Version: 2020.3
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Graphics.CopyTexture

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Declaration

public static void CopyTexture(Texture src, Texture dst);

Declaration

public static void CopyTexture(Texture src, int srcElement, int srcMip, Texture dst, int dstElement, int dstMip);

Declaration

public static void CopyTexture(Texture src, int srcElement, int srcMip, int srcX, int srcY, int srcWidth, int srcHeight, Texture dst, int dstElement, int dstMip, int dstX, int dstY);

Parameters

src Source texture.
dst Destination texture.
srcElement Source texture element (cubemap face, texture array layer or 3D texture depth slice).
srcMip Source texture mipmap level.
dstElement Destination texture element (cubemap face, texture array layer or 3D texture depth slice).
dstMip Destination texture mipmap level.
srcX X coordinate of source texture region to copy (left side is zero).
srcY Y coordinate of source texture region to copy (bottom is zero).
srcWidth Width of source texture region to copy.
srcHeight Height of source texture region to copy.
dstX X coordinate of where to copy region in destination texture (left side is zero).
dstY Y coordinate of where to copy region in destination texture (bottom is zero).

Description

Copy texture contents.

This function allows copying pixel data from one texture into another efficiently. It also allows copying from an element (e.g. cubemap face) or a specific mip level, and from a subregion of a texture.

When you copy from an element it does not perform any scaling. As a result, the source and destination sizes must be the same. Texture formats should be compatible, for example, TextureFormat.ARGB32 and RenderTextureFormat.ARGB32. MSAA sample counts for render textures should also be the same. Generally, you can always copy formats that are exactly the same, but format compatibility does vary between graphics APIs. On some platforms (e.g. D3D11) you can also copy between formats that are of the same bit width.

You can load Textures at different resolutions by using QualitySettings.masterTextureLimit. Note that this affects CopyTextures as you cannot copy a full mip between textures with different master texture limit values. If you need to copy between textures with a different master texture limit, use the region-based overload. The region-based overload adjusts the source rectangle based on the source texture's master texture limit. It also adjusts the destination offset based on the destination's master texture limit. For example, copying a 128x128 area from position 16,16 to position 32,32 results in the following behaviours in these example cases:

  • When the master texture limit is set to 0: Unity performs all copies as expected.
  • When the master texture limit is set to 2 and both textures are subject to the master texture limit: Unity adjusts the source rectangle to 32x32 and adjusts the offset to 4,4. Unity changes the destination offset to 8x8. Unity performs all copies as expected without awareness of the master texture limit setting.
  • When the master texture limit is set to 2, the source is a regular texture, and the destination is an array texture (array textures are never subject to the master texture limit): Unity adjusts the source rectangle to 32x32 and adjusts the offset to 4,4. Unity doesn't change the destination offset, which remains at 32x32.

Mipmap level arguments always apply to the texture as loaded under the current master texture limit. For example, a 256x256 texture with master texture limit set to 0 mip 1 refers to a 128x128 mip. However, if the mastertexture limit is set to 2 on that texture, mip 1 refers to a 32x32 mip. This means that in many cases when using CopyTexture you do not need to take the master texture limit into account in your calls. In less common calls (for example, copying from Texture2D to TextureArray) you do need to adjust for it. To copy textures in a cubemap array, calculate the destination element as 6 * cubemapIndex + faceIndex. As a result, the six faces from the cubemap at index 0 are elements 0,1,2... 5. The six faces from the cubemap at array index 1 are 6,7 .... 11 and so on.

Compressed texture formats add some restrictions to the CopyTexture with a region variant. For example, PVRTC formats are not supported since they are not block-based (for these formats you can only copy whole texture or whole mip level). For block-based formats (e.g. DXT, ETC), the region size and coordinates must be a multiple of compression block size (4 pixels for DXT).

If both source and destination textures are marked as "readable" (i.e. copy of data exists in system memory for reading/writing on the CPU), these functions copy it as well.

Some platforms might not have functionality of all sorts of texture copying (e.g. copy from a render texture into a regular texture). See CopyTextureSupport, and use SystemInfo.copyTextureSupport to check.

Calling Texture2D.Apply, Texture2DArray.Apply or Texture3D.Apply after CopyTexture yields undefined results as CopyTexture operates on GPU-side data exclusively, whereas Apply transfers data from CPU to GPU-side.

See Also: CopyTextureSupport.