// MinecraftPT — RTWSM Blur Importance
// Gaussian-blurs the importance map to make the warp smooth.

#include "/Lib/Settings.glsl"
#include "/Lib/Utilities.glsl"

const ivec3 workGroups = ivec3(32, 16, 1);
layout (local_size_x = 32, local_size_y = 32) in;

layout (r32f) uniform writeonly image2D img_rtwImportance2D;

uniform sampler2D rtwImportance2D;

void main(){
	ivec2 texel = ivec2(gl_GlobalInvocationID.xy);

	float importance = 0.0;
	float weightSum = 0.0;

	int radius = int(RTW_BLUR_FACTOR);

	for (int i = -radius; i <= radius; i++){
	for (int j = -radius; j <= radius; j++){
		vec2 coord = vec2(texel + ivec2(i, j)) / vec2(RTW_RESOLUTION, RTW_RESOLUTION_Y);
		float w = exp(-(i * i + j * j) / (2.0 * RTW_BLUR_FACTOR * RTW_BLUR_FACTOR));
		importance += textureLod(rtwImportance2D, coord, 0.0).r * w;
		weightSum += w;
	}}

	imageStore(img_rtwImportance2D, texel, vec4(importance / weightSum));
}