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view src/video/SDL_blit_1.c @ 5150:ad50b3db78bd

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The rendering functions take a context so it's clear what window they're drawing to. This also potentially opens to the door to multi-threaded rendering in the future.
author Sam Lantinga <slouken@libsdl.org>
date Tue, 01 Feb 2011 19:19:43 -0800
parents f7b03b6838cb
children b530ef003506
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2010 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"

#include "SDL_video.h"
#include "SDL_blit.h"
#include "SDL_sysvideo.h"
#include "SDL_endian.h"

/* Functions to blit from 8-bit surfaces to other surfaces */

static void
Blit1to1(SDL_BlitInfo * info)
{
#ifndef USE_DUFFS_LOOP
    int c;
#endif
    int width, height;
    Uint8 *src, *map, *dst;
    int srcskip, dstskip;

    /* Set up some basic variables */
    width = info->dst_w;
    height = info->dst_h;
    src = info->src;
    srcskip = info->src_skip;
    dst = info->dst;
    dstskip = info->dst_skip;
    map = info->table;

    while (height--) {
#ifdef USE_DUFFS_LOOP
        /* *INDENT-OFF* */
		DUFFS_LOOP(
			{
			  *dst = map[*src];
			}
			dst++;
			src++;
		, width);
        /* *INDENT-ON* */
#else
        for (c = width; c; --c) {
            *dst = map[*src];
            dst++;
            src++;
        }
#endif
        src += srcskip;
        dst += dstskip;
    }
}

/* This is now endian dependent */
#if ( SDL_BYTEORDER == SDL_LIL_ENDIAN )
#define HI	1
#define LO	0
#else /* ( SDL_BYTEORDER == SDL_BIG_ENDIAN ) */
#define HI	0
#define LO	1
#endif
static void
Blit1to2(SDL_BlitInfo * info)
{
#ifndef USE_DUFFS_LOOP
    int c;
#endif
    int width, height;
    Uint8 *src, *dst;
    Uint16 *map;
    int srcskip, dstskip;

    /* Set up some basic variables */
    width = info->dst_w;
    height = info->dst_h;
    src = info->src;
    srcskip = info->src_skip;
    dst = info->dst;
    dstskip = info->dst_skip;
    map = (Uint16 *) info->table;

#ifdef USE_DUFFS_LOOP
    while (height--) {
		/* *INDENT-OFF* */
		DUFFS_LOOP(
		{
			*(Uint16 *)dst = map[*src++];
			dst += 2;
		},
		width);
		/* *INDENT-ON* */
        src += srcskip;
        dst += dstskip;
    }
#else
    /* Memory align at 4-byte boundary, if necessary */
    if ((long) dst & 0x03) {
        /* Don't do anything if width is 0 */
        if (width == 0) {
            return;
        }
        --width;

        while (height--) {
            /* Perform copy alignment */
            *(Uint16 *) dst = map[*src++];
            dst += 2;

            /* Copy in 4 pixel chunks */
            for (c = width / 4; c; --c) {
                *(Uint32 *) dst = (map[src[HI]] << 16) | (map[src[LO]]);
                src += 2;
                dst += 4;
                *(Uint32 *) dst = (map[src[HI]] << 16) | (map[src[LO]]);
                src += 2;
                dst += 4;
            }
            /* Get any leftovers */
            switch (width & 3) {
            case 3:
                *(Uint16 *) dst = map[*src++];
                dst += 2;
            case 2:
                *(Uint32 *) dst = (map[src[HI]] << 16) | (map[src[LO]]);
                src += 2;
                dst += 4;
                break;
            case 1:
                *(Uint16 *) dst = map[*src++];
                dst += 2;
                break;
            }
            src += srcskip;
            dst += dstskip;
        }
    } else {
        while (height--) {
            /* Copy in 4 pixel chunks */
            for (c = width / 4; c; --c) {
                *(Uint32 *) dst = (map[src[HI]] << 16) | (map[src[LO]]);
                src += 2;
                dst += 4;
                *(Uint32 *) dst = (map[src[HI]] << 16) | (map[src[LO]]);
                src += 2;
                dst += 4;
            }
            /* Get any leftovers */
            switch (width & 3) {
            case 3:
                *(Uint16 *) dst = map[*src++];
                dst += 2;
            case 2:
                *(Uint32 *) dst = (map[src[HI]] << 16) | (map[src[LO]]);
                src += 2;
                dst += 4;
                break;
            case 1:
                *(Uint16 *) dst = map[*src++];
                dst += 2;
                break;
            }
            src += srcskip;
            dst += dstskip;
        }
    }
#endif /* USE_DUFFS_LOOP */
}

static void
Blit1to3(SDL_BlitInfo * info)
{
#ifndef USE_DUFFS_LOOP
    int c;
#endif
    int o;
    int width, height;
    Uint8 *src, *map, *dst;
    int srcskip, dstskip;

