luboslenco
124 lines
3.6 KiB
Plaintext
124 lines
3.6 KiB
Plaintext
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#[set(everything)]
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const constants: {
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empty: float4;
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};
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#[set(everything)]
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const sampler_linear: sampler;
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#[set(everything)]
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const height_map: tex2d;
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#[set(everything)]
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const normal_map: tex2d;
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const max_steps: float = 100.0;
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const ray_step: float = 0.005;
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const height_scale: float = 1.0;
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struct vert_in {
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pos: float2;
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}
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struct vert_out {
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pos: float4;
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tex: float2;
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}
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fun depth_to_ao_pass_vert(input: vert_in): vert_out {
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var output: vert_out;
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output.tex = input.pos.xy * 0.5 + 0.5;
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output.tex.y = 1.0 - output.tex.y;
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output.pos = float4(input.pos.xy, 0.0, 1.0);
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return output;
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}
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fun get_delta_height(hit_xy: float2, hit_z: float, uv: float2): float {
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var coord: float2 = uv + hit_xy;
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if (coord.x < 0.0 || coord.x > 1.0 || coord.y < 0.0 || coord.y > 1.0) {
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return 1000.0;
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}
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var sampled: float = sample_lod(height_map, sampler_linear, coord, 0.0).r * height_scale;
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return sampled - hit_z;
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}
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fun ray_cast(dir: float3, uv: float2, height: float): float {
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var n_dir: float3 = normalize(dir);
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var step_vec: float3 = n_dir * ray_step;
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var hit_xy: float2 = float2(0.0, 0.0);
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var hit_z: float = height + 0.001;
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var hit_coord: float3 = float3(hit_xy, hit_z);
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var prev_delta: float = get_delta_height(hit_xy, hit_z, uv);
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var prev_t: float = 0.0;
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hit_coord += step_vec;
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var t: float = ray_step;
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var i: int = 1;
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while (i < int(max_steps)) {
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var delta: float = get_delta_height(hit_coord.xy, hit_coord.z, uv);
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if (delta > 0.0 && delta < 0.2) {
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var prev_sdf: float = -prev_delta;
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var sdf: float = -delta;
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var fraction: float = prev_sdf / (prev_sdf - sdf);
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return prev_t + ray_step * fraction;
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}
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if (t > 0.02) { // max_radius
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return 0.02; // max_radius
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}
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prev_delta = delta;
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prev_t = t;
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hit_coord += step_vec;
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t += ray_step;
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i += 1;
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}
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return 0.02; // max_radius
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}
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fun tangent(n: float3): float3 {
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var t1: float3 = cross(n, float3(0.0, 0.0, 1.0));
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var t2: float3 = cross(n, float3(0.0, 1.0, 0.0));
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if (length(t1) > length(t2)) {
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return normalize(t1);
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}
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return normalize(t2);
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}
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fun depth_to_ao_pass_frag(input: vert_out): float4 {
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var height: float = sample_lod(height_map, sampler_linear, input.tex, 0.0).r * height_scale;
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var normal: float3 = sample_lod(normal_map, sampler_linear, input.tex, 0.0).rgb * 2.0 - 1.0;
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var n: float3 = normalize(normal);
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var o1: float3 = tangent(n);
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var o2: float3 = cross(o1, n);
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var c1: float3 = 0.5 * (o1 + o2);
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var c2: float3 = 0.5 * (o1 - o2);
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var col: float = ray_cast(lerp3(n, o1, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, -o1, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, o2, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, -o2, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, c1, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, -c1, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, c2, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, -c2, 0.5), input.tex, height);
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var d1: float3 = normalize(o1 + 0.5 * o2);
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var d2: float3 = normalize(o1 - 0.5 * o2);
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var d3: float3 = normalize(o2 + 0.5 * o1);
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var d4: float3 = normalize(o2 - 0.5 * o1);
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col += ray_cast(lerp3(n, d1, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, -d1, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, d2, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, -d2, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, d3, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, -d3, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, d4, 0.5), input.tex, height);
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col += ray_cast(lerp3(n, -d4, 0.5), input.tex, height);
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var f: float = (col / (16.0 * 0.02)); // max_radius
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return float4(f, f, f, 1.0);
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}
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#[pipe]
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struct pipe {
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vertex = depth_to_ao_pass_vert;
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fragment = depth_to_ao_pass_frag;
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}
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