#version 450 core
#include "common.glsl"
// Separable depth-aware blur of the half-res AO buffer.

in vec2 vUV;
layout(binding = 0) uniform sampler2D uAo;
layout(binding = 1) uniform sampler2D uDepth;
uniform vec2 uDir;  // texel step along the blur axis
layout(location = 0) out vec4 fragColor;

void main() {
    float d0 = linearDepth(texture(uDepth, vUV).r);
    float sum = 0.0, wsum = 0.0;
    for (int i = -4; i <= 4; ++i) {
        vec2 uv = vUV + uDir * float(i);
        float d = linearDepth(texture(uDepth, uv).r);
        float w = exp(-float(i * i) / 12.0) * exp(-abs(d - d0) / (0.03 * d0 + 0.05));
        sum += texture(uAo, uv).r * w;
        wsum += w;
    }
    fragColor = vec4(sum / max(wsum, 1e-4));
}