

includes/RT/Scene.hpp

@@ -22,7 +22,7 @@ struct GPUObject
 	alignas(16)	glm::vec3	color;
 	float					emission;
 	float					roughness;
-	float					specular;
+	float					metallic;
 
 	float					radius; // sphere
 	alignas(16) glm::vec3	normal; // plane

scenes/cornell.rt

@@ -1,12 +1,12 @@
 
 MAT     255 255 255     0.0     0.0 0.0
-MAT     255 255 255     5.0     0.0 0.0
+MAT     255 255 255     3.0    0.0 0.0
 
 MAT     255 100 100     0.0     0.0 0.0
 MAT     100 100 255     0.0     0.0 0.0
-MAT     100 255 100   0.0     0.0 0.0
+MAT     100 255 100  	0.0     0.5 0.0
 
-MAT     255 255 255   0.0     0.98 0.0
+MAT     255 255 255   	0.0    	1.0 0.0
 
 sp		0 -1 0		1		5
 

scenes/roughness.rt

@@ -0,0 +1,21 @@
+
+
+MAT	255 255 255		5.0		0.0 0.0 // white light 0
+
+MAT	255 50 50		0.0		0.0 0.0 // red 1
+MAT	50 50 50		0.0		0.0 0.0 // gray 2 
+MAT	50 255 50		0.0		0.0 0.0 // green 3
+MAT	255 255 255		0.0		0.0 0.0 // white 4
+
+// walls of a long width box
+
+pl	0 0 -3		0 0 1		4 // back wall
+pl	0 0 3		0 0 -1		4 // front wall
+pl	4 0 0		-1 0 0		3 // right wall
+pl	-4 0 0		1 0 0		1 // left wall
+pl	0 3 0		0 -1 0		2 // ceiling
+pl	0 -3 0		0 1 0		4 // floor
+
+// light quad
+qu	-1 2.9 -1	2 0 0		0 0 2		0
+

shaders/compute.glsl

@@ -10,7 +10,7 @@ struct GPUObject {
 	vec3    color;          // 12 + 4
 	float   emission;       // 4
 	float   roughness;      // 4
-	float   specular;       // 4
+	float   metallic;       // 4
 	
 	float   radius;         // 4
 	vec3	normal;			// 12 + 4
@@ -73,24 +73,27 @@ hitInfo	traceRay(Ray ray)
 	return (hit);
 }
 
-Ray		newRay(hitInfo hit, Ray ray, vec2 uv)
+Ray		newRay(hitInfo hit, Ray ray, inout uint rng_state)
 {
+	GPUObject	obj;
 	Ray			new_ray;
-	vec3	in_unit_sphere;
+	// vec3		in_unit_sphere;
 
-	in_unit_sphere = normalize(randomVec3(uv, u_time));
-	in_unit_sphere *= sign(dot(in_unit_sphere, hit.normal));
+	obj = objects[hit.obj_index];
 
-	vec3 diffuse_dir = normalize(hit.normal + in_unit_sphere);
+	// in_unit_sphere = normalize(randomVec3(uv, u_time));
+	// in_unit_sphere *= sign(dot(in_unit_sphere, hit.normal));
+	
+	vec3 diffuse_dir = normalize(randomHemisphereDirection(hit.normal, rng_state));
 	vec3 specular_dir = reflect(ray.direction, hit.normal);
 
 	new_ray.origin = hit.position + hit.normal * 0.001;
-	new_ray.direction = mix(diffuse_dir, specular_dir, objects[hit.obj_index].roughness);
+	new_ray.direction = mix(diffuse_dir, specular_dir, obj.roughness);
 
 	return (new_ray);
 }
 
-vec3    pathtrace(Ray ray, vec2 uv)
+vec3    pathtrace(Ray ray, inout uint rng_state)
 {
 	vec3	color = vec3(1.0);
 	vec3	light = vec3(0.0);
@@ -109,13 +112,12 @@ vec3    pathtrace(Ray ray, vec2 uv)
 		GPUObject obj = objects[hit.obj_index];
 
 		color *= obj.color;
-		if (obj.emission > 0.0)
-		{
-			light += obj.emission * obj.color;
-			break;
-		}
 
