view src/render/SDL_yuv_sw.c @ 5275:7aba0406c273

Frank Zago to sdl The following patch fixes some of the bitrot for the Nintendo DS port. The support is still basic at the moment, but it allows to run the "general" test under the current head of tree (parent: 5269:11bd1585efb5 tip). Most of the patch is mine, but I integrated a couple changes that John Magnotti posted on Feb 1st.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 12 Feb 2011 11:36:56 -0800
parents 11bd1585efb5
children
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2011 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 is the software implementation of the YUV texture support */

/* This code was derived from code carrying the following copyright notices:

 * Copyright (c) 1995 The Regents of the University of California.
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement is
 * hereby granted, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 * Copyright (c) 1995 Erik Corry
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement is
 * hereby granted, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 * 
 * IN NO EVENT SHALL ERIK CORRY BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
 * SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF
 * THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF ERIK CORRY HAS BEEN ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * ERIK CORRY SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
 * BASIS, AND ERIK CORRY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
 * UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 * Portions of this software Copyright (c) 1995 Brown University.
 * All rights reserved.
 * 
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement
 * is hereby granted, provided that the above copyright notice and the
 * following two paragraphs appear in all copies of this software.
 * 
 * IN NO EVENT SHALL BROWN UNIVERSITY BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF BROWN
 * UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * BROWN UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
 * BASIS, AND BROWN UNIVERSITY HAS NO OBLIGATION TO PROVIDE MAINTENANCE,
 * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */

#include "SDL_video.h"
#include "SDL_cpuinfo.h"
#include "SDL_yuv_sw_c.h"


/* The colorspace conversion functions */

#if (__GNUC__ > 2) && defined(__i386__) && __OPTIMIZE__ && SDL_ASSEMBLY_ROUTINES
extern void Color565DitherYV12MMX1X(int *colortab, Uint32 * rgb_2_pix,
                                    unsigned char *lum, unsigned char *cr,
                                    unsigned char *cb, unsigned char *out,
                                    int rows, int cols, int mod);
extern void ColorRGBDitherYV12MMX1X(int *colortab, Uint32 * rgb_2_pix,
                                    unsigned char *lum, unsigned char *cr,
                                    unsigned char *cb, unsigned char *out,
                                    int rows, int cols, int mod);
#endif

static void
Color16DitherYV12Mod1X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned short *row1;
    unsigned short *row2;
    unsigned char *lum2;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    row1 = (unsigned short *) out;
    row2 = row1 + cols + mod;
    lum2 = lum + cols;

    mod += cols + mod;

    y = rows / 2;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            ++cr;
            ++cb;

            L = *lum++;
            *row1++ = (unsigned short) (rgb_2_pix[L + cr_r] |
                                        rgb_2_pix[L + crb_g] |
                                        rgb_2_pix[L + cb_b]);

            L = *lum++;
            *row1++ = (unsigned short) (rgb_2_pix[L + cr_r] |
                                        rgb_2_pix[L + crb_g] |
                                        rgb_2_pix[L + cb_b]);


            /* Now, do second row.  */

            L = *lum2++;
            *row2++ = (unsigned short) (rgb_2_pix[L + cr_r] |
                                        rgb_2_pix[L + crb_g] |
                                        rgb_2_pix[L + cb_b]);

            L = *lum2++;
            *row2++ = (unsigned short) (rgb_2_pix[L + cr_r] |
                                        rgb_2_pix[L + crb_g] |
                                        rgb_2_pix[L + cb_b]);
        }

        /*
         * These values are at the start of the next line, (due
         * to the ++'s above),but they need to be at the start
         * of the line after that.
         */
        lum += cols;
        lum2 += cols;
        row1 += mod;
        row2 += mod;
    }
}

static void
Color24DitherYV12Mod1X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int value;
    unsigned char *row1;
    unsigned char *row2;
    unsigned char *lum2;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    row1 = out;
    row2 = row1 + cols * 3 + mod * 3;
    lum2 = lum + cols;

    mod += cols + mod;
    mod *= 3;

    y = rows / 2;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            ++cr;
            ++cb;

            L = *lum++;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            *row1++ = (value) & 0xFF;
            *row1++ = (value >> 8) & 0xFF;
            *row1++ = (value >> 16) & 0xFF;

