source: trunk/src/testing/app/volvis/vCut.cpp @ 4

/********************************************************************************
 * Volatile - Volume Visualization Software for SAGE
 * Copyright (C) 2004 Electronic Visualization Laboratory,
 * University of Illinois at Chicago
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
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 *  * Redistributions of source code must retain the above copyright
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 *  * Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following disclaimer
 *    in the documentation and/or other materials provided with the distribution.
 *  * Neither the name of the University of Illinois at Chicago nor
 *    the names of its contributors may be used to endorse or promote
 *    products derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Direct questions, comments etc about Volatile to www.evl.uic.edu/cavern/forum
 *********************************************************************************/s

#include "vCut.h"
#include "MatrixMath.h"
#include "global.h"

vCut::vCut() {
}



//called from textures draw
void vCut::setTransform(float objectXform[]) {
        float temp[3];
        temp[0]=objectXform[0]*global.cut.axis[0]+
                        objectXform[4]*global.cut.axis[1]+objectXform[8]*global.cut.axis[2];
        temp[1]=objectXform[1]*global.cut.axis[0]+
                        objectXform[5]*global.cut.axis[1]+objectXform[9]*global.cut.axis[2];
        temp[2]=objectXform[2]*global.cut.axis[0]+
                        objectXform[6]*global.cut.axis[1]+objectXform[10]*global.cut.axis[2];
        computeMatrix(global.cut.angle,temp,&global.cut.transform[0]);
}


void vCut::disable() {
        glDisable(GL_CLIP_PLANE0);
}

void vCut::enable() {
        global.cut.user[0] = -global.cut.transform[0];
        global.cut.user[1]=global.cut.transform[1];
        global.cut.user[2]=-global.cut.transform[2];

//      fprintf(stderr,"cut plane %f %f %f %f\n",global.cut.user[0],global.cut.user[1],
                        //              global.cut.user[2], global.cut.user[3]);
        //create the points for the corners of the clip plane
        for (int ii=0;ii<4;ii++){
                plane[ii*3+0]=global.cut.transform[0]*global.cut.user[3];
                plane[ii*3+1]=-global.cut.transform[1]*global.cut.user[3];
                plane[ii*3+2]=global.cut.transform[2]*global.cut.user[3];
                plane[ii*3+0]-=global.cut.transform[4]*((ii<2)?0.5f:-0.5f);
                plane[ii*3+1] +=global.cut.transform[5]*((ii<2)?0.5f:-0.5f);
                plane[ii*3+2]-=global.cut.transform[6]*((ii<2)?0.5f:-0.5f);
                plane[ii*3+0]-=global.cut.transform[8]*((ii&0x1)?-0.5f:0.5f);
                plane[ii*3+1]+=global.cut.transform[9]*((ii&0x1)?-0.5f:0.5f);
                plane[ii*3+2]-=global.cut.transform[10]*((ii&0x1)?-0.5f:0.5f);
        }

        //configure the clip planes
        glClipPlane(GL_CLIP_PLANE0,global.cut.user);
        glEnable(GL_CLIP_PLANE0);
}

void vCut::draw() {
        glEnable(GL_TEXTURE_3D);
        glDepthMask(GL_FALSE);
        glPolygonMode(GL_FRONT, GL_LINE);
        glPolygonMode(GL_BACK, GL_LINE);
        glBegin(GL_QUADS);
                glVertex3fv(&plane[0]);
                glVertex3fv(&plane[3]);
                glVertex3fv(&plane[9]);
                glVertex3fv(&plane[6]);
        glEnd();
        glDepthMask(GL_TRUE);

        glDisable(GL_ALPHA_TEST);
        glDisable(GL_TEXTURE_3D);

        glBegin(GL_LINES); //draw clip plane
                glColor3f(1.0f,0.0f,0.0f);
                glVertex3fv(&plane[0]);
                glVertex3fv(&plane[3]);
                glVertex3fv(&plane[3]);
                glVertex3fv(&plane[9]);
                glVertex3fv(&plane[9]);
                glVertex3fv(&plane[6]);
                glVertex3fv(&plane[6]);
                glVertex3fv(&plane[0]);
        glEnd();
}