/*****************************************************************
  texGrow.cpp
  by Dave Pape
  22 March 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 drawSquare(void);
void drawEverything(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;
Texture2D texture("aludiplt.tif");

bool transformTexture = false;


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, 15);
    light.setInfinitePosition(-5, 4, 1);
    
    glutMainLoop();
    return 0;
    }


void drawEverything(void)
    {
    dms::beginFrame();
    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();

    drawSquare();

    glutSwapBuffers();

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


void drawSquare(void)
    {
/*************** CODE OF INTEREST ******************************/
/* Compute the current size of the object, then use this value */
/* to scale both the geometry and the texture coordinates.     */
/*                                                             */
    GLfloat size = 1.0 + 3.0 * (sin(dms::currentTime()) + 1.0);
    if (transformTexture)
        {
        glMatrixMode(GL_TEXTURE);
         glLoadIdentity();
         glScalef(size, 1, 1);
        glMatrixMode(GL_MODELVIEW);
        }
    glScalef(size, 1, 1);
    
    texture.apply();
    glBegin(GL_QUADS);
     glTexCoord2f(0, 0);
     glVertex3f(-1, -1, 0);
     glTexCoord2f(1, 0);
     glVertex3f(1, -1, 0);
     glTexCoord2f(1, 1);
     glVertex3f(1, 1, 0);
     glTexCoord2f(0, 1);
     glVertex3f(-1, 1, 0);
    glEnd();
    texture.disable();
    }


void key(unsigned char k, int x, int y)
    {
    if (k == 27)
        exit(0);
    else if (k == ' ')
        transformTexture = !transformTexture;
    }


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)
    {
    glutPostRedisplay();
    }