            L = *lum++;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            *row1++ = (value) & 0xFF;
            *row1++ = (value >> 8) & 0xFF;
            *row1++ = (value >> 16) & 0xFF;


            /* Now, do second row.  */

            L = *lum2++;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            *row2++ = (value) & 0xFF;
            *row2++ = (value >> 8) & 0xFF;
            *row2++ = (value >> 16) & 0xFF;

            L = *lum2++;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            *row2++ = (value) & 0xFF;
            *row2++ = (value >> 8) & 0xFF;
            *row2++ = (value >> 16) & 0xFF;
        }

        /*
         * These values are at the start of the next line, (due
         * to the ++'s above),but they need to be at the start
         * of the line after that.
         */
        lum += cols;
        lum2 += cols;
        row1 += mod;
        row2 += mod;
    }
}

static void
Color32DitherYV12Mod1X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int *row1;
    unsigned int *row2;
    unsigned char *lum2;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    row1 = (unsigned int *) out;
    row2 = row1 + cols + mod;
    lum2 = lum + cols;

    mod += cols + mod;

    y = rows / 2;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            ++cr;
            ++cb;

            L = *lum++;
            *row1++ = (rgb_2_pix[L + cr_r] |
                       rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);

            L = *lum++;
            *row1++ = (rgb_2_pix[L + cr_r] |
                       rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);


            /* Now, do second row.  */

            L = *lum2++;
            *row2++ = (rgb_2_pix[L + cr_r] |
                       rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);

            L = *lum2++;
            *row2++ = (rgb_2_pix[L + cr_r] |
                       rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
        }

        /*
         * These values are at the start of the next line, (due
         * to the ++'s above),but they need to be at the start
         * of the line after that.
         */
        lum += cols;
        lum2 += cols;
        row1 += mod;
        row2 += mod;
    }
}

/*
 * In this function I make use of a nasty trick. The tables have the lower
 * 16 bits replicated in the upper 16. This means I can write ints and get
 * the horisontal doubling for free (almost).
 */
static void
Color16DitherYV12Mod2X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int *row1 = (unsigned int *) out;
    const int next_row = cols + (mod / 2);
    unsigned int *row2 = row1 + 2 * next_row;
    unsigned char *lum2;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    lum2 = lum + cols;

    mod = (next_row * 3) + (mod / 2);

    y = rows / 2;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            ++cr;
            ++cb;

            L = *lum++;
            row1[0] = row1[next_row] = (rgb_2_pix[L + cr_r] |
                                        rgb_2_pix[L + crb_g] |
                                        rgb_2_pix[L + cb_b]);
            row1++;

            L = *lum++;
            row1[0] = row1[next_row] = (rgb_2_pix[L + cr_r] |
                                        rgb_2_pix[L + crb_g] |
                                        rgb_2_pix[L + cb_b]);
            row1++;


            /* Now, do second row. */

            L = *lum2++;
            row2[0] = row2[next_row] = (rgb_2_pix[L + cr_r] |
                                        rgb_2_pix[L + crb_g] |
                                        rgb_2_pix[L + cb_b]);
            row2++;

            L = *lum2++;
            row2[0] = row2[next_row] = (rgb_2_pix[L + cr_r] |
                                        rgb_2_pix[L + crb_g] |
                                        rgb_2_pix[L + cb_b]);
            row2++;
        }

        /*
         * These values are at the start of the next line, (due
         * to the ++'s above),but they need to be at the start
         * of the line after that.
         */
        lum += cols;
        lum2 += cols;
        row1 += mod;
        row2 += mod;
    }
}

static void
Color24DitherYV12Mod2X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int value;
    unsigned char *row1 = out;
    const int next_row = (cols * 2 + mod) * 3;
    unsigned char *row2 = row1 + 2 * next_row;
    unsigned char *lum2;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    lum2 = lum + cols;

    mod = next_row * 3 + mod * 3;

    y = rows / 2;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            ++cr;
            ++cb;

            L = *lum++;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row1[0 + 0] = row1[3 + 0] = row1[next_row + 0] =
                row1[next_row + 3 + 0] = (value) & 0xFF;
            row1[0 + 1] = row1[3 + 1] = row1[next_row + 1] =
                row1[next_row + 3 + 1] = (value >> 8) & 0xFF;
            row1[0 + 2] = row1[3 + 2] = row1[next_row + 2] =
                row1[next_row + 3 + 2] = (value >> 16) & 0xFF;
            row1 += 2 * 3;

