SDL 2.0
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_SurfaceSDLgfx_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 77 of file SDL_rotate.c.

◆ MAX

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

Definition at line 65 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; \
} \
} \
}
GLenum src
GLenum GLenum dst
GLfloat angle
GLfloat GLfloat GLfloat GLfloat h
GLubyte GLubyte GLubyte GLubyte w
static void computeSourceIncrements90(SDL_Surface *src, int bpp, int angle, int flipx, int flipy, int *sincx, int *sincy, int *signx, int *signy)
Definition: SDL_rotate.c:154
uint8_t Uint8
Definition: SDL_stdinc.h:179

Definition at line 176 of file SDL_rotate.c.

Function Documentation

◆ _colorkey()

static Uint32 _colorkey ( SDL_Surface src)
static

Definition at line 83 of file SDL_rotate.c.

84{
85 Uint32 key = 0;
86 if (SDL_HasColorKey(src)) {
88 }
89 return key;
90}
#define SDL_HasColorKey
#define SDL_GetColorKey
uint32_t Uint32
Definition: SDL_stdinc.h:203
GLuint64 key
Definition: gl2ext.h:2192

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 230 of file SDL_rotate.c.

231{
232 int x, y, t1, t2, dx, dy, xd, yd, sdx, sdy, ax, ay, ex, ey, sw, sh;
233 tColorRGBA c00, c01, c10, c11, cswap;
234 tColorRGBA *pc, *sp;
235 int gap;
236
237 /*
238 * Variable setup
239 */
240 xd = ((src->w - dst->w) << 15);
241 yd = ((src->h - dst->h) << 15);
242 ax = (cx << 16) - (icos * cx);
243 ay = (cy << 16) - (isin * cx);
244 sw = src->w - 1;
245 sh = src->h - 1;
246 pc = (tColorRGBA*) dst->pixels;
247 gap = dst->pitch - dst->w * 4;
248
249 /*
250 * Switch between interpolating and non-interpolating code
251 */
252 if (smooth) {
253 for (y = 0; y < dst->h; y++) {
254 dy = cy - y;
255 sdx = (ax + (isin * dy)) + xd;
256 sdy = (ay - (icos * dy)) + yd;
257 for (x = 0; x < dst->w; x++) {
258 dx = (sdx >> 16);
259 dy = (sdy >> 16);
260 if (flipx) dx = sw - dx;
261 if (flipy) dy = sh - dy;
262 if ((dx > -1) && (dy > -1) && (dx < (src->w-1)) && (dy < (src->h-1))) {
263 sp = (tColorRGBA *) ((Uint8 *) src->pixels + src->pitch * dy) + dx;
264 c00 = *sp;
265 sp += 1;
266 c01 = *sp;
267 sp += (src->pitch/4);
268 c11 = *sp;
269 sp -= 1;
270 c10 = *sp;
271 if (flipx) {
272 cswap = c00; c00=c01; c01=cswap;
273 cswap = c10; c10=c11; c11=cswap;
274 }
275 if (flipy) {
276 cswap = c00; c00=c10; c10=cswap;
277 cswap = c01; c01=c11; c11=cswap;
278 }
279 /*
280 * Interpolate colors
281 */
282 ex = (sdx & 0xffff);
283 ey = (sdy & 0xffff);
284 t1 = ((((c01.r - c00.r) * ex) >> 16) + c00.r) & 0xff;
285 t2 = ((((c11.r - c10.r) * ex) >> 16) + c10.r) & 0xff;
286 pc->r = (((t2 - t1) * ey) >> 16) + t1;
287 t1 = ((((c01.g - c00.g) * ex) >> 16) + c00.g) & 0xff;
288 t2 = ((((c11.g - c10.g) * ex) >> 16) + c10.g) & 0xff;
289 pc->g = (((t2 - t1) * ey) >> 16) + t1;
290 t1 = ((((c01.b - c00.b) * ex) >> 16) + c00.b) & 0xff;
291 t2 = ((((c11.b - c10.b) * ex) >> 16) + c10.b) & 0xff;
292 pc->b = (((t2 - t1) * ey) >> 16) + t1;
293 t1 = ((((c01.a - c00.a) * ex) >> 16) + c00.a) & 0xff;
294 t2 = ((((c11.a - c10.a) * ex) >> 16) + c10.a) & 0xff;
295 pc->a = (((t2 - t1) * ey) >> 16) + t1;
296 }
297 sdx += icos;
298 sdy += isin;
299 pc++;
300 }
301 pc = (tColorRGBA *) ((Uint8 *) pc + gap);
302 }
303 } else {
304 for (y = 0; y < dst->h; y++) {
305 dy = cy - y;
306 sdx = (ax + (isin * dy)) + xd;
307 sdy = (ay - (icos * dy)) + yd;
308 for (x = 0; x < dst->w; x++) {
309 dx = (sdx >> 16);
310 dy = (sdy >> 16);
311 if ((unsigned)dx < (unsigned)src->w && (unsigned)dy < (unsigned)src->h) {
312 if(flipx) dx = sw - dx;
313 if(flipy) dy = sh - dy;
314 *pc = *((tColorRGBA *)((Uint8 *)src->pixels + src->pitch * dy) + dx);
315 }
316 sdx += icos;
317 sdy += isin;
318 pc++;
319 }
320 pc = (tColorRGBA *) ((Uint8 *) pc + gap);
321 }
322 }
323}
GLint GLint GLint GLint GLint GLint y
Definition: SDL_opengl.h:1574
GLint GLint GLint GLint GLint x
Definition: SDL_opengl.h:1574
GLuint GLfloat GLfloat GLfloat GLfloat GLfloat GLfloat GLfloat GLfloat GLfloat t1
Uint8 g
Definition: SDL_rotate.c:50
Uint8 a
Definition: SDL_rotate.c:52
Uint8 r
Definition: SDL_rotate.c:49
Uint8 b
Definition: SDL_rotate.c:51

