Quit #100

[Insectoid]

So, I've been working on a triangular collision detection program. I wrote a line of code to return the number of degrees in an angle, but it quits the program on that line with an error 'Quit #100'. There are no exit, quit, etc. statements in the entire program. Anyone know what this is?

code:

%length variables created with Math.Distance %cosine law to get angle angleC := arccosd ((lengthA **2)+(lengthB**2) - (2*lengthB*lengthC)*(lengthC**2))

Remember, I need help with the error, not the actual triangular collision

[The_Bean]

The reason for the problem is because arccosd(num:real) where -1<num<1 because cosine is adjacent/hypotenuse and since adjacent is always smaller than the hypotenuse num will have to be between -1 and 1.
I'm guessing your looking for arctand.

[Insectoid]

That could be it...

Funny, the equation given to me by my math teacher uses cos...(cosine law).

EDIT: Yeah, I do know trig. Just forgot that equation (I asked specifically for the one that returns angles given only side lengths). Just thought I mentioned that in case people were wondering why I'm asking my math teacher for trig equations...

[The_Bean]

Your teacher was right with using the cosine law, but you messed up the formula.

code:

a ** 2 = b ** 2 + c ** 2 - 2 * b * c * cosd (A) 2 * b * c * cosd (A) = b ** 2 + c ** 2 - a ** 2 cosd (A) = (b ** 2 + c ** 2 - a ** 2) / (2 * b * c) A = arccosd ((b ** 2 + c ** 2 - a ** 2) / (2 * b * c))

So replace it with

Turing:

angleC := arccosd ((lengthA ** 2 + lengthB ** 2 - lengthC ** 2) / (2 * lengthA * lengthB))

[Insectoid]

Ah! Thank you! (this was really rushed).

I had put this away for a bit to work on Perl, but I've decided to use it as my FP for CS. After I get it working in Turing, I'll change it to Java (because I want to concentrate on getting it to work without worrying about the complexities of that hideous language).

So, I need to make at least a simple triangular collision detection program, and then perhaps expand it to provide irregular collision detection based on combinations of triangles and rectangles, and then maybe do Asteroids.

[Insectoid]

Okay...more issues.

Quit #100 again, on this line:

code:

dotAngleA := arccosd (((dotLengthB **2)+(dotLengthC**2)-(lengthA **2))/(2*dotLengthB*dotLengthC))

This calculates the angle between 2 lines connecting the point to angles b and c. I'll try to supply a diagram to fully explain, as soon I figure out how to add text to an image in Pixen.

My way of doing this is, if any 1 of angles dotAngleA, B, or C are bigger than 180, the dot is not inside the triangle.

[The_Bean]

All i can come up with for you still getting an error is when:

code:

b**2+c**2-2*b*c>a**2

because your numerator would become greater than your denominator making a value greater than 1 or less than -1

EDIT

Now that I see the triangle (you managed edit before i put my post up), I don't think arccosd with produce a value greater than 180.

[Insectoid]

hmm...in theory that shouldn't happen...I know it's becoming greater than 1 or less than negative 1. I don't know why though.

[The_Bean]

Just tested it.

Turing:

for i : -10 .. 10     put arccosd (i / 10) end for

arccosd only produces between 0 and 180 because a triangle cannot have an interior angle greater than 180.

[Insectoid]

ah! thank you! Now how can I make it calculate over 180? is there a definite number range that will always produce over 180?

EDIT: lol, my 'hmm, that shouldn't happen' was before you edited your post.

EDIT 2: Wait, cos values follow a wave, so there isn't a definite set, is there?

EDIT 3: I'm on the IRC right now, wanna go on there? (if you have time to help me off-board)

[The_Bean]

Well since it cannot calculate over 180 were going to have to use something else. So...
You can use my idea from before.

Turing:

if b**2+c**2-2*b*c>a**2 then    %numerator is greater than denominator and    %angle will be greater than 180 end if

[Insectoid]

Here's my diagram of my other concept: (making this way more complicated than it needs to be)

[The_Bean]

Last night after getting a working concept myself I realized another problem with both of ares, you can have 2 triangles overlapping, but without any of their vertices inside the other. Although depending on the speed and size at wich you have them moving this probably wouldn't happen.

[Insectoid]

Oh, crap...Didn't even think of that. Hmm...This is going to be fun! We could try to modify the 'perfect' oval collision into triangles, and thus check previous frames to see if a collision occurred mid-frame.