            L = *lum++;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row1[0 + 0] = row1[3 + 0] = row1[next_row + 0] =
                row1[next_row + 3 + 0] = (value) & 0xFF;
            row1[0 + 1] = row1[3 + 1] = row1[next_row + 1] =
                row1[next_row + 3 + 1] = (value >> 8) & 0xFF;
            row1[0 + 2] = row1[3 + 2] = row1[next_row + 2] =
                row1[next_row + 3 + 2] = (value >> 16) & 0xFF;
            row1 += 2 * 3;


            /* Now, do second row. */

            L = *lum2++;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row2[0 + 0] = row2[3 + 0] = row2[next_row + 0] =
                row2[next_row + 3 + 0] = (value) & 0xFF;
            row2[0 + 1] = row2[3 + 1] = row2[next_row + 1] =
                row2[next_row + 3 + 1] = (value >> 8) & 0xFF;
            row2[0 + 2] = row2[3 + 2] = row2[next_row + 2] =
                row2[next_row + 3 + 2] = (value >> 16) & 0xFF;
            row2 += 2 * 3;

            L = *lum2++;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row2[0 + 0] = row2[3 + 0] = row2[next_row + 0] =
                row2[next_row + 3 + 0] = (value) & 0xFF;
            row2[0 + 1] = row2[3 + 1] = row2[next_row + 1] =
                row2[next_row + 3 + 1] = (value >> 8) & 0xFF;
            row2[0 + 2] = row2[3 + 2] = row2[next_row + 2] =
                row2[next_row + 3 + 2] = (value >> 16) & 0xFF;
            row2 += 2 * 3;
        }

        /*
         * These values are at the start of the next line, (due
         * to the ++'s above),but they need to be at the start
         * of the line after that.
         */
        lum += cols;
        lum2 += cols;
        row1 += mod;
        row2 += mod;
    }
}

static void
Color32DitherYV12Mod2X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int *row1 = (unsigned int *) out;
    const int next_row = cols * 2 + mod;
    unsigned int *row2 = row1 + 2 * next_row;
    unsigned char *lum2;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    lum2 = lum + cols;

    mod = (next_row * 3) + mod;

    y = rows / 2;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            ++cr;
            ++cb;

            L = *lum++;
            row1[0] = row1[1] = row1[next_row] = row1[next_row + 1] =
                (rgb_2_pix[L + cr_r] |
                 rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row1 += 2;

            L = *lum++;
            row1[0] = row1[1] = row1[next_row] = row1[next_row + 1] =
                (rgb_2_pix[L + cr_r] |
                 rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row1 += 2;


            /* Now, do second row. */

            L = *lum2++;
            row2[0] = row2[1] = row2[next_row] = row2[next_row + 1] =
                (rgb_2_pix[L + cr_r] |
                 rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row2 += 2;

            L = *lum2++;
            row2[0] = row2[1] = row2[next_row] = row2[next_row + 1] =
                (rgb_2_pix[L + cr_r] |
                 rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row2 += 2;
        }

        /*
         * These values are at the start of the next line, (due
         * to the ++'s above),but they need to be at the start
         * of the line after that.
         */
        lum += cols;
        lum2 += cols;
        row1 += mod;
        row2 += mod;
    }
}

static void
Color16DitherYUY2Mod1X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned short *row;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    row = (unsigned short *) out;

    y = rows;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            cr += 4;
            cb += 4;

            L = *lum;
            lum += 2;
            *row++ = (unsigned short) (rgb_2_pix[L + cr_r] |
                                       rgb_2_pix[L + crb_g] |
                                       rgb_2_pix[L + cb_b]);

            L = *lum;
            lum += 2;
            *row++ = (unsigned short) (rgb_2_pix[L + cr_r] |
                                       rgb_2_pix[L + crb_g] |
                                       rgb_2_pix[L + cb_b]);

        }

        row += mod;
    }
}

static void
Color24DitherYUY2Mod1X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int value;
    unsigned char *row;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    row = (unsigned char *) out;
    mod *= 3;
    y = rows;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            cr += 4;
            cb += 4;

            L = *lum;
            lum += 2;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            *row++ = (value) & 0xFF;
            *row++ = (value >> 8) & 0xFF;
            *row++ = (value >> 16) & 0xFF;