    /* Set up some basic variables */
    width = info->dst_w;
    height = info->dst_h;
    src = info->src;
    srcskip = info->src_skip;
    dst = info->dst;
    dstskip = info->dst_skip;
    map = info->table;

    while (height--) {
#ifdef USE_DUFFS_LOOP
		/* *INDENT-OFF* */
		DUFFS_LOOP(
			{
				o = *src * 4;
				dst[0] = map[o++];
				dst[1] = map[o++];
				dst[2] = map[o++];
			}
			src++;
			dst += 3;
		, width);
		/* *INDENT-ON* */
#else
        for (c = width; c; --c) {
            o = *src * 4;
            dst[0] = map[o++];
            dst[1] = map[o++];
            dst[2] = map[o++];
            src++;
            dst += 3;
        }
#endif /* USE_DUFFS_LOOP */
        src += srcskip;
        dst += dstskip;
    }
}

static void
Blit1to4(SDL_BlitInfo * info)
{
#ifndef USE_DUFFS_LOOP
    int c;
#endif
    int width, height;
    Uint8 *src;
    Uint32 *map, *dst;
    int srcskip, dstskip;

    /* Set up some basic variables */
    width = info->dst_w;
    height = info->dst_h;
    src = info->src;
    srcskip = info->src_skip;
    dst = (Uint32 *) info->dst;
    dstskip = info->dst_skip / 4;
    map = (Uint32 *) info->table;

    while (height--) {
#ifdef USE_DUFFS_LOOP
		/* *INDENT-OFF* */
		DUFFS_LOOP(
			*dst++ = map[*src++];
		, width);
		/* *INDENT-ON* */
#else
        for (c = width / 4; c; --c) {
            *dst++ = map[*src++];
            *dst++ = map[*src++];
            *dst++ = map[*src++];
            *dst++ = map[*src++];
        }
        switch (width & 3) {
        case 3:
            *dst++ = map[*src++];
        case 2:
            *dst++ = map[*src++];
        case 1:
            *dst++ = map[*src++];
        }
#endif /* USE_DUFFS_LOOP */
        src += srcskip;
        dst += dstskip;
    }
}

static void
Blit1to1Key(SDL_BlitInfo * info)
{
    int width = info->dst_w;
    int height = info->dst_h;
    Uint8 *src = info->src;
    int srcskip = info->src_skip;
    Uint8 *dst = info->dst;
    int dstskip = info->dst_skip;
    Uint8 *palmap = info->table;
    Uint32 ckey = info->colorkey;

    if (palmap) {
        while (height--) {
			/* *INDENT-OFF* */
			DUFFS_LOOP(
			{
				if ( *src != ckey ) {
				  *dst = palmap[*src];
				}
				dst++;
				src++;
			},
			width);
			/* *INDENT-ON* */
            src += srcskip;
            dst += dstskip;
        }
    } else {
        while (height--) {
			/* *INDENT-OFF* */
			DUFFS_LOOP(
			{
				if ( *src != ckey ) {
				  *dst = *src;
				}
				dst++;
				src++;
			},
			width);
			/* *INDENT-ON* */
            src += srcskip;
            dst += dstskip;
        }
    }
}

static void
Blit1to2Key(SDL_BlitInfo * info)
{
    int width = info->dst_w;
    int height = info->dst_h;
    Uint8 *src = info->src;
    int srcskip = info->src_skip;
    Uint16 *dstp = (Uint16 *) info->dst;
    int dstskip = info->dst_skip;
    Uint16 *palmap = (Uint16 *) info->table;
    Uint32 ckey = info->colorkey;

    /* Set up some basic variables */
    dstskip /= 2;

    while (height--) {
		/* *INDENT-OFF* */
		DUFFS_LOOP(
		{
			if ( *src != ckey ) {
				*dstp=palmap[*src];
			}
			src++;
			dstp++;
		},
		width);
		/* *INDENT-ON* */
        src += srcskip;
        dstp += dstskip;
    }
}

static void
Blit1to3Key(SDL_BlitInfo * info)
{
    int width = info->dst_w;
    int height = info->dst_h;
    Uint8 *src = info->src;
    int srcskip = info->src_skip;
    Uint8 *dst = info->dst;
    int dstskip = info->dst_skip;
    Uint8 *palmap = info->table;
    Uint32 ckey = info->colorkey;
    int o;

    while (height--) {
		/* *INDENT-OFF* */
		DUFFS_LOOP(
		{
			if ( *src != ckey ) {
				o = *src * 4;
				dst[0] = palmap[o++];
				dst[1] = palmap[o++];
				dst[2] = palmap[o++];
			}
			src++;
			dst += 3;
		},
		width);
		/* *INDENT-ON* */
        src += srcskip;
        dst += dstskip;
    }
}

static void
Blit1to4Key(SDL_BlitInfo * info)
{
    int width = info->dst_w;
    int height = info->dst_h;
    Uint8 *src = info->src;
    int srcskip = info->src_skip;
    Uint32 *dstp = (Uint32 *) info->dst;
    int dstskip = info->dst_skip;
    Uint32 *palmap = (Uint32 *) info->table;
    Uint32 ckey = info->colorkey;

