neingeist/c-exercises
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no need for the line-wise function anymore

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This commit is contained in:
neingeist 2014-05-11 15:18:11 +02:00
parent bbae44fec7
commit 0c634fa609
1 changed files with 38 additions and 43 deletions
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81
multibrot-openmp.c
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@ -44,40 +44,6 @@ pixel_t incolor() {
return 0x00000000; /* black */
}
/* Computes the visual representation of a mandelbrot set for a given line. */
void compmandelbrot_line(bitmap_t * mbrot, size_t y) {
for (size_t x = 0; x < mbrot->width; x++) {
float complex c = ((3.0f * x / mbrot->width) - 2.0f)
+ I * ((2.0f * y / mbrot->height) - 1.0f);
bool diverges = false;
float complex z = 0;
int it;
for (it = 1; it <= max_it; it++) {
/* z = z² + c */
z = cpowf(z, 2) + c;
/* If |z| ever gets greater than 2, it diverges. */
if (cabsf(z) > 2) {
diverges = true;
break;
}
}
uint32_t color;
if (diverges) {
color = outcolor(it);
} else {
color = incolor();
}
size_t i = y * mbrot->width + x;
mbrot->pixels[i] = color;
}
}
/* Mandelbrot bitmap. */
bitmap_t *mbrot;
@ -129,13 +95,13 @@ static int save_png_to_file(bitmap_t * bitmap, const char *path) {
/* Set image attributes. */
png_set_IHDR(png_ptr,
info_ptr,
bitmap->width,
bitmap->height,
depth,
PNG_COLOR_TYPE_RGB,
PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
info_ptr,
bitmap->width,
bitmap->height,
depth,
PNG_COLOR_TYPE_RGB,
PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
/* Initialize rows of PNG. */
row_pointers = png_malloc(png_ptr, bitmap->height * sizeof(png_byte *));
@ -184,9 +150,38 @@ int main() {
assert(mbrot->pixels != NULL);
/* Compute. */
#pragma omp parallel for
#pragma omp parallel for schedule (dynamic, 50000)
for (unsigned int y = 0; y < mbrot->height; y++) {
compmandelbrot_line(mbrot, y);
for (size_t x = 0; x < mbrot->width; x++) {
float complex c = ((3.0f * x / mbrot->width) - 2.0f)
+ I * ((2.0f * y / mbrot->height) - 1.0f);
bool diverges = false;
float complex z = 0;
int it;
for (it = 1; it <= max_it; it++) {
/* z = z² + c */
z = cpowf(z, 2) + c;
/* If |z| ever gets greater than 2, it diverges. */
if (cabsf(z) > 2) {
diverges = true;
break;
}
}
uint32_t color;
if (diverges) {
color = outcolor(it);
} else {
color = incolor();
}
size_t i = y * mbrot->width + x;
mbrot->pixels[i] = color;
}
}
/* Save PNG. */