Unity使用 16bit 压缩 Texture 颜色能均匀过渡

 

下面是unity自带 16bit 图 的效果，可以看到颜色过度的很不均匀，占用内存 0.5M

  

 

如果调成 truecolor 后 颜色过渡很均匀，而内存却占到 1.1 M

  

 

讲图片 后缀名改成  .Dither.png  结尾后回到 unity，设置贴图格式为 Truecolor 后，颜色过渡也很均匀，而且内存只占了 0.5M

 

以下代码来至 keijiro 的 github：unity-dither4444

 

 1 using UnityEngine;

 2 using UnityEditor;

 3 using System.Collections;

 4 

 5 class TextureModifier : AssetPostprocessor

 6 {

 7     void OnPreprocessTexture()

 8     {

 9         var importer = (assetImporter as TextureImporter);

10 

11         importer.textureType = TextureImporterType.GUI;

12 

13         if (assetPath.EndsWith ("Dither.png")) {

14             importer.textureFormat = TextureImporterFormat.RGBA32;

15         }

16     }

17 

18     void OnPostprocessTexture (Texture2D texture)

19     {

20         if (!assetPath.EndsWith ("Dither.png")) {

21             return;

22         }

23 

24         var texw = texture.width;

25         var texh = texture.height;

26 

27         var pixels = texture.GetPixels ();

28         var offs = 0;

29 

30         var k1Per15 = 1.0f / 15.0f;

31         var k1Per16 = 1.0f / 16.0f;

32         var k3Per16 = 3.0f / 16.0f;

33         var k5Per16 = 5.0f / 16.0f;

34         var k7Per16 = 7.0f / 16.0f;

35 

36         for (var y = 0; y < texh; y++) {

37             for (var x = 0; x < texw; x++) {

38                 float a = pixels [offs].a;

39                 float r = pixels [offs].r;

40                 float g = pixels [offs].g;

41                 float b = pixels [offs].b;

42 

43                 var a2 = Mathf.Clamp01 (Mathf.Floor (a * 16) * k1Per15);

44                 var r2 = Mathf.Clamp01 (Mathf.Floor (r * 16) * k1Per15);

45                 var g2 = Mathf.Clamp01 (Mathf.Floor (g * 16) * k1Per15);

46                 var b2 = Mathf.Clamp01 (Mathf.Floor (b * 16) * k1Per15);

47 

48                 var ae = a - a2;

49                 var re = r - r2;

50                 var ge = g - g2;

51                 var be = b - b2;

52 

53                 pixels [offs].a = a2;

54                 pixels [offs].r = r2;

55                 pixels [offs].g = g2;

56                 pixels [offs].b = b2;

57 

58                 var n1 = offs + 1;

59                 var n2 = offs + texw - 1;

60                 var n3 = offs + texw;

61                 var n4 = offs + texw + 1;

62 

63                 if (x < texw - 1) {

64                     pixels [n1].a += ae * k7Per16;

65                     pixels [n1].r += re * k7Per16;

66                     pixels [n1].g += ge * k7Per16;

67                     pixels [n1].b += be * k7Per16;

68                 }

69 

70                 if (y < texh - 1) {

71                     pixels [n3].a += ae * k5Per16;

72                     pixels [n3].r += re * k5Per16;

73                     pixels [n3].g += ge * k5Per16;

74                     pixels [n3].b += be * k5Per16;

75 

76                     if (x > 0) {

77                         pixels [n2].a += ae * k3Per16;

78                         pixels [n2].r += re * k3Per16;

79                         pixels [n2].g += ge * k3Per16;

80                         pixels [n2].b += be * k3Per16;

81                     }

82 

83                     if (x < texw - 1) {

84                         pixels [n4].a += ae * k1Per16;

85                         pixels [n4].r += re * k1Per16;

86                         pixels [n4].g += ge * k1Per16;

87                         pixels [n4].b += be * k1Per16;

88                     }

89                 }

90 

91                 offs++;

92             }

93         }

94 

95         texture.SetPixels (pixels);

96         EditorUtility.CompressTexture (texture, TextureFormat.RGBA4444, TextureCompressionQuality.Best);

97     }

98 }