Direction vector

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2 comments, last by Farraj 11 years, 8 months ago
Me again, with another question.
Suppose I have two sprites on screen, sprite A at position (3,5) sprite B at (8,10).I want sprite B to move towards A with the speed of 1 pixel per second.
So I calculate the direction vector from B to A : dir=B-A=(5,5) . Its length "L" will be sqrt(5*5+5*5)=sqrt(50).
I normalize it dir=(5/L, 5/L).The components will now be : dir =(0.7,0.7) .I multiply each by the speed, but in this case they will stay the same.
I update the new position B(8.7,10.7) but the components will have to be type casted to int when I call SDL_BlitSurface().So going by my logic, sprite B will always stay at the same position.
What am I doing wrong ?
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Will it?
next frame, the values should be (9.4,11.4) and at that point it will have moved.
Unless you for some reason destroy the value when you typecast.
Gosh, I feel so stupid. Thanks for enlightening me xD !
lol, I read 2/3 of your post and thought this guy knows what he's talking about. What could be the problem :P

Same answer as the above. Just keep looking, it will move :P

Good luck man :)

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