Fullscreen TRIANGLE

fullscreen_tri.program

#version 330 core

layout(location = 0) in vec4 PositionIn;

const vec2 verts[3] = vec2[]( vec2(-1, -1), vec2(3, -1), vec2(-1, 3) );
const vec2 uvs[3] = vec2[]( vec2(0, 2), vec2(2, 2), vec2(0, 0) );

out block
{
    vec2 texcoord;
} OUT;

void main()
{
    vec2 position2 = verts[ gl_VertexID ];
    vec2 texcoord = uvs[ gl_VertexID ];
    OUT.texcoord = texcoord;
    gl_Position = vec4( position2, 0.0, 1.0 );
}