drawtools.c

/*
    C-Dogs SDL
    A port of the legendary (and fun) action/arcade cdogs.
    Copyright (C) 1995 Ronny Wester
    Copyright (C) 2003 Jeremy Chin 
    Copyright (C) 2003-2007 Lucas Martin-King 

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

-------------------------------------------------------------------------------

 draw-tools.c - miscellaneous drawing functions 
 
 Author: $Author: lmartinking $
 Rev:    $Revision: 250 $
 URL:    $HeadURL: svn://svn.icculus.org/cdogs-sdl/trunk/src/drawtools.c $
 ID:     $Id: drawtools.c 250 2007-07-06 16:38:43Z lmartinking $
 
*/ 

#include <stdio.h>

#include "drawtools.h"
#include "utils.h"
#include "blit.h"
#include "grafx.h"


void	Draw_Point (const int x, const int y, const unsigned char c)
{
	unsigned char *screen = GetDstScreen();
	
	//debug("(%d, %d)\n", x, y);
	
	screen[PixelIndex(x, y, SCREEN_WIDTH, SCREEN_HEIGHT)] = c;
}

static
void
Draw_StraightLine (const int x1, const int y1, const int x2, const int y2, const unsigned char c)
{
	register int i;
	register int start, end;
	
	if (x1 == x2) {					/* vertical line */
		if (y2 > y1) {
			start = y1;
			end = y2;
		} else {
			start = y2;
			end = y1;
		}
		
		for (i = start; i <= end; i++) {
			Draw_Point(x1, i, c);
		}
	} else if (y1 == y2) {				/* horizontal line */
		if (x2 > x1) {
			start = x1;
			end = x2;
		} else {
			start = x2;
			end = x1;
		}
			    
		for (i = start; i <= end; i++) {
			Draw_Point(i, y1, c);
		}
	}
	return;
}

#define ABS(x)	( x > 0 ? x : (-x) )

static void
Draw_DiagonalLine (const int x1, const int y1, const int x2, const int y2, const unsigned char c)
{
	register int i;
	register int start, end;
	
	if (x1 < x2) {
		start = x1;
		end = x2;
	} else {
		start = x2;
		end = x1;
	}
	
	for (i = start; i < end; i++) {
		Draw_Point(i, i, c);
	}
	
	return;
}

static void
Draw_OtherLine	(const int x1, const int y1, const int x2, const int y2, const unsigned char c)
{
	printf("### Other lines not yet implemented! ###\n");
}

void	Draw_Line  (const int x1, const int y1, const int x2, const int y2, const unsigned char c)
{
	//debug("(%d, %d) -> (%d, %d)\n", x1, y1, x2, y2);
	
	if (x1 == x2 || y1 == y2) 
		Draw_StraightLine(x1, y1, x2, y2, c);
	else if (ABS((x2 - x1)) == ABS((y1 - y2)))
		Draw_DiagonalLine(x1, y1, x2, y2, c);
	else
		Draw_OtherLine(x1, y1, x2, y2, c);
	
	return;
}