Adapted Escape the Dawn engine.

src/Shaders/Skybox.frag.glsl

@@ -0,0 +1,15 @@
+#version 430
+
+uniform samplerCube CubemapTexture;
+
+in VertexData {
+	vec3 TextureCoord;
+} Input;
+
+out vec4 FragColor;
+
+void main()
+{
+	FragColor = texture(CubemapTexture, Input.TextureCoord);
+	//FragColor = vec4(1.0, 1.0, 1.0, 0.0);
+}