// Tex.cpp     
// NKU CSC 480 - Kirby
// -----------------------------------------------------------------------
// Demonstrating texture mapping.
// 
// Requires a 256x256 24-bit .bmp file (e.g "stucco24.bmp" or "turl.bmp").
// You can use a program (like Windows Paint) to convert your favorite jpg.
// -----------------------------------------------------------------------


#include <GL/glut.h>
#include <iostream>
#include "Stopwatch.h"   // on course website
#include "Bmp.h"         // on course website
using namespace std ;


// Bitmap dimensions for texture mapping (must be power of 2).
const int W = 256, H = 256 ;           


// Stopwatch for controlling animation.
static Stopwatch* G_pStopwatch ;



void lighting()
// Set up lighting. 
{
    // Initialize lighting mechanisms.
    glEnable( GL_DEPTH_TEST ) ;
    glPolygonMode( GL_FRONT, GL_FILL ) ;
    glEnable( GL_NORMALIZE ) ; 
    glEnable( GL_LIGHTING ) ;

    // One Phong light source.
    float lightPos[]= {1,1,1,0} ;  // at infinity
    float GRAY[]= {0.7,0.7,0.7,0}, WHITE[]={1,1,1,0} ; 
    glLightfv( GL_LIGHT0, GL_POSITION, lightPos ) ; 
    glLightfv( GL_LIGHT0, GL_DIFFUSE, WHITE ) ;
    glLightfv( GL_LIGHT0, GL_AMBIENT, GRAY ) ; 
    glEnable( GL_LIGHT0 ) ;
}



void projectionTrans()
// Set up projection.
{
    // Projection: slight perspective.
    glMatrixMode( GL_PROJECTION ) ;
    glLoadIdentity() ;
    gluPerspective( 25.0, 1,  10,14 ) ;
}



void viewTrans()
// Set up viewing.
{
    // View: Camera out on z axis looking toward origin.
    glMatrixMode( GL_MODELVIEW ) ;
    glLoadIdentity() ;
    gluLookAt( 0,0,12, 0,0,0, 0,1,0 ) ;
}



void modelTrans()
// Set up modeling.
{
    // Model: tumbling as a composition of rotations.
    glMatrixMode( GL_MODELVIEW ) ;
    double degrees= G_pStopwatch->getValue() * 0.04 ;
    glRotated( degrees, 1,1,1 ) ;
    glRotated( degrees, -1,1,1) ;
}



void texturedSquare()
// Draw a 2x2 square with current texture, centered at (0,0,1) parallel xy plane.
{
    glBegin( GL_POLYGON ) ;

        glNormal3d( 0,0,1 ) ; // same normal for all four vertices

        glTexCoord2d( 0, 0 ) ;   glVertex3d( -1,-1, 1 ) ; // lower left  z=1 plane
        glTexCoord2d( 1, 0 ) ;   glVertex3d(  1,-1, 1 ) ; // lower right z=1 plane
        glTexCoord2d( 1, 1 ) ;   glVertex3d(  1, 1, 1 ) ; // upper right z=1 plane
        glTexCoord2d( 0, 1 ) ;   glVertex3d( -1, 1, 1 ) ; // upper left  z=1 plane
    
    glEnd() ;
}



void texturedCube()
// Textured cube with corners at +/- 1.0. Made out of 6 textured squares. 
{
    glEnable( GL_TEXTURE_2D );
   
    texturedSquare() ;      // +z  face
    
    glPushMatrix() ;
        glRotated( 180, 0,1,0 ) ;
        texturedSquare() ;  // -z face
    glPopMatrix() ;
    
    glPushMatrix() ;
        glRotated( 90, 0,1,0 ) ;
        texturedSquare() ;  // +x face
    glPopMatrix() ;
    
    glPushMatrix() ;
        glRotated( -90, 0,1,0 ) ;
        texturedSquare() ;  // -x face
    glPopMatrix() ;
    
    glPushMatrix() ;
        glRotated( 90, 1,0,0 ) ;
        texturedSquare() ;  // +y face
    glPopMatrix() ;
    
    glPushMatrix() ;
        glRotated( -90, 1,0,0 ) ;
        texturedSquare() ;  // -y face
    glPopMatrix() ;
    
    glDisable(GL_TEXTURE_2D);
}




void display()  
// Display the scene: a rotating cube. 
{
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ) ;

    viewTrans() ;
    modelTrans() ;

    texturedCube() ;
    glutSwapBuffers() ;
}



void animate()  
// One frame of animation.
{
    glutPostRedisplay() ;
}



void toggleAnimation() 
// Toggle animation on and off. 
{
    if ( G_pStopwatch->isStopped() )
    {
        G_pStopwatch->start() ;
        glutIdleFunc( animate ) ;
    }
    else
    {
        G_pStopwatch->stop() ;
        glutIdleFunc( NULL ) ;
    }
}



void kbDispatch( unsigned char ch, int x, int y )
// Space bar toggles animation. 
{
    if ( ch == ' ' )
        toggleAnimation() ;
    glutPostRedisplay() ;
}



void initTextureMapping( GLubyte img[W][H][3] )
// Define how the texture is to be mapped to polygons.
{
    // Set current texture to img[][][]. 
    glTexImage2D( GL_TEXTURE_2D, 0, 3, W, H, 0, GL_RGB, GL_UNSIGNED_BYTE, img ) ;
    
    // Repeat the texture outside when texture coordinates exceed [0,1]^2.
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
    
    // Optimal handling of magnification and minimization with perspective.
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR ) ; 
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR ) ;
}



void getTextureFromBMP( GLubyte img[W][H][3], const string& bmpfilename )  
// Load a bitmap from a 24-bit *.bmp file into the OpenGL-style "texture array" img[][][]. 
{
    Bmp bmp( bmpfilename ) ;
    
    assert( W <= bmp.getWidth() &&  H <= bmp.getHeight() ) ;

    for ( int i=0 ; i < H ; ++i )
        for ( int j=0 ; j < W ; ++j )
            bmp.getPixel( i,j, img[i][j] ) ;
}



int main( int argc, char** argv )
{
    // Initialize OpenGL. 
    glutInit( &argc, argv ) ;
    glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH ) ; 

    // Window attributes.
    glutInitWindowSize( 700, 700 ) ;
    glutInitWindowPosition( 100, 100 ) ;
    glutCreateWindow( "Tex" ) ;

    // Register callbacks.
    glutKeyboardFunc( kbDispatch ) ;        
    glutDisplayFunc( display ) ;  
    glutIdleFunc( animate ) ;

    // Initialize animation motor, initially on. 
    G_pStopwatch= new Stopwatch ;
    G_pStopwatch->start() ;

    // Texture from file.
    GLubyte img[H][W][3] ;  //  OpenGL style texture array
    getTextureFromBMP( img, "stucco24.bmp" ) ; 
    initTextureMapping( img ) ;
    
    // Set up fixed light source and perspective. 
    lighting() ;
    projectionTrans() ; 

    // Go.
    glutMainLoop() ;
    
    return 0 ;
}