+ /* For the back face we need to negate the X and Y component
+ * dot products. dots.Z has the negated back-face specular
+ * exponent. We swizzle that into the W position. This
+ * negation makes the back-face specular term positive again.
+ */
+ dots = negate(swizzle(dots,X,Y,W,Z));
+
+ if (!is_undef(att)) {
+ emit_op1(p, OPCODE_LIT, lit, 0, dots);
+ emit_op2(p, OPCODE_MUL, lit, 0, lit, att);
+ emit_op3(p, OPCODE_MAD, _bfc0, 0, swizzle1(lit,X), ambient, _bfc0);
+ }
+ else if (!p->state->material_shininess_is_zero) {
+ emit_op1(p, OPCODE_LIT, lit, 0, dots);
+ emit_op2(p, OPCODE_ADD, _bfc0, 0, ambient, _bfc0); /**/
+ }
+ else {
+ emit_degenerate_lit(p, lit, dots);
+ emit_op2(p, OPCODE_ADD, _bfc0, 0, ambient, _bfc0);
+ }
+