/*

 *  glutSurfaceTexture.cpp

 *  GLUTTest

 *

 *  Created by GGS on Wed Feb 12 2003.

 *  Copyright (c) 2003-2004 Apple. All rights reserved.

 *

    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.

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                please do not use, install, modify or redistribute this Apple software.

                In consideration of your agreement to abide by the following terms, and subject

                to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs

                copyrights in this original Apple software (the "Apple Software"), to use,

                reproduce, modify and redistribute the Apple Software, with or without

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                the Apple Software.  Neither the name, trademarks, service marks or logos of

                Apple Computer, Inc. may be used to endorse or promote products derived from the

                Apple Software without specific prior written permission from Apple.  Except as

                expressly stated in this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any patent rights that

                may be infringed by your derivative works or by other works in which the Apple

                Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

                WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

                WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR

                PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

                COMBINATION WITH YOUR PRODUCTS.

                IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

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 */

#include <string.h>

#include <stdio.h>

#include <math.h>

#include <stdlib.h>

#include <GLUT/glut.h>

#include <OpenGL/glext.h>

#include <OpenGL/gl.h>

#include <OpenGL/glu.h>

#include "trackball.h"

#include "stanfordbunny.h"

#define DTOR 0.0174532925

#define CROSSPROD(p1,p2,p3) \

   p3.x = p1.y*p2.z - p1.z*p2.y; \

   p3.y = p1.z*p2.x - p1.x*p2.z; \

   p3.z = p1.x*p2.y - p1.y*p2.x

enum {

    kTextureSize = 256

};

typedef struct {

   GLdouble x,y,z;

} recVec;

typedef struct {

    recVec viewPos; // View position

    recVec viewDir; // View direction vector

    recVec viewUp; // View up direction

    recVec rotPoint; // Point to rotate about

    GLdouble focalLength; // Focal Length along view direction

    GLdouble aperture; // gCamera aperture

    GLdouble eyeSep; // Eye separation

    GLint screenWidth,screenHeight; // current window/screen height and width

} recCamera;

GLfloat gShapeSize = 7.0f;

GLint gDollyPanStartPoint[2] = {0, 0};

GLfloat gTrackBallRotation [4] = {0.0, 0.0, 0.0, 0.0};

GLboolean gDolly = GL_FALSE;

GLboolean gPan = GL_FALSE;

GLboolean gTrackBall = GL_FALSE;

GLfloat gWorldRotation [4] = {100.0, -0.7, 0.6, 0.5};

GLboolean gRectTexture = GL_FALSE;

GLboolean gSurfaceTexture = GL_TRUE;

GLint gTextureWidth = kTextureSize;

GLint gTextureHeight = kTextureSize;

GLboolean gLines = GL_FALSE;

GLboolean gPolygons = GL_TRUE;

GLboolean gShowHelp = GL_TRUE;

GLboolean gShowInfo = GL_TRUE;

recCamera gCamera;

recVec gOrigin = {0.0, 0.0, 0.0};

int gLastKey = ' ';

int gMainWindow = 0, gTextureWindow = 0;

GLint gSurfaceTexName = 0;

GLint gTextureValid = 0;

GLuint gBunnyWireList = NULL;

GLuint gBunnySolidList = NULL;

GLboolean gBunnyLines = GL_FALSE;

// simple cube data

GLint cube_num_vertices = 8;

GLfloat cube_vertices [8][3] = {

{1.0, 1.0, 1.0}, {1.0, -1.0, 1.0}, {-1.0, -1.0, 1.0}, {-1.0, 1.0, 1.0},

{1.0, 1.0, -1.0}, {1.0, -1.0, -1.0}, {-1.0, -1.0, -1.0}, {-1.0, 1.0, -1.0} };

GLint num_faces = 6;

short cube_faces [6][4] = {

{3, 2, 1, 0}, {2, 3, 7, 6}, {0, 1, 5, 4}, {3, 0, 4, 7}, {1, 2, 6, 5}, {4, 5, 6, 7} };

GLdouble cube_texCoords [2][4] = {

{0.0, 0.0, 1.0, 1.0}, {0.0, 1.0, 1.0, 0.0} };

#pragma mark ---- gCamera control ----

void gCameraReset(void)

