游戏中纹理压缩格式之Texture压缩纹理特殊处理

记载目录

1.杂言杂语2.压缩纹理特殊处理    RGBA16 + Dithering 处理    ETC1的通道剥离    ETC1的shader

杂言杂语

上一篇文章写了Texture压缩纹理，由于篇幅太长的原因没有写压缩纹理特殊处理方式，这里做一个补充。进入正题先来碗鸡汤吧 [你编程不厉害， 是因为还不够努力]http://www.cnblogs.com/aspwebchh/p/7567106.html不说其它的了，进入正题。

压缩纹理特殊处理

RGBA16 + Dithering 处理

RGBA16 为什么要进行抖动处理呢？ 看效果图

抖动处理代码：

        /// <summary>        /// Floyd–Steinberg dithering        /// 抖动处理，需要给图片进行抖动处理        /// 需要注意的是 需要进行抖动处理的是RGBA32的纹理进行抖动处理，再压缩为16位        /// </summary>       private static void SetTextureDither(string tex_path)        {            SetTextureReadable(tex_path, true);            var texture = AssetDatabase.LoadAssetAtPath(tex_path, typeof(Texture2D)) as Texture2D;            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;   // (x+1,y)                    var n2 = offs + texw - 1; // (x-1 , y+1)                    var n3 = offs + texw;  // (x, y+1)                    var n4 = offs + texw + 1; // (x+1 , y+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++;                }            }            SetTextureReadable(tex_path, false);            SaveTexture(tex_path, texture, pixels);        }

ETC1的通道剥离

        /// <summary>        /// 剥离alpha必须得从RGBA32或者RGBA24剥离        /// 从RGBA32剥离alpha通道        /// </summary>        private static void ChangeTextureToAlphaTexture(string tex_path ,string alpha_tex_path)        {            SetTextureReadable(tex_path, true);            Texture2D sourcetex = AssetDatabase.LoadAssetAtPath(tex_path, typeof(Texture2D)) as Texture2D;            Color[] colors = sourcetex.GetPixels();            SetTextureReadable(tex_path, false);            // 格式化通道            Texture2D tex_alpha = new Texture2D(sourcetex.width, sourcetex.height, UnityEngine.TextureFormat.RGB24, false);            Color[] alpha_colors = new Color[colors.Length];            for (int i = 0; i < colors.Length; ++i)            {                alpha_colors[i].r = colors[i].a;                alpha_colors[i].g = colors[i].a;                alpha_colors[i].b = colors[i].a;            }            SaveTexture(alpha_tex_path, tex_alpha, alpha_colors);        }

ETC1的shader

    Shader "Unlit/Transparent Colored ETC1"      {          Properties          {              _MainTex ("Base (RGB)", 2D) = "black" {}              _MainTex_A ("Alpha (A)", 2D) = "white" {}          }          SubShader          {              LOD 200              Tags              {                  "Queue" = "Transparent"                  "IgnoreProjector" = "True"                  "RenderType" = "Transparent"              }              Pass              {                  Cull Off                  Lighting Off                  ZWrite Off                  Fog { Mode Off }                  Offset -1, -1                  Blend SrcAlpha OneMinusSrcAlpha                  CGPROGRAM                  #pragma vertex vert                  #pragma fragment frag                             #include "UnityCG.cginc"                  sampler2D _MainTex;                  sampler2D _MainTex_A;                  float4 _MainTex_ST;                  struct appdata_t                  {                      float4 vertex : POSITION;                      float2 texcoord : TEXCOORD0;                      fixed4 color : COLOR;                  };                  struct v2f                  {                      float4 vertex : SV_POSITION;                      half2 texcoord : TEXCOORD0;                      fixed4 color : COLOR;                  };                  v2f o;                  v2f vert (appdata_t v)                  {                      o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);                      o.texcoord = v.texcoord;                      o.color = v.color;                      return o;                  }                  fixed4 frag (v2f IN) : COLOR                  {                      fixed4 col;                      col.rgb = tex2D(_MainTex, IN.texcoord).rgb;                      col.a = tex2D(_MainTex_A, IN.texcoord).b;                      if (IN.color.r < 0.001 && IN.color.g > 0.001 && IN.color.b > 0.001)                        {                            float grey = dot(col.rgb, float3(0.299, 0.587, 0.114));                            col.rgb = float3(grey, grey, grey);                        }                        else                            col = col * IN.color;                      return col;                  }                  ENDCG              }          }          SubShader          {              LOD 100              Tags              {                  "Queue" = "Transparent"                  "IgnoreProjector" = "True"                  "RenderType" = "Transparent"              }              Pass              {                  Cull Off                  Lighting Off                  ZWrite Off                  Fog { Mode Off }                  Offset -1, -1                  ColorMask RGB                  Blend SrcAlpha OneMinusSrcAlpha                  ColorMaterial AmbientAndDiffuse                  SetTexture [_MainTex]                  {                      Combine Texture * Primary                  }              }          }      }