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GLUTCore.cpp

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#include "GLUTCore.h"
#include <stdio.h>
#if defined( _WIN32 )
#include <time.h>
#else
#include <sys/time.h>
#endif

#ifdef GLEXT
#include "GLEXTHandler.h"
#endif

#include <stdlib.h>

float GLUTCore::fGLUTCamDistance;
GLUTCore GLUT;

//Default usage parameters for the mouse motion functs.
int oldX, oldY, buttonPressed = 0, rbuttonPressed = 0;

void DefaultMousePress( int b, int state, int x, int y )
{
    GLUT.miLastMouseX = x; GLUT.miLastMouseY = y;
    if( b == GLUT_LEFT_BUTTON )
        buttonPressed = !buttonPressed;
    if( b == GLUT_RIGHT_BUTTON )
        rbuttonPressed = !rbuttonPressed;
}

void DefaultMouseDrag( int x, int y )
{
    //Find the amount moved from last frame to this frame.
    float dx = x - GLUT.miLastMouseX;
    float dy = y - GLUT.miLastMouseY;
    GLUT.miLastMouseX = x;
    GLUT.miLastMouseY = y;
    if( buttonPressed )
    {
        //Update the absolute difference of mouse location since start.
        GLUT.miSetMouseX += (int)dx;
        GLUT.miSetMouseY += (int)dy;
    }
    if( rbuttonPressed )
    {
        GLUTCore::fGLUTCamDistance += dy/10.0;
        DefaultReshape( GLUT.miWidth, GLUT.miHeight );
    }
    glLoadIdentity();
    glTranslatef( 0.0f, 0.0f, -GLUTCore::fGLUTCamDistance );
    glRotatef( GLUT.miSetMouseY*0.5f, 1.0f, 0.0f, 0.0f );
    glRotatef( GLUT.miSetMouseX*0.5f, 0.0f, 0.0f, 1.0f );
}

void DefaultReshape( int Width, int Height )
{
    //set up a projection, rotation and general camera stuff with respect to mouse input
    GLUT.miWidth = Width;
    GLUT.miHeight = Height;
    glViewport( 0, 0, (GLint)Width, (GLint)Height );
    glMatrixMode( GL_PROJECTION );
    glLoadIdentity();
    gluPerspective( 45.0f, (float)Width/(float)Height, 0.1f, 100.0f );
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef( 0.0f, 0.0f, -GLUTCore::fGLUTCamDistance );
    glRotatef( GLUT.miSetMouseY*0.5f, 1.0f, 0.0f, 0.0f );
    glRotatef( GLUT.miSetMouseX*0.5f, 0.0f, 0.0f, 1.0f );
}

void DefaultDraw()
{
    glClearColor(.1,.1,.2,0.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glBegin( GL_QUADS );
    glVertex3f( -1.0f, -1.0f, 0.0f );
    glVertex3f( 1.0f, -1.0f, 0.0f );
    glVertex3f( 1.0f, 1.0f, 0.0f );
    glVertex3f( -1.0f, 1.0f, 0.0f );
    glEnd();

    //Swap the buffers and tell GLUT to call the redraw function again.
    glutSwapBuffers();
    glutPostRedisplay();
}

GLUTCore::GLUTCore()
{
    mDF = DefaultDraw;
    mRS = DefaultReshape;
    mMP = DefaultMousePress;
    mMD = DefaultMouseDrag;
    miSetMouseX = 0;
    miSetMouseY = 0;
}

float GLUTCore::TackFPS()
{
#ifdef WIN32
    //On Win32, there's some bugs with the GLUT causing it not to exit,
    //this checks and exits.  After benchmarking, this proved to add minimal
    //overhead.
    if( !wglGetCurrentDC() ) exit ( 0 );
#endif
    unsigned iCurSecond, iCurMillisecond;
    iNumFrames++;
    #if defined( WIN32 )
        SYSTEMTIME systemTime;
        GetSystemTime( &systemTime );
        iCurSecond = systemTime.wSecond;
        iCurMillisecond = systemTime.wMilliseconds*1000;
    #else
        struct timeval T;
        gettimeofday( &T, 0 );
        iCurSecond = T.tv_sec;
        iCurMillisecond = T.tv_usec;
    #endif
    if( iCurSecond != iLastSecond )
    {
        iLastSecond = iCurSecond;
        printf( "FPS: %d\n", iNumFrames );
        iNumFrames = 0;
    }
    iDeltaMS = (iCurSecond - iTmrLastSecond)*1000000 + (iCurMillisecond - iTmrLastMillisecond );
    iTmrLastSecond = iCurSecond;
    iTmrLastMillisecond = iCurMillisecond;
    return ((float)iDeltaMS)/1000000.0f;
}

void WMClose()
{
    exit( 0 );
}

void GLUTCore::Init( int argc, char**argv, int iWidth, int iHeight, char * sName )
{
    fGLUTCamDistance = 5.0;
    iNumFrames = 0;
    iLastSecond = 0;
    miWidth = iWidth;
    miHeight = iHeight;
    /* ask for a window at 0,0 with dimensions winWidth, winHeight */
    /* need color, depth (for 3D drawing) and double buffer (smooth display) */
    glutInit( &argc, argv );
    glutInitWindowPosition( 0, 0 );
    glutInitWindowSize( iWidth, iHeight );
    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
    glutCreateWindow(sName);
    
    /* set callback functions to be called by GLUT for drawing, window
    resize, keypress, mouse button press, and mouse movement */
    glutDisplayFunc(mDF);
    glutReshapeFunc(mRS);
    glutMouseFunc(  mMP);
    glutMotionFunc( mMD);
    glutPassiveMotionFunc( mMD );
    
#ifdef GLEXT
    SetupAllExtensions();
#endif

}

void GLUTCore::DrawAndDoMainLoop()
{
    //Pre-emptively call the resize and draw functions to get the cycle going
    mRS( miWidth, miHeight );
    mDF();
    glutMainLoop();
}

//Copyright 2007 Charles Lohr, Dr. Marc Olano under the MIT/X11 License

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© 2005-2007 Charles Lohr, Joshua Allen, David Chapman, Andrew Lohr. All material including documentation under the MIT/X11 license.