+
+vec3 tex_chess(in vec3 col1, in vec3 col2, in vec2 spos)
+{
+ float foo = step(0.5, mod(spos.x * 8.0, 1.0)) * 2.0 - 1.0;
+ float bar = step(0.5, mod(spos.y * 24.0, 1.0)) * 2.0 - 1.0;
+
+ float xor = (foo * bar) * 0.5 + 0.5;
+
+ return mix(col1, col2, xor);
+}