#version 300 es #ifdef GL_ES precision mediump float; #endif out vec2 tex; void main() { float idHigh = float(gl_VertexID >> 1); float idLow = float(gl_VertexID & int(1)); float x = idHigh * 4.0 - 1.0; float y = idLow * 4.0 - 1.0; float u = idHigh * 2.0; float v = idLow * 2.0; gl_Position = vec4(x, y, 0.0, 1.0); tex = vec2(u, v); }