flash.vert -> quad.vert

render.conf

@@ -1,6 +1,6 @@
 vert[SCENE] = shaders/main.vert
 frag[SCENE] = shaders/main.frag
-vert[POST0] = shaders/flash.vert
+vert[POST0] = shaders/quad.vert
 frag[POST0] = shaders/flash.frag
 vert[POST1] = shaders/ripple.vert
 frag[POST1] = shaders/ripple.frag

shaders/flash.vert

@@ -1,12 +0,0 @@
-#version 330
-
-precision mediump float;
-
-out vec2 uv;
-
-void main(void)
-{
-    uv.x = (gl_VertexID & 1);
-    uv.y = ((gl_VertexID >> 1) & 1);
-    gl_Position = vec4(uv * 2.0 - 1.0, 0.0, 1.0);
-}

shaders/quad.vert

@@ -0,0 +1,16 @@
+// Single triangle strip quad generated entirely on the vertex shader.
+// Simply do glDrawArrays(GL_TRIANGLE_STRIP, 0, 4) and the shader
+// generates 4 points from gl_VertexID. No Vertex Attributes are
+// required.
+#version 330
+
+precision mediump float;
+
+out vec2 uv;
+
+void main(void)
+{
+    uv.x = (gl_VertexID & 1);
+    uv.y = ((gl_VertexID >> 1) & 1);
+    gl_Position = vec4(uv * 2.0 - 1.0, 0.0, 1.0);
+}