playcanvas
Version:
PlayCanvas WebGL game engine
43 lines (35 loc) • 2 kB
JavaScript
// Contrast Adaptive Sharpening (CAS) is used to apply the sharpening. It's based on AMD's
// FidelityFX CAS, WebGL implementation: https://www.shadertoy.com/view/wtlSWB. It's best to run it
// on a tone-mapped color buffer after post-processing, but before the UI, and so this is the
// obvious place to put it to avoid a separate render pass, even though we need to handle running it
// before the tone-mapping.
var composeCasPS = /* glsl */ `
uniform float sharpness;
// reversible LDR <-> HDR tone mapping, as CAS needs LDR input
float maxComponent(float x, float y, float z) { return max(x, max(y, z)); }
vec3 toSDR(vec3 c) { return c / (1.0 + maxComponent(c.r, c.g, c.b)); }
vec3 toHDR(vec3 c) { return c / (1.0 - maxComponent(c.r, c.g, c.b)); }
vec3 applyCas(vec3 color, vec2 uv, float sharpness) {
float x = sceneTextureInvRes.x;
float y = sceneTextureInvRes.y;
// sample 4 neighbors around the already sampled pixel, and convert it to SDR
vec3 a = toSDR(texture2DLod(sceneTexture, uv + vec2(0.0, -y), 0.0).rgb);
vec3 b = toSDR(texture2DLod(sceneTexture, uv + vec2(-x, 0.0), 0.0).rgb);
vec3 c = toSDR(color.rgb);
vec3 d = toSDR(texture2DLod(sceneTexture, uv + vec2(x, 0.0), 0.0).rgb);
vec3 e = toSDR(texture2DLod(sceneTexture, uv + vec2(0.0, y), 0.0).rgb);
// apply the sharpening
float min_g = min(a.g, min(b.g, min(c.g, min(d.g, e.g))));
float max_g = max(a.g, max(b.g, max(c.g, max(d.g, e.g))));
float sharpening_amount = sqrt(min(1.0 - max_g, min_g) / max_g);
float w = sharpening_amount * sharpness;
vec3 res = (w * (a + b + d + e) + c) / (4.0 * w + 1.0);
// remove negative colors
res = max(res, 0.0);
// convert back to HDR
return toHDR(res);
}
`;
export { composeCasPS as default };