From 8700c2223ab60db994376b39e4e74a6309d5154a Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Tue, 22 Mar 2022 19:45:56 +0400
Subject: [PATCH] Add NV12 -> RGB shader.

---
 ui/gl/gl_shader.cpp | 31 ++++++++++++++++++++++++++-----
 ui/gl/gl_shader.h   |  1 +
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/ui/gl/gl_shader.cpp b/ui/gl/gl_shader.cpp
index 2f47edd..e28bfed 100644
--- a/ui/gl/gl_shader.cpp
+++ b/ui/gl/gl_shader.cpp
@@ -80,6 +80,16 @@ uniform sampler2D s_texture;
 	};
 }
 
+QString FragmentYUV2RGB() {
+	return R"(
+	result = vec4(
+		1.164 * y + 1.596 * v,
+		1.164 * y - 0.392 * u - 0.813 * v,
+		1.164 * y + 2.17 * u,
+		1.);
+)";
+}
+
 ShaderPart FragmentSampleYUV420Texture() {
 	return {
 		.header = R"(
@@ -92,12 +102,23 @@ uniform sampler2D v_texture;
 	float y = texture2D(y_texture, v_texcoord).a - 0.0625;
 	float u = texture2D(u_texture, v_texcoord).a - 0.5;
 	float v = texture2D(v_texture, v_texcoord).a - 0.5;
-	result = vec4(
-		1.164 * y + 1.596 * v,
-		1.164 * y - 0.392 * u - 0.813 * v,
-		1.164 * y + 2.17 * u,
-		1.);
+)" + FragmentYUV2RGB(),
+	};
+}
+
+ShaderPart FragmentSampleNV12Texture() {
+	return {
+		.header = R"(
+varying vec2 v_texcoord;
+uniform sampler2D y_texture;
+uniform sampler2D uv_texture;
 )",
+		.body = R"(
+	float y = texture2D(y_texture, v_texcoord).a - 0.0625;
+	vec2 uv = texture2D(uv_texture, v_texcoord).rg - vec2(0.5, 0.5);
+	float u = uv.x;
+	float v = uv.y;
+)" + FragmentYUV2RGB(),
 	};
 }
 
diff --git a/ui/gl/gl_shader.h b/ui/gl/gl_shader.h
index 5dce379..521b311 100644
--- a/ui/gl/gl_shader.h
+++ b/ui/gl/gl_shader.h
@@ -24,6 +24,7 @@ struct ShaderPart {
 [[nodiscard]] ShaderPart VertexPassTextureCoord(char prefix = 'v');
 [[nodiscard]] ShaderPart FragmentSampleARGB32Texture();
 [[nodiscard]] ShaderPart FragmentSampleYUV420Texture();
+[[nodiscard]] ShaderPart FragmentSampleNV12Texture();
 [[nodiscard]] ShaderPart FragmentGlobalOpacity();
 [[nodiscard]] ShaderPart VertexViewportTransform();
 [[nodiscard]] ShaderPart FragmentRoundCorners();