References tColorRGBA::a, tColorRGBA::b, tColorRGBA::g, 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 154 of file SDL_rotate.c.

156{
157 int pitch = flipy ? -src->pitch : src->pitch;
158 if (flipx) {
159 bpp = -bpp;
160 }
161 switch (angle) { /* 0:0 deg, 1:90 deg, 2:180 deg, 3:270 deg */
162 case 0: *sincx = bpp; *sincy = pitch - src->w * *sincx; *signx = *signy = 1; break;
163 case 1: *sincx = -pitch; *sincy = bpp - *sincx * src->h; *signx = 1; *signy = -1; break;
164 case 2: *sincx = -bpp; *sincy = -src->w * *sincx - pitch; *signx = *signy = -1; break;
165 case 3: default: *sincx = pitch; *sincy = -*sincx * src->h - bpp; *signx = -1; *signy = 1; break;
166 }
167 if (flipx) {
168 *signx = -*signx;
169 }
170 if (flipy) {
171 *signy = -*signy;
172 }
173}

◆ 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 415 of file SDL_rotate.c.

416{
417 SDL_Surface *rz_dst;
418 int is8bit, angle90;
419 int i;
420 SDL_BlendMode blendmode;
421 Uint32 colorkey = 0;
422 int colorKeyAvailable = SDL_FALSE;
423 double sangleinv, cangleinv;
424
425 /* Sanity check */
426 if (src == NULL)
427 return NULL;
428
429 if (SDL_HasColorKey(src)) {
430 if (SDL_GetColorKey(src, &colorkey) == 0) {
431 colorKeyAvailable = SDL_TRUE;
432 }
433 }
434
435 /* This function requires a 32-bit surface or 8-bit surface with a colorkey */
436 is8bit = src->format->BitsPerPixel == 8 && colorKeyAvailable;
437 if (!(is8bit || (src->format->BitsPerPixel == 32 && src->format->Amask)))
438 return NULL;
439
440 /* Calculate target factors from sin/cos and zoom */
441 sangleinv = sangle*65536.0;
442 cangleinv = cangle*65536.0;
443
444 /* Alloc space to completely contain the rotated surface */
445 rz_dst = NULL;
446 if (is8bit) {
447 /* Target surface is 8 bit */
448 rz_dst = SDL_CreateRGBSurface(0, dstwidth, dstheight + GUARD_ROWS, 8, 0, 0, 0, 0);
449 if (rz_dst != NULL) {
450 for (i = 0; i < src->format->palette->ncolors; i++) {
451 rz_dst->format->palette->colors[i] = src->format->palette->colors[i];
452 }
453 rz_dst->format->palette->ncolors = src->format->palette->ncolors;
454 }
455 } else {
456 /* Target surface is 32 bit with source RGBA ordering */
457 rz_dst = SDL_CreateRGBSurface(0, dstwidth, dstheight + GUARD_ROWS, 32,
458 src->format->Rmask, src->format->Gmask,
459 src->format->Bmask, src->format->Amask);
460 }
461
462 /* Check target */
463 if (rz_dst == NULL)
464 return NULL;
465
466 /* Adjust for guard rows */
467 rz_dst->h = dstheight;
468
469 SDL_GetSurfaceBlendMode(src, &blendmode);
470
471 if (colorKeyAvailable == SDL_TRUE) {
472 /* If available, the colorkey will be used to discard the pixels that are outside of the rotated area. */
473 SDL_SetColorKey(rz_dst, SDL_TRUE, colorkey);
474 SDL_FillRect(rz_dst, NULL, colorkey);
475 } else if (blendmode == SDL_BLENDMODE_NONE) {
476 blendmode = SDL_BLENDMODE_BLEND;
477 } else if (blendmode == SDL_BLENDMODE_MOD) {
478 /* Without a colorkey, the target texture has to be white for the MOD blend mode so
479 * that the pixels outside the rotated area don't affect the destination surface.
480 */
481 colorkey = SDL_MapRGBA(rz_dst->format, 255, 255, 255, 0);
482 SDL_FillRect(rz_dst, NULL, colorkey);
483 /* Setting a white colorkey for the destination surface makes the final blit discard
484 * all pixels outside of the rotated area. This doesn't interfere with anything because
