X-Git-Url: https://git.sesse.net/?p=movit;a=blobdiff_plain;f=gamma_expansion_effect.frag;h=359b026450c916f52d9f486bac11c2f6dcff3b71;hp=4a5db9e178d53abbdc0c22a76a3c0c439baab564;hb=refs%2Fheads%2Fepoxy;hpb=2ced784c6599cb0b21427481ee17f4c8f6afdada

diff --git a/gamma_expansion_effect.frag b/gamma_expansion_effect.frag
index 4a5db9e..359b026 100644
--- a/gamma_expansion_effect.frag
+++ b/gamma_expansion_effect.frag
@@ -1,11 +1,19 @@
-// Expand sRGB gamma curve.
+// Expand 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);
+
+	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;
 
-	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 f = vec3(greaterThan(x.rgb, vec3(PREFIX(beta))));
+	x = vec4(mix(a, b, f), x.a);
 
 	return x;
 }