view src/video/ataricommon/SDL_atarigl_c.h @ 2042:3908e1f808e1

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 b657f0bc72c2
children 99210400e8b9
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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"

/* Atari OSMesa.ldg implementation of SDL OpenGL support */

#ifndef _SDL_ATARIGL_H_
#define _SDL_ATARIGL_H_

#if SDL_VIDEO_OPENGL
#include <GL/osmesa.h>
#endif

#include "../SDL_sysvideo.h"

struct SDL_GLDriverData
{

    int gl_active;              /* to stop switching drivers while we have a valid context */

    int gl_oldmesa;             /* Old OpenGL support ? */

    int gl_pixelsize;           /* for CopyShadow functions */

    SDL_bool gl_upsidedown;     /* Some implementations draw upside down */

    Uint8 *gl_shadow;           /* Shadow buffer for old implementations */

    /* for unsupported OSMesa buffer formats */
    void (*ConvertSurface) (_THIS, SDL_Surface * surface);

    /* to convert the shadow buffer to the screen format */
    void (*CopyShadow) (_THIS, SDL_Surface * surface);

#if SDL_VIDEO_OPENGL
    OSMesaContext ctx;

    /* OpenGL functions */
    void (*glGetIntegerv) (GLenum pname, GLint * value);
    void (*glFinish) (void);
    void (*glFlush) (void);

    /* osmesa.ldg */
      OSMesaContext(*OSMesaCreateContextExt) (GLenum format, GLint depthBits,
                                              GLint stencilBits,
                                              GLint accumBits,
                                              OSMesaContext sharelist);
    void (*OSMesaDestroyContext) (OSMesaContext ctx);
      GLboolean(*OSMesaMakeCurrent) (OSMesaContext ctx, void *buffer,
                                     GLenum type, GLsizei width,
                                     GLsizei height);
    void (*OSMesaPixelStore) (GLint pname, GLint value);
    void *(*OSMesaGetProcAddress) (const char *funcName);

    /* mesa_gl.ldg, tiny_gl.ldg */
    void *(*OSMesaCreateLDG) (long format, long type, long width,
                              long height);
    void (*OSMesaDestroyLDG) (void);

    /* Info needed to compare existing context with new asked one */
    int width, height;
    GLenum format;
    GLint depth, stencil, accum;
#endif
};

/* Variable names */
#define gl_active		(_this->gl_data->gl_active)
#define gl_ctx			(_this->gl_data->ctx)
#define gl_oldmesa		(_this->gl_data->gl_oldmesa)
#define gl_pixelsize	(_this->gl_data->gl_pixelsize)
#define gl_upsidedown	(_this->gl_data->gl_upsidedown)
#define gl_shadow		(_this->gl_data->gl_shadow)
#define gl_convert		(_this->gl_data->ConvertSurface)
#define gl_copyshadow	(_this->gl_data->CopyShadow)
#define gl_curformat	(_this->gl_data->format)
#define gl_curdepth		(_this->gl_data->depth)
#define gl_curstencil	(_this->gl_data->stencil)
#define gl_curaccum		(_this->gl_data->accum)
#define gl_curwidth		(_this->gl_data->width)
#define gl_curheight	(_this->gl_data->height)

/* OpenGL functions */
extern int SDL_AtariGL_Init(_THIS, SDL_Surface * current);
extern void SDL_AtariGL_Quit(_THIS, SDL_bool unload);
extern void SDL_AtariGL_InitPointers(_THIS);

extern int SDL_AtariGL_LoadLibrary(_THIS, const char *path);
extern void *SDL_AtariGL_GetProcAddress(_THIS, const char *proc);
extern int SDL_AtariGL_GetAttribute(_THIS, SDL_GLattr attrib, int *value);
extern int SDL_AtariGL_MakeCurrent(_THIS);
extern void SDL_AtariGL_SwapBuffers(_THIS);

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