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Added a helper function SDL_LockTextureToSurface()

Similar to SDL_LockTexture(), except the locked area is exposed as a SDL surface.
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1bsyl committed Sep 30, 2019
1 parent f46ac1e commit 1ae61f1009abff4cf7c5d85d33da4b3d7b4e208b
@@ -1,6 +1,13 @@

This is a list of major changes in SDL's version history.

---------------------------------------------------------------------------
2.0.11/12:
---------------------------------------------------------------------------

General:
* Added SDL_LockTextureToSurface(), similar to SDL_LockTexture() but the locked area is exposed as a SDL surface.

---------------------------------------------------------------------------
2.0.10:
---------------------------------------------------------------------------
@@ -430,10 +430,31 @@ extern DECLSPEC int SDLCALL SDL_LockTexture(SDL_Texture * texture,
const SDL_Rect * rect,
void **pixels, int *pitch);

/**
* \brief Lock a portion of the texture for write-only pixel access.
* Expose it as a SDL surface.
*
* \param texture The texture to lock for access, which was created with
* ::SDL_TEXTUREACCESS_STREAMING.
* \param rect A pointer to the rectangle to lock for access. If the rect
* is NULL, the entire texture will be locked.
* \param surface This is filled in with a SDL surface representing the locked area
* Surface is freed internally after calling SDL_UnlockTexture or SDL_DestroyTexture.
*
* \return 0 on success, or -1 if the texture is not valid or was not created with ::SDL_TEXTUREACCESS_STREAMING.
*
* \sa SDL_UnlockTexture()
*/
extern DECLSPEC int SDLCALL SDL_LockTextureToSurface(SDL_Texture *texture,
const SDL_Rect *rect,
SDL_Surface **surface);

/**
* \brief Unlock a texture, uploading the changes to video memory, if needed.
* If SDL_LockTextureToSurface() was called for locking, the SDL surface is freed.
*
* \sa SDL_LockTexture()
* \sa SDL_LockTextureToSurface()
*/
extern DECLSPEC void SDLCALL SDL_UnlockTexture(SDL_Texture * texture);

@@ -315,6 +315,7 @@
#define SDL_UpdateTexture SDL_UpdateTexture_REAL
#define SDL_UpdateYUVTexture SDL_UpdateYUVTexture_REAL
#define SDL_LockTexture SDL_LockTexture_REAL
#define SDL_LockTextureToSurface SDL_LockTextureToSurface_REAL
#define SDL_UnlockTexture SDL_UnlockTexture_REAL
#define SDL_RenderTargetSupported SDL_RenderTargetSupported_REAL
#define SDL_SetRenderTarget SDL_SetRenderTarget_REAL
@@ -346,6 +346,7 @@ SDL_DYNAPI_PROC(int,SDL_GetTextureBlendMode,(SDL_Texture *a, SDL_BlendMode *b),(
SDL_DYNAPI_PROC(int,SDL_UpdateTexture,(SDL_Texture *a, const SDL_Rect *b, const void *c, int d),(a,b,c,d),return)
SDL_DYNAPI_PROC(int,SDL_UpdateYUVTexture,(SDL_Texture *a, const SDL_Rect *b, const Uint8 *c, int d, const Uint8 *e, int f, const Uint8 *g, int h),(a,b,c,d,e,f,g,h),return)
SDL_DYNAPI_PROC(int,SDL_LockTexture,(SDL_Texture *a, const SDL_Rect *b, void **c, int *d),(a,b,c,d),return)
SDL_DYNAPI_PROC(int,SDL_LockTextureToSurface,(SDL_Texture *a, const SDL_Rect *b, SDL_Surface **c),(a,b,c),return)
SDL_DYNAPI_PROC(void,SDL_UnlockTexture,(SDL_Texture *a),(a),)
SDL_DYNAPI_PROC(SDL_bool,SDL_RenderTargetSupported,(SDL_Renderer *a),(a),return)
SDL_DYNAPI_PROC(int,SDL_SetRenderTarget,(SDL_Renderer *a, SDL_Texture *b),(a,b),return)
@@ -1680,6 +1680,45 @@ SDL_LockTexture(SDL_Texture * texture, const SDL_Rect * rect,
}
}

int
SDL_LockTextureToSurface(SDL_Texture *texture, const SDL_Rect *rect,
SDL_Surface **surface)
{
SDL_Rect r;
void *pixels = NULL;
int pitch, ret;

if (texture == NULL || surface == NULL) {
return -1;
}

if (rect == NULL) {
r.x = 0;
r.y = 0;
r.w = texture->w;
r.h = texture->h;
} else {
r.x = rect->x;
r.y = rect->y;
r.w = SDL_min(texture->w - rect->x, rect->w);
r.h = SDL_min(texture->h - rect->y, rect->h);
}

ret = SDL_LockTexture(texture, &r, &pixels, &pitch);
if (ret < 0) {
return ret;
}

texture->locked_surface = SDL_CreateRGBSurfaceWithFormatFrom(pixels, r.w, r.h, 0, pitch, texture->format);
if (texture->locked_surface == NULL) {
SDL_UnlockTexture(texture);
return -1;
}

*surface = texture->locked_surface;
return 0;
}

static void
SDL_UnlockTextureYUV(SDL_Texture * texture)
{
@@ -1738,6 +1777,9 @@ SDL_UnlockTexture(SDL_Texture * texture)
SDL_Renderer *renderer = texture->renderer;
renderer->UnlockTexture(renderer, texture);
}

SDL_FreeSurface(texture->locked_surface);
texture->locked_surface = NULL;
}

SDL_bool
@@ -3090,6 +3132,10 @@ SDL_DestroyTexture(SDL_Texture * texture)
SDL_free(texture->pixels);

renderer->DestroyTexture(renderer, texture);

SDL_FreeSurface(texture->locked_surface);
texture->locked_surface = NULL;

SDL_free(texture);
}

@@ -60,6 +60,7 @@ struct SDL_Texture
void *pixels;
int pitch;
SDL_Rect locked_rect;
SDL_Surface *locked_surface; /**< Locked region exposed as a SDL surface */

Uint32 last_command_generation; /* last command queue generation this texture was in. */

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