1 /* 2 * function: kernel_gauss 3 * input: image2d_t as read only 4 * output: image2d_t as write only 5 * workitem = 4x2 pixel ouptut 6 * GAUSS_RADIUS must be defined in build options. 7 */ 8 9 #ifndef GAUSS_RADIUS 10 #define GAUSS_RADIUS 2 11 #endif 12 13 #define GAUSS_SCALE (2 * GAUSS_RADIUS + 1) 14 15 __kernel void kernel_gauss (__read_only image2d_t input, __write_only image2d_t output, __global float *table) 16 { 17 int x = get_global_id (0); 18 int y = get_global_id (1); 19 sampler_t sampler = CLK_NORMALIZED_COORDS_FALSE | CLK_ADDRESS_CLAMP_TO_EDGE | CLK_FILTER_NEAREST; 20 21 float4 in1; 22 int i, j; 23 int index; 24 float4 out1 = (float4)(0.0f, 0.0f, 0.0f, 0.0f); 25 float4 out2 = (float4)(0.0f, 0.0f, 0.0f, 0.0f); 26 27 for(i = 0; i < GAUSS_SCALE + 1; i++) 28 for(j = 0; j < GAUSS_SCALE + 3; j++) { 29 in1 = read_imagef (input, sampler, (int2)(4 * x - GAUSS_RADIUS + j, 2 * y - GAUSS_RADIUS + i)); 30 //first line 31 if (i < GAUSS_SCALE) { 32 index = i * GAUSS_SCALE + j; 33 out1.x += (j < GAUSS_SCALE ? table[index] * in1.x : 0.0f); 34 index -= 1; 35 out1.y += ((j < GAUSS_SCALE + 1) && j > 0 ? table[index] * in1.x : 0.0f); 36 index -= 1; 37 out1.z += ((j < GAUSS_SCALE + 2) && j > 1 ? table[index] * in1.x : 0.0f); 38 index -= 1; 39 out1.w += (j > 2 ? table[index] * in1.x : 0.0f); 40 } 41 //second line 42 if (i > 0) { 43 index = (i - 1) * GAUSS_SCALE + j; 44 out2.x += (j < GAUSS_SCALE ? table[index] * in1.x : 0.0f); 45 index -= 1; 46 out2.y += ((j < GAUSS_SCALE + 1) && j > 0 ? table[index] * in1.x : 0.0f); 47 index -= 1; 48 out2.z += ((j < GAUSS_SCALE + 2) && j > 1 ? table[index] * in1.x : 0.0f); 49 index -= 1; 50 out2.w += (j > 2 ? table[index] * in1.x : 0.0f); 51 } 52 } 53 54 write_imagef(output, (int2)(x, 2 * y), out1); 55 write_imagef(output, (int2)(x, 2 * y + 1), out2); 56 57 } 58 59
