//  tilting  
//  Tilting transformation is defined by multiplication of two
//  rotation matrices, that are rotation theta about z-axis and
//  rotation phi about x-axis.
//  Parallel Projection onto xy plane.
//  Tilting is used for viewing transformation in following examples.
//  T. Kosaka CS TNCT 5Aug2002

#include <stdio.h>
#include <math.h>
#include <GL/glut.h>
#include "drawtools3D.h"

void userdraw(void);

void display(void)
{
    glClear( GL_COLOR_BUFFER_BIT);
    userdraw();
    glutSwapBuffers();
}

//////////////////////////////////////////////////////////////////
void drawcharX(float x,float y)
{
    drawLine(x,y,x+10,y+12);drawLine(x,y+12,x+10,y);
}

void drawcharY(float x,float y)
{
    drawLine(x+5,y,x+5,y+7);drawLine(x,y+12,x+5,y+7);drawLine(x+10,y+12,x+5,y+7);
}

void drawcharZ(float x,float y)
{
    drawLine(x,y+12,x+10,y+12);drawLine(x+10,y+12,x,y);drawLine(x,y,x+10,y);
}

void drawAxes(matrix3D_t view)
{
#define HALFAXIS  220
#define HALFAXIS1 (HALFAXIS-10)
    point3D_t axes[14]={
        {-HALFAXIS,0,0},{HALFAXIS,0,0},{HALFAXIS1,5,0},{HALFAXIS1,0,0},{0,0,0},
        {0,-HALFAXIS,0},{0,HALFAXIS,0},{0,HALFAXIS1,5},{0,HALFAXIS1,0},{0,0,0},
        {0,0,-HALFAXIS},{0,0,HALFAXIS},{5,0,HALFAXIS1},{0,0,HALFAXIS1}
    };
    vector3D_t vec[14];
    int i;
    for (i=0;i<14;i++) {
        vec[i]=Point2Vector(axes[i]);
        vec[i]=view*vec[i];
    }
    drawPolyline(vec,14);
    drawcharX(vec[1].v[0],vec[1].v[1]);
    drawcharY(vec[6].v[0],vec[6].v[1]);
    drawcharZ(vec[11].v[0]-14,vec[11].v[1]);
}

//////////////////////////////////////////////////////////////////

void userdraw(void)
{
    static int tick=0;
    float theta;
    float phi;
    matrix3D_t tilting;
    int disp=(tick/100)%4;
    int tickindisp=tick%100;
    point3D_t ef[10]={
        {10,100,0},{10,10,0},{30,10,0},{30,40,0},{60,40,0},
        {60,60,0},{30,60,0},{30,80,0},{70,80,0},{70,100,0}
    };
    int i;
    color_t white={1.,1.,1.};
    color_t cyan={0.,1.,1.};

    vector3D_t vec[10];

    switch(disp) {
    case 0:
        theta=0;phi=0;
        break;
    case 1:
        theta=-0.5*tickindisp/100.;phi=0;
        break;
    case 2:
        theta=-0.5;phi=0.5*tickindisp/100.;
        break;
    case 3:
        theta=-0.5;phi=0.5;
        break;
    default:
        break;
    }
    tilting=rotationXMTX(phi)*rotationYMTX(theta);
    setColor(white);
    drawAxes(tilting);
    setColor(cyan);
    for (i=0;i<10;i++) {
        vec[i]=Point2Vector(ef[i]);
        vec[i]=tilting*vec[i];
    }
    drawPolygon(vec,10);
    tick++;
}

int main(int argc, char **argv)
{
    glutInit(&argc,argv);
    glutInitDisplayMode ( GLUT_DOUBLE | GLUT_RGB );
    glutInitWindowPosition(100,100);
    glutInitWindowSize(640,480);
    glutCreateWindow ("tilting");
    glClearColor(0.0, 0.0, 0.0, 0.0);
    gluOrtho2D(-320., 320., -240.0, 240.0);
      // Define the dimensions of the Orthographic Viewing Volume
    glutIdleFunc(display); // idle event call back
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;
}