SDL_rotate.c File Reference

#include "../../SDL_internal.h"
#include <stdlib.h>
#include <string.h>
#include "SDL.h"
#include "SDL_rotate.h"

Include dependency graph for SDL_rotate.c:

Go to the source code of this file.

Data Structures
struct	tColorRGBA
struct	tColorY

Macros
#define	MAX(a, b)   (((a) > (b)) ? (a) : (b))
#define	GUARD_ROWS   (2)
#define	TRANSFORM_SURFACE_90(pixelType)

Functions
static Uint32	_colorkey (SDL_Surface *src)
void	SDLgfx_rotozoomSurfaceSizeTrig (int width, int height, double angle, int *dstwidth, int *dstheight, double *cangle, double *sangle)
static void	computeSourceIncrements90 (SDL_Surface *src, int bpp, int angle, int flipx, int flipy, int *sincx, int *sincy, int *signx, int *signy)
static void	transformSurfaceRGBA90 (SDL_Surface *src, SDL_Surface *dst, int angle, int flipx, int flipy)
static void	transformSurfaceY90 (SDL_Surface *src, SDL_Surface *dst, int angle, int flipx, int flipy)
static void	_transformSurfaceRGBA (SDL_Surface *src, SDL_Surface *dst, int cx, int cy, int isin, int icos, int flipx, int flipy, int smooth)
static void	transformSurfaceY (SDL_Surface *src, SDL_Surface *dst, int cx, int cy, int isin, int icos, int flipx, int flipy)
SDL_Surface *	SDLgfx_rotateSurface (SDL_Surface *src, double angle, int centerx, int centery, int smooth, int flipx, int flipy, int dstwidth, int dstheight, double cangle, double sangle)

Macro Definition Documentation

GUARD_ROWS

#define GUARD_ROWS   (2)

Definition at line 79 of file SDL_rotate.c.

MAX

#define MAX	(		a,
			b
	)		(((a) > (b)) ? (a) : (b))

Definition at line 67 of file SDL_rotate.c.

TRANSFORM_SURFACE_90

#define TRANSFORM_SURFACE_90

(

pixelType

)

Value:

    int dy, dincy = dst->pitch - dst->w*sizeof(pixelType), sincx, sincy, signx, signy;                      \
    Uint8 *sp = (Uint8*)src->pixels, *dp = (Uint8*)dst->pixels, *de;                                        \
                                                                                                            \
    computeSourceIncrements90(src, sizeof(pixelType), angle, flipx, flipy, &sincx, &sincy, &signx, &signy); \
    if (signx < 0) sp += (src->w-1)*sizeof(pixelType);                                                      \
    if (signy < 0) sp += (src->h-1)*src->pitch;                                                             \
                                                                                                            \
    for (dy = 0; dy < dst->h; sp += sincy, dp += dincy, dy++) {                                             \
        if (sincx == sizeof(pixelType)) { /* if advancing src and dest equally, use memcpy */               \
            SDL_memcpy(dp, sp, dst->w*sizeof(pixelType));                                                   \
            sp += dst->w*sizeof(pixelType);                                                                 \
            dp += dst->w*sizeof(pixelType);                                                                 \
        } else {                                                                                            \
            for (de = dp + dst->w*sizeof(pixelType); dp != de; sp += sincx, dp += sizeof(pixelType)) {      \
                *(pixelType*)dp = *(pixelType*)sp;                                                          \
            }                                                                                               \
        }                                                                                                   \
    }

Definition at line 178 of file SDL_rotate.c.

Function Documentation

_colorkey()

static Uint32 _colorkey ( SDL_Surface *  src )

static

Definition at line 85 of file SDL_rotate.c.

{
    Uint32 key = 0;
    if (SDL_HasColorKey(src)) {
        SDL_GetColorKey(src, &key);
    }
    return key;
}

References SDL_GetColorKey, and SDL_HasColorKey.

Referenced by transformSurfaceY().

_transformSurfaceRGBA()

static void _transformSurfaceRGBA ( SDL_Surface *  src, SDL_Surface *  dst, int  cx, int  cy, int  isin, int  icos, int  flipx, int  flipy, int  smooth  )

static

Definition at line 232 of file SDL_rotate.c.

