bluecore/ode/src/collision_trimesh_plane.cpp

/*************************************************************************
 *                                                                       *
 * Open Dynamics Engine, Copyright (C) 2001-2003 Russell L. Smith.       *
 * All rights reserved.  Email: russ@q12.org   Web: www.q12.org          *
 *                                                                       *
 * This library is free software; you can redistribute it and/or         *
 * modify it under the terms of EITHER:                                  *
 *   (1) 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. The text of the GNU Lesser      *
 *       General Public License is included with this library in the     *
 *       file LICENSE.TXT.                                               *
 *   (2) The BSD-style license that is included with this library in     *
 *       the file LICENSE-BSD.TXT.                                       *
 *                                                                       *
 * 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 files    *
 * LICENSE.TXT and LICENSE-BSD.TXT for more details.                     *
 *                                                                       *
 *************************************************************************/

// TriMesh - Plane collider by David Walters, July 2006

#include <ode/collision.h>
#include <ode/matrix.h>
#include <ode/rotation.h>
#include <ode/odemath.h>

#if dTRIMESH_ENABLED

#include "collision_util.h"
#include "collision_std.h"

#define TRIMESH_INTERNAL
#include "collision_trimesh_internal.h"

#if dTRIMESH_OPCODE
int dCollideTrimeshPlane( dxGeom *o1, dxGeom *o2, int flags, dContactGeom* contacts, int skip )
{
	dIASSERT( skip >= (int)sizeof( dContactGeom ) );
	dIASSERT( o1->type == dTriMeshClass );
	dIASSERT( o2->type == dPlaneClass );

	// Alias pointers to the plane and trimesh
	dxTriMesh* trimesh = (dxTriMesh*)( o1 );
	dxPlane* plane = (dxPlane*)( o2 );

	int contact_count = 0;

	// Cache the maximum contact count.
	const int contact_max = ( flags & 0x0ffff );

	// Degenerate case where there are no contact slots.
	if ( contact_count >= contact_max )
		return contact_count; // <=== STOP HERE

	// Cache trimesh position and rotation.
	const dVector3& trimesh_pos = *(const dVector3*)dGeomGetPosition( trimesh );
	const dMatrix3& trimesh_R = *(const dMatrix3*)dGeomGetRotation( trimesh );

	//
	// For all triangles.
	//

	// Cache the triangle count.
	const int tri_count = trimesh->Data->Mesh.GetNbTriangles();

	VertexPointers VP;
	dReal alpha;
	dVector3 vertex;

#ifndef dSINGLE
	dVector3 int_vertex;		// Intermediate vertex for double precision mode.
#endif // dSINGLE

	// For each triangle
	for ( int t = 0; t < tri_count; ++t )
	{
		// Get triangle, which should also use callback.
		trimesh->Data->Mesh.GetTriangle( VP, t );

		// For each vertex.
		for ( int v = 0; v < 3; ++v )
		{
			//
			// Get Vertex
			//

#ifdef dSINGLE

			dMULTIPLY0_331( vertex, trimesh_R, (float*)( VP.Vertex[ v ] ) );

#else // dDOUBLE

			// OPCODE data is in single precision format.
			int_vertex[ 0 ] = VP.Vertex[ v ]->x;
			int_vertex[ 1 ] = VP.Vertex[ v ]->y;
			int_vertex[ 2 ] = VP.Vertex[ v ]->z;

			dMULTIPLY0_331( vertex, trimesh_R, int_vertex );

#endif // dSINGLE/dDOUBLE
			
			vertex[ 0 ] += trimesh_pos[ 0 ];
			vertex[ 1 ] += trimesh_pos[ 1 ];
			vertex[ 2 ] += trimesh_pos[ 2 ];


			//
			// Collision?
			//

			// If alpha < 0 then point is if front of plane. i.e. no contact
			// If alpha = 0 then the point is on the plane
			alpha = plane->p[ 3 ] - dDOT( plane->p, vertex );
      
			// If alpha > 0 the point is behind the plane. CONTACT!
			if ( alpha > 0 )
			{
				// Alias the contact
                dContactGeom* contact = SAFECONTACT( flags, contacts, contact_count, skip );

				contact->pos[ 0 ] = vertex[ 0 ];
				contact->pos[ 1 ] = vertex[ 1 ];
				contact->pos[ 2 ] = vertex[ 2 ];

				contact->normal[ 0 ] = plane->p[ 0 ];
				contact->normal[ 1 ] = plane->p[ 1 ];
				contact->normal[ 2 ] = plane->p[ 2 ];

				contact->depth = alpha;
				contact->g1 = plane;
				contact->g2 = trimesh;

				++contact_count;

				// All contact slots are full?
				if ( contact_count >= contact_max )
					return contact_count; // <=== STOP HERE
			}
		}
	}

	// Return contact count.
	return contact_count;
}
#endif // dTRIMESH_OPCODE

#if dTRIMESH_GIMPACT
int dCollideTrimeshPlane( dxGeom *o1, dxGeom *o2, int flags, dContactGeom* contacts, int skip )
{
	dIASSERT( skip >= (int)sizeof( dContactGeom ) );
	dIASSERT( o1->type == dTriMeshClass );
	dIASSERT( o2->type == dPlaneClass );

	// Alias pointers to the plane and trimesh
	dxTriMesh* trimesh = (dxTriMesh*)( o1 );
	vec4f plane;
	dGeomPlaneGetParams(o2, plane);

	//Find collision

	GDYNAMIC_ARRAY collision_result;
	GIM_CREATE_TRIMESHPLANE_CONTACTS(collision_result);

	gim_trimesh_plane_collision(&trimesh->m_collision_trimesh,plane,&collision_result);

	if(collision_result.m_size == 0 )
	{
	    GIM_DYNARRAY_DESTROY(collision_result);
	    return 0;
	}


	dContactGeom* pcontact;
	int contactcount = 0;
	vec4f * planecontact_results = GIM_DYNARRAY_POINTER(vec4f,collision_result);

    for(unsigned int i = 0; i < collision_result.m_size; i++ )
	{
        if(contactcount < (flags & 0xffff))
        {
            pcontact = SAFECONTACT(flags, contacts, contactcount, skip);
            contactcount++;
            pcontact->pos[0] = (*planecontact_results)[0];
            pcontact->pos[1] = (*planecontact_results)[1];
            pcontact->pos[2] = (*planecontact_results)[2];
            pcontact->pos[3] = 1.0f;

            pcontact->normal[0] = plane[0];
            pcontact->normal[1] = plane[1];
            pcontact->normal[2] = plane[2];
            pcontact->normal[3] = 0;

            pcontact->depth = (*planecontact_results)[3];
            pcontact->g1 = o1;
            pcontact->g2 = o2;

        }
        planecontact_results++;
	 }

	 GIM_DYNARRAY_DESTROY(collision_result);

	return contactcount;
}
#endif // dTRIMESH_GIMPACT


#endif // dTRIMESH_ENABLED