#version 440 layout(location = 0) in vec3 position; layout(location = 1) in vec3 color; layout(location = 4) out VertOut { vec3 v_color; int a; float b; }; void main() { gl_Position = vec4(position, 1.0); v_color = color; a = gl_VertexIndex; b = 13.0f + gl_VertexIndex; }