{

   gCamera.aperture = 40;

   gCamera.focalLength = 10;

   gCamera.rotPoint = gOrigin;

   gCamera.viewPos.x = 0.0;

   gCamera.viewPos.y = 0.0;

   gCamera.viewPos.z = -gCamera.focalLength;

   gCamera.viewDir.x = -gCamera.viewPos.x; 

   gCamera.viewDir.y = -gCamera.viewPos.y; 

   gCamera.viewDir.z = -gCamera.viewPos.z;

   gCamera.viewUp.x = 0;  

   gCamera.viewUp.y = 1; 

   gCamera.viewUp.z = 0;

}

#pragma mark ---- Utilities ----

void

drawGLString(GLfloat x, GLfloat y, char *string)

{

  int len, i;

  glRasterPos2f(x, y);

  len = (int) strlen(string);

  for (i = 0; i < len; i++) {

    glutBitmapCharacter(GLUT_BITMAP_HELVETICA_10, string[i]);

  }

}

#pragma mark ---- Drawing ----

void SetLighting(void)

{

    GLfloat mat_ambient[] = {0.329412, 0.223529, 0.027451, 1.0};

    GLfloat mat_diffuse[] = {0.780392, 0.568627, 0.113725, 1.0};

    GLfloat mat_specular[] = {0.992157, 0.941176, 0.807843, 1.0};

    GLfloat mat_shininess[] = {27.8974};

    GLfloat position[4] = {7.0,-7.0,12.0,0.0};

    GLfloat ambient[4]  = {0.2,0.2,0.2,1.0};

    GLfloat diffuse[4]  = {0.9,0.9,0.9,1.0};

    GLfloat specular[4] = {1.0,1.0,1.0,1.0};

    glMaterialfv (GL_FRONT, GL_AMBIENT, mat_ambient);

    glMaterialfv (GL_FRONT, GL_DIFFUSE, mat_diffuse);

    glMaterialfv (GL_FRONT, GL_SPECULAR, mat_specular);

    glMaterialfv (GL_FRONT, GL_SHININESS, mat_shininess);

    glLightfv(GL_LIGHT0,GL_POSITION,position);

    glLightfv(GL_LIGHT0,GL_AMBIENT,ambient);

    glLightfv(GL_LIGHT0,GL_DIFFUSE,diffuse);

    glLightfv(GL_LIGHT0,GL_SPECULAR,specular);

    glEnable(GL_LIGHT0);

}

void drawGLText (GLint window_width, GLint window_height)

{

    char outString [256] = "";

    GLint matrixMode;

    GLint vp[4];

    GLint lineSpacing = 13;

    GLint line = 0;

    GLint startOffest = 7;

    glGetIntegerv(GL_VIEWPORT, vp);

    glViewport(0, 0, window_width, window_height);

    glGetIntegerv(GL_MATRIX_MODE, &matrixMode);

    glMatrixMode(GL_PROJECTION);

    glPushMatrix();

    glLoadIdentity();

    glMatrixMode(GL_MODELVIEW);

    glPushMatrix();

    glLoadIdentity();

    glScalef(2.0f / window_width, -2.0f / window_height, 1.0f);

    glTranslatef(-window_width / 2.0f, -window_height / 2.0f, 0.0f);

    // draw 

    glColor3f (1.0, 1.0, 0.0);

    if (gShowInfo) {

        sprintf (outString, "Camera Position: (%0.1f, %0.1f, %0.1f)", gCamera.viewPos.x, gCamera.viewPos.y, gCamera.viewPos.z);

        drawGLString (10, window_height - (lineSpacing * line++) - startOffest, outString);

        sprintf (outString, "Trackball Rotation: (%0.1f, %0.2f, %0.2f, %0.2f)", gTrackBallRotation[0], gTrackBallRotation[1], gTrackBallRotation[2], gTrackBallRotation[3]);

        drawGLString (10, window_height - (lineSpacing * line++) - startOffest, outString);

        sprintf (outString, "World Rotation: (%0.1f, %0.2f, %0.2f, %0.2f)", gWorldRotation[0], gWorldRotation[1], gWorldRotation[2], gWorldRotation[3]);

        drawGLString (10, window_height - (lineSpacing * line++) - startOffest, outString);

        sprintf (outString, "Aperture: %0.1f", gCamera.aperture);

        drawGLString (10, window_height - (lineSpacing * line++) - startOffest, outString);

        sprintf (outString, "Focus Distance: %0.1f", gCamera.focalLength);

        drawGLString (10, window_height - (lineSpacing * line++) - startOffest, outString);

