>Is there a mathematical formula I can use to precisely calculate the numbers because something as simple as "45' angle up means .5/.5" isn't working. I could manually tweak the numbers and eyeball it but I'm sure there has to be a formula.
Because you're using the wrong formula (and an incomplete one too). This is all Pythagorean theorem:
A^2=B^2+C^2
Y_____
|_| /
| /
B| / A (Speed)
| /
|/
Angle
To find for Y, your values are:
The angle - 30°, 45°, whatever
A - the speed vector (the Hypotenuse)
B - Y (Adjacent side)
C - Opposite side
Given the angle and the length of vector A, you can solve for any of the others:
cosine(angle)=Adjacent/Hypotenuse
Adjacent=cosine(angle)Hyposneuse
Y=cos(angle)Speed
Similarily, for X:
X=sin(angle)Speed
For 45°, it's actually about 0.707/0.707" not .5/.5"
And that's only part way there - you still have to account for aspect ratio (4:3) and you should normalise it into byte form (preferably 2 bytes but YMMV).
Adjusting for aspect ratio:
Y=cos(angle)Speed*4
X=sin(angle)Speed*3
As 2 bytes values:
Y=cos(angle)Speed*256
X=sin(angle)Speed*192
And then make a table of that for however many angles you want.
Chris...
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