From 637db7ca9d0641a0dd29d83c81e2780d2674475c Mon Sep 17 00:00:00 2001 From: badlogic Date: Wed, 5 Dec 2018 15:50:26 +0100 Subject: [PATCH] [libgdx] Fix attempt for #1219. Avoid singularities that can arise when clipping polygon and to be clipped triangle overlap in some of their vertices. --- .../spine/utils/SkeletonClipping.java | 24 ++++++++++++++----- 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/utils/SkeletonClipping.java b/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/utils/SkeletonClipping.java index 7c3a12959..34616eb43 100644 --- a/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/utils/SkeletonClipping.java +++ b/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/utils/SkeletonClipping.java @@ -248,14 +248,26 @@ public class SkeletonClipping { } // v1 inside, v2 outside float c0 = inputY2 - inputY, c2 = inputX2 - inputX; - float ua = (c2 * (edgeY - inputY) - c0 * (edgeX - inputX)) / (c0 * (edgeX2 - edgeX) - c2 * (edgeY2 - edgeY)); - output.add(edgeX + (edgeX2 - edgeX) * ua); - output.add(edgeY + (edgeY2 - edgeY) * ua); + float s = (c0 * (edgeX2 - edgeX) - c2 * (edgeY2 - edgeY)); + if (Math.abs(s) > 0.000001f) { + float ua = (c2 * (edgeY - inputY) - c0 * (edgeX - inputX)) / s; + output.add(edgeX + (edgeX2 - edgeX) * ua); + output.add(edgeY + (edgeY2 - edgeY) * ua); + } else { + output.add(edgeX); + output.add(edgeY); + } } else if (side2) { // v1 outside, v2 inside float c0 = inputY2 - inputY, c2 = inputX2 - inputX; - float ua = (c2 * (edgeY - inputY) - c0 * (edgeX - inputX)) / (c0 * (edgeX2 - edgeX) - c2 * (edgeY2 - edgeY)); - output.add(edgeX + (edgeX2 - edgeX) * ua); - output.add(edgeY + (edgeY2 - edgeY) * ua); + float s = (c0 * (edgeX2 - edgeX) - c2 * (edgeY2 - edgeY)); + if (Math.abs(s) > 0.000001f) { + float ua = (c2 * (edgeY - inputY) - c0 * (edgeX - inputX)) / s; + output.add(edgeX + (edgeX2 - edgeX) * ua); + output.add(edgeY + (edgeY2 - edgeY) * ua); + } else { + output.add(edgeX); + output.add(edgeY); + } output.add(inputX2); output.add(inputY2); }