texture import settings

sRGB (Color Texture)

• instructs the GPU to convert data from sRGB color (gamma) space to linear color space when it samples the texture in a shader
  • gamma space: 更接近人眼明暗感知, eg:伽馬校正
  • linear space: 線性顏色空間，更精確

Alpha Source

• Specify how the alpha channel of the Texture is generated
  • Input Texture Alpha: This uses the alpha from the input Texture if a Texture is provided.

Alpha is Transparency

• Enable this property to dilate(膨脹) the color and avoid filtering artifacts on the edges if the alpha channel you specify is Transparency.
  • filtering artifacts: 過(guò)濾偽影是指在數(shù)字信號(hào)處理中，由于采樣、量化等原因，信號(hào)中出現(xiàn)的不真實(shí)的頻率成分，需要通過(guò)濾波器進(jìn)行去除。

Non Power of 2(非2的冪)

• defines a scaling behavior at import time
  • Ideally, Texture dimension sizes should be powers of two on each side (that is, 2, 4 ... 512, 1024 pixels (px), and so on)
  • Options:
    • To nearest: Scale the Texture to the nearest power-of-two dimension size at import time. For example, a 257x511 px Texture is scaled to 256x512 px.

Read/Write Enabled

• 可讀紋理，便于腳本Texture2D.SetPixels/GetPixels方法獲取
  • doubles the amount of memory

Streaming Mip Maps

• 指的是動(dòng)態(tài)生成和加載mip貼圖級(jí)別的技術(shù)
• mipmaps:trades a small amount of CPU resources to save a potentially large amount of GPU memory
  • 是一組不同分辨率的紋理,包含從高到低一系列縮小版本的同一紋理。
  • 其目的是根據(jù)視角和表面細(xì)節(jié)自動(dòng)選擇合適分辨率的紋理加速渲染
  • mip是多級(jí)漸進(jìn)紋理(multum in parvo)的縮寫,意為“小空間內(nèi)的許多信息”。

Generate Mip Maps

• 生成mip貼圖

ASTC 4x4

• 紋理壓縮格式：“自適應(yīng)表面壓縮紋理”(Adaptive Scalable Texture Compression)
• ASTC 4x4指的是該格式使用4x4個(gè)像素為基本壓縮單位,每個(gè)塊包含16個(gè)像素。它提供RGB和RGBA兩種紋理壓縮格式,RGBA格式還具有alpha通道