Texture.updateCount

描述

每当 Texture 更新时，此计数器都会递增。

注意：如果从 GPU 端执行更新，则应自行递增计数器。（例如，当将内容blit到RenderTexture时）。（参见IncrementUpdateCount）。

using UnityEngine;
using System.Collections.Generic;

public class MyTextureCache
{
    struct TextureCacheMeta
    {
        internal int index;
        internal uint updateCount;
    }

    Dictionary<Texture, TextureCacheMeta> m_TextureMetas = new Dictionary<Texture, TextureCacheMeta>();
    RenderTexture m_Cache;

    public Texture cache { get { return m_Cache; } }

    public int CacheTexture(Texture Texture)
    {
        var index = -1;
        TextureCacheMeta meta;
        if (m_TextureMetas.TryGetValue(Texture, out meta))
        {
            if (meta.updateCount != Texture.updateCount)
            {
                // Texture has changed since last caching
                // So blit again into the cache Texture
                BlitTextureAt(meta.index, Texture);
                meta.updateCount = Texture.updateCount;
                m_TextureMetas[Texture] = meta;
            }
        }
        else
        {
            index = GetNextIndex();
            if (index < 0)
            {
                Debug.LogError("Invalid index");
                return -1;
            }

            m_TextureMetas[Texture] = new TextureCacheMeta
            {
                index = index,
                updateCount = Texture.updateCount
            };
        }
        return index;
    }

    void BlitTextureAt(int index, Texture Texture) { /* copy pixels in cache */ }
    int GetNextIndex() { return -1; /* Get next index to use in the cache */ }
}