void
update_colors(struct mandelbrot_param* param)
{
// Gradient color
int start_r, start_g, start_b, end_r, end_g, end_b;
// Other control variables
int i;
if(color != NULL)
{
free(color);
}
color = malloc(sizeof(int) * num_colors(param));
// Start color
start_r = 219;
start_g = 57;
start_b = 0;
// Stop color
end_r = 0;
end_g = 0;
end_b = 0;
// Initialize the color vector
for (i = 0; i < num_colors(param); i++)
{
color[i]
= (((int) ((end_g - start_g) * ((double) i / num_colors(param)) + start_g)
& 255) << 16) + (((int) ((end_r - start_r) * ((double) i
/ num_colors(param)) + start_r) & 255) << 8) + (((int) ((end_b - start_b)
* ((double) i / num_colors(param)) + start_b) & 255) << 0);
}
}
void
update_colors(struct mandelbrot_param* param)
{
// Gradient color
color_t start, stop;
// Other control variables
int i;
if(color != NULL)
{
free(color);
}
color = malloc(sizeof(color_t) * num_colors(param));
// Start color
start.red = 219;
start.green = 57;
start.blue = 0;
// Stop color
stop.red = 0;
stop.green = 0;
stop.blue = 0;
// Initialize the color vector
for (i = 0; i < num_colors(param); i++)
{
color[i].green = (stop.green - start.green) * ((double) i / num_colors(param)) + start.green;
color[i].red = (stop.red - start.red) * ((double) i / num_colors(param)) + start.red;
color[i].blue = (stop.blue - start.blue) * ((double) i / num_colors(param)) + start.blue;
}
}
static void
compute_chunk(struct mandelbrot_param *args)
{
int i, j, val;
float Cim, Cre;
color_t pixel;
// Iterate through lines
for (i = args->begin_h; i < args->end_h; i++)
{
// Iterate through pixels in a line
for (j = args->begin_w; j < args->end_w; j++)
{
// Convert the coordinate of the pixel to be calculated to both
// real and imaginary parts of the complex number to be checked
Cim = (float) i / args->height * (args->upper_i - args->lower_i)
+ args->lower_i;
Cre = (float) j / args->width * (args->upper_r - args->lower_r)
+ args->lower_r;
// Gets the value returned by is_in_mandelbrot() and scale it
// from 0 to 255, or -1 if (Cre, Cim) is in the mandelbrot set.
val = is_in_Mandelbrot(Cre, Cim, args->maxiter);
// Change a negative value to 0 in val to make mandelbrot
// elements to appear black in the final picture.
pixel = val > args->maxiter ? args->mandelbrot_color : color[val
% num_colors(args)];
ppm_write(args->picture, j, i, pixel);
}
}
}
/***** You may modify this portion *****/
static void
compute_chunk(struct mandelbrot_param *args, int offseti, int offsetj)
{
int i, j, val;
float Cim, Cre;
color_t pixel;
//#pragma omp parallel for schedule(dynamic, 1) private(i,j,pixel,Cim,Cre,val)
for (i = 0; i < args->height; i++)
{
for (j = 0; j < args->width; j++)
{
// Convert the coordinate of the pixel to be calculated to both
// real and imaginary parts of the complex number to be checked
Cim = (float) i / args->height * (args->upper_i - args->lower_i)
+ args->lower_i;
Cre = (float) j / args->width * (args->upper_r - args->lower_r)
+ args->lower_r;
// Gets the value returned by is_in_mandelbrot() and scale it
// from 0 to 255, or -1 if (Cre, Cim) is in the mandelbrot set.
val = is_in_Mandelbrot(Cre, Cim, args->maxiter);
// Change a negative value to 0 in val to make mandelbrot
// elements to appear black in the final picture.
val = val > args->maxiter ? args->mandelbrot_color : color[val
% num_colors(args)];
// Permute green, red and blue to get different fancy colors
pixel.green = val >> 16 & 255;
pixel.red = val >> 8 & 255;
pixel.blue = val & 255;
ppm_write(args->picture, j + offsetj, i + offseti, pixel);
}
}
}
