Correction for negative affine parallax

2026-05-21 16:23:23 -05:00
1 changed files with 7 additions and 2 deletions
@@ -1065,8 +1065,13 @@ static void vipDrawAffine(VB *sim, World *world) {

            /* Adjust left-edge parameters */
            if ((mp < 0) ^ i) {
-                mx += dx * (wx + mp);
-                my += dy * (wx + mp);
+                if (mp < 0) {
+                    mx += dx * (wx - mp);
+                    my += dy * (wx - mp);
+                } else {
+                    mx += dx * (wx + mp);
+                    my += dy * (wx + mp);
+                }
            } else {
                mx += dx * wx;
                my += dy * wx;