dlls/d3dx9_36/mesh.c

 /*
 * Mesh operations specific to D3DX9.
 *
 * Copyright (C) 2009 David Adam
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include "config.h"
#include "windef.h"
#include "wingdi.h"
#include "d3dx9.h"


/*************************************************************************
 * D3DXIntersectTri
 */
BOOL WINAPI D3DXIntersectTri(CONST D3DXVECTOR3 *p0, CONST D3DXVECTOR3 *p1, CONST D3DXVECTOR3 *p2, CONST D3DXVECTOR3 *praypos, CONST D3DXVECTOR3 *praydir, FLOAT *pu, FLOAT *pv, FLOAT *pdist)
{
    D3DXMATRIX m;
    D3DXVECTOR4 vec;

    m.m[0][0] = p1->x - p0->x;
    m.m[1][0] = p2->x - p0->x;
    m.m[2][0] = -praydir->x;
    m.m[3][0] = 0.0f;
    m.m[0][1] = p1->y - p0->z;
    m.m[1][1] = p2->y - p0->z;
    m.m[2][1] = -praydir->y;
    m.m[3][1] = 0.0f;
    m.m[0][2] = p1->z - p0->z;
    m.m[1][2] = p2->z - p0->z;
    m.m[2][2] = -praydir->z;
    m.m[3][2] = 0.0f;
    m.m[0][3] = 0.0f;
    m.m[1][3] = 0.0f;
    m.m[2][3] = 0.0f;
    m.m[3][3] = 1.0f;

    vec.x = praypos->x - p0->x;
    vec.y = praypos->y - p0->y;
    vec.z = praypos->z - p0->z;
    vec.w = 0.0f;

    if ( D3DXMatrixInverse(&m, NULL, &m) )
    {
        D3DXVec4Transform(&vec, &vec, &m);
        if ( (vec.x >= 0.0f) && (vec.y >= 0.0f) && (vec.x + vec.y <= 1.0f) && (vec.z >= 0.0f) )
        {
            *pu = vec.x;
            *pv = vec.y;
            *pdist = fabs( vec.z );
            return TRUE;
        }
    }

    return FALSE;
}