sf::Sprite FloodFill or Masking?

[zackh]

In the game I'm writing I need the ability to change parts of a sf::Sprite as if I were using a flood/seed fill algorithm. Before I go on to write that up, is there a way to 'mask' parts of a sf::Sprite with a color based on the sf::Image color?

For example, if I had a map of countries with different greyscale values for each country, does a method exist where I could change the color of a country by picking the greyscale value and masking red (for example) over all pixels of that value.

If not, I suppose it's on to writing a flood/seed fill algorithm or splitting the map into several PNGs with an alpha layer (not excited about the latter idea).

[zackh]

For anyone interested:

Code: [Select]


#include <vector>

struct Point
{
Point(int x, int y) : X(x), Y(y) { }

int X, Y;
};

void fill(int x, int y, sf::Color fill, sf::Image* img)
{
int w = img->GetWidth(), h = img->GetHeight();
if (x < 0 || x > w-1 || y < 0 || y > h-1)
return;

sf::Color seedColor = img->GetPixel(x, y);
std::vector<Point> points;
points.push_back(Point(x, y));

while (points.size() > 0)
{
Point p = points.back();
int tx = p.X, ty = p.Y;
points.pop_back();

if (ty < 0 || ty > h-1 || tx < 0 || tx > w-1)
continue;

sf::Color col = img->GetPixel(tx, ty);
if (col == seedColor)
{
img->SetPixel(tx, ty, fill);
points.push_back(Point(tx+1, ty));
points.push_back(Point(tx-1, ty));
points.push_back(Point(tx, ty+1));
points.push_back(Point(tx, ty-1));
}
}
}

fill(75, 75, sf::Color(255, 0, 0), ImgManager::Instance()->getResource("test.bmp"));


The question still stands though. I'm not sure that it's quite fast enough to be used in the middle of a game (No other PCs to test it on atm).

[Recruit0]

I'm also interested in this function. I'll list below things that may help speed up the process (or not):

• OpenGL
• Masking
• Binary Search
• Spiral (box) search
• Scan line search
• Edge detection then polygon fill algorithm
• Memcpy()