A load of stuff

shaders/simple_shader.vert

@@ -1,10 +1,7 @@
 #version 450
 
-vec2 positions[3] = vec2[] (
-    vec2(0.0, -0.5),
-    vec2(0.5, 0.5),
-    vec2(-0.5, 0.5)
-);
+layout(location = 0) in vec2 position;
+
 void main() {
-  gl_Position = vec4(positions[gl_VertexIndex], 0.0, 1.0);
+  gl_Position = vec4(position, 0.0, 1.0);
 }