void IndexTable::Calculate (int sides)
{
IndexBuffer *buf = &buffers[sides];
buf->Init (sizeof(index_t)*MAX_INDICES);
index_t *begin = (index_t*)buf->LockData (), *i = begin;
int ystart = 0, xstart = 0;
int yend = QUAD_W, xend = QUAD_W;
if (sides & left_bit) xstart++;
if (sides & right_bit) xend--;
if (sides & up_bit) ystart++;
if (sides & down_bit) yend--;
if (sides & up_bit) {
for (int x=xstart;x<QUAD_W;x++) {
if (x&1) {
TRI(x-1, x+1, VERTC+x);
if (x<xend) TRI(x+1, VERTC+x+1, VERTC+x);
} else {
TRI(x, VERTC+x+1, VERTC+x);
}
}
}
for (int y=ystart;y<QUAD_W;y++)
{
if (sides & left_bit) {
if (y&1) {
TRI(VRT(0,y-1),VRT(1,y),VRT(0,y+1));
if (y<yend) TRI(VRT(1,y),VRT(1,y+1),VRT(0,y+1));
} else {
TRI(VRT(0,y),VRT(1,y),VRT(1,y+1));
}
}
if (y>=ystart && y<yend) {
for (int x=xstart;x<xend;x++)
{
TRI(y*VERTC+x, y*VERTC+x+1, (y+1)*VERTC+x+1);
TRI(y*VERTC+x, (y+1)*VERTC+x+1, (y+1)*VERTC+x);
}
}
if (sides & right_bit) {
int x=QUAD_W-1;
if (y&1) {
TRI(VRT(x+1,y-1),VRT(x+1,y+1),VRT(x,y));
if(y<yend) TRI(VRT(x,y),VRT(x+1,y+1),VRT(x,y+1));
} else {
TRI(VRT(x,y),VRT(x+1,y),VRT(x,y+1));
}
}
}
if (sides & down_bit) {
int y=QUAD_W-1;
for (int x=xstart;x<QUAD_W;x++) {
if (x&1) {
TRI(VRT(x,y),VRT(x+1,y+1),VRT(x-1,y+1));
if (x<xend) TRI(VRT(x,y),VRT(x+1,y),VRT(x+1,y+1));
} else {
TRI(VRT(x,y),VRT(x+1,y),VRT(x,y+1));
}
}
}
size[sides]=i-begin;
assert (size[sides]<=MAX_INDICES);
buf->UnlockData ();
}
