SDL_LockTexture

SDL_LockTexture

Use this function to lock a portion of the texture for write-only pixel access.
使用该函数可以锁定纹理的一部分，该部分像素只有可写的访问权限。

Syntax 语法

int SDL_LockTexture(SDL_Texture*    texture,
                    const SDL_Rect* rect,
                    void**          pixels,
                    int*            pitch)

Function Parameters 函数参数

texture	the texture to lock for access, which was created with SDL_TEXTUREACCESS_STREAMING	为访问并要锁定的纹理，该纹理在创建时必须使用SDL_TEXTUREACCESS_STREAMING
rect	an SDL_Rect structure representing the area to lock for access; NULL to lock the entire texture	代表要锁定访问的区域的SDL_Rect结构，或为NULL以代表锁定整个纹理。
pixels	this is filled in with a pointer to the locked pixels, appropriately offset by the locked area	一个指针的地址，该指针指向锁定的像素，该区块的像素已根据锁定的区域做好了偏移处理。
pitch	this is filled in with the pitch of the locked pixels; the pitch is the length of one row in bytes	一个变量的地址，该变量为锁定的像素的对齐长度。该值为每一行像素的字节长度。

Return Value 返回值

Returns 0 on success or a negative error code if the texture is not valid or was not created with SDL_TEXTUREACCESS_STREAMING; call SDL_GetError() for more information.
执行成功返回0，若纹理无效，或该纹理不是用SDL_TEXTUREACCESS_STREAMING创建的则返回一个负的错误码。调用SDL_GetError()以获取更多的错误信息。

Code Examples 代码示例

暂无

Remarks 注意

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.
为了优化，获取访问用以编辑的像素并不需要包含旧的像素数据。这是一个只写的操作，而且如果你需要得到纹理数据的一份拷贝，你应该在应用层面做这一操作。

You must use SDL_UnlockTexture() to unlock the pixels and apply any changes.
你必须调用SDL_UnlockTexture()来解除锁定并且应用任何改变。

Related Functions 相关函数

SDL_UnlockTexture

Translated by SteDeshain
Reference to http://wiki.libsdl.org/SDL_LockTexture