Improved auto-exposure and bloom

game_folder/shaders/compute/Bloom_horiz.glsl

@@ -60,7 +60,7 @@ void main() {
 
 	vec3 conv1 = vec3(0), conv2 = vec3(0);
 	int center = local_indx.x+group_size/2;
-	for(int i = max(center-int(width*5),0); i < min(center+int(width*5),buffer_size); i++)
+	for(int i = max(center-int(width*15),0); i < min(center+int(width*15),buffer_size); i++)
 	{
 		float coord = float(center-i)/width;
 		conv1 += exp(-k1*pow(coord,2))*color_buffer[i];

game_folder/shaders/compute/Bloom_vertic.glsl

@@ -63,7 +63,7 @@ void main() {
 
 	vec3 conv1 = vec3(0), conv2 = vec3(0);
 	int center = local_indx.y+group_size/2;
-	for(int i = max(center-int(width*5),0); i < min(center+int(width*5),buffer_size); i++)
+	for(int i = max(center-int(width*15),0); i < min(center+int(width*15),buffer_size); i++)
 	{
 		float coord = float(center-i)/width;
 		conv1 += exp(-k1*pow(coord,2))*color_buffer_hoz1[i];

game_folder/shaders/compute/auto_exposure_weighting.glsl

@@ -0,0 +1,19 @@
+#version 430
+
+/// DO NOT CHANGE
+#define group_size 16
+
+layout(local_size_x = group_size, local_size_y = group_size) in;
+
+layout(rgba8, binding = 0) uniform image2D final_color; 
+layout(rgba32f, binding = 1) uniform image2D output_w; 
+
+void main() {
+	ivec2 global_pos = ivec2(gl_GlobalInvocationID.xy);
+	ivec2 local_indx = ivec2(gl_LocalInvocationID.xy);
+	vec2 img_size = vec2(imageSize(final_color));
+
+	vec4 color = imageLoad(final_color, global_pos);
+	float weight = max(1.0 - length(vec2(global_pos)/img_size - 0.5), 0.f);
+	imageStore(output_w, global_pos,  vec4(length(color.xyz)*weight, weight, 0, 1));
+}

game_folder/shaders/compute/bloom.glsl

@@ -8,6 +8,6 @@ vec3 bloom_radius(vec3 color, float exposure)
 vec3 bloom_treshold(vec3 color, float exposure)
 {
 	color = clamp(color*exposure, 0, 30)/exposure;
-	vec3 mapped = Camera.bloomradius*(0.5f * tanh(2*(color * exposure - Camera.bloomtreshold)) + 0.5f);
-	return color*mapped;
+	vec3 mapped = Camera.bloomintensity*pow(color,vec3(2.f));
+	return mapped;
 }

src/Camera.cpp

@@ -100,7 +100,7 @@ void Camera::SetDirZ(vec3 dir)
 	dirz.z = dir.z;
 }
 
-#define target_brightness 0.7f
+#define target_brightness 0.85f
 void Camera::UpdateExposure(float illumination)
 {
 	exposure += auto_exposure_speed*(target_brightness - illumination)*exposure;

src/Renderer.cpp

@@ -107,6 +107,9 @@ void Renderer::Initialize(int w, int h, std::string config_f)
 		}
 	}
 
+	illumination_texture = GenerateTexture(width, height);
+	weight_shader = ComputeShader(compute_folder + "/auto_exposure_weighting.glsl");
+
 	config.close();
 }
 
@@ -184,6 +187,8 @@ void Renderer::ReInitialize(int w, int h)
 		}
 	}
 
+	illumination_texture = GenerateTexture(width, height);
+
 	config.close();
 }
 
@@ -268,14 +273,25 @@ void Renderer::Render()
 
 float Renderer::EvaluateAvgIllumination()
 {
+	//precalculation
+	glBindImageTexture(0, shader_textures[global_size.size() - 1][0], 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+	glBindImageTexture(1, illumination_texture, 0, GL_FALSE, 0, GL_READ_WRITE, GL_RGBA32F);
+	weight_shader.Run(vec2(ceil(width/16.f), ceil(height / 16.f)));
+	for (int k = 0; k < 2; k++)
+	{
+		glBindImageTexture(k, 0, 0, 0, 0, 0, 0);
+	}
+
+
+	//get the average of the texture using mipmaps
 	float* avg = new float[4];
 	int mipmap_level = floor(log2(float(std::max(width, height))));
-	glBindTexture(GL_TEXTURE_2D, shader_textures[global_size.size()-1][0]);
+	glBindTexture(GL_TEXTURE_2D, illumination_texture);
 	glGenerateMipmap(GL_TEXTURE_2D);
 	glGetTexImage(GL_TEXTURE_2D, mipmap_level, GL_RGBA, GL_FLOAT, avg);
 	GLenum err = glGetError();
 	glBindTexture(GL_TEXTURE_2D, 0);
-	return sqrt(avg[0] * avg[0] + avg[1] * avg[1] + avg[2] * avg[2]);
+	return avg[0] / avg[1];
 }
 
 GLuint Renderer::GenerateTexture(float w, float h)

src/Renderer.h

@@ -56,4 +56,7 @@ class Renderer
 	std::vector<GLuint> main_textures;
 	std::vector<std::vector<GLuint>> shader_textures;
 	std::vector<sf::Texture> input_textures;
+
+	GLuint illumination_texture;
+	ComputeShader weight_shader;
 };