{
    int x, y, t1, t2, dx, dy, xd, yd, sdx, sdy, ax, ay, ex, ey, sw, sh;
    tColorRGBA c00, c01, c10, c11, cswap;
    tColorRGBA *pc, *sp;
    int gap;
 
    /*
    * Variable setup
    */
    xd = ((src->w - dst->w) << 15);
    yd = ((src->h - dst->h) << 15);
    ax = (cx << 16) - (icos * cx);
    ay = (cy << 16) - (isin * cx);
    sw = src->w - 1;
    sh = src->h - 1;
    pc = (tColorRGBA*) dst->pixels;
    gap = dst->pitch - dst->w * 4;
 
    /*
    * Switch between interpolating and non-interpolating code
    */
    if (smooth) {
        for (y = 0; y < dst->h; y++) {
            dy = cy - y;
            sdx = (ax + (isin * dy)) + xd;
            sdy = (ay - (icos * dy)) + yd;
            for (x = 0; x < dst->w; x++) {
                dx = (sdx >> 16);
                dy = (sdy >> 16);
                if (flipx) dx = sw - dx;
                if (flipy) dy = sh - dy;
                if ((dx > -1) && (dy > -1) && (dx < (src->w-1)) && (dy < (src->h-1))) {
                    sp = (tColorRGBA *) ((Uint8 *) src->pixels + src->pitch * dy) + dx;
                    c00 = *sp;
                    sp += 1;
                    c01 = *sp;
                    sp += (src->pitch/4);
                    c11 = *sp;
                    sp -= 1;
                    c10 = *sp;
                    if (flipx) {
                        cswap = c00; c00=c01; c01=cswap;
                        cswap = c10; c10=c11; c11=cswap;
                    }
                    if (flipy) {
                        cswap = c00; c00=c10; c10=cswap;
                        cswap = c01; c01=c11; c11=cswap;
                    }
                    /*
                    * Interpolate colors
                    */
                    ex = (sdx & 0xffff);
                    ey = (sdy & 0xffff);
                    t1 = ((((c01.r - c00.r) * ex) >> 16) + c00.r) & 0xff;
                    t2 = ((((c11.r - c10.r) * ex) >> 16) + c10.r) & 0xff;
                    pc->r = (((t2 - t1) * ey) >> 16) + t1;
                    t1 = ((((c01.g - c00.g) * ex) >> 16) + c00.g) & 0xff;
                    t2 = ((((c11.g - c10.g) * ex) >> 16) + c10.g) & 0xff;
                    pc->g = (((t2 - t1) * ey) >> 16) + t1;
                    t1 = ((((c01.b - c00.b) * ex) >> 16) + c00.b) & 0xff;
                    t2 = ((((c11.b - c10.b) * ex) >> 16) + c10.b) & 0xff;
                    pc->b = (((t2 - t1) * ey) >> 16) + t1;
                    t1 = ((((c01.a - c00.a) * ex) >> 16) + c00.a) & 0xff;
                    t2 = ((((c11.a - c10.a) * ex) >> 16) + c10.a) & 0xff;
                    pc->a = (((t2 - t1) * ey) >> 16) + t1;
                }
                sdx += icos;
                sdy += isin;
                pc++;
            }
            pc = (tColorRGBA *) ((Uint8 *) pc + gap);
        }
    } else {
        for (y = 0; y < dst->h; y++) {
            dy = cy - y;
            sdx = (ax + (isin * dy)) + xd;
            sdy = (ay - (icos * dy)) + yd;
            for (x = 0; x < dst->w; x++) {
                dx = (sdx >> 16);
                dy = (sdy >> 16);
                if ((unsigned)dx < (unsigned)src->w && (unsigned)dy < (unsigned)src->h) {
                    if(flipx) dx = sw - dx;
                    if(flipy) dy = sh - dy;
                    *pc = *((tColorRGBA *)((Uint8 *)src->pixels + src->pitch * dy) + dx);
                }
                sdx += icos;
                sdy += isin;
                pc++;
            }
            pc = (tColorRGBA *) ((Uint8 *) pc + gap);
        }
    }
}

References tColorRGBA::a, tColorRGBA::b, tColorRGBA::g, if, and tColorRGBA::r.