-		ray = newRay(hit, ray, uv);
+		light += obj.emission * obj.color;
+		if (obj.emission > 0.0)
+			break;
+
+		ray = newRay(hit, ray, rng_state);
 	}
 	return (color * light);
 }
@@ -129,6 +131,9 @@ void main()
 	vec2 uv = (vec2(pixel_coords) / u_resolution) * 2.0 - 1.0;;
 	uv.x *= u_resolution.x / u_resolution.y;
 	
+	uint rng_state = uint(u_resolution.x) * uint(pixel_coords.y) + pixel_coords.x;
+	rng_state = rng_state + u_frameCount * 719393;
+
 	float fov = 90.0;
 	float focal_length = 1.0 / tan(radians(fov) / 2.0);
 	vec3 view_space_ray = normalize(vec3(uv.x, uv.y, -focal_length));
@@ -136,8 +141,8 @@ void main()
 	vec3 ray_direction = normalize((inverse(u_viewMatrix) * vec4(view_space_ray, 0.0)).xyz);
 	Ray ray = Ray(u_cameraPosition, ray_direction);
 
-	vec3 color = pathtrace(ray, uv);
-	color = vec3(sqrt(color.x), sqrt(color.y), sqrt(color.z));
+	vec3 color = pathtrace(ray, rng_state);
+	// color = vec3(sqrt(color.x), sqrt(color.y), sqrt(color.z));
 	
 	float blend = 1.0 / float(u_frameCount + 1);
     vec4 accum = imageLoad(accumulation_image, pixel_coords);

shaders/random.glsl

@@ -42,3 +42,32 @@ vec3 randomVec3(vec2 uv, float time)
 {
     return (vec3((random(uv, time) - 0.5) * 2, (random(uv, time) - 0.5) * 2, (random(uv, time) - 0.5) * 2));
 }
+
+float randomValue(inout uint rng_state)
+{
+	rng_state = rng_state * 747796405 + 2891336453;
+	uint result = ((rng_state >> ((rng_state >> 28) + 4)) ^ rng_state) * 277803737;
+	result = (result >> 22) ^ result;
+	return (result / 4294967295.0);
+}
+
+float randomValueNormalDistribution(inout uint rng_state)
+{
+	float theta = 2.0 * 3.14159265359 * randomValue(rng_state);
+	float rho = sqrt(-2.0 * log(randomValue(rng_state)));
+	return (rho * cos(theta));
+}
+
+vec3 randomDirection(inout uint rng_state)
+{
+	float x = randomValueNormalDistribution(rng_state);
+	float y = randomValueNormalDistribution(rng_state);
+	float z = randomValueNormalDistribution(rng_state);
+	return normalize(vec3(x, y, z));
+}
+
+vec3 randomHemisphereDirection(vec3 normal, inout uint rng_state)
+{
+	vec3 direction = randomDirection(rng_state);
+	return (direction * sign(dot(normal, direction)));
+}

srcs/class/Scene.cpp

@@ -76,7 +76,7 @@ void		Scene::updateGPUData()
 		gpu_obj.color = mat->color;
 		gpu_obj.emission = mat->emission;
 		gpu_obj.roughness = mat->roughness;
-		gpu_obj.specular = mat->specular;
+		gpu_obj.metallic = mat->metallic;
 				
 		gpu_obj.type = static_cast<int>(obj->getType());
 		

srcs/class/SceneParser.cpp

@@ -38,10 +38,10 @@ void	SceneParser::parseMaterial(std::stringstream &line)
 	float		r,g,b;
 	float		emission;
 	float		roughness;
-	float		specular;
+	float		metallic;
 	Material	*mat;
 
-	if (!(line >> r >> g >> b >> emission >> roughness >> specular))
+	if (!(line >> r >> g >> b >> emission >> roughness >> metallic))
 		throw std::runtime_error("Material: Missing material properties");
 
 	mat = new Material;
@@ -49,7 +49,7 @@ void	SceneParser::parseMaterial(std::stringstream &line)
 	mat->color = glm::vec3(r / 255.0f, g / 255.0f, b / 255.0f);
 	mat->emission = emission;
 	mat->roughness = roughness;
-	mat->specular = specular;
+	mat->metallic = metallic;
 
 	_scene->addMaterial(mat);
 }