            L = *lum;
            lum += 2;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            *row++ = (value) & 0xFF;
            *row++ = (value >> 8) & 0xFF;
            *row++ = (value >> 16) & 0xFF;

        }
        row += mod;
    }
}

static void
Color32DitherYUY2Mod1X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int *row;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    row = (unsigned int *) out;
    y = rows;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            cr += 4;
            cb += 4;

            L = *lum;
            lum += 2;
            *row++ = (rgb_2_pix[L + cr_r] |
                      rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);

            L = *lum;
            lum += 2;
            *row++ = (rgb_2_pix[L + cr_r] |
                      rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);


        }
        row += mod;
    }
}

/*
 * In this function I make use of a nasty trick. The tables have the lower
 * 16 bits replicated in the upper 16. This means I can write ints and get
 * the horisontal doubling for free (almost).
 */
static void
Color16DitherYUY2Mod2X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int *row = (unsigned int *) out;
    const int next_row = cols + (mod / 2);
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;

    y = rows;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            cr += 4;
            cb += 4;

            L = *lum;
            lum += 2;
            row[0] = row[next_row] = (rgb_2_pix[L + cr_r] |
                                      rgb_2_pix[L + crb_g] |
                                      rgb_2_pix[L + cb_b]);
            row++;

            L = *lum;
            lum += 2;
            row[0] = row[next_row] = (rgb_2_pix[L + cr_r] |
                                      rgb_2_pix[L + crb_g] |
                                      rgb_2_pix[L + cb_b]);
            row++;

        }
        row += next_row;
    }
}

static void
Color24DitherYUY2Mod2X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int value;
    unsigned char *row = out;
    const int next_row = (cols * 2 + mod) * 3;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;
    y = rows;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            cr += 4;
            cb += 4;

            L = *lum;
            lum += 2;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row[0 + 0] = row[3 + 0] = row[next_row + 0] =
                row[next_row + 3 + 0] = (value) & 0xFF;
            row[0 + 1] = row[3 + 1] = row[next_row + 1] =
                row[next_row + 3 + 1] = (value >> 8) & 0xFF;
            row[0 + 2] = row[3 + 2] = row[next_row + 2] =
                row[next_row + 3 + 2] = (value >> 16) & 0xFF;
            row += 2 * 3;

            L = *lum;
            lum += 2;
            value = (rgb_2_pix[L + cr_r] |
                     rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row[0 + 0] = row[3 + 0] = row[next_row + 0] =
                row[next_row + 3 + 0] = (value) & 0xFF;
            row[0 + 1] = row[3 + 1] = row[next_row + 1] =
                row[next_row + 3 + 1] = (value >> 8) & 0xFF;
            row[0 + 2] = row[3 + 2] = row[next_row + 2] =
                row[next_row + 3 + 2] = (value >> 16) & 0xFF;
            row += 2 * 3;

        }
        row += next_row;
    }
}

static void
Color32DitherYUY2Mod2X(int *colortab, Uint32 * rgb_2_pix,
                       unsigned char *lum, unsigned char *cr,
                       unsigned char *cb, unsigned char *out,
                       int rows, int cols, int mod)
{
    unsigned int *row = (unsigned int *) out;
    const int next_row = cols * 2 + mod;
    int x, y;
    int cr_r;
    int crb_g;
    int cb_b;
    int cols_2 = cols / 2;
    mod += mod;
    y = rows;
    while (y--) {
        x = cols_2;
        while (x--) {
            register int L;

            cr_r = 0 * 768 + 256 + colortab[*cr + 0 * 256];
            crb_g = 1 * 768 + 256 + colortab[*cr + 1 * 256]
                + colortab[*cb + 2 * 256];
            cb_b = 2 * 768 + 256 + colortab[*cb + 3 * 256];
            cr += 4;
            cb += 4;

            L = *lum;
            lum += 2;
            row[0] = row[1] = row[next_row] = row[next_row + 1] =
                (rgb_2_pix[L + cr_r] |
                 rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row += 2;

            L = *lum;
            lum += 2;
            row[0] = row[1] = row[next_row] = row[next_row + 1] =
                (rgb_2_pix[L + cr_r] |
                 rgb_2_pix[L + crb_g] | rgb_2_pix[L + cb_b]);
            row += 2;


