implement a ping-pong framebuffer

data/shaders/copyframebuffer.frag

@@ -0,0 +1,13 @@
+#version 330
+
+uniform sampler2D uTexture;
+
+in vec2 fPosition;
+in vec2 fTextureCoordinate;
+
+layout (location = 0) out vec4 oColour;
+
+void main()
+{
+    oColour = texture(uTexture, fTextureCoordinate);
+}

data/shaders/copyframebuffer.vert

@@ -0,0 +1,42 @@
+#version 330
+
+uniform ivec2 uScreenSize;
+uniform ivec4 uBounds;
+uniform ivec4 uTextureCoordinates;
+
+in int vIndex;
+
+out vec2 fPosition;
+out vec2 fTextureCoordinate;
+
+void main()
+{
+    vec2 pos;
+    switch (vIndex) {
+    case 0:
+        pos = uBounds.xy;
+        fTextureCoordinate = uTextureCoordinates.xy;
+        break;
+    case 1:
+        pos = uBounds.zy;
+        fTextureCoordinate = uTextureCoordinates.zy;
+        break;
+    case 2:
+        pos = uBounds.zw;
+        fTextureCoordinate = uTextureCoordinates.zw;
+        break;
+    case 3:
+        pos = uBounds.xw;
+        fTextureCoordinate = uTextureCoordinates.xw;
+        break;
+    }
+
+    fPosition = pos;
+
+    // Transform screen coordinates to viewport
+    pos.x = (pos.x * (2.0 / uScreenSize.x)) - 1.0;
+    pos.y = (pos.y * (2.0 / uScreenSize.y)) - 1.0;
+    pos.y *= -1;
+
+    gl_Position = vec4(pos, 0.0, 1.0);
+}