/*****************************************************************
  transparency.cpp
  by Dave Pape
  20 April 2003

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

using namespace dms;

void createScene(Object& root);
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;
Object root;
Color transparentBlue(0, 0, 1, 0.5);
Material material(transparentBlue);


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, 2, 5);
    light.setInfinitePosition(1, 1, 1);
    createScene(root);

    glutMainLoop();
    return 0;
    }


void createScene(Object& root)
    {
    Square * square;
    Material * material;
        
    square = new Square(-50, -50, 50, 50, DMS_Y);
    material = new Material(Color::Green);
    square->setMaterial(*material);
    root.attach(*square);
    }


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();
    root.drawAll();
    glTranslatef(0, 2, 0);
    glRotatef(currentTime()*10, 1, 1, 1);

#if 1
    glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
    glutSolidTeapot(1.0);
    glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
    glDepthFunc(GL_EQUAL);
#endif

    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    material.apply();
    glutSolidTeapot(1.0);
    material.disable();
    glDisable(GL_BLEND);

    glDepthFunc(GL_LESS);

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


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


void specialkey(int k, int x, int y)
    {
    if (k == GLUT_KEY_LEFT)
        camera.turn(1);
    else if (k == GLUT_KEY_RIGHT)
        camera.turn(-1);
    else if (k == GLUT_KEY_UP)
        camera.pitch(1);
    else if (k == GLUT_KEY_DOWN)
        camera.pitch(-1);
    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();
    }