        }

        row += next_row;
    }
}

/*
 * How many 1 bits are there in the Uint32.
 * Low performance, do not call often.
 */
static int
number_of_bits_set(Uint32 a)
{
    if (!a)
        return 0;
    if (a & 1)
        return 1 + number_of_bits_set(a >> 1);
    return (number_of_bits_set(a >> 1));
}

/*
 * How many 0 bits are there at least significant end of Uint32.
 * Low performance, do not call often.
 */
static int
free_bits_at_bottom(Uint32 a)
{
    /* assume char is 8 bits */
    if (!a)
        return sizeof(Uint32) * 8;
    if (((Sint32) a) & 1l)
        return 0;
    return 1 + free_bits_at_bottom(a >> 1);
}

static int
SDL_SW_SetupYUVDisplay(SDL_SW_YUVTexture * swdata, Uint32 target_format)
{
    Uint32 *r_2_pix_alloc;
    Uint32 *g_2_pix_alloc;
    Uint32 *b_2_pix_alloc;
    int i;
    int bpp;
    Uint32 Rmask, Gmask, Bmask, Amask;

    if (!SDL_PixelFormatEnumToMasks
        (target_format, &bpp, &Rmask, &Gmask, &Bmask, &Amask) || bpp < 15) {
        SDL_SetError("Unsupported YUV destination format");
        return -1;
    }

    swdata->target_format = target_format;
    r_2_pix_alloc = &swdata->rgb_2_pix[0 * 768];
    g_2_pix_alloc = &swdata->rgb_2_pix[1 * 768];
    b_2_pix_alloc = &swdata->rgb_2_pix[2 * 768];

    /* 
     * Set up entries 0-255 in rgb-to-pixel value tables.
     */
    for (i = 0; i < 256; ++i) {
        r_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(Rmask));
        r_2_pix_alloc[i + 256] <<= free_bits_at_bottom(Rmask);
        r_2_pix_alloc[i + 256] |= Amask;
        g_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(Gmask));
        g_2_pix_alloc[i + 256] <<= free_bits_at_bottom(Gmask);
        g_2_pix_alloc[i + 256] |= Amask;
        b_2_pix_alloc[i + 256] = i >> (8 - number_of_bits_set(Bmask));
        b_2_pix_alloc[i + 256] <<= free_bits_at_bottom(Bmask);
        b_2_pix_alloc[i + 256] |= Amask;
    }

    /*
     * If we have 16-bit output depth, then we double the value
     * in the top word. This means that we can write out both
     * pixels in the pixel doubling mode with one op. It is 
     * harmless in the normal case as storing a 32-bit value
     * through a short pointer will lose the top bits anyway.
     */
    if (SDL_BYTESPERPIXEL(target_format) == 2) {
        for (i = 0; i < 256; ++i) {
            r_2_pix_alloc[i + 256] |= (r_2_pix_alloc[i + 256]) << 16;
            g_2_pix_alloc[i + 256] |= (g_2_pix_alloc[i + 256]) << 16;
            b_2_pix_alloc[i + 256] |= (b_2_pix_alloc[i + 256]) << 16;
        }
    }

    /*
     * Spread out the values we have to the rest of the array so that
     * we do not need to check for overflow.
     */
    for (i = 0; i < 256; ++i) {
        r_2_pix_alloc[i] = r_2_pix_alloc[256];
        r_2_pix_alloc[i + 512] = r_2_pix_alloc[511];
        g_2_pix_alloc[i] = g_2_pix_alloc[256];
        g_2_pix_alloc[i + 512] = g_2_pix_alloc[511];
        b_2_pix_alloc[i] = b_2_pix_alloc[256];
        b_2_pix_alloc[i + 512] = b_2_pix_alloc[511];
    }

