/*
 *  a1p2.cpp
 *  CompFormApp
 *
 *  Created by Matthew Parker on 9/7/07.
 *  Copyright 2007 __MyCompanyName__. All rights reserved.
 *
 */

#include <a1p3.h>

#include <gl/glut.h>

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

void drawLandscape(void){
    
   
    //Sky
   
    for(float y = TOP; y >= HORIZON; y--){
        glColor3f(0,0.25,HORIZON/y);

        glBegin(GL_QUADS);   
   
        glVertex2f(0, y);    
        glVertex2f(X_BORDER,y);
        glVertex2f(X_BORDER, y + 1);
        glVertex2f(0, y + 1);
   
        glEnd();
    }
   
    //Ground
   
    for(float y = 0; y < HORIZON; y++){
        glColor3f(1,y/HORIZON/2,0.1);

        glBegin(GL_QUADS);   
   
        glVertex2f(0, y);    
        glVertex2f(X_BORDER,y);
        glVertex2f(X_BORDER, y + 1);
        glVertex2f(0, y + 1);
   
        glEnd();
    }
   
    //Draw mountains
    for(float x = 0; x < X_BORDER; x = x + 200){   
        glBegin(GL_TRIANGLES);   

        glVertex2f(x, HORIZON);    
        glVertex2f(x + 100, HORIZON + 100 + mouseY/2);
        glVertex2f(x + 200, HORIZON);
   
        glEnd();
    }
   
    for(float x = 100; x < X_BORDER; x = x + 320){   
        glBegin(GL_TRIANGLES);   

        glVertex2f(x, HORIZON);    
        glVertex2f(x + 160, HORIZON + 50 + mouseY/3);
        glVertex2f(x + 320, HORIZON);
   
        glEnd();
    }
   
    //Cloud
   
    glColor4f(1,1,1,mouseX/X_BORDER * 2);
    
    glBegin(GL_TRIANGLE_FAN);   
    
    for(int i = 0; i < cloudPtsLength; i = i + 2){
        glVertex2f(cloudPts[i][0],cloudPts[i][1]);
        glVertex2f(cloudPts[i+1][0],cloudPts[i+1][1]);
    }
    
    glEnd();
    
//     River
    glColor4f(0.1,0.5,1,1); 
    
    glBegin(GL_TRIANGLE_STRIP);   

    for(int i = 0; i < riverPtsLength; i = i + 2){
        glVertex2f(riverPts[i][0] - mouseMove,riverPts[i][1]);
        glVertex2f(riverPts[i+1][0] + mouseMove,riverPts[i+1][1]);
    }
    
    glEnd();
}

void displayFunc ( void )        //what to display on screen (only place to draw on screen)
{
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );    //clears the screen (clear color and depth)

    // place your drawing code here

    drawLandscape();
   
    glutPostRedisplay();                        //redraw off screen buffer (allows for animation)
    glutSwapBuffers();                        //switch from off screen buffer to on screen buffer
}


void reshapeFunc ( int w, int h )    //resize the window
{
    windowW = w;                            //update global variables
    windowH = h;                           

    glViewport( 0, 0, w, h );                    //window coords, drawing region of window
    glMatrixMode( GL_PROJECTION );                //how the camera operates
    glLoadIdentity();                            //
    gluOrtho2D( 0,w,0,h );                        //

    glMatrixMode( GL_MODELVIEW );                    //defines what you're drawing
    glLoadIdentity();
}


void mouseDownFunc ( int button, int state, int x, int y )    //called when mouse is pressed (button = which button, state = up or down, x/y = position)
{
    mouseX = x;                                //set our global mouseX to x
    mouseY = windowH - y;                        //set our global mouseY to the invert of y
   
    if(state == 0){
        printf("{%d,%d}, \n", x, windowH - y);                    //prints out x, y
    }
}


void mouseMoveFunc ( int x, int y )                   
{
    if(mouseX != x){
        mouseMove++;
    }
   
    mouseX = x;
    mouseY = windowH - y;
}


void mouseDragFunc ( int x, int y )
{
    mouseX = x;
    mouseY = windowH - y;
}


void keyboardFunc ( unsigned char key, int x, int y )        //called when a keyboard button is pressed
{
}


void arrowKeyFunc ( int a_keys, int x, int y )            //called when special keys are pressed (arrows, shift, etc)
{
}


void init ( GLvoid )                            //minimal amount of OpenGL initialization
{
    glShadeModel( GL_SMOOTH );
    glClearColor( 1.0, 1.0, 1.0, 1.0 );
    glEnable ( GL_COLOR_MATERIAL );
    glEnable( GL_BLEND );
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
}


int main ( int argc, char** argv )                  //  * = pointer (** double pointer)
{
    glutInit( &argc, argv );                      // & = take the address of
   
    glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE );      // double buffered
    glutInitWindowSize( windowW, windowH ); 

    // take other functions = callback   
   
    glutCreateWindow( "CompFormApp" );

    glutDisplayFunc( displayFunc );                   //display screen
    glutReshapeFunc( reshapeFunc );                //reshape window size
    glutMouseFunc( mouseDownFunc );                //mouse click
    glutMotionFunc( mouseDragFunc );                //dragging mouse
    glutPassiveMotionFunc( mouseMoveFunc );            //moving mouse
    glutKeyboardFunc( keyboardFunc );                //key down
    glutSpecialFunc( arrowKeyFunc );                //special case for arrow key presses/shift/etc.

    init();
   
    glutMainLoop( );                            //runs the glut environment, prevents program from reaching return
 
    return 0;                                //place holder return for main
}