Referenced by SDLgfx_rotateSurface().

computeSourceIncrements90()

static void computeSourceIncrements90 ( SDL_Surface *  src, int  bpp, int  angle, int  flipx, int  flipy, int *  sincx, int *  sincy, int *  signx, int *  signy  )

static

Definition at line 156 of file SDL_rotate.c.

{
    int pitch = flipy ? -src->pitch : src->pitch;
    if (flipx) {
        bpp = -bpp;
    }
    switch (angle) { /* 0:0 deg, 1:90 deg, 2:180 deg, 3:270 deg */
    case 0: *sincx = bpp; *sincy = pitch - src->w * *sincx; *signx = *signy = 1; break;
    case 1: *sincx = -pitch; *sincy = bpp - *sincx * src->h; *signx = 1; *signy = -1; break;
    case 2: *sincx = -bpp; *sincy = -src->w * *sincx - pitch; *signx = *signy = -1; break;
    case 3: default: *sincx = pitch; *sincy = -*sincx * src->h - bpp; *signx = -1; *signy = 1; break;
    }
    if (flipx) {
        *signx = -*signx;
    }
    if (flipy) {
        *signy = -*signy;
    }
}

References bpp.

SDLgfx_rotateSurface()

SDL_Surface* SDLgfx_rotateSurface	(	SDL_Surface *	src,
		double	angle,
		int	centerx,
		int	centery,
		int	smooth,
		int	flipx,
		int	flipy,
		int	dstwidth,
		int	dstheight,
		double	cangle,
		double	sangle
	)

Definition at line 417 of file SDL_rotate.c.

{
    SDL_Surface *rz_dst;
    int is8bit, angle90;
    int i;
    SDL_BlendMode blendmode;
    Uint32 colorkey = 0;
    int colorKeyAvailable = SDL_FALSE;
    double sangleinv, cangleinv;
 
    /* Sanity check */
    if (src == NULL)
        return NULL;
 
    if (SDL_HasColorKey(src)) {
        if (SDL_GetColorKey(src, &colorkey) == 0) {
            colorKeyAvailable = SDL_TRUE;
        }
    }
 
    /* This function requires a 32-bit surface or 8-bit surface with a colorkey */
    is8bit = src->format->BitsPerPixel == 8 && colorKeyAvailable;
    if (!(is8bit || (src->format->BitsPerPixel == 32 && src->format->Amask)))
        return NULL;
 
    /* Calculate target factors from sin/cos and zoom */
    sangleinv = sangle*65536.0;
    cangleinv = cangle*65536.0;
 
    /* Alloc space to completely contain the rotated surface */
    rz_dst = NULL;
    if (is8bit) {
        /* Target surface is 8 bit */
        rz_dst = SDL_CreateRGBSurface(0, dstwidth, dstheight + GUARD_ROWS, 8, 0, 0, 0, 0);
        if (rz_dst != NULL) {
            for (i = 0; i < src->format->palette->ncolors; i++) {
                rz_dst->format->palette->colors[i] = src->format->palette->colors[i];
            }
            rz_dst->format->palette->ncolors = src->format->palette->ncolors;
        }
    } else {
        /* Target surface is 32 bit with source RGBA ordering */
        rz_dst = SDL_CreateRGBSurface(0, dstwidth, dstheight + GUARD_ROWS, 32,
                                      src->format->Rmask, src->format->Gmask,
                                      src->format->Bmask, src->format->Amask);
    }
 
    /* Check target */
    if (rz_dst == NULL)
        return NULL;
 
    /* Adjust for guard rows */
    rz_dst->h = dstheight;
 
