package collision import ( "git.kirsle.net/apps/doodle/lib/render" ) // IndexTuple holds two integers used as array indexes. type IndexTuple [2]int // BetweenBoxes checks if there is a collision between any // two bounding rectangles. // // This returns a generator that spits out indexes of the // intersecting boxes. func BetweenBoxes(boxes []render.Rect) chan IndexTuple { generator := make(chan IndexTuple) go func() { // Outer loop: test each box for intersection with the others. for i, box := range boxes { for j := i + 1; j < len(boxes); j++ { if box.Intersects(boxes[j]) { generator <- IndexTuple{i, j} } } } close(generator) }() return generator }