/*
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* Java port of Bullet (c) 2008 Martin Dvorak <jezek2@advel.cz>
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*
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* This source file is part of GIMPACT Library.
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*
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* For the latest info, see http://gimpact.sourceforge.net/
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*
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* Copyright (c) 2007 Francisco Leon Najera. C.C. 80087371.
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* email: projectileman@yahoo.com
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*
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* This software is provided 'as-is', without any express or implied warranty.
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* In no event will the authors be held liable for any damages arising from
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* the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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package com.bulletphysics.extras.gimpact;
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import com.bulletphysics.BulletGlobals;
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import com.bulletphysics.linearmath.VectorUtil;
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import com.bulletphysics.util.ArrayPool;
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import com.bulletphysics.util.ObjectArrayList;
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import javax.vecmath.Vector3f;
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import javax.vecmath.Vector4f;
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/**
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*
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* @author jezek2
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*/
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class ClipPolygon {
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public static float distance_point_plane(Vector4f plane, Vector3f point) {
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return VectorUtil.dot3(point, plane) - plane.w;
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}
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/**
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* Vector blending. Takes two vectors a, b, blends them together.
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*/
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public static void vec_blend(Vector3f vr, Vector3f va, Vector3f vb, float blend_factor) {
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vr.scale(1f - blend_factor, va);
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vr.scaleAdd(blend_factor, vb, vr);
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}
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/**
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* This function calcs the distance from a 3D plane.
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*/
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public static void plane_clip_polygon_collect(Vector3f point0, Vector3f point1, float dist0, float dist1, ObjectArrayList<Vector3f> clipped, int[] clipped_count) {
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boolean _prevclassif = (dist0 > BulletGlobals.SIMD_EPSILON);
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boolean _classif = (dist1 > BulletGlobals.SIMD_EPSILON);
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if (_classif != _prevclassif) {
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float blendfactor = -dist0 / (dist1 - dist0);
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vec_blend(clipped.getQuick(clipped_count[0]), point0, point1, blendfactor);
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clipped_count[0]++;
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}
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if (!_classif) {
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clipped.getQuick(clipped_count[0]).set(point1);
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clipped_count[0]++;
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}
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}
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/**
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* Clips a polygon by a plane.
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*
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* @return The count of the clipped counts
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*/
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public static int plane_clip_polygon(Vector4f plane, ObjectArrayList<Vector3f> polygon_points, int polygon_point_count, ObjectArrayList<Vector3f> clipped) {
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ArrayPool<int[]> intArrays = ArrayPool.get(int.class);
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int[] clipped_count = intArrays.getFixed(1);
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clipped_count[0] = 0;
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// clip first point
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float firstdist = distance_point_plane(plane, polygon_points.getQuick(0));
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if (!(firstdist > BulletGlobals.SIMD_EPSILON)) {
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clipped.getQuick(clipped_count[0]).set(polygon_points.getQuick(0));
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clipped_count[0]++;
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}
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float olddist = firstdist;
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for (int i=1; i<polygon_point_count; i++) {
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float dist = distance_point_plane(plane, polygon_points.getQuick(i));
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plane_clip_polygon_collect(
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polygon_points.getQuick(i - 1), polygon_points.getQuick(i),
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olddist,
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dist,
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clipped,
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clipped_count);
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olddist = dist;
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}
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// RETURN TO FIRST point
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plane_clip_polygon_collect(
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polygon_points.getQuick(polygon_point_count - 1), polygon_points.getQuick(0),
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olddist,
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firstdist,
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clipped,
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clipped_count);
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int ret = clipped_count[0];
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intArrays.release(clipped_count);
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return ret;
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}
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/**
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* Clips a polygon by a plane.
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*
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* @param clipped must be an array of 16 points.
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* @return the count of the clipped counts
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*/
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public static int plane_clip_triangle(Vector4f plane, Vector3f point0, Vector3f point1, Vector3f point2, ObjectArrayList<Vector3f> clipped) {
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ArrayPool<int[]> intArrays = ArrayPool.get(int.class);
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int[] clipped_count = intArrays.getFixed(1);
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clipped_count[0] = 0;
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// clip first point0
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float firstdist = distance_point_plane(plane, point0);
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if (!(firstdist > BulletGlobals.SIMD_EPSILON)) {
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clipped.getQuick(clipped_count[0]).set(point0);
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clipped_count[0]++;
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}
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// point 1
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float olddist = firstdist;
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float dist = distance_point_plane(plane, point1);
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plane_clip_polygon_collect(
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point0, point1,
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olddist,
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dist,
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clipped,
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clipped_count);
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olddist = dist;
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// point 2
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dist = distance_point_plane(plane, point2);
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plane_clip_polygon_collect(
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point1, point2,
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olddist,
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dist,
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clipped,
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clipped_count);
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olddist = dist;
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// RETURN TO FIRST point0
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plane_clip_polygon_collect(
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point2, point0,
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olddist,
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firstdist,
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clipped,
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clipped_count);
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int ret = clipped_count[0];
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intArrays.release(clipped_count);
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return ret;
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}
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}
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