Add background shaders

shader/background.vert

@@ -0,0 +1,11 @@
+#version 430 core
+layout (location = 0) in vec4 params;
+layout (location = 1) in vec2 winSize;
+out vec4 vParams;
+out vec2 vWinSize;
+void main()
+{
+  gl_Position = vec4(0,0,0,0);
+  vParams = params;
+  vWinSize = winSize;
+}