drawing an adaptive 2D "grapheditor-like" grid

[fasteez]

someone gave me this (from flipcode.com forum)
i post it here if someone is looking for
same kind of code

int layerspace = 8; // 8 lines form a mayor grid
int layermax = someconst; // How many layers you would like

float gridsize = 8; // Default grid size
float zoom = 1; // Zoom from your ortho camera

// See that more than minlinecount lines are onscreen
if (gridsize * zoom / screensize > minlinecount)
{
while (gridsize * zoom / screensize > minlinecount)
{
gridsize /= layerspace;

// Abort if gridsize < some epsilon
}
}
else
{
// See that less than maxlinecount lines are onscreen
while (gridsize * zoom / screensize < maxlinecount)
{
gridsize *= layerspace;

// Abort if gridsize > some delta
}
}


glBegin(GL_LINES);

// Render each grid layer
for (int layer = 0;
layer <= layermax;
++layer)
{
// Find on-grid position nearest to camera
int camgridx = (int)_fmodf(camposx, gridsize);
int camgridy = (int)_fmodf(camposy, gridsize);

// Build gridextents
int gridextents = screensize / gridsize + 1;

glColor3fv(layercols[layer]);

// Transform to camgrid lock position
glTranslatei(camgridx, camgridy, 0);

for (int i = -gridextents;
i <= gridextents;
++i)
{
// Render all grid lines not on nexthigher layer
if (layer == layermax ||
abs(i + camgridx) % layerspace != 0)
{
glLine2i(-gridextents, i);
glLine2i(gridextents, i);
}

if (layer == layermax ||
abs(i + camgridy) % layerspace != 0)
{
glLine2i(i, -gridextents);
glLine2i(i, gridextents);
}
}

// Move on to next grid size
gridsize *= layerspace;
}

glEnd();

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