void OnPreprocessTexture()
{
var importer = (assetImporter as TextureImporter);
if (Dither.isDither(assetPath))
{
importer.textureType = TextureImporterType.Default;
importer.npotScale = TextureImporterNPOTScale.ToNearest;
importer.isReadable = false;
importer.textureFormat = TextureImporterFormat.RGBA32;
}
}
void OnPostprocessTexture(Texture2D texture)
{
if (!Dither.isDither(assetPath))
{
return;
}
var texw = texture.width;
var texh = texture.height;
var pixels = texture.GetPixels();
var offs = 0;
var k1Per15 = 1.0f / 15.0f;
var k1Per16 = 1.0f / 16.0f;
var k3Per16 = 3.0f / 16.0f;
var k5Per16 = 5.0f / 16.0f;
var k7Per16 = 7.0f / 16.0f;
for (var y = 0; y < texh; ++y)
{
for (var x = 0; x < texw; ++x)
{
float a = pixels[offs].a;
float r = pixels[offs].r;
float g = pixels[offs].g;
float b = pixels[offs].b;
var a2 = Mathf.Clamp01(Mathf.Floor(a * 16) * k1Per15);
var r2 = Mathf.Clamp01(Mathf.Floor(r * 16) * k1Per15);
var g2 = Mathf.Clamp01(Mathf.Floor(g * 16) * k1Per15);
var b2 = Mathf.Clamp01(Mathf.Floor(b * 16) * k1Per15);
var ae = a - a2;
var re = r - r2;
var ge = g - g2;
var be = b - b2;
pixels[offs].a = a2;
pixels[offs].r = r2;
pixels[offs].g = g2;
pixels[offs].b = b2;
var n1 = offs + 1;
var n2 = offs + texw - 1;
var n3 = offs + texw;
var n4 = offs + texw + 1;
if (x < texw - 1)
{
pixels[n1].a += ae * k7Per16;
pixels[n1].r += re * k7Per16;
pixels[n1].g += ge * k7Per16;
pixels[n1].b += be * k7Per16;
}
if (y < texh - 1)
{
pixels[n3].a += ae * k5Per16;
pixels[n3].r += re * k5Per16;
pixels[n3].g += ge * k5Per16;
pixels[n3].b += be * k5Per16;
if (x > 0)
{
pixels[n2].a += ae * k3Per16;
pixels[n2].r += re * k3Per16;
pixels[n2].g += ge * k3Per16;
pixels[n2].b += be * k3Per16;
}
if (x < texw - 1)
{
pixels[n4].a += ae * k1Per16;
pixels[n4].r += re * k1Per16;
pixels[n4].g += ge * k1Per16;
pixels[n4].b += be * k1Per16;
}
}
++offs;
}
}
texture.SetPixels(pixels);
EditorUtility.CompressTexture(texture, TextureFormat.RGBA4444, TextureCompressionQuality.Best);
}