    }

    if (gShowHelp) {

        line = 1;

        sprintf (outString, "Controls:\n");

        drawGLString (10, (lineSpacing * line++) + startOffest, outString);

        sprintf (outString, "left button drag: rotate camera\n");

        drawGLString (10, (lineSpacing * line++) + startOffest, outString);

        sprintf (outString, "right (or crtl-left) button drag: dolly (zoom) camera\n");

        drawGLString (10, (lineSpacing * line++) + startOffest, outString);

        sprintf (outString, "arrows: aperture & focal length\n");

        drawGLString (10, (lineSpacing * line++) + startOffest, outString);

        sprintf (outString, "S: toggle surface texture\n");

        drawGLString (10, (lineSpacing * line++) + startOffest, outString);

        sprintf (outString, "H: toggle help\n");

        drawGLString (10, (lineSpacing * line++) + startOffest, outString);

        sprintf (outString, "I: toggle info\n");

        drawGLString (10, (lineSpacing * line++) + startOffest, outString);

    }

    glPopMatrix();

    glMatrixMode(GL_PROJECTION);

    glPopMatrix();

    glMatrixMode(matrixMode);

    glViewport(vp[0], vp[1], vp[2], vp[3]);

}

static void DrawCube (GLfloat fSize, GLint texWidth, GLint texHeight)

{

    long f, i;

    glEnable (GL_POLYGON_OFFSET_FILL);

    if (gPolygons)

    {

        glColor3f (1.0, 1.0, 1.0);

        glBegin (GL_QUADS);

        for (f = 0; f < num_faces; f++)

            for (i = 0; i < 4; i++)

            {

                glVertex3f(cube_vertices[cube_faces[f][i]][0] * fSize, cube_vertices[cube_faces[f][i]][1] * fSize, cube_vertices[cube_faces[f][i]][2] * fSize);

                glTexCoord2d (cube_texCoords [0][i] * (gRectTexture ? texWidth : 1.0f), 

                              cube_texCoords [1][i] * (gRectTexture ? texHeight : 1.0f));

            }

        glEnd ();

    }

    if (gLines)

    {

        glDisable(gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D);

        glColor3f (0.0, 1.0, 1.0);

        for (f = 0; f < num_faces; f++)

        {

            glBegin (GL_LINE_LOOP);

                for (i = 0; i < 4; i++)

                    glVertex3f(cube_vertices[cube_faces[f][i]][0] * fSize, cube_vertices[cube_faces[f][i]][1] * fSize, cube_vertices[cube_faces[f][i]][2] * fSize);

            glEnd ();

        }

    }

    glDisable (GL_POLYGON_OFFSET_FILL);

}

void initMain (void)

{

    glEnable(GL_DEPTH_TEST);

    glShadeModel(GL_SMOOTH);    

    glFrontFace(GL_CCW);

    glPolygonOffset (1.0, 1.0);

    glEnable (GL_ALPHA_TEST); 

    glAlphaFunc (GL_GREATER, 0.5);

    glPolygonOffset (1.0, 1.0);

    gRectTexture = gluCheckExtension ((GLubyte *)"GL_EXT_texture_rectangle", glGetString (GL_EXTENSIONS)); // can we use texture rectangle

    glClearColor (0.2f, 0.2f, 0.4f, 1.0f);

    glEnable (GL_BLEND);

    glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    gLines = GL_FALSE; //  do not draw edges

    gCameraReset ();

}

void initTexture (void)

{

    glEnable(GL_DEPTH_TEST);

    glShadeModel(GL_SMOOTH);    

    glEnable(GL_CULL_FACE);

    glFrontFace(GL_CCW);

    glColor3f(1.0,1.0,1.0);

    gBunnySolidList = GenStanfordBunnySolidList ();

    gBunnyWireList = GenStanfordBunnyWireList ();

    glClearColor(0.0,0.0,0.0,0.0);

    SetLighting();

    glEnable(GL_LIGHTING);

    glDisable(gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D); // disable texturing

}

#pragma mark ---- GLUT callbacks ----

void reshape (int w, int h)

{

    glViewport(0,0,(GLsizei)w,(GLsizei)h);

    gCamera.screenWidth = w;

    gCamera.screenHeight = h;

    glutPostRedisplay();

}

void texturereshape (int w, int h)

{

    if (!gRectTexture) { // if we require power of two, do not resize

        glutReshapeWindow (kTextureSize, kTextureSize);

        return;

