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Fixed bug 4188 - Software renderer SDL_RenderCopyEx blits corrupt ima…
…ge under certain cases

Sylvain

Re-opening this issue.

It fixes the test-case, but it introduces a regression with another bug (bug #4313).

So here's a new patch that activate cropping of the source surface to solve the issue.
It also reverts the wrong changeset.
It prevents unneeded colorkey error message.
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slouken committed Oct 30, 2018
1 parent 950f39e commit da56cef
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Showing 2 changed files with 21 additions and 11 deletions.
5 changes: 5 additions & 0 deletions src/render/software/SDL_render_sw.c
Expand Up @@ -657,6 +657,11 @@ SW_RenderCopyEx(SDL_Renderer * renderer, SDL_Texture * texture,
blitRequired = SDL_TRUE;
}

/* srcrect is not selecting the whole src surface, so cropping is needed */
if (!(srcrect->w == src->w && srcrect->h == src->h && srcrect->x == 0 && srcrect->y == 0)) {
blitRequired = SDL_TRUE;
}

/* The color and alpha modulation has to be applied before the rotation when using the NONE and MOD blend modes. */
if ((blendmode == SDL_BLENDMODE_NONE || blendmode == SDL_BLENDMODE_MOD) && (alphaMod & rMod & gMod & bMod) != 255) {
applyModulation = SDL_TRUE;
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27 changes: 16 additions & 11 deletions src/render/software/SDL_rotate.c
Expand Up @@ -83,7 +83,9 @@ static Uint32
_colorkey(SDL_Surface *src)
{
Uint32 key = 0;
SDL_GetColorKey(src, &key);
if (SDL_HasColorKey(src)) {
SDL_GetColorKey(src, &key);
}
return key;
}

Expand Down Expand Up @@ -150,17 +152,17 @@ SDLgfx_rotozoomSurfaceSizeTrig(int width, int height, double angle,
/* Computes source pointer X/Y increments for a rotation that's a multiple of 90 degrees. */
static void
computeSourceIncrements90(SDL_Surface * src, int bpp, int angle, int flipx, int flipy,
int *sincx, int *sincy, int *signx, int *signy, SDL_Surface *dst)
int *sincx, int *sincy, int *signx, int *signy)
{
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 - dst->w * *sincx; *signx = *signy = 1; break;
case 1: *sincx = -pitch; *sincy = bpp - *sincx * dst->h; *signx = 1; *signy = -1; break;
case 2: *sincx = -bpp; *sincy = -dst->w * *sincx - pitch; *signx = *signy = -1; break;
case 3: default: *sincx = pitch; *sincy = -*sincx * dst->h - bpp; *signx = -1; *signy = 1; break;
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;
Expand All @@ -175,9 +177,10 @@ computeSourceIncrements90(SDL_Surface * src, int bpp, int angle, int flipx, int
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, dst); \
if (signx < 0) sp += (dst->w-1)*sizeof(pixelType); \
if (signy < 0) sp += (dst->h-1)*src->pitch; \
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)); \
Expand Down Expand Up @@ -423,8 +426,10 @@ SDLgfx_rotateSurface(SDL_Surface * src, double angle, int centerx, int centery,
if (src == NULL)
return NULL;

if (SDL_GetColorKey(src, &colorkey) == 0) {
colorKeyAvailable = SDL_TRUE;
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 */
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