In ResampleEffect, precompute the Lanczos function into a table.
[movit] / gamma_expansion_effect.frag
index 4733656..051d2fa 100644 (file)
@@ -1,11 +1,20 @@
 // Expand gamma curve.
 
+// Implicit uniforms:
+// 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 = INPUT(tc);
 
-       x.r = texture1D(PREFIX(expansion_curve_tex), x.r).x;
-       x.g = texture1D(PREFIX(expansion_curve_tex), x.g).x;
-       x.b = texture1D(PREFIX(expansion_curve_tex), x.b).x;
+       vec3 a = x.rgb * PREFIX(linear_scale);
+
+       // Fourth-order polynomial approximation to pow(). See the .cpp file for details.
+       vec3 b = PREFIX(c0) + (PREFIX(c1) + (PREFIX(c2) + (PREFIX(c3) + PREFIX(c4) * x.rgb) * x.rgb) * x.rgb) * x.rgb;
+
+       vec3 f = vec3(greaterThan(x.rgb, vec3(PREFIX(beta))));
+       x = vec4(mix(a, b, f), x.a);
 
        return x;
 }