Texture2D.PackTextures

Parameters

Returns

Rect[] An array of rectangles containing the UV coordinates in the atlas for each input texture, or null if packing fails.

Description

Packs multiple Textures into a texture atlas.

This function will replace the current texture with the atlas made from the supplied textures. The size, format and mipmaps of any of the textures can change after packing.

The resulting texture atlas will be as large as needed to fit all input textures but only up to maximumAtlasSize in each dimension. If the input textures can't all fit into a texture atlas of the desired size then they will be scaled down to fit.

If you have compressed all input textures, and the following conditions are met, Unity also compresses the output atlas:

• All input textures are of the same compressed type, or are a mixture of compatible types
• padding is zero
• All input textures do not have mipmaps

If any of the input images have mipmaps and the padding value is greater than zero, the atlas texture is uncompressed. This is because of alignment restrictions on the compressed data. If you have not compressed one or more input textures, the atlas remains in the uncompressed format RGBA32. If the texture atlas remains compressed and has a padding value is greater than zero, the padding value is rounded up to the next multiple of four. This happens because of alignment restrictions on compressed data.

This is a shortlist of compressed formats. You can find the full list in TextureFormat:

• ETC
• ETC2
• EAC
• DXT
• ASTC
• PVRTC

You can mix these types in an atlas, where they stay compressed:

• DXT1 and TextureFormat::pref:DXT5 result in a DXT5 atlas.
• ETC2_RGB, ETC_RGB4, and ETC2_RGBA8 restult in a ETC2_RGBA8 atlas.

If none of the input textures have mipmaps, the atlas also has no mipmaps.

If makeNoLongerReadable is true then the texture will be marked as no longer readable and memory will be freed after uploading to the GPU. By default makeNoLongerReadable is set to false.

using UnityEngine;

public class Example : MonoBehaviour
{
    // Source textures.
    Texture2D[] atlasTextures;

    // Rectangles for individual atlas textures.
    Rect[] rects;

    void Start()
    {
        // Pack the individual textures into the smallest possible space,
        // while leaving a two pixel gap between their edges.
        Texture2D atlas = new Texture2D(8192, 8192);
        rects = atlas.PackTextures(atlasTextures, 2, 8192);
    }
}