    }

    glViewport(0,0,(GLsizei)w,(GLsizei)h);

    gTextureWidth = w;

    gTextureHeight = h;

    if (0 != gSurfaceTexName) { // force texture update

        glutSetWindow (gMainWindow);

        glDeleteTextures (1, &gSurfaceTexName);

        glFlush();

        gSurfaceTexName = 0;

        glutSetWindow (gTextureWindow);

    }

    glutPostRedisplay();

    glutPostWindowRedisplay(gMainWindow);

}

void texturedisplay(void)

{

    static GLfloat fRot [3] = { 0.0, 0.0, 0.0 };

    static GLfloat fVel [3] = { 0.3, 0.1, 0.2 };

    static GLfloat fAccel [3] = { 0.003, -0.005, 0.004 };

    GLfloat fVMax = 2.0;

    short i;

    // do spin velocities

    for (i = 0; i < 3; i++) {

        fVel[i] += fAccel[i];

        if (fVel[i] > fVMax) {

            fAccel[i] *= -1.0;

            fVel[i] = fVMax;

        } else if (fVel[i] < -fVMax) {

            fAccel[i] *= -1.0;

            fVel[i] = -fVMax;

        }

        fRot[i] += fVel[i];

        while (fRot[i] > 360.0)

            fRot[i] -= 360.0;

        while (fRot[i] < -360.0)

            fRot[i] += 360.0;

    }

    // Viewing transformation

    glMatrixMode (GL_PROJECTION);

    glLoadIdentity ();

    gluPerspective (45.0, 1.0, 1.0, 5.0);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glTranslatef(0.0, 0.0, -2.0);

    glRotatef (fRot[0], 1.0, 0.0, 0.0);

    glRotatef (fRot[1], 0.0, 1.0, 0.0);

    glRotatef (fRot[2], 0.0, 0.0, 1.0);

    // fill surface texture, this could be any GL content...

    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    if (gBunnyLines) {

        glDisable (GL_LIGHTING);

        glColor3f (1.0, 1.0, 1.0); // no coloring

        glCallList (gBunnyWireList);

    } else {

        glEnable(GL_LIGHTING);

        glCallList (gBunnySolidList);

    }

    glutSwapBuffers();

    gTextureValid = 1;

}

void maindisplay(void)

{

    GLdouble ratio, radians, wd2;

    GLdouble left, right, top, bottom, near, far;

    if (!gTextureValid) { // ensure we have a valid texture to draw with

        glutSetWindow (gTextureWindow);

        texturedisplay();

        glutSetWindow (gMainWindow);

    }   

    near = -gCamera.viewPos.z - gShapeSize * 0.5;

    if (near < 0.1) near = 0.1;

    far = -gCamera.viewPos.z + gShapeSize * 0.5;

    // Misc stuff

    ratio  = gCamera.screenWidth / (double)gCamera.screenHeight;

    radians = DTOR * gCamera.aperture / 2;

    wd2     = near * tan(radians);

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glMatrixMode (GL_PROJECTION);

    glLoadIdentity ();

    left  = - ratio * wd2;

    right =   ratio * wd2;

    top    =   wd2;

    bottom = - wd2;

    glFrustum (left, right, bottom, top, near, far);

    glMatrixMode (GL_MODELVIEW);

    glLoadIdentity ();

    gluLookAt (gCamera.viewPos.x, gCamera.viewPos.y, gCamera.viewPos.z,

            gCamera.viewPos.x + gCamera.viewDir.x,

            gCamera.viewPos.y + gCamera.viewDir.y,

            gCamera.viewPos.z + gCamera.viewDir.z,

            gCamera.viewUp.x, gCamera.viewUp.y ,gCamera.viewUp.z);

    // track ball rotation

    glRotatef (gTrackBallRotation[0], gTrackBallRotation[1], gTrackBallRotation[2], gTrackBallRotation[3]);

    glRotatef (gWorldRotation[0], gWorldRotation[1], gWorldRotation[2], gWorldRotation[3]);

    if (gSurfaceTexture) { // if surface texturing is on

        glEnable(gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D); // enable texturing 

#pragma mark === SurfaceTexture ===

        if (0 == gSurfaceTexName) {

            glGenTextures (1, &gSurfaceTexName);

            glBindTexture (gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D, gSurfaceTexName);

            // the following is superfluous for texture rectangle but required for texture 2D without mipmaps

            glTexParameterf (gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

            glutSurfaceTexture (gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D, GL_RGBA8, gTextureWindow);

        } else {

            glBindTexture (gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D, gSurfaceTexName);

