Variable glsl_getQuadVertexPositionConst
glsl_getQuadVertexPosition: "\nvec2 getQuadVertexPosition(vec2 lower, vec2 upper) {\n const vec2 coeffs[] = vec2[](\n vec2(0.0, 0.0),\n vec2(0.0, 1.0),\n vec2(1.0, 1.0),\n vec2(1.0, 1.0),\n vec2(1.0, 0.0),\n vec2(0.0, 0.0)\n );\n int v = gl_VertexID % 6;\n return mix(lower, upper, coeffs[v]);\n}\n" = ...