noperspective layout (location = 1) out vec2 vcoord_Stage0; void main() { int x = gl_InstanceID % 200; int y = gl_InstanceID / 200; int ileft = (gl_InstanceID * 929) % 17; int iright = (ileft + 1) + (gl_InstanceID * 1637) % (17 - ileft); int itop = (gl_InstanceID * 313) % 17; int ibot = (itop + 1) + (gl_InstanceID * 1901) % (17 - itop); float outset = 0.03125; outset = 0 == (x + y) % 2 ? -outset : outset; float l = float(ileft) / 16.0 - outset; float r = float(iright) / 16.0 + outset; float t = float(itop) / 16.0 - outset; float b = float(ibot) / 16.0 + outset; vec2 vertexpos; vertexpos.x = float(x) + (0 == gl_VertexID % 2 ? l : r); vertexpos.y = float(y) + (0 == gl_VertexID / 2 ? t : b); vcoord_Stage0.x = float(0 == gl_VertexID % 2 ? -1 : 1); vcoord_Stage0.y = float(0 == gl_VertexID / 2 ? -1 : 1); gl_Position = vec4(vertexpos.x, vertexpos.y, 0.0, 1.0); }