    /* You have chosen wisely... */
    switch (swdata->format) {
    case SDL_PIXELFORMAT_YV12:
    case SDL_PIXELFORMAT_IYUV:
        if (SDL_BYTESPERPIXEL(target_format) == 2) {
#if (__GNUC__ > 2) && defined(__i386__) && __OPTIMIZE__ && SDL_ASSEMBLY_ROUTINES
            /* inline assembly functions */
            if (SDL_HasMMX() && (Rmask == 0xF800) &&
                (Gmask == 0x07E0) && (Bmask == 0x001F)
                && (swdata->w & 15) == 0) {
/*printf("Using MMX 16-bit 565 dither\n");*/
                swdata->Display1X = Color565DitherYV12MMX1X;
            } else {
/*printf("Using C 16-bit dither\n");*/
                swdata->Display1X = Color16DitherYV12Mod1X;
            }
#else
            swdata->Display1X = Color16DitherYV12Mod1X;
#endif
            swdata->Display2X = Color16DitherYV12Mod2X;
        }
        if (SDL_BYTESPERPIXEL(target_format) == 3) {
            swdata->Display1X = Color24DitherYV12Mod1X;
            swdata->Display2X = Color24DitherYV12Mod2X;
        }
        if (SDL_BYTESPERPIXEL(target_format) == 4) {
#if (__GNUC__ > 2) && defined(__i386__) && __OPTIMIZE__ && SDL_ASSEMBLY_ROUTINES
            /* inline assembly functions */
            if (SDL_HasMMX() && (Rmask == 0x00FF0000) &&
                (Gmask == 0x0000FF00) &&
                (Bmask == 0x000000FF) && (swdata->w & 15) == 0) {
/*printf("Using MMX 32-bit dither\n");*/
                swdata->Display1X = ColorRGBDitherYV12MMX1X;
            } else {
/*printf("Using C 32-bit dither\n");*/
                swdata->Display1X = Color32DitherYV12Mod1X;
            }
#else
            swdata->Display1X = Color32DitherYV12Mod1X;
#endif
            swdata->Display2X = Color32DitherYV12Mod2X;
        }
        break;
    case SDL_PIXELFORMAT_YUY2:
    case SDL_PIXELFORMAT_UYVY:
    case SDL_PIXELFORMAT_YVYU:
        if (SDL_BYTESPERPIXEL(target_format) == 2) {
            swdata->Display1X = Color16DitherYUY2Mod1X;
            swdata->Display2X = Color16DitherYUY2Mod2X;
        }
        if (SDL_BYTESPERPIXEL(target_format) == 3) {
            swdata->Display1X = Color24DitherYUY2Mod1X;
            swdata->Display2X = Color24DitherYUY2Mod2X;
        }
        if (SDL_BYTESPERPIXEL(target_format) == 4) {
            swdata->Display1X = Color32DitherYUY2Mod1X;
            swdata->Display2X = Color32DitherYUY2Mod2X;
        }
        break;
    default:
        /* We should never get here (caught above) */
        break;
    }

    if (swdata->display) {
        SDL_FreeSurface(swdata->display);
        swdata->display = NULL;
    }
    return 0;
}

SDL_SW_YUVTexture *
SDL_SW_CreateYUVTexture(Uint32 format, int w, int h)
{
    SDL_SW_YUVTexture *swdata;
    int *Cr_r_tab;
    int *Cr_g_tab;
    int *Cb_g_tab;
    int *Cb_b_tab;
    int i;
    int CR, CB;

    swdata = (SDL_SW_YUVTexture *) SDL_calloc(1, sizeof(*swdata));
    if (!swdata) {
        SDL_OutOfMemory();
        return NULL;
    }

    switch (format) {
    case SDL_PIXELFORMAT_YV12:
    case SDL_PIXELFORMAT_IYUV:
    case SDL_PIXELFORMAT_YUY2:
    case SDL_PIXELFORMAT_UYVY:
    case SDL_PIXELFORMAT_YVYU:
        break;
    default:
        SDL_SetError("Unsupported YUV format");
        return NULL;
    }

    swdata->format = format;
    swdata->target_format = SDL_PIXELFORMAT_UNKNOWN;
    swdata->w = w;
    swdata->h = h;
    swdata->pixels = (Uint8 *) SDL_malloc(w * h * 2);
    swdata->colortab = (int *) SDL_malloc(4 * 256 * sizeof(int));
    swdata->rgb_2_pix = (Uint32 *) SDL_malloc(3 * 768 * sizeof(Uint32));
    if (!swdata->pixels || !swdata->colortab || !swdata->rgb_2_pix) {
        SDL_OutOfMemory();
        SDL_SW_DestroyYUVTexture(swdata);
        return NULL;
    }

