From 1b00a18b7c50e54928dcd273d2b6800f0c0a24f0 Mon Sep 17 00:00:00 2001
From: Mikhail Burakov <mburakov@mailbox.org>
Date: Sun, 19 Mar 2023 12:30:24 +0100
Subject: Add colorspace and ranges handling to streamer

---
 luma.glsl | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

(limited to 'luma.glsl')

diff --git a/luma.glsl b/luma.glsl
index cc56377..4dac957 100644
--- a/luma.glsl
+++ b/luma.glsl
@@ -16,15 +16,18 @@
  */
 
 uniform sampler2D img_input;
+uniform mediump mat3 colorspace;
+uniform mediump vec3 ranges[2];
 
 varying mediump vec2 texcoord;
 
-mediump float rgb2luma(in mediump vec4 rgb) {
-  // mburakov: This hardcodes BT.709 full-range.
-  return rgb.r * 0.2126 + rgb.g * 0.7152 + rgb.b * 0.0722;
+mediump vec3 rgb2yuv(in mediump vec3 rgb) {
+  mediump vec3 yuv = colorspace * rgb.rgb + vec3(0.0, 0.5, 0.5);
+  return ranges[0] + yuv * ranges[1];
 }
 
 void main() {
   mediump vec4 rgb = texture2D(img_input, texcoord);
-  gl_FragColor = vec4(rgb2luma(rgb), 0.0, 0.0, 1.0);
+  mediump vec3 yuv = rgb2yuv(rgb.rgb);
+  gl_FragColor = vec4(yuv.x, 0.0, 0.0, 1.0);
 }
-- 
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