1 files changed, 30 insertions, 0 deletions
diff --git a/luma.glsl b/luma.glsl
new file mode 100644
index 0000000..cc56377
--- /dev/null
+++ b/luma.glsl
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2023 Mikhail Burakov. This file is part of streamer.
+ *
+ * streamer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * streamer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with streamer.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+uniform sampler2D img_input;
+
+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;
+}
+
+void main() {
+  mediump vec4 rgb = texture2D(img_input, texcoord);
+  gl_FragColor = vec4(rgb2luma(rgb), 0.0, 0.0, 1.0);
+}