feat: change covert yuv to rgb param

Close #46

QtScrcpy/device/render/qyuvopenglwidget.cpp

@@ -50,14 +50,18 @@ static QString s_fragShader = R"(
     {
         vec3 yuv;
         vec3 rgb;
+        // SDL2-2.0.10\src\render\opengl\SDL_shaders_gl.c BT709_SHADER_CONSTANTS
+        const vec3 Rcoeff = vec3(1.1644,  0.000,  1.7927);
+        const vec3 Gcoeff = vec3(1.1644, -0.2132, -0.5329);
+        const vec3 Bcoeff = vec3(1.1644,  2.1124,  0.000);
         // 根据指定的纹理textureY和坐标textureOut来采样
         yuv.x = texture2D(textureY, textureOut).r;
         yuv.y = texture2D(textureU, textureOut).r - 0.5;
         yuv.z = texture2D(textureV, textureOut).r - 0.5;
         // 采样完转为rgb
-        rgb = mat3(1.0, 1.0, 1.0,
-                    0.0, -0.39465, 2.03211,
-                    1.13983, -0.58060, 0.0) * yuv;
+        rgb.r = dot(yuv, Rcoeff);
+        rgb.g = dot(yuv, Gcoeff);
+        rgb.b = dot(yuv, Bcoeff);
         // 输出颜色值
         gl_FragColor = vec4(rgb, 1.0);
     }