Files
OrcaSlicer/resources/shaders/110/ssao.fs
2026-05-18 17:50:01 -03:00

89 lines
3.1 KiB
GLSL

#version 110
/**
* SSAO Shader - GLSL 110 version with highlight protection
* Preserves brightness on upward-facing surfaces (top areas)
*/
uniform sampler2D color_texture;
uniform sampler2D depth_texture;
uniform sampler2D normal_texture;
uniform vec2 inv_tex_size;
uniform float z_near;
uniform float z_far;
varying vec2 tex_coord;
float linearize_depth(float depth)
{
float z = depth * 2.0 - 1.0;
return (2.0 * z_near * z_far) / (z_far + z_near - z * (z_far - z_near));
}
void main()
{
vec3 base = texture2D(color_texture, tex_coord).rgb;
float depth_center = linearize_depth(texture2D(depth_texture, tex_coord).r);
// Sample normal at current fragment (range: -1 to 1)
vec3 normal_center = texture2D(normal_texture, tex_coord).rgb * 2.0 - 1.0;
// Calculate how much the surface faces upward
// up_factor = 1.0 for surfaces pointing straight up (0,0,1)
// up_factor = 0.0 for surfaces pointing down or sideways
float up_factor = max(0.0, normal_center.z); // Assuming Z is up axis
// Alternative: if Y is up, use normal_center.y
// Enhance brightness on top surfaces (reduce AO effect)
// Top surfaces get only 30% of AO, bottom surfaces get 100%
float highlight_protection = mix(1.0, 0.3, up_factor);
// Adaptive sampling radius
float radius = mix(1.5, 4.0, depth_center / z_far);
vec2 offsets[8];
offsets[0] = vec2( 1.0, 0.0);
offsets[1] = vec2( 0.707, 0.707);
offsets[2] = vec2( 0.0, 1.0);
offsets[3] = vec2(-0.707, 0.707);
offsets[4] = vec2(-1.0, 0.0);
offsets[5] = vec2(-0.707,-0.707);
offsets[6] = vec2( 0.0, -1.0);
offsets[7] = vec2( 0.707,-0.707);
float occlusion = 0.0;
int valid_samples = 0;
for (int i = 0; i < 8; ++i) {
vec2 uv = tex_coord + offsets[i] * inv_tex_size * radius;
uv = clamp(uv, vec2(0.001), vec2(0.999));
float sample_depth = linearize_depth(texture2D(depth_texture, uv).r);
float depth_diff = max(0.0, depth_center - sample_depth);
float threshold = 0.015 * (0.5 + depth_center / z_far);
float contribution = smoothstep(0.001, threshold, depth_diff);
float diagonal_weight = 1.0 - abs(offsets[i].x * offsets[i].y) * 0.5;
occlusion += contribution * diagonal_weight;
valid_samples++;
}
if (valid_samples > 0)
occlusion /= float(valid_samples);
// Apply highlight protection - flatter/top-like surfaces get less darkening
float ao_intensity = 0.55 * highlight_protection;
float ambient_occlusion = 1.0 - occlusion * ao_intensity;
// Different min values for top vs bottom surfaces
float ao_min = mix(0.45, 0.70, up_factor); // Bottom: 0.45, Top: 0.70
ambient_occlusion = clamp(ambient_occlusion, ao_min, 1.0);
// Boost brightness on top surfaces (optional)
float brightness_boost = 1.0 + up_factor * 0.15; // 15% extra brightness on top
ambient_occlusion = pow(ambient_occlusion, 1.1) * brightness_boost;
ambient_occlusion = clamp(ambient_occlusion, 0.45, 1.05);
gl_FragColor = vec4(base * ambient_occlusion, 1.0);
}