#version 120 attribute vec2 z; uniform float rotation_angle; void main() { gl_Position.x = z.x * cos(rotation_angle) - z.y * sin(rotation_angle); gl_Position.y = z.x * sin(rotation_angle) + z.y * cos(rotation_angle); gl_Position.z = 0.; gl_Position.w = 1.; gl_PointSize = 32.; }