485 * white pixels are already a no-op and the MOD blend mode does not interact with alpha.
486 */
487 SDL_SetColorKey(rz_dst, SDL_TRUE, colorkey);
488 }
489
490 SDL_SetSurfaceBlendMode(rz_dst, blendmode);
491
492 /* Lock source surface */
493 if (SDL_MUSTLOCK(src)) {
495 }
496
497 /* check if the rotation is a multiple of 90 degrees so we can take a fast path and also somewhat reduce
498 * the off-by-one problem in _transformSurfaceRGBA that expresses itself when the rotation is near
499 * multiples of 90 degrees.
500 */
501 angle90 = (int)(angle/90);
502 if (angle90 == angle/90) {
503 angle90 %= 4;
504 if (angle90 < 0) angle90 += 4; /* 0:0 deg, 1:90 deg, 2:180 deg, 3:270 deg */
505 } else {
506 angle90 = -1;
507 }
508
509 if (is8bit) {
510 /* Call the 8-bit transformation routine to do the rotation */
511 if(angle90 >= 0) {
512 transformSurfaceY90(src, rz_dst, angle90, flipx, flipy);
513 } else {
514 transformSurfaceY(src, rz_dst, centerx, centery, (int)sangleinv, (int)cangleinv,
515 flipx, flipy);
516 }
517 } else {
518 /* Call the 32-bit transformation routine to do the rotation */
519 if (angle90 >= 0) {
520 transformSurfaceRGBA90(src, rz_dst, angle90, flipx, flipy);
521 } else {
522 _transformSurfaceRGBA(src, rz_dst, centerx, centery, (int)sangleinv, (int)cangleinv,
523 flipx, flipy, smooth);
524 }
525 }
526
527 /* Unlock source surface */
528 if (SDL_MUSTLOCK(src)) {
530 }
531
532 /* Return rotated surface */
533 return rz_dst;
534}
SDL_BlendMode
The blend mode used in SDL_RenderCopy() and drawing operations.
Definition: SDL_blendmode.h:41
@ SDL_BLENDMODE_NONE
Definition: SDL_blendmode.h:42
@ SDL_BLENDMODE_BLEND
Definition: SDL_blendmode.h:44
@ SDL_BLENDMODE_MOD
Definition: SDL_blendmode.h:50
#define SDL_SetColorKey
#define SDL_GetSurfaceBlendMode
#define SDL_MapRGBA
#define SDL_SetSurfaceBlendMode
#define SDL_UnlockSurface
#define SDL_LockSurface
#define SDL_CreateRGBSurface
#define SDL_FillRect
#define GUARD_ROWS
Definition: SDL_rotate.c:77
static void _transformSurfaceRGBA(SDL_Surface *src, SDL_Surface *dst, int cx, int cy, int isin, int icos, int flipx, int flipy, int smooth)
Definition: SDL_rotate.c:230
static void transformSurfaceY90(SDL_Surface *src, SDL_Surface *dst, int angle, int flipx, int flipy)
Definition: SDL_rotate.c:203
static void transformSurfaceRGBA90(SDL_Surface *src, SDL_Surface *dst, int angle, int flipx, int flipy)
Definition: SDL_rotate.c:197
static void transformSurfaceY(SDL_Surface *src, SDL_Surface *dst, int cx, int cy, int isin, int icos, int flipx, int flipy)
Definition: SDL_rotate.c:344
@ SDL_TRUE
Definition: SDL_stdinc.h:164
@ SDL_FALSE
Definition: SDL_stdinc.h:163
#define SDL_MUSTLOCK(S)
Definition: SDL_surface.h:62
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int in i)
Definition: SDL_x11sym.h:50
#define NULL
Definition: begin_code.h:167
SDL_Color * colors
Definition: SDL_pixels.h:307
SDL_Palette * palette
Definition: SDL_pixels.h:318
A collection of pixels used in software blitting.
Definition: SDL_surface.h:71
SDL_PixelFormat * format
Definition: SDL_surface.h:73

References _transformSurfaceRGBA(), SDL_Palette::colors, SDL_Surface::format, GUARD_ROWS, SDL_Surface::h, i, SDL_Palette::ncolors, NULL, SDL_PixelFormat::palette, SDL_BLENDMODE_BLEND, SDL_BLENDMODE_MOD, 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 106 of file SDL_rotate.c.

