http://blog.csdn.net/a3070173/archive/2008/11/27/3390477.aspx

1. 图像过滤无论是在作图工具还是特效的实现上都时有运用,这里发一些通常会使用到的图像
2. 过滤着色器供有需要的朋友参考.
3. 备注:这里列出的都是片元着色器,顶点着色器都是一样地简单变换顶点和传递纹理坐标.
5. 高斯过滤 - 常用于进行图像模糊
6. 横向过滤:
7. const int g_iWeightNumber = 17;
8.                                     
9. uniform sampler2D g_FilterTexture;  // 被过滤纹理
10. uniform float g_aryWeight[g_iWeightNumber]; // Blur权重数组
11. uniform vec2 g_aryVerticalOffset[g_iWeightNumber];  // 横向Blur偏移数组
13. void main()
14. {
15.     vec4 vec4Sum = vec4(0.0);
16.     for(int i = 0; i < g_iWeightNumber; ++i)
17.     {
18.         vec4Sum += texture2D(g_FilterTexture, gl_TexCoord[0].st + g_aryVerticalOffset[i])*g_aryWeight[i];
19.     }
20.         
21.     gl_FragColor = vec4Sum;
22. }
23. 纵向过滤:
24. const int g_iWeightNumber = 17;
25.                                     
26. uniform sampler2D g_FilterTexture;  // 被过滤纹理
27. uniform float g_aryWeight[g_iWeightNumber]; // Blur权重数组
28. uniform vec2 g_aryHorizontalOffset[g_iWeightNumber];    // 横向Blur偏移数组
30. void main()
31. {
32.     vec4 vec4Sum = vec4(0.0);
33.     for(int i = 0; i < g_iWeightNumber; ++i)
34.     {
35.         vec4Sum += texture2D(g_FilterTexture, gl_TexCoord[0].st + g_aryHorizontalOffset[i])*g_aryWeight[i];
36.     }
37.         
38.     gl_FragColor = vec4Sum;
39. }
41. Mean过滤 - 用于纹理抗锯齿
42. // Mean kernel
43. // 1 1 1
44. // 1 1 1
45. // 1 1 1    
46. const int g_iWeightNumber = 9;
47.                                     
48. uniform sampler2D g_FilterTexture;  // 被过滤纹理
49. uniform float g_aryWeight[g_iWeightNumber]; // Blur权重数组
50. uniform vec2 g_aryOffset[g_iWeightNumber];  // 横向Blur偏移数组
52. void main()
53. {
54.     vec4 vec4Sum = vec4(0.0);
55.     if (gl_TexCoord[0].s < 0.495)
56.     {
57.         for(int i = 0; i < g_iWeightNumber; ++i)
58.         {
59.             vec4Sum += texture2D(g_FilterTexture, gl_TexCoord[0].st + g_aryOffset[i])*g_aryWeight[i];
60.         }
61.     }
62.     else if (gl_TexCoord[0].s > 0.505)
63.     {
64.         vec4Sum = texture2D(g_FilterTexture, gl_TexCoord[0].st);
65.     }
66.     else
67.     {
68.         vec4Sum = vec4(1.0, 0.0, 0.0, 1.0);
69.     }
71.     gl_FragColor = vec4Sum;
72. }
74. Laplacian过滤 - 用于突显图像轮廓
75. // Edge detection kernel (Laplacian filter).
76. // 0  -1 0
77. // -1  4 -1
78. // 0  -1 0      
79. const int g_iWeightNumber = 9;
80.                                     
81. uniform sampler2D g_FilterTexture;  // 被过滤纹理
82. uniform float g_aryWeight[g_iWeightNumber]; // Blur权重数组
83. uniform vec2 g_aryOffset[g_iWeightNumber];  // 横向Blur偏移数组
85. void main()
86. {
87.     vec4 vec4Sum = vec4(0.0);
88.     if (gl_TexCoord[0].s < 0.495)
89.     {
90.         for(int i = 0; i < g_iWeightNumber; ++i)
91.         {
92.             vec4Sum += texture2D(g_FilterTexture, gl_TexCoord[0].st + g_aryOffset[i])*g_aryWeight[i];
93.         }
94.         vec4 vec4BaseColor = texture2D(g_FilterTexture, gl_TexCoord[0].st);
95.         vec4Sum += vec4BaseColor*0.1;
96.     }
97.     else if (gl_TexCoord[0].s > 0.505)
98.     {
99.         vec4Sum = texture2D(g_FilterTexture, gl_TexCoord[0].st);
100.     }
101.     else
102.     {
103.         vec4Sum = vec4(1.0, 0.0, 0.0, 1.0);
104.     }
106.     gl_FragColor = vec4Sum;
107. }
109. Emboss过滤 - used to simulate the relief of an image
110. // Emboss filter
111. // 2   0  0
112. // 0  -1  0
113. // 0   0  -1        
114. const int g_iWeightNumber = 9;
115.                                     
116. uniform sampler2D g_FilterTexture;  // 被过滤纹理
117. uniform float g_aryWeight[g_iWeightNumber]; // Blur权重数组
118. uniform vec2 g_aryOffset[g_iWeightNumber];  // 横向Blur偏移数组
120. void main()
121. {
122.     vec4 vec4Sum = vec4(0.0);
123.     if (gl_TexCoord[0].s < 0.495)
124.     {
125.         for(int i = 0; i < g_iWeightNumber; ++i)
126.         {
127.             vec4Sum += texture2D(g_FilterTexture, gl_TexCoord[0].st + g_aryOffset[i])*g_aryWeight[i];
128.         }
129.         vec4Sum += 0.5;
130.     }
131.     else if (gl_TexCoord[0].s > 0.505)
132.     {
133.         vec4Sum = texture2D(g_FilterTexture, gl_TexCoord[0].st);
134.     }
135.     else
136.     {
137.         vec4Sum = vec4(1.0, 0.0, 0.0, 1.0);
138.     }
140.     gl_FragColor = vec4Sum;
141. }
143. Sharpness过滤 - 突显图像的细节
144. // Sharpness filter
145. // -1  -1  -1
146. // -1   9  -1
147. // -1  -1  -1       
148. const int g_iWeightNumber = 9;
149.                                     
150. uniform sampler2D g_FilterTexture;  // 被过滤纹理
151. uniform float g_aryWeight[g_iWeightNumber]; // Blur权重数组
152. uniform vec2 g_aryOffset[g_iWeightNumber];  // 横向Blur偏移数组
154. void main()
155. {
156.     vec4 vec4Sum = vec4(0.0);
157.     if (gl_TexCoord[0].s < 0.495)
158.     {
159.         for(int i = 0; i < g_iWeightNumber; ++i)
160.         {
161.             vec4Sum += texture2D(g_FilterTexture, gl_TexCoord[0].st + g_aryOffset[i])*g_aryWeight[i];
162.         }
163.     }
164.     else if (gl_TexCoord[0].s > 0.505)
165.     {
166.         vec4Sum = texture2D(g_FilterTexture, gl_TexCoord[0].st);
167.     }
168.     else
169.     {
170.         vec4Sum = vec4(1.0, 0.0, 0.0, 1.0);
171.     }
173.     gl_FragColor = vec4Sum;
174. }
176. Demo效果截图:
177. 
179. 
180. 
181. 
182. 
183. exe文件:http://www.fileupyours.com/view/219112/GLSL/Image%20Filter%20Demo.rar