Updated shader to now require a vertex buffer to be bound

bin/shaders/src/simple.vert

@@ -1,21 +1,11 @@
 #version 450
 
+layout(location = 0) in vec2 in_position;
+layout(location = 1) in vec3 in_colour;
 layout(location = 0) out vec3 fragColour;
 
-vec2 positions[3] = vec2[](
-    vec2(0.0, -0.5),
-    vec2(0.5, 0.5),
-    vec2(-0.5, 0.5)
-);
-
-vec3 colours[3] = vec3[](
-    vec3(1.0, 0.0, 0.0),
-    vec3(0.0, 1.0, 0.0),
-    vec3(0.0, 0.0, 1.0)
-);
-
 void main()
 {
-    gl_Position = vec4(positions[gl_VertexIndex], 0.0, 1.0);
-    fragColour = colours[gl_VertexIndex];
+    gl_Position = vec4(in_position, 0.0, 1.0);
+    fragColour = in_colour;
 }