add ACES tonemapping, fix #120

ref_vk/shaders/ray.rgen

@@ -61,7 +61,7 @@ bool shadowed(vec3 pos, vec3 dir, float dist) {
 	return payload_shadow.shadow;
 }
 
-const float color_factor = 1000.;
+const float color_factor = 600.;
 
 vec3 sampleSurfaceTriangle(vec3 color, vec3 view_dir, MaterialProperties material, mat4x3 emissive_transform, mat3 emissive_transform_normal, uint triangle_index, uint index_offset, uint vertex_offset) {
 	const uint first_index_offset = index_offset + triangle_index * 3;
@@ -134,7 +134,6 @@ vec3 sampleSurfaceTriangle(vec3 color, vec3 view_dir, MaterialProperties materia
 	if (shadowed(payload_opaque.hit_pos_t.xyz, light_dir, sqrt(light_dist2)))
 		return vec3(0.);
 
-	//return vec3(color_factor);// color;
 	return color;
 }
 
@@ -291,6 +290,24 @@ vec3 traceAdditive(vec3 origin, vec3 direction, float ray_distance) {
 	return payload_additive.color * color_factor;
 }
 
+// Blatantly copypasted from https://www.shadertoy.com/view/XsGfWV
+vec3 aces_tonemap(vec3 color){
+	mat3 m1 = mat3(
+		0.59719, 0.07600, 0.02840,
+		0.35458, 0.90834, 0.13383,
+		0.04823, 0.01566, 0.83777
+	);
+	mat3 m2 = mat3(
+		1.60475, -0.10208, -0.00327,
+		-0.53108,  1.10813, -0.07276,
+		-0.07367, -0.00605,  1.07602
+	);
+	vec3 v = m1 * color;
+	vec3 a = v * (v + 0.0245786) - 0.000090537;
+	vec3 b = v * (0.983729 * v + 0.4329510) + 0.238081;
+	return pow(clamp(m2 * (a / b), 0.0, 1.0), vec3(1.0 / 2.2));
+}
+
 void main() {
 	rand01_state = push_constants.random_seed + gl_LaunchIDEXT.x * 1833 +  gl_LaunchIDEXT.y * 31337;
 	vec2 uv = (gl_LaunchIDEXT.xy + .5) / gl_LaunchSizeEXT.xy * 2. - 1.;
@@ -423,11 +440,16 @@ void main() {
 		throughput *= brdfWeight;
 	} // for all bounces
 
+	if (false)
 	{
 		vec3 prev_frame = imageLoad(previous_frame, ivec2(gl_LaunchIDEXT.xy)).rgb;
 		prev_frame *= prev_frame;
 		prev_frame *= color_factor;
 		C = mix(C, prev_frame, push_constants.prev_frame_blend_factor);
 	}
-	imageStore(image, ivec2(gl_LaunchIDEXT.xy), vec4(sqrt(C/color_factor), 1.));
+
+	C /= color_factor;
+	C = aces_tonemap(C);
+
+	imageStore(image, ivec2(gl_LaunchIDEXT.xy), vec4(C, 1.));
 }