Redo FBO association yet again, this time per-texture.

[movit] / gamma_compression_effect.frag

diff --git a/gamma_compression_effect.frag b/gamma_compression_effect.frag
index 8944982f6ad19c20161bcd077811b50cb20c46a5..e1e786cdf91426174011568b1367b913f3ff9d80 100644 (file)
--- a/gamma_compression_effect.frag
+++ b/gamma_compression_effect.frag
@@ -1,11 +1,24 @@
-// Compress to sRGB gamma curve.
+// Compress gamma curve.
+
+uniform float PREFIX(linear_scale);
+uniform float PREFIX(c0), PREFIX(c1), PREFIX(c2), PREFIX(c3), PREFIX(c4);
+uniform float PREFIX(beta);
 
 vec4 FUNCNAME(vec2 tc) {
-       vec4 x = LAST_INPUT(tc);
+       vec4 x = INPUT(tc);
+
+       // We could reasonably get values outside (0.0, 1.0), but the formulas below
+       // are not valid outside that range, so clamp before we do anything else.
+       x.rgb = clamp(x.rgb, 0.0, 1.0);
+
+       vec3 a = x.rgb * PREFIX(linear_scale);
+
+       // Fourth-order polynomial approximation to pow(). See the .cpp file for details.
+       vec3 s = sqrt(x.rgb);
+       vec3 b = PREFIX(c0) + (PREFIX(c1) + (PREFIX(c2) + (PREFIX(c3) + PREFIX(c4) * s) * s) * s) * s;
 
-       x.r = texture1D(PREFIX(compression_curve_tex), x.r).x;
-       x.g = texture1D(PREFIX(compression_curve_tex), x.g).x;
-       x.b = texture1D(PREFIX(compression_curve_tex), x.b).x;
+       vec3 f = vec3(greaterThan(x.rgb, vec3(PREFIX(beta))));
+       x = vec4(mix(a, b, f), x.a);
 
        return x;
 }