SDL:Tutorials:Collision Detection between 2 SDL Surfaces
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Help in the categorization process by discussing where it should go. a pixel perfect collision test between SDL_Surface *a positioned at (104,600) SDL_Surface *b positioned at (708,256) if(SDL_CollidePixel(a,104,600 , b,708,256)) // ... SDL_Surface bounding box intersection (fast but inaccurate) SDL_Surface *a positioned at (104,600) SDL_Surface *b positioned at (708,256) if(SDL_CollideBoundingBox(a,104,600 , b,708,256)) // ... SDL_Rect bounding box intersection SDL_Rect a; SDL_Rect b; if(SDL_CollideBoundingBox(a,b)) // ... circle intersection (better than bounding box test on smaller objects such as bullets) circle A has centre at (10,90) with a radius of 3 circle B has centre at (7,600) with a radius of 10 allow a gap between circles of 2 if(SDL_CollideBoundingCircle(10,90,3 , 7,600,10 , 2)) // ... circle intersection, but approximated from SDL_Surfaces. radius and centre of the circle is approximated from the width and height of the surface. i.e a surface with width of 4 and height of 6 would have an approximate radius of 2.5 ((4+6)/2/2)and the centre would be offseted by (2,3) SDL_Surface *a positioned at (104,600) with width and height (4,6) SDL_Surface *b positioned at (708,256) with width and height (8,11) allow a gap between circles of 3 if(SDL_CollideBoundingCircle(a,104,600 , b,708,256 , 3) // ... // the algorithm approximates SDL_Surface *a centre at (106,603) with radius 2 (radius rounded down) SDL_Surface *b centre at (712,261) with radius 9 (radius and y rounded down) |
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