defs.h

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/*=========================================================================

GFX - a small graphics library 

Copyright (C) 2004  Rafael de Oliveira Jannone

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

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

Contact the author:
        by e-mail : rafael AT jannone DOT org
        homepage  : http://jannone.org/gfxlib
        ICQ UIN   : 10115284

See the License at http://www.gnu.org/copyleft/lesser.txt

=========================================================================*/

// DEFS.H : shared defines

/* === WARNING ==

        This is a work-in-progress, meaning that most of this code is unstable
        and it's subject to future changes.  Also, most of it is very hackish,
        not properly cleaned up nor tested.

   === WARNING == */

#ifndef DEFS_H
#define DEFS_H

// trivial stuff

#define u_int   unsigned int
#define u_char  unsigned char
#define bool    char
#define true    1
#define false   0
#ifndef NULL
        #define NULL 0
#endif

// screen mapping

#define map_block(x,y)  ((((y) & ~(7)) << 5) + ((x) & ~(7)))

#define map_pixel(x,y)  (map_block(x,y) + ((y) & 7))
/*
        here is how it works:

        // map the row start (by row I mean a block of 8 lines)
        addr = (y & ~(7)) << 5;         // this is the same as (y / 8) * 256

        // then we aim for the column (column = block of 8 pixels)
        addr += (x & ~(7));     // this is the same as (x / 8) * 8

        // finally, aim for the remaining "sub-row" inside the row block
        addr += (y & 7);
*/

#define map_subpixel(x) (128 >> ((x) & 7))

#define LONG(v) ((long)(v))

// fixed point arithmetic

#define i2f(v)  ((v) << 6)

#define f2i(v)  ((v) >> 6)

#define mulfx(x,y)      ((LONG(y) * LONG(x)) >> 6)

#define divfx(x,y)      ((LONG(x) << 6) / LONG(y))

#define sqrfx(x)        ((LONG(x) * LONG(x)) >> 6)

#define sqrtfx(x)       (LONG(sqrt(x)) << 3)
// formula: sqrt(N * 64) = sqrt(N) * sqrt(64) -> must compensate with 64/sqrt(64) = 8

#define wgavgfx(x, y, w)        (mulfx(i2f(1) - w, x) + mulfx(w, y))

// malloc helpers

#define new(x)          ((x*)malloc(sizeof(x)))

#define newa(x, c)      ((x*)malloc(sizeof(x) * c))

#endif

---