47 lines
1.3 KiB
Common Lisp
47 lines
1.3 KiB
Common Lisp
__kernel void mandelbrot(__global unsigned char *out_buff, unsigned int iter, double cx, double cy, double xs, double ys, unsigned int width, unsigned int height)
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{
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const int idx = get_global_id(0);
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unsigned int i;
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double z_real, z_imag;
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double z2_real, z2_imag;
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double pt_real, pt_imag;
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double color_scale;
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unsigned int r, g, b;
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const unsigned int pix_x = idx % width;
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const unsigned int pix_y = (unsigned int)idx / width;
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const double val_per_x_pixel = xs / (width - 1);
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const double val_per_y_pixel = ys / (height - 1);
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pt_real = (((double)pix_x - (double)(width - 1) / 2)) * val_per_x_pixel + cx;
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pt_imag = (((double)pix_y - (double)(height - 1) / 2)) * val_per_y_pixel + cy;
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z_real = 0.0;
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z_imag = 0.0;
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for (i = 0; i < iter; i++) {
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z2_real = z_real * z_real - z_imag * z_imag;
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z2_imag = 2.0 * z_real * z_imag;
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z_real = z2_real + pt_real;
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z_imag = z2_imag + pt_imag;
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if ((z_real * z_real + z_imag * z_imag) >= 4.0)
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break;
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}
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color_scale = (double)(i) / (double)iter;
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if (i != iter) {
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r = (unsigned char)(255.0 * sqrt((1-color_scale)));
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g = (unsigned char)(255.0 * color_scale*color_scale);
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b = (unsigned char)(255.0 * color_scale);
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} else {
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r = g = b = 0;
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}
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out_buff[idx*3] = r;
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out_buff[idx*3+1] = g;
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out_buff[idx*3+2] = b;
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}
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