The texture to lock for access, which was created with SDL_TEXTUREACCESS_STREAMING.
An SDL_Rect structure representing the area to lock for access; null to lock the entire texture.
This is filled in with a pointer to the locked pixels, appropriately offset by the locked area.
This is filled in with the pitch of the locked pixels; the pitch is the length of one row in bytes.
true on success or false if the texture is not valid or was not created with SDL_TEXTUREACCESS_STREAMING; call SDL_GetError for more information.
Threadsafety: This function should only be called on the main thread.
Lock a portion of the texture for **write-only** pixel access.
As an optimization, the pixels made available for editing don't necessarily contain the old texture data. This is a write-only operation, and if you need to keep a copy of the texture data you should do that at the application level.
You must use SDL_UnlockTexture to unlock the pixels and apply any changes.