        }

        glColor3f (1.0, 1.0, 1.0); // no coloring

    } else { // disable if no surface texture context

        glDisable(gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D);

        glColor3f (0.8f, 0.1f, 0.1f); // red cube

    }

    DrawCube(2.0, gTextureWidth, gTextureHeight); // draw a cube with the faces textured with surface texture

    glDisable(gRectTexture ? GL_TEXTURE_RECTANGLE_EXT : GL_TEXTURE_2D); // enable texturing 

    drawGLText (gCamera.screenWidth, gCamera.screenHeight);

    // this could be used for testing/exprimentation by forcing the texture to be deleted every frame

//  if (0 != gSurfaceTexName) { // force texture deletion

//      glDeleteTextures (1, &gSurfaceTexName);

//      gSurfaceTexName = 0;

//  }

    glutSwapBuffers();

}

void animate(void)

{

    // ensure we are current window (since are calling display directly)

    glutSetWindow (gTextureWindow);

    texturedisplay();

    glutPostWindowRedisplay(gMainWindow);

}

void special(int key, int px, int py)

{

  gLastKey = key;

  switch (key) {

    case GLUT_KEY_UP: // arrow forward, close in on world

        gCamera.focalLength -= 0.5f;

        if (gCamera.focalLength < 0.0f)

            gCamera.focalLength = 0.0f;

        glutPostRedisplay();

        break;

    case GLUT_KEY_DOWN: // arrow back, back away from world

        gCamera.focalLength += 0.5f;

        glutPostRedisplay();

        break;

    case GLUT_KEY_LEFT: // arrow left, smaller aperture

        gCamera.aperture -= 0.5f;

        if (gCamera.aperture < 0.0f)

            gCamera.aperture = 0.0f;

        glutPostRedisplay();

        break;

    case GLUT_KEY_RIGHT: // arrow right, larger aperture

        gCamera.aperture += 0.5f;

        glutPostRedisplay();

        break;

  }

}

void mouseDolly (int x, int y)

{

    if (gDolly) {

        GLfloat dolly = (gDollyPanStartPoint[1] - y) * -gCamera.viewPos.z / 200.0f;

        GLfloat eyeRelative = gCamera.eyeSep / gCamera.focalLength;

        gCamera.focalLength += gCamera.focalLength / gCamera.viewPos.z * dolly; 

        if (gCamera.focalLength < 1.0)

            gCamera.focalLength = 1.0;

        gCamera.eyeSep = gCamera.focalLength * eyeRelative;

        gCamera.viewPos.z += dolly;

        if (gCamera.viewPos.z == 0.0) // do not let z = 0.0

            gCamera.viewPos.z = 0.0001;

        gDollyPanStartPoint[0] = x;

        gDollyPanStartPoint[1] = y;

        glutPostRedisplay();

    }

}

void mousePan (int x, int y)

{

    if (gPan) {

        GLfloat panX = (gDollyPanStartPoint[0] - x) / (900.0f / -gCamera.viewPos.z);

        GLfloat panY = (gDollyPanStartPoint[1] - y) / (900.0f / -gCamera.viewPos.z);

        gCamera.viewPos.x -= panX;

        gCamera.viewPos.y -= panY;

        gDollyPanStartPoint[0] = x;

        gDollyPanStartPoint[1] = y;

        glutPostRedisplay();

    }

}

void mouseTrackball (int x, int y)

{

    if (gTrackBall) {

        rollToTrackball (x, y, gTrackBallRotation);

        glutPostRedisplay();

    }

}

void mouse (int button, int state, int x, int y)

{

    if ((button == GLUT_LEFT_BUTTON) && (state == GLUT_DOWN)) {

        if (gDolly) { // if we are currently dollying, end dolly

            mouseDolly (x, y);

            gDolly = GL_FALSE;

            glutMotionFunc (NULL);

            gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

            glutMotionFunc (NULL);

        } else if (gPan) {

            mousePan (x, y);

            gPan = GL_FALSE;

            glutMotionFunc (NULL);

            gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

            glutMotionFunc (NULL);

        }

        startTrackball (x, y, 0, 0, gCamera.screenWidth, gCamera.screenHeight);

        glutMotionFunc (mouseTrackball);

        gTrackBall = GL_TRUE;

