luboslenco
81 lines
2.3 KiB
Plaintext
81 lines
2.3 KiB
Plaintext
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#[set(everything)]
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const constants: {
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screen_size_inv: float2;
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current_mip_level: int;
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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 tex: tex2d;
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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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const bloom_knee: float = 0.5;
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const bloom_threshold: float = 0.8;
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const epsilon: float = 0.000062;
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fun bloom_downsample_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 clamp_coord(coord: float2, texel_size: float2): float2 {
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var lo: float2 = texel_size * 0.5;
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var hi: float2 = float2(1.0, 1.0) - lo;
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return float2(clamp(coord.x, lo.x, hi.x), clamp(coord.y, lo.y, hi.y));
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}
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fun downsample_dual_filter(tex_coord: float2, texel_size: float2): float3 {
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var delta: float3 = float3(texel_size.xy, texel_size.x) * float3(0.5, 0.5, -0.5);
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var result: float3;
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result = sample_lod(tex, sampler_linear, clamp_coord(tex_coord, texel_size), 0.0).rgb * 4.0;
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result += sample_lod(tex, sampler_linear, clamp_coord(tex_coord - delta.xy, texel_size), 0.0).rgb;
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result += sample_lod(tex, sampler_linear, clamp_coord(tex_coord - delta.zy, texel_size), 0.0).rgb;
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result += sample_lod(tex, sampler_linear, clamp_coord(tex_coord + delta.zy, texel_size), 0.0).rgb;
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result += sample_lod(tex, sampler_linear, clamp_coord(tex_coord + delta.xy, texel_size), 0.0).rgb;
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return result * (1.0 / 8.0);
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}
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fun bloom_downsample_pass_frag(input: vert_out): float4 {
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var color: float4;
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color.rgb = downsample_dual_filter(input.tex, constants.screen_size_inv);
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if (constants.current_mip_level == 0) {
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var brightness: float = max(color.r, max(color.g, color.b));
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var softening_curve: float = brightness - bloom_threshold + bloom_knee;
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softening_curve = clamp(softening_curve, 0.0, 2.0 * bloom_knee);
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softening_curve = softening_curve * softening_curve / (4.0 * bloom_knee + epsilon);
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var contribution_factor: float = max(softening_curve, brightness - bloom_threshold);
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contribution_factor /= max(epsilon, brightness);
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color.rgb = color.rgb * contribution_factor;
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}
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color.a = 1.0;
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return color;
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}
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#[pipe]
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struct pipe {
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vertex = bloom_downsample_pass_vert;
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fragment = bloom_downsample_pass_frag;
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}
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