/*****************************************************************
  offset.cpp
  by Dave Pape
  22 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>
#include "TexFont.h"

using namespace dms;

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;

TexFont * txfFont;


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, 3, 40);
    txfFont = txfLoadFont("default.txf");
    txfEstablishTexture(txfFont, 0, GL_TRUE);
    
    glutMainLoop();
    return 0;
    }


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();

    glPushMatrix();
     glRotatef(currentTime()*30, 0, 1, 0);

     glColor3f(0.1, 0.3, 1);
     glBegin(GL_QUADS);
      glVertex2f(-10, -10);
      glVertex2f(10, -10);
      glVertex2f(10, 10);
      glVertex2f(-10, 10);
     glEnd();

//     glDepthFunc(GL_EQUAL);
     glEnable(GL_POLYGON_OFFSET_FILL);
     glPolygonOffset(0, -20);

     glColor3f(0.8, 0.2, 0.4);
     glEnable(GL_TEXTURE_2D);
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     char *str = "Offset Test";
     int width, ascent, descent;
     txfGetStringMetrics(txfFont, str, strlen(str), &width, &ascent, &descent);
     glTranslatef(-8, 0, 0.0);
     glScalef(16.0/width, 16.0/width, 16.0/width);
     txfRenderString(txfFont, str, strlen(str));
     glDisable(GL_TEXTURE_2D);
     glDisable(GL_BLEND);
     glDisable(GL_POLYGON_OFFSET_FILL);
     glDepthFunc(GL_LESS);

    glPopMatrix();

    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(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();
    }