109{
110 /* The trig code below gets the wrong size (due to FP inaccuracy?) when angle is a multiple of 90 degrees */
111 int angle90 = (int)(angle/90);
112 if(angle90 == angle/90) { /* if the angle is a multiple of 90 degrees */
113 angle90 %= 4;
114 if(angle90 < 0) angle90 += 4; /* 0:0 deg, 1:90 deg, 2:180 deg, 3:270 deg */
115 if(angle90 & 1) {
116 *dstwidth = height;
117 *dstheight = width;
118 *cangle = 0;
119 *sangle = angle90 == 1 ? -1 : 1; /* reversed because our rotations are clockwise */
120 } else {
121 *dstwidth = width;
122 *dstheight = height;
123 *cangle = angle90 == 0 ? 1 : -1;
124 *sangle = 0;
125 }
126 } else {
127 double x, y, cx, cy, sx, sy;
128 double radangle;
129 int dstwidthhalf, dstheighthalf;
130 /*
131 * Determine destination width and height by rotating a centered source box
132 */
133 radangle = angle * (M_PI / -180.0); /* reverse the angle because our rotations are clockwise */
134 *sangle = SDL_sin(radangle);
135 *cangle = SDL_cos(radangle);
136 x = (double)(width / 2);
137 y = (double)(height / 2);
138 cx = *cangle * x;
139 cy = *cangle * y;
140 sx = *sangle * x;
141 sy = *sangle * y;
142
143 dstwidthhalf = MAX((int)
144 SDL_ceil(MAX(MAX(MAX(SDL_fabs(cx + sy), SDL_fabs(cx - sy)), SDL_fabs(-cx + sy)), SDL_fabs(-cx - sy))), 1);
145 dstheighthalf = MAX((int)
146 SDL_ceil(MAX(MAX(MAX(SDL_fabs(sx + cy), SDL_fabs(sx - cy)), SDL_fabs(-sx + cy)), SDL_fabs(-sx - cy))), 1);
147 *dstwidth = 2 * dstwidthhalf;
148 *dstheight = 2 * dstheighthalf;
149 }
150}
#define SDL_sin
#define SDL_fabs
#define SDL_cos
#define SDL_ceil
GLint GLint GLsizei width
Definition: SDL_opengl.h:1572
GLint GLint GLsizei GLsizei height
Definition: SDL_opengl.h:1572
#define MAX(a, b)
Definition: SDL_rotate.c:65

References 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 197 of file SDL_rotate.c.

198{
200}
#define TRANSFORM_SURFACE_90(pixelType)
Definition: SDL_rotate.c:176

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 344 of file SDL_rotate.c.

345{
346 int x, y, dx, dy, xd, yd, sdx, sdy, ax, ay;
347 tColorY *pc;
348 int gap;
349
350 /*
351 * Variable setup
352 */
353 xd = ((src->w - dst->w) << 15);
354 yd = ((src->h - dst->h) << 15);
355 ax = (cx << 16) - (icos * cx);
356 ay = (cy << 16) - (isin * cx);
357 pc = (tColorY*) dst->pixels;
358 gap = dst->pitch - dst->w;
359 /*
360 * Clear surface to colorkey
361 */
362 SDL_memset(pc, (int)(_colorkey(src) & 0xff), dst->pitch * dst->h);
363 /*
364 * Iterate through destination surface
365 */
366 for (y = 0; y < dst->h; y++) {
367 dy = cy - y;
368 sdx = (ax + (isin * dy)) + xd;
369 sdy = (ay - (icos * dy)) + yd;
370 for (x = 0; x < dst->w; x++) {
371 dx = (sdx >> 16);
372 dy = (sdy >> 16);
373 if ((unsigned)dx < (unsigned)src->w && (unsigned)dy < (unsigned)src->h) {
374 if (flipx) dx = (src->w-1)-dx;
375 if (flipy) dy = (src->h-1)-dy;
376 *pc = *((tColorY *)src->pixels + src->pitch * dy + dx);
377 }
378 sdx += icos;
379 sdy += isin;
380 pc++;
381 }
382 pc += gap;
383 }
384}
#define SDL_memset
static Uint32 _colorkey(SDL_Surface *src)
Definition: SDL_rotate.c:83

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 203 of file SDL_rotate.c.

204{
206}

References TRANSFORM_SURFACE_90.

Referenced by SDLgfx_rotateSurface().