    SDL_GetSurfaceBlendMode(src, &blendmode);
 
    if (colorKeyAvailable == SDL_TRUE) {
        /* If available, the colorkey will be used to discard the pixels that are outside of the rotated area. */
        SDL_SetColorKey(rz_dst, SDL_TRUE, colorkey);
        SDL_FillRect(rz_dst, NULL, colorkey);
    } else if (blendmode == SDL_BLENDMODE_NONE) {
        blendmode = SDL_BLENDMODE_BLEND;
    } else if (blendmode == SDL_BLENDMODE_MOD || blendmode == SDL_BLENDMODE_MUL) {
        /* Without a colorkey, the target texture has to be white for the MOD and MUL blend mode so
         * that the pixels outside the rotated area don't affect the destination surface.
         */
        colorkey = SDL_MapRGBA(rz_dst->format, 255, 255, 255, 0);
        SDL_FillRect(rz_dst, NULL, colorkey);
        /* Setting a white colorkey for the destination surface makes the final blit discard
         * all pixels outside of the rotated area. This doesn't interfere with anything because
         * white pixels are already a no-op and the MOD blend mode does not interact with alpha.
         */
        SDL_SetColorKey(rz_dst, SDL_TRUE, colorkey);
    }
 
    SDL_SetSurfaceBlendMode(rz_dst, blendmode);
 
    /* Lock source surface */
    if (SDL_MUSTLOCK(src)) {
        SDL_LockSurface(src);
    }
 
    /* check if the rotation is a multiple of 90 degrees so we can take a fast path and also somewhat reduce
     * the off-by-one problem in _transformSurfaceRGBA that expresses itself when the rotation is near
     * multiples of 90 degrees.
     */
    angle90 = (int)(angle/90);
    if (angle90 == angle/90) {
        angle90 %= 4;
        if (angle90 < 0) angle90 += 4; /* 0:0 deg, 1:90 deg, 2:180 deg, 3:270 deg */
    } else {
        angle90 = -1;
    }
 
    if (is8bit) {
        /* Call the 8-bit transformation routine to do the rotation */
        if(angle90 >= 0) {
            transformSurfaceY90(src, rz_dst, angle90, flipx, flipy);
        } else {
            transformSurfaceY(src, rz_dst, centerx, centery, (int)sangleinv, (int)cangleinv,
                              flipx, flipy);
        }
    } else {
        /* Call the 32-bit transformation routine to do the rotation */
        if (angle90 >= 0) {
            transformSurfaceRGBA90(src, rz_dst, angle90, flipx, flipy);
        } else {
            _transformSurfaceRGBA(src, rz_dst, centerx, centery, (int)sangleinv, (int)cangleinv,
                                  flipx, flipy, smooth);
        }
    }
 
    /* Unlock source surface */
    if (SDL_MUSTLOCK(src)) {
        SDL_UnlockSurface(src);
    }
 
    /* Return rotated surface */
    return rz_dst;
}

References _transformSurfaceRGBA(), SDL_Palette::colors, SDL_Surface::format, GUARD_ROWS, SDL_Surface::h, i, int(), SDL_Palette::ncolors, NULL, SDL_PixelFormat::palette, SDL_BLENDMODE_BLEND, SDL_BLENDMODE_MOD, SDL_BLENDMODE_MUL, SDL_BLENDMODE_NONE, SDL_CreateRGBSurface, SDL_FALSE, SDL_FillRect, SDL_GetColorKey, SDL_GetSurfaceBlendMode, SDL_HasColorKey, SDL_LockSurface, SDL_MapRGBA, SDL_MUSTLOCK, SDL_SetColorKey, SDL_SetSurfaceBlendMode, SDL_TRUE, SDL_UnlockSurface, transformSurfaceRGBA90(), transformSurfaceY(), and transformSurfaceY90().

Referenced by SW_RenderCopyEx().

SDLgfx_rotozoomSurfaceSizeTrig()

void SDLgfx_rotozoomSurfaceSizeTrig	(	int	width,
		int	height,
		double	angle,
		int *	dstwidth,
		int *	dstheight,
		double *	cangle,
		double *	sangle
	)

Definition at line 108 of file SDL_rotate.c.

