70 lines
1.7 KiB
Common Lisp
70 lines
1.7 KiB
Common Lisp
float map_x(int x, int width, float zoom)
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{
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return (((float)x / (float)width) * (3.5 * zoom)) - (2.5 - (1.0 - zoom));
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}
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float map_y(int y, int height, float zoom)
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{
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return (((float)y / (float)height) * (2.0 * zoom)) - (1.00001 - (1.0 - zoom));
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}
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__kernel void fractal_point(__global const int *res_x,
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__global const int *res_y,
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__global const int *line,
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__global const float *zoom,
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__global int *graph_line)
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{
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// Get the index of the current element
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int image_x = get_global_id(0);
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int image_y = *line;
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float pos_x = map_x(image_x, *res_x, *zoom);
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float pos_y = map_y(image_y, *res_y, *zoom);
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float x = 0.0;
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float y = 0.0;
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float q, x_term;
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// Period-2 bulb check
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if (((pos_x + 1.0) * (pos_x + 1.0) + pos_y * pos_y) < 0.0625)
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{
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graph_line[image_x] = 0;
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return;
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}
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// Cardioid check
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x_term = pos_x - 0.25;
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q = x_term * x_term + pos_y * pos_y;
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q = q * (q + x_term);
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if (q < (0.25 * pos_y * pos_y))
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{
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graph_line[image_x] = 0;
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return;
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}
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int iteration = 0;
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int max_iteration = 256;
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float xtemp, xx, yy, xplusy;
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while (iteration < max_iteration)
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{
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xx = x * x;
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yy = y * y;
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xplusy = x + y;
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if ((xx) + (yy) > (4.0)) break;
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xtemp = xx - yy + pos_x;
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y = xplusy * xplusy - xx - yy;
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y = y + pos_y;
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x = xtemp;
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iteration++;
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}
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if (iteration > max_iteration)
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{
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graph_line[image_x] = 0;
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}
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else
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{
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graph_line[image_x] = iteration;
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}
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}
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