Setup entry point + integrated moonworks stuff

Nerfed.Runtime/Graphics/StockShaders/Source/video_yuv2rgba.frag

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+/*
+ * This effect is based on the YUV-to-RGBA GLSL shader found in SDL.
+ * Thus, it also released under the zlib license:
+ * http://libsdl.org/license.php
+ */
+#version 450
+
+layout(location = 0) in vec2 TexCoord;
+
+layout(location = 0) out vec4 FragColor;
+
+layout(set = 2, binding = 0) uniform sampler2D YSampler;
+layout(set = 2, binding = 1) uniform sampler2D USampler;
+layout(set = 2, binding = 2) uniform sampler2D VSampler;
+
+/* More info about colorspace conversion:
+ * http://www.equasys.de/colorconversion.html
+ * http://www.equasys.de/colorformat.html
+ */
+
+const vec3 offset = vec3(-0.0625, -0.5, -0.5);
+const vec3 Rcoeff = vec3(1.164,  0.000,  1.793);
+const vec3 Gcoeff = vec3(1.164, -0.213, -0.533);
+const vec3 Bcoeff = vec3(1.164,  2.112,  0.000);
+
+void main()
+{
+	vec3 yuv;
+	yuv.x = texture(YSampler, TexCoord).r;
+	yuv.y = texture(USampler, TexCoord).r;
+	yuv.z = texture(VSampler, TexCoord).r;
+	yuv += offset;
+
+	FragColor.r = dot(yuv, Rcoeff);
+	FragColor.g = dot(yuv, Gcoeff);
+	FragColor.b = dot(yuv, Bcoeff);
+	FragColor.a = 1.0;
+}