{
    /* The trig code below gets the wrong size (due to FP inaccuracy?) when angle is a multiple of 90 degrees */
    int angle90 = (int)(angle/90);
    if(angle90 == angle/90) { /* if the angle is a multiple of 90 degrees */
        angle90 %= 4;
        if(angle90 < 0) angle90 += 4; /* 0:0 deg, 1:90 deg, 2:180 deg, 3:270 deg */
        if(angle90 & 1) {
            *dstwidth  = height;
            *dstheight = width;
            *cangle = 0;
            *sangle = angle90 == 1 ? -1 : 1; /* reversed because our rotations are clockwise */
        } else {
            *dstwidth  = width;
            *dstheight = height;
            *cangle = angle90 == 0 ? 1 : -1;
            *sangle = 0;
        }
    } else {
        double x, y, cx, cy, sx, sy;
        double radangle;
        int dstwidthhalf, dstheighthalf;
        /*
        * Determine destination width and height by rotating a centered source box
        */
        radangle = angle * (M_PI / -180.0); /* reverse the angle because our rotations are clockwise */
        *sangle = SDL_sin(radangle);
        *cangle = SDL_cos(radangle);
        x = (double)(width / 2);
        y = (double)(height / 2);
        cx = *cangle * x;
        cy = *cangle * y;
        sx = *sangle * x;
        sy = *sangle * y;
 
        dstwidthhalf = MAX((int)
            SDL_ceil(MAX(MAX(MAX(SDL_fabs(cx + sy), SDL_fabs(cx - sy)), SDL_fabs(-cx + sy)), SDL_fabs(-cx - sy))), 1);
        dstheighthalf = MAX((int)
            SDL_ceil(MAX(MAX(MAX(SDL_fabs(sx + cy), SDL_fabs(sx - cy)), SDL_fabs(-sx + cy)), SDL_fabs(-sx - cy))), 1);
        *dstwidth = 2 * dstwidthhalf;
        *dstheight = 2 * dstheighthalf;
    }
}

References int(), MAX, SDL_ceil, SDL_cos, SDL_fabs, and SDL_sin.

Referenced by SW_RenderCopyEx().

transformSurfaceRGBA90()

static void transformSurfaceRGBA90 ( SDL_Surface *  src, SDL_Surface *  dst, int  angle, int  flipx, int  flipy  )

static

Definition at line 199 of file SDL_rotate.c.

{
    TRANSFORM_SURFACE_90(tColorRGBA);
}

References TRANSFORM_SURFACE_90.

Referenced by SDLgfx_rotateSurface().

transformSurfaceY()

static void transformSurfaceY ( SDL_Surface *  src, SDL_Surface *  dst, int  cx, int  cy, int  isin, int  icos, int  flipx, int  flipy  )

static

Definition at line 346 of file SDL_rotate.c.

{
    int x, y, dx, dy, xd, yd, sdx, sdy, ax, ay;
    tColorY *pc;
    int gap;
 
    /*
    * Variable setup
    */
    xd = ((src->w - dst->w) << 15);
    yd = ((src->h - dst->h) << 15);
    ax = (cx << 16) - (icos * cx);
    ay = (cy << 16) - (isin * cx);
    pc = (tColorY*) dst->pixels;
    gap = dst->pitch - dst->w;
    /*
    * Clear surface to colorkey
    */
    SDL_memset(pc, (int)(_colorkey(src) & 0xff), dst->pitch * dst->h);
    /*
    * Iterate through destination surface
    */
    for (y = 0; y < dst->h; y++) {
        dy = cy - y;
        sdx = (ax + (isin * dy)) + xd;
        sdy = (ay - (icos * dy)) + yd;
        for (x = 0; x < dst->w; x++) {
            dx = (sdx >> 16);
            dy = (sdy >> 16);
            if ((unsigned)dx < (unsigned)src->w && (unsigned)dy < (unsigned)src->h) {
                if (flipx) dx = (src->w-1)-dx;
                if (flipy) dy = (src->h-1)-dy;
                *pc = *((tColorY *)src->pixels + src->pitch * dy + dx);
            }
            sdx += icos;
            sdy += isin;
            pc++;
        }
        pc += gap;
    }
}

References _colorkey(), and SDL_memset.

Referenced by SDLgfx_rotateSurface().

transformSurfaceY90()

static void transformSurfaceY90 ( SDL_Surface *  src, SDL_Surface *  dst, int  angle, int  flipx, int  flipy  )

static

Definition at line 205 of file SDL_rotate.c.

{
    TRANSFORM_SURFACE_90(tColorY);
}

References TRANSFORM_SURFACE_90.

Referenced by SDLgfx_rotateSurface().