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view src/audio/SDL_mixer.c @ 1675:d33dcfc3fde7 SDL-1.3

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Overlay functions are being replaced by YUV textures. If the driver doesn't support YUV textures, they can be emulated by backing the texture with an RGB texture and using the software conversion routines. Note that it doesn't make sense to lock a portion of a YV12 texture, since you'd need to return three pixel pointers and pitch values instead of the one that's available through the API. I'm guessing that's one of the reasons DirectX 9 doesn't support this format at all.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 11 Jun 2006 07:30:16 +0000
parents 4da1ee79c9af
children
line wrap: on
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

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

/* This provides the default mixing callback for the SDL audio routines */

#include "SDL_cpuinfo.h"
#include "SDL_timer.h"
#include "SDL_audio.h"
#include "SDL_sysaudio.h"
#include "SDL_mixer_MMX.h"
#include "SDL_mixer_MMX_VC.h"
#include "SDL_mixer_m68k.h"

/* This table is used to add two sound values together and pin
 * the value to avoid overflow.  (used with permission from ARDI)
 * Changed to use 0xFE instead of 0xFF for better sound quality.
 */
static const Uint8 mix8[] = {
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03,
    0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
    0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
    0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
    0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
    0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
    0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
    0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B,
    0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
    0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71,
    0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C,
    0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
    0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92,
    0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D,
    0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8,
    0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3,
    0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE,
    0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9,
    0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
    0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
    0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,
    0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5,
    0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
    0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE
};

/* The volume ranges from 0 - 128 */
#define ADJUST_VOLUME(s, v)	(s = (s*v)/SDL_MIX_MAXVOLUME)
#define ADJUST_VOLUME_U8(s, v)	(s = (((s-128)*v)/SDL_MIX_MAXVOLUME)+128)

void
SDL_MixAudio(Uint8 * dst, const Uint8 * src, Uint32 len, int volume)
{
    Uint16 format;

    if (volume == 0) {
        return;
    }
    /* Mix the user-level audio format */
    if (current_audio) {
        if (current_audio->convert.needed) {
            format = current_audio->convert.src_format;
        } else {
            format = current_audio->spec.format;
        }
    } else {
        /* HACK HACK HACK */
        format = AUDIO_S16;
    }
    switch (format) {

    case AUDIO_U8:
        {
#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
            SDL_MixAudio_m68k_U8((char *) dst, (char *) src,
                                 (unsigned long) len, (long) volume,
                                 (char *) mix8);
#else
            Uint8 src_sample;

            while (len--) {
                src_sample = *src;
                ADJUST_VOLUME_U8(src_sample, volume);
                *dst = mix8[*dst + src_sample];
                ++dst;
                ++src;
            }
#endif
        }
        break;

    case AUDIO_S8:
        {
#if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
            if (SDL_HasMMX()) {
                SDL_MixAudio_MMX_S8((char *) dst, (char *) src,
                                    (unsigned int) len, (int) volume);
            } else
#elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
            if (SDL_HasMMX()) {
                SDL_MixAudio_MMX_S8_VC((char *) dst, (char *) src,
                                       (unsigned int) len, (int) volume);
            } else
#endif
#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
                SDL_MixAudio_m68k_S8((char *) dst, (char *) src,
                                     (unsigned long) len, (long) volume);
#else
            {
                Sint8 *dst8, *src8;
                Sint8 src_sample;
                int dst_sample;
                const int max_audioval = ((1 << (8 - 1)) - 1);
                const int min_audioval = -(1 << (8 - 1));

                src8 = (Sint8 *) src;
                dst8 = (Sint8 *) dst;
                while (len--) {
                    src_sample = *src8;
                    ADJUST_VOLUME(src_sample, volume);
                    dst_sample = *dst8 + src_sample;
                    if (dst_sample > max_audioval) {
                        *dst8 = max_audioval;
                    } else if (dst_sample < min_audioval) {
                        *dst8 = min_audioval;
                    } else {
                        *dst8 = dst_sample;
                    }
                    ++dst8;
                    ++src8;
                }
            }
#endif
        }
        break;

    case AUDIO_S16LSB:
        {
#if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
            if (SDL_HasMMX()) {
                SDL_MixAudio_MMX_S16((char *) dst, (char *) src,
                                     (unsigned int) len, (int) volume);
            } else
#elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
            if (SDL_HasMMX()) {
                SDL_MixAudio_MMX_S16_VC((char *) dst, (char *) src,
                                        (unsigned int) len, (int) volume);
            } else
#endif
#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
                SDL_MixAudio_m68k_S16LSB((short *) dst, (short *) src,
                                         (unsigned long) len, (long) volume);
#else
            {
                Sint16 src1, src2;
                int dst_sample;
                const int max_audioval = ((1 << (16 - 1)) - 1);
                const int min_audioval = -(1 << (16 - 1));

                len /= 2;
                while (len--) {
                    src1 = ((src[1]) << 8 | src[0]);
                    ADJUST_VOLUME(src1, volume);
                    src2 = ((dst[1]) << 8 | dst[0]);
                    src += 2;
                    dst_sample = src1 + src2;
                    if (dst_sample > max_audioval) {
                        dst_sample = max_audioval;
                    } else if (dst_sample < min_audioval) {
                        dst_sample = min_audioval;
                    }
                    dst[0] = dst_sample & 0xFF;
                    dst_sample >>= 8;
                    dst[1] = dst_sample & 0xFF;
                    dst += 2;
                }
            }
#endif
        }
        break;

    case AUDIO_S16MSB:
        {
#if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
            SDL_MixAudio_m68k_S16MSB((short *) dst, (short *) src,
                                     (unsigned long) len, (long) volume);
#else
            Sint16 src1, src2;
            int dst_sample;
            const int max_audioval = ((1 << (16 - 1)) - 1);
            const int min_audioval = -(1 << (16 - 1));

            len /= 2;
            while (len--) {
                src1 = ((src[0]) << 8 | src[1]);
                ADJUST_VOLUME(src1, volume);
                src2 = ((dst[0]) << 8 | dst[1]);
                src += 2;
                dst_sample = src1 + src2;
                if (dst_sample > max_audioval) {
                    dst_sample = max_audioval;
                } else if (dst_sample < min_audioval) {
                    dst_sample = min_audioval;
                }
                dst[1] = dst_sample & 0xFF;
                dst_sample >>= 8;
                dst[0] = dst_sample & 0xFF;
                dst += 2;
            }
#endif
        }
        break;

    default:                   /* If this happens... FIXME! */
        SDL_SetError("SDL_MixAudio(): unknown audio format");
        return;
    }
}

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