btTriangleShapeEx.cpp

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/*
This source file is part of GIMPACT Library.
 
For the latest info, see http://gimpact.sourceforge.net/
 
Copyright (c) 2007 Francisco Leon Najera. C.C. 80087371.
email: projectileman@yahoo.com
 
 
This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it freely,
subject to the following restrictions:
 
1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
 
#include "btTriangleShapeEx.h"
 
void GIM_TRIANGLE_CONTACT::merge_points(const btVector4& plane,
                                        btScalar margin, const btVector3* points, int point_count)
{
    m_point_count = 0;
    m_penetration_depth = -1000.0f;
 
    int point_indices[MAX_TRI_CLIPPING];
 
    int _k;
 
    for (_k = 0; _k < point_count; _k++)
    {
        btScalar _dist = -bt_distance_point_plane(plane, points[_k]) + margin;
 
        if (_dist >= 0.0f)
        {
            if (_dist > m_penetration_depth)
            {
                m_penetration_depth = _dist;
                point_indices[0] = _k;
                m_point_count = 1;
            }
            else if ((_dist + SIMD_EPSILON) >= m_penetration_depth)
            {
                point_indices[m_point_count] = _k;
                m_point_count++;
            }
        }
    }
 
    for (_k = 0; _k < m_point_count; _k++)
    {
        m_points[_k] = points[point_indices[_k]];
    }
}
 
bool btPrimitiveTriangle::overlap_test_conservative(const btPrimitiveTriangle& other)
{
    btScalar total_margin = m_margin + other.m_margin;
    // classify points on other triangle
    btScalar dis0 = bt_distance_point_plane(m_plane, other.m_vertices[0]) - total_margin;
 
    btScalar dis1 = bt_distance_point_plane(m_plane, other.m_vertices[1]) - total_margin;
 
    btScalar dis2 = bt_distance_point_plane(m_plane, other.m_vertices[2]) - total_margin;
 
    if (dis0 > 0.0f && dis1 > 0.0f && dis2 > 0.0f) return false;
 
    // classify points on this triangle
    dis0 = bt_distance_point_plane(other.m_plane, m_vertices[0]) - total_margin;
 
    dis1 = bt_distance_point_plane(other.m_plane, m_vertices[1]) - total_margin;
 
    dis2 = bt_distance_point_plane(other.m_plane, m_vertices[2]) - total_margin;
 
    if (dis0 > 0.0f && dis1 > 0.0f && dis2 > 0.0f) return false;
 
    return true;
}
 
int btPrimitiveTriangle::clip_triangle(btPrimitiveTriangle& other, btVector3* clipped_points)
{
    // edge 0
 
    btVector3 temp_points[MAX_TRI_CLIPPING];
 
    btVector4 edgeplane;
 
    get_edge_plane(0, edgeplane);
 
    int clipped_count = bt_plane_clip_triangle(
        edgeplane, other.m_vertices[0], other.m_vertices[1], other.m_vertices[2], temp_points);
 
    if (clipped_count == 0) return 0;
 
    btVector3 temp_points1[MAX_TRI_CLIPPING];
 
    // edge 1
    get_edge_plane(1, edgeplane);
 
    clipped_count = bt_plane_clip_polygon(edgeplane, temp_points, clipped_count, temp_points1);
 
    if (clipped_count == 0) return 0;
 
    // edge 2
    get_edge_plane(2, edgeplane);
 
    clipped_count = bt_plane_clip_polygon(
        edgeplane, temp_points1, clipped_count, clipped_points);
 
    return clipped_count;
}
 
bool btPrimitiveTriangle::find_triangle_collision_clip_method(btPrimitiveTriangle& other, GIM_TRIANGLE_CONTACT& contacts)
{
    btScalar margin = m_margin + other.m_margin;
 
    btVector3 clipped_points[MAX_TRI_CLIPPING];
    int clipped_count;
    //create planes
    // plane v vs U points
 
    GIM_TRIANGLE_CONTACT contacts1;
 
    contacts1.m_separating_normal = m_plane;
 
    clipped_count = clip_triangle(other, clipped_points);
 
    if (clipped_count == 0)
    {
        return false;  //Reject
    }
 
    //find most deep interval face1
    contacts1.merge_points(contacts1.m_separating_normal, margin, clipped_points, clipped_count);
    if (contacts1.m_point_count == 0) return false;  // too far
    //Normal pointing to this triangle
    contacts1.m_separating_normal *= -1.f;
 
    //Clip tri1 by tri2 edges
    GIM_TRIANGLE_CONTACT contacts2;
    contacts2.m_separating_normal = other.m_plane;
 
    clipped_count = other.clip_triangle(*this, clipped_points);
 
    if (clipped_count == 0)
    {
        return false;  //Reject
    }
 
    //find most deep interval face1
    contacts2.merge_points(contacts2.m_separating_normal, margin, clipped_points, clipped_count);
    if (contacts2.m_point_count == 0) return false;  // too far
 
    if (contacts2.m_penetration_depth < contacts1.m_penetration_depth)
    {
        contacts.copy_from(contacts2);
    }
    else
    {
        contacts.copy_from(contacts1);
    }
    return true;
}
 
 
bool btTriangleShapeEx::overlap_test_conservative(const btTriangleShapeEx& other)
{
    btScalar total_margin = getMargin() + other.getMargin();
 
    btVector4 plane0;
    buildTriPlane(plane0);
    btVector4 plane1;
    other.buildTriPlane(plane1);
 
    // classify points on other triangle
    btScalar dis0 = bt_distance_point_plane(plane0, other.m_vertices1[0]) - total_margin;
 
    btScalar dis1 = bt_distance_point_plane(plane0, other.m_vertices1[1]) - total_margin;
 
    btScalar dis2 = bt_distance_point_plane(plane0, other.m_vertices1[2]) - total_margin;
 
    if (dis0 > 0.0f && dis1 > 0.0f && dis2 > 0.0f) return false;
 
    // classify points on this triangle
    dis0 = bt_distance_point_plane(plane1, m_vertices1[0]) - total_margin;
 
    dis1 = bt_distance_point_plane(plane1, m_vertices1[1]) - total_margin;
 
    dis2 = bt_distance_point_plane(plane1, m_vertices1[2]) - total_margin;
 
    if (dis0 > 0.0f && dis1 > 0.0f && dis2 > 0.0f) return false;
 
    return true;
}