unity通过算法压缩图片Texture2D（unity压缩文件）

当使用unity开发过程中，需要用到图片压缩的时候，往往会不知所措，下面为压缩图片的算法，仅供参考：

public enum ImageFilterMode : int

{

Nearest = 0,

Biliner = 1,

Average = 2//最优

}

//压缩图片

public Texture2D ResizeTexture(Texture2D pSource, ImageFilterMode pFilterMode, Vector2 newSize)

{

//*** Variables

int i;

//*** Get All the source pixels

Color[] aSourceColor = pSource.GetPixels(0);

Vector2 vSourceSize = new Vector2(pSource.width, pSource.height);

//*** Calculate New Size

float xWidth = Mathf.RoundToInt(newSize.x);

float xHeight = Mathf.RoundToInt(newSize.y);

//*** Make New

Texture2D oNewTex = new Texture2D((int)xWidth, (int)xHeight, TextureFormat.RGBA32, false);

//*** Make destination array

int xLength = (int)xWidth * (int)xHeight;

Color[] aColor = new Color[xLength];

Vector2 vPixelSize = new Vector2(vSourceSize.x / xWidth, vSourceSize.y / xHeight);

//*** Loop through destination pixels and process

Vector2 vCenter = new Vector2();

for (i = 0; i < xLength; i++)

{

//*** Figure out x&y

float xX = (float)i % xWidth;

float xY = Mathf.Floor((float)i / xWidth);

//*** Calculate Center

vCenter.x = (xX / xWidth) * vSourceSize.x;

vCenter.y = (xY / xHeight) * vSourceSize.y;

//*** Do Based on mode

//*** Nearest neighbour (testing)

if (pFilterMode == ImageFilterMode.Nearest)

{

//*** Nearest neighbour (testing)

vCenter.x = Mathf.Round(vCenter.x);

vCenter.y = Mathf.Round(vCenter.y);

//*** Calculate source index

int xSourceIndex = (int)((vCenter.y * vSourceSize.x) + vCenter.x);

//*** Copy Pixel

aColor[i] = aSourceColor[xSourceIndex];

}

//*** Bilinear

else if (pFilterMode == ImageFilterMode.Biliner)

{

//*** Get Ratios

float xRatioX = vCenter.x - Mathf.Floor(vCenter.x);

float xRatioY = vCenter.y - Mathf.Floor(vCenter.y);

//*** Get Pixel index's

int xIndexTL = (int)((Mathf.Floor(vCenter.y) * vSourceSize.x) + Mathf.Floor(vCenter.x));

int xIndexTR = (int)((Mathf.Floor(vCenter.y) * vSourceSize.x) + Mathf.Ceil(vCenter.x));

int xIndexBL = (int)((Mathf.Ceil(vCenter.y) * vSourceSize.x) + Mathf.Floor(vCenter.x));

int xIndexBR = (int)((Mathf.Ceil(vCenter.y) * vSourceSize.x) + Mathf.Ceil(vCenter.x));

//*** Calculate Color

aColor[i] = Color.Lerp(

Color.Lerp(aSourceColor[xIndexTL], aSourceColor[xIndexTR], xRatioX),

Color.Lerp(aSourceColor[xIndexBL], aSourceColor[xIndexBR], xRatioX),

xRatioY

);

}

//*** Average

else if (pFilterMode == ImageFilterMode.Average)

{

//*** Calculate grid around point

int xXFrom = (int)Mathf.Max(Mathf.Floor(vCenter.x - (vPixelSize.x * 0.5f)), 0);

int xXTo = (int)Mathf.Min(Mathf.Ceil(vCenter.x + (vPixelSize.x * 0.5f)), vSourceSize.x);

int xYFrom = (int)Mathf.Max(Mathf.Floor(vCenter.y - (vPixelSize.y * 0.5f)), 0);

int xYTo = (int)Mathf.Min(Mathf.Ceil(vCenter.y + (vPixelSize.y * 0.5f)), vSourceSize.y);

//*** Loop and accumulate

Vector4 oColorTotal = new Vector4();

Color oColorTemp = new Color();

float xGridCount = 0;

for (int iy = xYFrom; iy < xYTo; iy++)

{

for (int ix = xXFrom; ix < xXTo; ix++)

{

//*** Get Color

oColorTemp += aSourceColor[(int)(((float)iy * vSourceSize.x) + ix)];

//*** Sum

xGridCount++;

}

}

//*** Average Color

aColor[i] = oColorTemp / (float)xGridCount;

}

}

//*** Set Pixels

oNewTex.SetPixels(aColor);

oNewTex.Apply();

//*** Return

return oNewTex;

}