diff --git a/libweston/renderer-gl/fragment.glsl b/libweston/renderer-gl/fragment.glsl
index 1a8b1ef8..7361df71 100644
--- a/libweston/renderer-gl/fragment.glsl
+++ b/libweston/renderer-gl/fragment.glsl
@@ -127,14 +127,17 @@ uniform sampler2D tex2;
 uniform float view_alpha;
 uniform vec4 unicolor;
 
+#define MAX_CURVE_PARAMS 10
+#define MAX_CURVESET_PARAMS (MAX_CURVE_PARAMS * 3)
+
 uniform HIGHPRECISION sampler2D color_pre_curve_lut_2d;
 uniform HIGHPRECISION vec2 color_pre_curve_lut_scale_offset;
-uniform HIGHPRECISION float color_pre_curve_params[30];
+uniform HIGHPRECISION float color_pre_curve_params[MAX_CURVESET_PARAMS];
 uniform bool color_pre_curve_clamped_input;
 
 uniform HIGHPRECISION sampler2D color_post_curve_lut_2d;
 uniform HIGHPRECISION vec2 color_post_curve_lut_scale_offset;
-uniform HIGHPRECISION float color_post_curve_params[30];
+uniform HIGHPRECISION float color_post_curve_params[MAX_CURVESET_PARAMS];
 uniform bool color_post_curve_clamped_input;
 
 #if DEF_COLOR_MAPPING == SHADER_COLOR_MAPPING_3DLUT
@@ -245,19 +248,22 @@ powlin(float x, float g, float a, float b, float c, float d)
 }
 
 float
-sample_color_pre_curve_linpow(float x, compile_const int color_channel)
+sample_linpow(float params[MAX_CURVESET_PARAMS], bool must_clamp,
+	      float x, compile_const int color_channel)
 {
 	float g, a, b, c, d;
 
-	/* For each color channel we have 10 parameters. The params are
-	 * linearized in an array of size 30, in RGB order. */
-	g = color_pre_curve_params[0 + (color_channel * 10)];
-	a = color_pre_curve_params[1 + (color_channel * 10)];
-	b = color_pre_curve_params[2 + (color_channel * 10)];
-	c = color_pre_curve_params[3 + (color_channel * 10)];
-	d = color_pre_curve_params[4 + (color_channel * 10)];
+	/*
+	 * For each color channel we have MAX_CURVE_PARAMS parameters.
+	 * The parameters for the three curves are stored in RGB order.
+	 */
+	g = params[0 + color_channel * MAX_CURVE_PARAMS];
+	a = params[1 + color_channel * MAX_CURVE_PARAMS];
+	b = params[2 + color_channel * MAX_CURVE_PARAMS];
+	c = params[3 + color_channel * MAX_CURVE_PARAMS];
+	d = params[4 + color_channel * MAX_CURVE_PARAMS];
 
-	if (color_pre_curve_clamped_input)
+	if (must_clamp)
 		x = clamp(x, 0.0, 1.0);
 
 	/* We use mirroring for negative input values. */
@@ -267,6 +273,15 @@ sample_color_pre_curve_linpow(float x, compile_const int color_channel)
 	return linpow(x, g, a, b, c, d);
 }
 
+vec3
+sample_linpow_vec3(float params[MAX_CURVESET_PARAMS], bool must_clamp,
+		   vec3 color)
+{
+	return vec3(sample_linpow(params, must_clamp, color.r, 0),
+		    sample_linpow(params, must_clamp, color.g, 1),
+		    sample_linpow(params, must_clamp, color.b, 2));
+}
+
 float
 sample_color_pre_curve_powlin(float x, compile_const int color_channel)
 {
@@ -290,29 +305,6 @@ sample_color_pre_curve_powlin(float x, compile_const int color_channel)
 	return powlin(x, g, a, b, c, d);
 }
 
-float
-sample_color_post_curve_linpow(float x, compile_const int color_channel)
-{
-	float g, a, b, c, d;
-
-	/* For each color channel we have 10 parameters. The params are
-	 * linearized in an array of size 30, in RGB order. */
-	g = color_post_curve_params[0 + (color_channel * 10)];
-	a = color_post_curve_params[1 + (color_channel * 10)];
-	b = color_post_curve_params[2 + (color_channel * 10)];
-	c = color_post_curve_params[3 + (color_channel * 10)];
-	d = color_post_curve_params[4 + (color_channel * 10)];
-
-	if (color_post_curve_clamped_input)
-		x = clamp(x, 0.0, 1.0);
-
-	/* We use mirroring for negative input values. */
-	if (x < 0.0)
-		return -linpow(-x, g, a, b, c, d);
-
-	return linpow(x, g, a, b, c, d);
-}
-
 float
 sample_color_post_curve_powlin(float x, compile_const int color_channel)
 {
@@ -348,10 +340,9 @@ color_pre_curve(vec3 color)
 				       color_pre_curve_lut_scale_offset,
 				       color);
 	} else if (c_color_pre_curve == SHADER_COLOR_CURVE_LINPOW) {
-		ret.r = sample_color_pre_curve_linpow(color.r, 0);
-		ret.g = sample_color_pre_curve_linpow(color.g, 1);
-		ret.b = sample_color_pre_curve_linpow(color.b, 2);
-		return ret;
+		return sample_linpow_vec3(color_pre_curve_params,
+					  color_pre_curve_clamped_input,
+					  color);
 	} else if (c_color_pre_curve == SHADER_COLOR_CURVE_POWLIN) {
 		ret.r = sample_color_pre_curve_powlin(color.r, 0);
 		ret.g = sample_color_pre_curve_powlin(color.g, 1);
@@ -399,10 +390,9 @@ color_post_curve(vec3 color)
 				       color_post_curve_lut_scale_offset,
 				       color);
 	} else if (c_color_post_curve == SHADER_COLOR_CURVE_LINPOW) {
-		ret.r = sample_color_post_curve_linpow(color.r, 0);
-		ret.g = sample_color_post_curve_linpow(color.g, 1);
-		ret.b = sample_color_post_curve_linpow(color.b, 2);
-		return ret;
+		return sample_linpow_vec3(color_post_curve_params,
+					  color_post_curve_clamped_input,
+					  color);
 	} else if (c_color_post_curve == SHADER_COLOR_CURVE_POWLIN) {
 		ret.r = sample_color_post_curve_powlin(color.r, 0);
 		ret.g = sample_color_post_curve_powlin(color.g, 1);