//icosahedron
//  showing icosahedron rotating
// T. Kosaka CS TNCT 2001
// icosahedron
//  showing icosahedron rotating
// T. Kosaka CS TNCT 7Aug2002
#include <stdio.h>
#include <math.h>
#include <GL/glut.h>
#include "drawtools3D.h"
#ifndef M_PI
#define M_PI 3.141592653589793
#endif

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]);
}

//////////////////////////////////////////////////////////////////
typedef struct {
    int NumberofVertices; //in the face
    short int pnt[32];
} face_t;
typedef struct {
    int NumberofVertices; //of the object
    point3D_t pnt[100];
    int NumberofFaces; //of the object
    face_t fc[32];
} polyhedron_t;

static void makeIcosahedron(polyhedron_t &icosahedron,float size)
{
    // size : an edge length of the icosahedron
    float r1,r2,h1,h2,h3;
    float th0[2],h[2];
    int i,j,k;
    float th;
    face_t face[]={
        {3,{0,1,2}},{3,{0,2,3}},{3,{0,3,4}},{3,{0,4,5}},{3,{0,5,1}},
        {3,{1,6,2}},{3,{2,7,3}},{3,{3,8,4}},{3,{4,9,5}},{3,{5,10,1}},
        {3,{2,6,7}},{3,{3,7,8}},{3,{4,8,9}},{3,{5,9,10}},{3,{1,10,6}},
        {3,{6,11,7}},{3,{7,11,8}},{3,{8,11,9}},{3,{9,11,10}},{3,{10,11,6}}
    }; // every face has five vertices and showing vertex numbers

    icosahedron.NumberofVertices=12;

    r1=size*0.5/tan(0.2*M_PI); // a radius of an inscribed circle of the triangle
    r2=size*0.5/sin(0.2*M_PI); // a radius of a circumscribed circle of the triangle
    h1=sqrt(size*size-r2*r2);                     // height of vertex 1
    h2=h1+sqrt(3.0/4.0*size*size-(r2-r1)*(r2-r1));// height of vertex 1
    h3=h1+h2;                               // height of the icosahedron
    icosahedron.pnt[0].z=0.0;
    icosahedron.pnt[0].x=0.0;
    icosahedron.pnt[0].y=h3-h3/2;
    icosahedron.pnt[11].z=0.0;
    icosahedron.pnt[11].x=0.0;
    icosahedron.pnt[11].y=0.0-h3/2;
    th0[0]=0.0; h[0]=h2;
    th0[1]=0.2*M_PI; h[1]=h1;
    for (i = 0; i<2; i++){
        for (j = 0; j<5; j++){
            th=0.4*M_PI*(float)j+th0[i];
            k=5*i+j+1;
            icosahedron.pnt[k].z=-r2*sin(th);
            icosahedron.pnt[k].x=r2*cos(th);
            icosahedron.pnt[k].y=h[i]-h3/2;
        }
    }

    icosahedron.NumberofFaces=20;

    for (i = 0; i<icosahedron.NumberofFaces; i++){
        icosahedron.fc[i]=face[i];
    }
}

void userdraw(void)
{
    static int tick=0;
    static polyhedron_t icosahedron;
    float theta=0.5;
    matrix3D_t tilting=rotationXMTX(theta)*rotationYMTX(-theta);
    color_t white={1.,1.,1.};
    int disp=(tick/200)%6;
    int tickindisp=tick%200;
    vector3D_t unitz={0,0,1,1};
    vector3D_t LightVector0=rotationYMTX(0.2)*rotationXMTX(-1.2)*unitz;
    vector3D_t LightVector=tilting*LightVector0;
    vector3D_t ViewVector={0,0,1,1};
    color_t Cyan={0,1,1};
    color_t Blue={0,0,1};
    color_t Yellow={1,1,0};
    vector3D_t vec[32];
    vector3D_t vecbuff[32];
    vector3D_t NormalVector;
    vector3D_t buff[32];
    float normalzi;//z of normal vector of the face
    float normalz[32];//z of normal vector of the face
    matrix3D_t rot,prs,mat;
    color_t fillcolor;
    int i,j;

    if (tick==0) makeIcosahedron(icosahedron,150);
    setColor(white);
    drawAxes(tilting);

