#version 450 core vec2 positions[3] = vec2[]( vec2(0.0, -0.5), vec2(0.5, 0.5), vec2(-0.5, 0.5) ); vec3 colors[3] = vec3[]( vec3(1.0, 0.0, 0.0), vec3(0.0, 1.0, 0.0), vec3(0.0, 0.0, 1.0) ); layout(location = 0) out vec3 out_frag_color; void main() { gl_Position = vec4(positions[gl_VertexIndex], 0.0, 1.0); out_frag_color = colors[gl_VertexIndex]; }