    /* Set up some basic variables */
    dstskip /= 4;

    while (height--) {
		/* *INDENT-OFF* */
		DUFFS_LOOP(
		{
			if ( *src != ckey ) {
				*dstp = palmap[*src];
			}
			src++;
			dstp++;
		},
		width);
		/* *INDENT-ON* */
        src += srcskip;
        dstp += dstskip;
    }
}

static void
Blit1toNAlpha(SDL_BlitInfo * info)
{
    int width = info->dst_w;
    int height = info->dst_h;
    Uint8 *src = info->src;
    int srcskip = info->src_skip;
    Uint8 *dst = info->dst;
    int dstskip = info->dst_skip;
    SDL_PixelFormat *dstfmt = info->dst_fmt;
    const SDL_Color *srcpal = info->src_fmt->palette->colors;
    int dstbpp;
    const int A = info->a;

    /* Set up some basic variables */
    dstbpp = dstfmt->BytesPerPixel;

    while (height--) {
        int sR, sG, sB;
        int dR, dG, dB;
	    	/* *INDENT-OFF* */
	    	DUFFS_LOOP4(
			{
			        Uint32 pixel;
				sR = srcpal[*src].r;
				sG = srcpal[*src].g;
				sB = srcpal[*src].b;
				DISEMBLE_RGB(dst, dstbpp, dstfmt,
					     pixel, dR, dG, dB);
				ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);
			  	ASSEMBLE_RGB(dst, dstbpp, dstfmt, dR, dG, dB);
				src++;
				dst += dstbpp;
			},
			width);
	    	/* *INDENT-ON* */
        src += srcskip;
        dst += dstskip;
    }
}

static void
Blit1toNAlphaKey(SDL_BlitInfo * info)
{
    int width = info->dst_w;
    int height = info->dst_h;
    Uint8 *src = info->src;
    int srcskip = info->src_skip;
    Uint8 *dst = info->dst;
    int dstskip = info->dst_skip;
    SDL_PixelFormat *srcfmt = info->src_fmt;
    SDL_PixelFormat *dstfmt = info->dst_fmt;
    const SDL_Color *srcpal = info->src_fmt->palette->colors;
    Uint32 ckey = info->colorkey;
    int dstbpp;
    const int A = info->a;

    /* Set up some basic variables */
    dstbpp = dstfmt->BytesPerPixel;

    while (height--) {
        int sR, sG, sB;
        int dR, dG, dB;
		/* *INDENT-OFF* */
		DUFFS_LOOP(
		{
			if ( *src != ckey ) {
			        Uint32 pixel;
				sR = srcpal[*src].r;
				sG = srcpal[*src].g;
				sB = srcpal[*src].b;
				DISEMBLE_RGB(dst, dstbpp, dstfmt,
							pixel, dR, dG, dB);
				ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);
			  	ASSEMBLE_RGB(dst, dstbpp, dstfmt, dR, dG, dB);
			}
			src++;
			dst += dstbpp;
		},
		width);
		/* *INDENT-ON* */
        src += srcskip;
        dst += dstskip;
    }
}

static const SDL_BlitFunc one_blit[] = {
    NULL, Blit1to1, Blit1to2, Blit1to3, Blit1to4
};

static const SDL_BlitFunc one_blitkey[] = {
    NULL, Blit1to1Key, Blit1to2Key, Blit1to3Key, Blit1to4Key
};

SDL_BlitFunc
SDL_CalculateBlit1(SDL_Surface * surface)
{
    int which;
    SDL_PixelFormat *dstfmt;

    dstfmt = surface->map->dst->format;
    if (dstfmt->BitsPerPixel < 8) {
        which = 0;
    } else {
        which = dstfmt->BytesPerPixel;
    }
    switch (surface->map->info.flags & ~SDL_COPY_RLE_MASK) {
    case 0:
        return one_blit[which];

    case SDL_COPY_COLORKEY:
        return one_blitkey[which];

    case SDL_COPY_MODULATE_ALPHA | SDL_COPY_BLEND:
        /* Supporting 8bpp->8bpp alpha is doable but requires lots of
           tables which consume space and takes time to precompute,
           so is better left to the user */
        return which >= 2 ? Blit1toNAlpha : NULL;

    case SDL_COPY_COLORKEY | SDL_COPY_MODULATE_ALPHA | SDL_COPY_BLEND:
        return which >= 2 ? Blit1toNAlphaKey : NULL;
    }
    return NULL;
}

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