    /* Generate the tables for the display surface */
    Cr_r_tab = &swdata->colortab[0 * 256];
    Cr_g_tab = &swdata->colortab[1 * 256];
    Cb_g_tab = &swdata->colortab[2 * 256];
    Cb_b_tab = &swdata->colortab[3 * 256];
    for (i = 0; i < 256; i++) {
        /* Gamma correction (luminescence table) and chroma correction
           would be done here.  See the Berkeley mpeg_play sources.
         */
        CB = CR = (i - 128);
        Cr_r_tab[i] = (int) ((0.419 / 0.299) * CR);
        Cr_g_tab[i] = (int) (-(0.299 / 0.419) * CR);
        Cb_g_tab[i] = (int) (-(0.114 / 0.331) * CB);
        Cb_b_tab[i] = (int) ((0.587 / 0.331) * CB);
    }

    /* Find the pitch and offset values for the overlay */
    switch (format) {
    case SDL_PIXELFORMAT_YV12:
    case SDL_PIXELFORMAT_IYUV:
        swdata->pitches[0] = w;
        swdata->pitches[1] = swdata->pitches[0] / 2;
        swdata->pitches[2] = swdata->pitches[0] / 2;
        swdata->planes[0] = swdata->pixels;
        swdata->planes[1] = swdata->planes[0] + swdata->pitches[0] * h;
        swdata->planes[2] = swdata->planes[1] + swdata->pitches[1] * h / 2;
        break;
    case SDL_PIXELFORMAT_YUY2:
    case SDL_PIXELFORMAT_UYVY:
    case SDL_PIXELFORMAT_YVYU:
        swdata->pitches[0] = w * 2;
        swdata->planes[0] = swdata->pixels;
        break;
    default:
        /* We should never get here (caught above) */
        break;
    }

    /* We're all done.. */
    return (swdata);
}

int
SDL_SW_QueryYUVTexturePixels(SDL_SW_YUVTexture * swdata, void **pixels,
                             int *pitch)
{
    *pixels = swdata->planes[0];
    *pitch = swdata->pitches[0];
    return 0;
}

int
SDL_SW_UpdateYUVTexture(SDL_SW_YUVTexture * swdata, const SDL_Rect * rect,
                        const void *pixels, int pitch)
{
    switch (swdata->format) {
    case SDL_PIXELFORMAT_YV12:
    case SDL_PIXELFORMAT_IYUV:
        if (rect
            && (rect->x != 0 || rect->y != 0 || rect->w != swdata->w
                || rect->h != swdata->h)) {
            SDL_SetError
                ("YV12 and IYUV textures only support full surface updates");
            return -1;
        }
        SDL_memcpy(swdata->pixels, pixels,
                   (swdata->h * swdata->w) + (swdata->h * swdata->w) / 2);
        break;
    case SDL_PIXELFORMAT_YUY2:
    case SDL_PIXELFORMAT_UYVY:
    case SDL_PIXELFORMAT_YVYU:
        {
            Uint8 *src, *dst;
            int row;
            size_t length;

            src = (Uint8 *) pixels;
            dst =
                swdata->planes[0] + rect->y * swdata->pitches[0] +
                rect->x * 2;
            length = rect->w * 2;
            for (row = 0; row < rect->h; ++row) {
                SDL_memcpy(dst, src, length);
                src += pitch;
                dst += swdata->pitches[0];
            }
        }
        break;
    }
    return 0;
}

int
SDL_SW_LockYUVTexture(SDL_SW_YUVTexture * swdata, const SDL_Rect * rect,
                      void **pixels, int *pitch)
{
    switch (swdata->format) {
    case SDL_PIXELFORMAT_YV12:
    case SDL_PIXELFORMAT_IYUV:
        if (rect
            && (rect->x != 0 || rect->y != 0 || rect->w != swdata->w
                || rect->h != swdata->h)) {
            SDL_SetError
                ("YV12 and IYUV textures only support full surface locks");
            return -1;
        }
        break;
    }

    *pixels = swdata->planes[0] + rect->y * swdata->pitches[0] + rect->x * 2;
    *pitch = swdata->pitches[0];
    return 0;
}

void
SDL_SW_UnlockYUVTexture(SDL_SW_YUVTexture * swdata)
{
}

int
SDL_SW_CopyYUVToRGB(SDL_SW_YUVTexture * swdata, const SDL_Rect * srcrect,
                    Uint32 target_format, int w, int h, void *pixels,
                    int pitch)
{
    int stretch;
    int scale_2x;
    Uint8 *lum, *Cr, *Cb;
    int mod;

