From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Tue, 28 Jul 2015 12:01:45 +0000 (+0200)
Subject: Save a mul in YCbCrInput by folding the scaling into the matrix.
X-Git-Tag: 1.2.0~48
X-Git-Url: https://git.sesse.net/?p=movit;a=commitdiff_plain;h=61e2a7671f7b22227dcdc34dd303ae4fcc802aaa;hp=db7e679496cb587f6197822171f6fbcd61a7a6b7

Save a mul in YCbCrInput by folding the scaling into the matrix.
---

diff --git a/ycbcr_input.cpp b/ycbcr_input.cpp
index 22d689d..25fb979 100644
--- a/ycbcr_input.cpp
+++ b/ycbcr_input.cpp
@@ -143,7 +143,8 @@ void YCbCrInput::set_gl_state(GLuint glsl_program_num, const string& prefix, uns
 
 string YCbCrInput::output_fragment_shader()
 {
-	float coeff[3], offset[3], scale[3];
+	float coeff[3], offset[3];
+	double scale[3];
 
 	switch (ycbcr_format.luma_coefficients) {
 	case YCBCR_REC_601:
@@ -209,11 +210,13 @@ string YCbCrInput::output_fragment_shader()
 	// Inverting the matrix gives us what we need to go from YCbCr back to RGB.
 	Matrix3d ycbcr_to_rgb = rgb_to_ycbcr.inverse();
 
+	// Fold in the scaling.
+	ycbcr_to_rgb *= Map<const Vector3d>(scale).asDiagonal();
+
 	string frag_shader;
 
 	frag_shader = output_glsl_mat3("PREFIX(inv_ycbcr_matrix)", ycbcr_to_rgb);
 	frag_shader += output_glsl_vec3("PREFIX(offset)", offset[0], offset[1], offset[2]);
-	frag_shader += output_glsl_vec3("PREFIX(scale)", scale[0], scale[1], scale[2]);
 
 	float cb_offset_x = compute_chroma_offset(
 		ycbcr_format.cb_x_position, ycbcr_format.chroma_subsampling_x, widths[1]);
diff --git a/ycbcr_input.frag b/ycbcr_input.frag
index fbf20d1..bd6ff76 100644
--- a/ycbcr_input.frag
+++ b/ycbcr_input.frag
@@ -14,7 +14,6 @@ vec4 FUNCNAME(vec2 tc) {
 	ycbcr.z = tex2D(PREFIX(tex_cr), tc + PREFIX(cr_offset)).x;
 
 	ycbcr -= PREFIX(offset);
-	ycbcr *= PREFIX(scale);
 
 	vec4 rgba;
 	rgba.rgb = PREFIX(inv_ycbcr_matrix) * ycbcr;