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How to check the intersection of two rectangles?
Suppose you have a rotated rectangle and a basic shape that rotation doesn’t matter for (such as a point, circle, or a line segment), and you want to check whether the two are intersecting – be that for collision handling, hit testing, or whatever else.
How to calculate intersection of rotated rectangles in Python?
For the first issue, instead of doing image manipulation, you can instead do an exact calculation by finding the intersections of the edges of the rotated rectangles, constructing the polygon that is the overlapping area, and then calculating the area of that polygon. This is much faster and uses much less memory.
How do you find the position of a rectangle when it is rotated?
If you are to subtract rectangle’s position from each of the shape positions and rotate them for the opposite of rectangle’s rotation angle, you would have the local coordinates for a system where the rectangle sits unrotated at 0,0 and the shape floats relative to it.
How to intersection over Union for rotated rectangles?
Looking at the images you provided, most red rectangles are quite small relative to the whole domain. In that case, a possible approach might be to divide the domain into smaller tiles, and for each tile have a list of rectangles that are overlapping that tile.
Can you use intersection check for Axis aligned rectangles?
At this point you can use the generally trivial intersection checks for axis-aligned rectangles/bounding boxes. The above description translates into code in a fairly straightforward way,
When to stop the search for a point of intersection?
Once a point of intersection is found check if it resides between inside the imaginary rectangle created by the corresponding 4 points. When ever such a point is found conclude that they intersect and stop the search. If the above 2 tests return false then these 2 rectangles do not overlap.