unusual collision detection

Alright, I've got a game that I've been overhauling recently to make it wii friendly...

original game:
http://ian.janasnyder.com/valo.htm

wii beta:
http://ian.janasnyder.com/valoWii.htm

Right now, my problem is collision detection, I've got a system for wii which I think is faster, but less accurate.

The code I'm using for the wii version has shown profuse problems with collision detection, I'm not sure how you would run this kind of thing efficiently for this type of game, does anyone have any pointers?

Code:

---

function bleh() {
        y3 = int(_ymouse/30);
        x3 = int(_xmouse/30);
        y1 = _ymouse;
        x1 = _xmouse;
        if (y3 > y2) {
                n = y2;
                n2 = y3;
        } else {
                n = y3;
                n2 = y2;
        }
        yd = y1 - y0;
        xd = x1 - x0;
        m = yd/xd;
        b = y3 - m*x3;
        for (n; n <= n2; n++) {
                n1 = (n - b)/m
                q = _root["myMap"+game.currentMap][n][n1];
                select = "t_"+n+"_"+n1;
                atile = _root.tiles[_root.select]
                if (drawn == 1) {
                        if (q == 1) {
                                atile.gotoAndStop(3);
                        }
                        if (q == 2) {
                                atile.gotoAndStop(6);
                        }
                        if (q == 3) {
                                atile.gotoAndStop(8);
                        }
                        if (q == 7) {
                                atile.gotoAndStop(11);
                        }
                        if (q == 8) {
                                atile.gotoAndStop(13);
                        }
                }
        }
        y2 = int(_ymouse/30);
        x2 = int(_xmouse/30);
        y0 = _ymouse;
        x0 = _xmouse;
}

---

I get the slope between the last mouse position and the current, and then run a for loop to see what tiles hit that line. Any suggestions?


btw, the tile numerical values are:
blue = 1
red = 2
green = 3
enemy = 5
yellow = 7
purple = 8

Dont you need to use integers for it to work? I mean, what if the m and b are something like 1.247545689745?

I'm not sure why non-int would be less accurate, I would think that sometimes you would need that odd slope that isn't a number of degrees divisible by 45, but somehow, integers do work better...(?)

But I think I've found the major thing that was lacking from the script, I had a for loop that checked only for tiles on the _y, but if you drew a completely horizontal line, it wouldn't register anything at all. Of course, that would also play into effect when you have lines drawn that aren't totally vertical as well...it would always miss some tiles.

So I added a loop that checks for the _x

Code:

---

function bleh() {
        y3 = int(_ymouse/30);
        x3 = int(_xmouse/30);
        y1 = _ymouse;
        x1 = _xmouse;
        if (y3 > y2) {
                n = y2;
                n2 = y3;
        } else {
                n = y3;
                n2 = y2;
        }
        yd = y1 - y0;
        xd = x1 - x0;
        m = int(yd/xd);
        b = int(y3 - m*x3);
        for (n; n <= n2; n++) {
                n1 = (n - b)/m
                q = _root["myMap"+game.currentMap][n][n1];
                select = "t_"+n+"_"+n1;
                atile = _root.tiles[_root.select]
                if (drawn == 1) {
                        if (q == 1) {
                                atile.gotoAndStop(3);
                        }
                        if (q == 2) {
                                atile.gotoAndStop(6);
                        }
                        if (q == 3) {
                                atile.gotoAndStop(8);
                        }
                        if (q == 7) {
                                atile.gotoAndStop(11);
                        }
                        if (q == 8) {
                                atile.gotoAndStop(13);
                        }
                }
        }
        if (x3 > x2) {
                n = x2;
                n2 = x3;
        } else {
                n = x3;
                n2 = x2;
        }
        for (n; n <= n2; n++) {
                n1 = m*n + b;
                q = _root["myMap"+game.currentMap][n1][n];
                select = "t_"+n1+"_"+n;
                atile = _root.tiles[_root.select]
                if (drawn == 1) {
                        if (q == 1) {
                                atile.gotoAndStop(3);
                        }
                        if (q == 2) {
                                atile.gotoAndStop(6);
                        }
                        if (q == 3) {
                                atile.gotoAndStop(8);
                        }
                        if (q == 7) {
                                atile.gotoAndStop(11);
                        }
                        if (q == 8) {
                                atile.gotoAndStop(13);
                        }
                }
        }
        y2 = int(_ymouse/30);
        x2 = int(_xmouse/30);
        y0 = _ymouse;
        x0 = _xmouse;
}

---

So, it basically works, but it still can't tell what the width of the line is and check for that...does anyone have any clever tricks?