/* anything related to drawing is in here
 * including texture loading and setting */

#ifndef __DRAW_H__
#define __DRAW_H__

#include "common.h"

extern PEmitter theEmitter[2];

int drawGLScene( GLvoid )
{
    /* These are to calculate our fps */
    static GLint T0     = 0;
    GLint t = 0;
    static GLint Frames = 0;

    /* Clear The Screen And The Depth Buffer */
    glPointSize(3.0f);
    
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity( );
    glTranslatef(0.0f, 1.0f, -20.0f);
    

    DrawEmitter(&theEmitter[0]);
    DrawEmitter(&theEmitter[1]);

    /* Draw it to the screen */
    SDL_GL_SwapBuffers( );

    Frames++;
    t = SDL_GetTicks();
	if (t - T0 >= 1000) {
	    GLfloat seconds = (t - T0) / 1000.0;
	    GLfloat fps = Frames / seconds;
	    printf("%d frames in %g seconds = %g FPS (new time %g)\n", Frames, seconds, fps, (float)time(NULL));
	    T0 = t;
	    Frames = 0;
	}

    UpdateEmitter(&theEmitter[0], t - T0);
    UpdateEmitter(&theEmitter[1], t - T0);

    T0 = t;
    
    return( TRUE );
}

/* function to reset our viewport after a window resize */
int resizeWindow( int width, int height )
{
    GLfloat ratio;

    /* Protect against a divide by zero */
    if ( height == 0 ) height = 1;

    ratio = ( GLfloat )width / ( GLfloat )height;

    /* set the viewport, viewing volume, perspective, etc etc */

    glViewport( 0, 0, ( GLint )width, ( GLint )height );
    glMatrixMode( GL_PROJECTION );
    glLoadIdentity( );
    gluPerspective( 45.0f, ratio, 0.1f, 100.0f );
    glMatrixMode( GL_MODELVIEW );

    /* Reset The Modelview matrix */
    glLoadIdentity( );

    return( TRUE );
}

/* general OpenGL initialization function */
int initGL( GLvoid )
{

    /* Setup shading, clearing, depth testing, and rendering hints */
    glShadeModel( GL_SMOOTH );
    glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
    glClearDepth( 1.0f );
    glEnable( GL_DEPTH_TEST );
    glDepthFunc( GL_LEQUAL );
    glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE);

    return( TRUE );
}

#endif // __DRAW_H__