    setColor(Cyan);
    switch(disp) {
    case 0: //with all faces
        glutSetWindowTitle(" - with all faces");
        rot=rotationYMTX(0.02*tickindisp);
        mat=tilting*rot;
        for (i=0;i<icosahedron.NumberofVertices;i++) {
            vec[i]=Point2Vector(icosahedron.pnt[i]);
            vec[i]=mat*vec[i];
        }
        for (i=0;i<icosahedron.NumberofFaces;i++) {
            for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                buff[j]=vec[icosahedron.fc[i].pnt[j]];
            }
            drawPolygon(buff,icosahedron.fc[i].NumberofVertices);
        }
        break;
    case 1: //removing hidden faces
        glutSetWindowTitle("icosahedron - removing hidden faces");
        rot=rotationYMTX(0.02*tickindisp);
        mat=tilting*rot;
        for (i=0;i<icosahedron.NumberofVertices;i++) {
            vec[i]=Point2Vector(icosahedron.pnt[i]);
            vec[i]=mat*vec[i];
        }
        for (i=0;i<icosahedron.NumberofFaces;i++) {
            for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                vecbuff[j]=vec[icosahedron.fc[i].pnt[j]];
            }
            NormalVector=(vecbuff[1]-vecbuff[0])^(vecbuff[2]-vecbuff[0]);
            normalzi=NormalVector.v[2];
            if (0.<normalzi) {
                for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                    buff[j]=vec[icosahedron.fc[i].pnt[j]];
                }
                drawPolygon(buff,icosahedron.fc[i].NumberofVertices);
            }
        }
        break;
    case 2: //visible or invisible
        glutSetWindowTitle("icosahedron - visible or invisible");
        rot=rotationYMTX(0.02*tickindisp);
        mat=tilting*rot;
        for (i=0;i<icosahedron.NumberofVertices;i++) {
            vec[i]=Point2Vector(icosahedron.pnt[i]);
            vec[i]=mat*vec[i];
        }
        setColor(Blue);
        for (i=0;i<icosahedron.NumberofFaces;i++) {
            for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                vecbuff[j]=vec[icosahedron.fc[i].pnt[j]];
            }
            NormalVector=(vecbuff[1]-vecbuff[0])^(vecbuff[2]-vecbuff[0]);
            normalz[i]=NormalVector.v[2];
            if (normalz[i]<0.) {
                for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                    buff[j]=vec[icosahedron.fc[i].pnt[j]];
                }
                drawPolygon(buff,icosahedron.fc[i].NumberofVertices);
            }
        }
        setColor(Cyan);
        for (i=0;i<icosahedron.NumberofFaces;i++) {
            if (0.<=normalz[i]) {
                for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                    vecbuff[j]=vec[icosahedron.fc[i].pnt[j]];
                }
                drawPolygon(vecbuff,icosahedron.fc[i].NumberofVertices);
            }
        }
        break;
    case 3: //removing hidden faces and filling
        glutSetWindowTitle("icosahedron - removing hidden faces and filling");
        rot=rotationYMTX(0.02*tickindisp);
        mat=tilting*rot;
        for (i=0;i<icosahedron.NumberofVertices;i++) {
            vec[i]=Point2Vector(icosahedron.pnt[i]);
            vec[i]=mat*vec[i];
        }
        for (i=0;i<icosahedron.NumberofFaces;i++) {
            for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                vecbuff[j]=vec[icosahedron.fc[i].pnt[j]];
            }
            NormalVector=(vecbuff[1]-vecbuff[0])^(vecbuff[2]-vecbuff[0]);
            normalzi=NormalVector.v[2];
            if (0.<normalzi) {
                fillPolygon(vecbuff,icosahedron.fc[i].NumberofVertices,Cyan);
                setColor(Yellow);
                drawPolygon(vecbuff,icosahedron.fc[i].NumberofVertices);
            }
        }
        break;
    case 4: //removing hidden faces and perspective projection
        glutSetWindowTitle("icosahedron - removing hidden faces and perspective projection");
        rot=rotationYMTX(0.02*tickindisp);
        prs=perspectiveMTX(1000.);
        mat=prs*tilting*rot;
        for (i=0;i<icosahedron.NumberofVertices;i++) {
            vec[i]=Point2Vector(icosahedron.pnt[i]);
            vec[i]=mat*vec[i];
            vec[i]=homogenizeVector(vec[i]);
        }
        setColor(Blue);
        for (i=0;i<icosahedron.NumberofFaces;i++) {
            for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                vecbuff[j]=vec[icosahedron.fc[i].pnt[j]];
            }
            NormalVector=(vecbuff[1]-vecbuff[0])^(vecbuff[2]-vecbuff[0]);
            normalz[i]=NormalVector.v[2];
            if (normalz[i]<0.) {
                drawPolygon(vecbuff,icosahedron.fc[i].NumberofVertices);
            }
        }
        setColor(Cyan);
        for (i=0;i<icosahedron.NumberofFaces;i++) {
            if (0.<=normalz[i]) {
                for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                    vecbuff[j]=vec[icosahedron.fc[i].pnt[j]];
                }
                drawPolygon(vecbuff,icosahedron.fc[i].NumberofVertices);
            }
        }
        break;
    case 5: //removing hidden faces and Phong model Flat shading
        glutSetWindowTitle("icosahedron - removing hidden faces and Phong model Flat shading");
        rot=rotationYMTX(0.02*tickindisp);
        mat=tilting*rot;
        for (i=0;i<icosahedron.NumberofVertices;i++) {
            vec[i]=Point2Vector(icosahedron.pnt[i]);
            vec[i]=mat*vec[i];
        }
        for (i=0;i<icosahedron.NumberofFaces;i++) {
            for (j=0;j<icosahedron.fc[i].NumberofVertices;j++) {
                vecbuff[j]=vec[icosahedron.fc[i].pnt[j]];
            }
            NormalVector=(vecbuff[1]-vecbuff[0])^(vecbuff[2]-vecbuff[0]);
            normalzi=NormalVector.v[2];
            if (0.<normalzi) {
                NormalVector=unitVector(NormalVector);
                fillcolor=PhongModel(LightVector,NormalVector,ViewVector,Cyan);
                fillPolygon(vecbuff,icosahedron.fc[i].NumberofVertices,fillcolor);
            }
        }
        break;
    default:
        break;
    }
    tick++;
}

int main(int argc, char **argv)
{
    glutInit(&argc,argv);
    glutInitDisplayMode ( GLUT_DOUBLE | GLUT_RGB );
    glutInitWindowPosition(100,100);
    glutInitWindowSize(640,480);
    glutCreateWindow ("icosahedron");
    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;
}