/*
 * MIT License
 * Author: Mark Allyn
 *
 * sweep.vert — fullscreen quad vertex shader used by the phosphor
 * accumulation ping-pong pass. vTexCoord maps 1:1 to the phosphor
 * FBO in PPI space (u=0 west, u=1 east, v=0 south, v=1 north).
 */
#version 330 core

layout(location = 0) in vec2 aPos;  // clip-space quad [-1,+1]^2

out vec2 vTexCoord;

void main() {
    gl_Position = vec4(aPos, 0.0, 1.0);
    vTexCoord   = aPos * 0.5 + 0.5;   // [0,1]^2
}