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view src/video/xbios/SDL_xbios_sb3.h @ 2042:3908e1f808e1

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Fixed bug #292 I might be on crack here. It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and right channels of a stereo stream together, and clamps the new mono channel if it would overflow. Shouldn't it be dividing by 2 to average the two sample points instead of clamping? Otherwise the mono sample point's volume doubles in the conversion. This would also make the conversion faster, as it replaces two branches per sample frame with a bitwise shift. --ryan.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 24 Sep 2006 15:56:36 +0000
parents c121d94672cb
children 99210400e8b9
line wrap: on
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

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

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/*
	ScreenBlaster 3 definitions

	Patrice Mandin
*/

#ifndef _SDL_xbios_sb3_h_
#define _SDL_xbios_sb3_h_

/*--- Defines ---*/

#ifndef C_SCPN
#define C_SCPN 0x5343504EL
#endif

#define SCPN_DEV_1BPP	0
#define SCPN_DEV_2BPP	1
#define SCPN_DEV_4BPP	2
#define SCPN_DEV_8BPP	3
#define SCPN_DEV_16BPP	4

extern const int SDL_XBIOS_scpn_planes_device[];

/*--- Types ---*/

typedef struct
{
    unsigned short virtual_width;       /* Virtual screen width */
    unsigned short virtual_height;      /* Virtual screen height */
    unsigned short visible_width;       /* Visible width */
    unsigned short visible_height;      /* Visible height */
    unsigned short h_pos;       /* Horizontal position in virtual screen */
    unsigned short v_pos;       /* Vertical position in virtual screen */
    unsigned short dummy;
    unsigned long size;         /* Size of screen in bytes */
    unsigned short device;      /* Device number to find planes = getRez() */
    /* = Index in scpn_planes_device[] */
} __attribute__ ((packed)) scpn_screeninfo_t;

typedef struct
{
    unsigned long magic;        /* just a BRA assembler jump */
    unsigned short version;
    void *dummy1;
    unsigned short ptsout0_1;
    unsigned short ptsout0_2;
    unsigned short dummy3;
    unsigned char date[8];      /* Date of program build */
    unsigned char asm_string[30];       /* 10 times the 'ASM' string */
    unsigned short dummy4;
    scpn_screeninfo_t *screen_info;
    unsigned short dummy6;
} __attribute__ ((packed)) scpn_cookie_t;

/*--- Function prototypes ---*/

int SDL_XBIOS_SB3Usable(scpn_cookie_t * cookie_scpn);

void SDL_XBIOS_SB3Init(_THIS, scpn_cookie_t * cookie_scpn);

#endif /* _SDL_xbios_sb3_h_ */
/* vi: set ts=4 sw=4 expandtab: */