    /* Make sure we're set up to display in the desired format */
    if (target_format != swdata->target_format) {
        if (SDL_SW_SetupYUVDisplay(swdata, target_format) < 0) {
            return -1;
        }
    }

    stretch = 0;
    scale_2x = 0;
    if (srcrect->x || srcrect->y || srcrect->w < swdata->w
        || srcrect->h < swdata->h) {
        /* The source rectangle has been clipped.
           Using a scratch surface is easier than adding clipped
           source support to all the blitters, plus that would
           slow them down in the general unclipped case.
         */
        stretch = 1;
    } else if ((srcrect->w != w) || (srcrect->h != h)) {
        if ((w == 2 * srcrect->w) && (h == 2 * srcrect->h)) {
            scale_2x = 1;
        } else {
            stretch = 1;
        }
    }
    if (stretch) {
        int bpp;
        Uint32 Rmask, Gmask, Bmask, Amask;

        if (swdata->display) {
            swdata->display->w = w;
            swdata->display->h = h;
            swdata->display->pixels = pixels;
            swdata->display->pitch = pitch;
        } else {
            /* This must have succeeded in SDL_SW_SetupYUVDisplay() earlier */
            SDL_PixelFormatEnumToMasks(target_format, &bpp, &Rmask, &Gmask,
                                       &Bmask, &Amask);
            swdata->display =
                SDL_CreateRGBSurfaceFrom(pixels, w, h, bpp, pitch, Rmask,
                                         Gmask, Bmask, Amask);
            if (!swdata->display) {
                return (-1);
            }
        }
        if (!swdata->stretch) {
            /* This must have succeeded in SDL_SW_SetupYUVDisplay() earlier */
            SDL_PixelFormatEnumToMasks(target_format, &bpp, &Rmask, &Gmask,
                                       &Bmask, &Amask);
            swdata->stretch =
                SDL_CreateRGBSurface(0, swdata->w, swdata->h, bpp, Rmask,
                                     Gmask, Bmask, Amask);
            if (!swdata->stretch) {
                return (-1);
            }
        }
        pixels = swdata->stretch->pixels;
        pitch = swdata->stretch->pitch;
    }
    switch (swdata->format) {
    case SDL_PIXELFORMAT_YV12:
        lum = swdata->planes[0];
        Cr = swdata->planes[1];
        Cb = swdata->planes[2];
        break;
    case SDL_PIXELFORMAT_IYUV:
        lum = swdata->planes[0];
        Cr = swdata->planes[2];
        Cb = swdata->planes[1];
        break;
    case SDL_PIXELFORMAT_YUY2:
        lum = swdata->planes[0];
        Cr = lum + 3;
        Cb = lum + 1;
        break;
    case SDL_PIXELFORMAT_UYVY:
        lum = swdata->planes[0] + 1;
        Cr = lum + 1;
        Cb = lum - 1;
        break;
    case SDL_PIXELFORMAT_YVYU:
        lum = swdata->planes[0];
        Cr = lum + 1;
        Cb = lum + 3;
        break;
    default:
        SDL_SetError("Unsupported YUV format in copy");
        return (-1);
    }
    mod = (pitch / SDL_BYTESPERPIXEL(target_format));

    if (scale_2x) {
        mod -= (swdata->w * 2);
        swdata->Display2X(swdata->colortab, swdata->rgb_2_pix,
                          lum, Cr, Cb, pixels, swdata->h, swdata->w, mod);
    } else {
        mod -= swdata->w;
        swdata->Display1X(swdata->colortab, swdata->rgb_2_pix,
                          lum, Cr, Cb, pixels, swdata->h, swdata->w, mod);
    }
    if (stretch) {
        SDL_Rect rect = *srcrect;
        SDL_SoftStretch(swdata->stretch, &rect, swdata->display, NULL);
    }
    return 0;
}

void
SDL_SW_DestroyYUVTexture(SDL_SW_YUVTexture * swdata)
{
    if (swdata) {
        if (swdata->pixels) {
            SDL_free(swdata->pixels);
        }
        if (swdata->colortab) {
            SDL_free(swdata->colortab);
        }
        if (swdata->rgb_2_pix) {
            SDL_free(swdata->rgb_2_pix);
        }
        if (swdata->stretch) {
            SDL_FreeSurface(swdata->stretch);
        }
        if (swdata->display) {
            SDL_FreeSurface(swdata->display);
        }
        SDL_free(swdata);
    }
}

/* vi: set ts=4 sw=4 expandtab: */