/*****************************************************************
  contour.cpp
  by Dave Pape
  30 Mar 2003

*****************************************************************/
#include <stdlib.h>
#include <math.h>
#include <unistd.h>
#include <stdio.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <dms/dms.h>

using namespace dms;

void createScene(Object& root);
void drawEverything(void);
void drawPlane(void);

void key(unsigned char k, int x, int y);
void specialkey(int k, int x, int y);
void idle(void);


PerspCamera camera;
Light light;
Object root;
Texture1D contourTex("contour.tif");


int main(int argc, char *argv[])
    {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(512,512);
    glutCreateWindow(argv[0]);
    
    glutDisplayFunc(drawEverything);
    glutKeyboardFunc(key);
    glutSpecialFunc(specialkey);
    glutIdleFunc(idle);
    
    camera.setPosition(0, 0, 8);
    light.setInfinitePosition(-1, 1, 2);
    createScene(root);
    
    glutMainLoop();
    return 0;
    }


GLfloat planeCoefficients[4] = { 1, 0, 0, 0 };

void createScene(Object& root)
    {
    QuadricObject *ball = new QuadricObject;
    ball->makeSphere(1.0, 32, 16);
    ball->setMaterial(*(new Material(Color::White)));
    ball->setTexture(contourTex);
    ball->setUseTexture(GL_TRUE);
    root.attach(*ball);
    
    glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
    glTexGenfv(GL_S, GL_OBJECT_PLANE, planeCoefficients);
    }


void drawEverything(void)
    {
    glClearColor(0.5, 0.7, 1.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glEnable(GL_DEPTH_TEST);
    
    camera.apply();
    
    light.apply();

    glEnable(GL_TEXTURE_GEN_S);

    contourTex.apply();
    glColor3f(1, 1, 1);
    glBegin(GL_QUADS);
     glVertex3f(-3.25, -1, 0);
     glVertex3f(-1.25, -1, 0);
     glVertex3f(-1.25, 1, 0);
     glVertex3f(-3.25, 1, 0);
    glEnd();
    contourTex.disable();

    root.drawAll();

    glDisable(GL_TEXTURE_GEN_S);

    drawPlane();
    
    glutSwapBuffers();

    checkGLError("end-of-frame");
    }


void drawPlane(void)
    {
    float A = planeCoefficients[0];
    float B = planeCoefficients[1];
    float C = planeCoefficients[2];
    float D = planeCoefficients[3];
    Vector3 p0, p1, p2, p3;
    glColor4f(0, 0, 1, 0.4);
    Transparency::StandardBlend.apply();
    if (A != 0)
        {
        p0.set((-D+10*B+10*C)/A, -10, -10);
        p1.set((-D-10*B+10*C)/A, 10, -10);
        p2.set((-D-10*B-10*C)/A, 10, 10);
        p3.set((-D+10*B-10*C)/A, -10, 10);
        }
    else if (B != 0)
        {
        p0.set(-10, (-D+10*A+10*C)/B, -10);
        p1.set(10, (-D-10*A+10*C)/B, -10);
        p2.set(10, (-D-10*A-10*C)/B, 10);
        p3.set(-10, (-D+10*A-10*C)/B, 10);
        }
    else if (C != 0)
        {
        p0.set(-10, -10, (-D+10*A+10*B)/C);
        p1.set(10, -10, (-D-10*A+10*B)/C);
        p2.set(10, 10, (-D-10*A-10*B)/C);
        p3.set(-10, 10, (-D+10*A-10*B)/C);
        }
    glBegin(GL_QUADS);
     glVertex3fv(p0.vec);
     glVertex3fv(p1.vec);
     glVertex3fv(p2.vec);
     glVertex3fv(p3.vec);
    glEnd();
    Transparency::StandardBlend.disable();
    }


void key(unsigned char k, int x, int y)
    {
    if (k == 27)
        exit(0);
    else if (k == 'a')
        {
        planeCoefficients[3] += 0.1;
        glTexGenfv(GL_S, GL_OBJECT_PLANE, planeCoefficients);
        }
    else if (k == 's')
        {
        planeCoefficients[3] -= 0.1;
        glTexGenfv(GL_S, GL_OBJECT_PLANE, planeCoefficients);
        }
    }


void specialkey(int k, int x, int y)
    {
    if (k == GLUT_KEY_LEFT)
        camera.turn(3);
    else if (k == GLUT_KEY_RIGHT)
        camera.turn(-3);
    else if (k == GLUT_KEY_UP)
        camera.pitch(2);
    else if (k == GLUT_KEY_DOWN)
        camera.pitch(-2);
    else if (k == GLUT_KEY_HOME)
        camera.moveForward(0.25);
    else if (k == GLUT_KEY_END)
        camera.moveForward(-0.25);
    else if (k == GLUT_KEY_PAGE_UP)
        camera.zoom(-1);
    else if (k == GLUT_KEY_PAGE_DOWN)
        camera.zoom(1);
    }


void idle(void)
    {
    root.updateAll();
    glutPostRedisplay();
    }