    } else if ((button == GLUT_LEFT_BUTTON) && (state == GLUT_UP)) {

        gTrackBall = GL_FALSE;

        glutMotionFunc (NULL);

        rollToTrackball (x, y, gTrackBallRotation);

        if (gTrackBallRotation[0] != 0.0)

            addToRotationTrackball (gTrackBallRotation, gWorldRotation);

        gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

    }

    else if ((button == GLUT_RIGHT_BUTTON) && (state == GLUT_DOWN)) {

        if (gTrackBall) {// if we are currently trackballing, end trackball

            gTrackBall = GL_FALSE;

            glutMotionFunc (NULL);

            rollToTrackball (x, y, gTrackBallRotation);

            if (gTrackBallRotation[0] != 0.0)

                addToRotationTrackball (gTrackBallRotation, gWorldRotation);

            gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

        } else if (gPan) {

            mousePan (x, y);

            gPan = GL_FALSE;

            glutMotionFunc (NULL);

            gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

            glutMotionFunc (NULL);

        }

        gDollyPanStartPoint[0] = x;

        gDollyPanStartPoint[1] = y;

        glutMotionFunc (mouseDolly);

        gDolly = GL_TRUE;

    } else if ((button == GLUT_RIGHT_BUTTON) && (state == GLUT_UP)) {

        mouseDolly (x, y);

        gDolly = GL_FALSE;

        glutMotionFunc (NULL);

        gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

        glutMotionFunc (NULL);

    }

    else if ((button == GLUT_MIDDLE_BUTTON) && (state == GLUT_DOWN)) {

        if (gTrackBall) {// if we are currently trackballing, end trackball

            gTrackBall = GL_FALSE;

            glutMotionFunc (NULL);

            rollToTrackball (x, y, gTrackBallRotation);

            if (gTrackBallRotation[0] != 0.0)

                addToRotationTrackball (gTrackBallRotation, gWorldRotation);

            gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

        } else if (gDolly) {

            mouseDolly (x, y);

            gDolly = GL_FALSE;

            glutMotionFunc (NULL);

            gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

            glutMotionFunc (NULL);

        }

        gDollyPanStartPoint[0] = x;

        gDollyPanStartPoint[1] = y;

        glutMotionFunc (mousePan);

        gPan = GL_TRUE;

    } else if ((button == GLUT_MIDDLE_BUTTON) && (state == GLUT_UP)) {

        mousePan (x, y);

        gPan = GL_FALSE;

        glutMotionFunc (NULL);

        gTrackBallRotation [0] = gTrackBallRotation [1] = gTrackBallRotation [2] = gTrackBallRotation [3] = 0.0f;

        glutMotionFunc (NULL);

    }

}

void key(unsigned char inkey, int px, int py)

{

  gLastKey = inkey;

  switch (inkey) {

    case 27:

        exit(0);

        break;

    case 'h': // help

    case 'H':

        gShowHelp =  1 - gShowHelp;

        glutPostWindowRedisplay(gMainWindow);

        break;

    case 'i': // info

    case 'I':

        gShowInfo =  1 - gShowInfo;

        glutPostWindowRedisplay(gMainWindow);

        break;

    case 's': // control surface texturing

    case 'S':

        gSurfaceTexture = 1 - gSurfaceTexture;

        break;

    case 'w': // wire frame

    case 'W':

        gBunnyLines = 1 - gBunnyLines;

        break;

  }

}

void mainclose (void)

{

    if (0 != gSurfaceTexName) { // force texture update

        glutSetWindow (gMainWindow);

        glDeleteTextures (1, &gSurfaceTexName);

        glFlush();

        gSurfaceTexName = 0;

    }

}

#pragma mark ---- main ----

int main (int argc, const char * argv[])

{

    glutInit(&argc, (char **)argv);

    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); // non-stereo for main window

    glutInitWindowPosition (300, 50);

    glutInitWindowSize (800, 600);

    gMainWindow = glutCreateWindow("GLUTSurfaceTexture");

    initMain(); // GL init

    glutReshapeFunc (reshape);

    glutDisplayFunc (maindisplay);

    glutKeyboardFunc (key);

    glutSpecialFunc (special);

    glutMouseFunc (mouse);

    glutWMCloseFunc (mainclose);

    glutInitWindowSize (kTextureSize, kTextureSize);

    glutInitWindowPosition (40, 50);

    gTextureWindow = glutCreateWindow("Surface Texture");

    initTexture(); // GL init

    glutKeyboardFunc (key);

    glutDisplayFunc (texturedisplay);

    glutReshapeFunc (texturereshape);

    glutIdleFunc (animate);

    glutWMCloseFunc (mainclose);

    glutMainLoop();

    return 0;

}