pixels/shaders/shader.vert

// IMPORTANT: This shader needs to be compiled out-of-band to SPIR-V
// See: https://github.com/parasyte/pixels/issues/9

#version 450

out gl_PerVertex {
    vec4 gl_Position;
};

layout(location = 0) out vec2 v_TexCoord;

const vec2 positions[6] = vec2[6](
    // Upper left triangle
    vec2(-1.0, -1.0),
    vec2(1.0, -1.0),
    vec2(-1.0, 1.0),

    // Lower right triangle
    vec2(-1.0, 1.0),
    vec2(1.0, -1.0),
    vec2(1.0, 1.0)
);

const vec2 uv[6] = vec2[6](
    // Upper left triangle
    vec2(0.0, 0.0),
    vec2(1.0, 0.0),
    vec2(0.0, 1.0),

    // Lower right triangle
    vec2(0.0, 1.0),
    vec2(1.0, 0.0),
    vec2(1.0, 1.0)
);

void main() {
    v_TexCoord = uv[gl_VertexIndex];
    gl_Position = vec4(positions[gl_VertexIndex], 0.0, 1.0);
}