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How does collision detection work in a polygon?
There are several methods, the simple is just to check if there is and overlap in X or Y bounds. This however only works with rectangles aligned with the axis. There is bounds checking, is the corner of one object withing the bounds of coordinates of the other. From there collision detection gets more advanced.
How to detect if two polygons are intersecting?
To detect if two polygons are intersecting, we use the Separating Axis Theorem. The idea is to find a line that separates both polygons – if such a line exists, the polygons are not intersecting (Fig. 1). The implementation of this theorem is relatively simple, and could be summed up in this pseudo code:
How to use collision detection in C + +?
From there collision detection gets more advanced. Checking to see if there is a line one can draw between them in any direction and such. Left, top corner (x,y). Width, height. Left, top corner (x1,y1). (x>=x1) and (x<=x1+width) => collision for x axis. For y axis this same but with y and y1 and height.
How are helper functions used in polygoncollision function?
Two helper functions are used by the PolygonCollision function. The first one is used to project a polygon onto an axis: The second one returns the signed distance between two given projections:
Is there a way to see if two polygons are touching?
I found a simple way to see if two are touching by just checking if any lines on the two rectangles are colliding, but this will not work if one polygon is in another. Does anyone know a more efficient way to do this or just a way that works?
How is bounds checking used in collision detection?
There is bounds checking, is the corner of one object withing the bounds of coordinates of the other. From there collision detection gets more advanced. Checking to see if there is a line one can draw between them in any direction and such.
We have a function to check if a point is in a polygon and it can be used for every vertex in a polygon to allow us to check if a polygon is in a polygon. So if all 5 points of a pentagon are not inside a polygon then we know the polygons are not colliding and if at least one point is inside then we know the polygon is colliding.
How to draw a polygon on top of an image?
To draw a semi-transparent polygon on top of img, make a copy of the image. One the copy, draw the polygon in full color without alpha. Then use Image.blend to combine the original image with the copy with a set level of alpha.
Can you tell if a polygon is colliding with another polygon?
Polygons don’t have a set radius or a set width and height so we can’t use the previous methods. Let’s take a look at some polygons that are colliding and see what we can tell about polygon collisions. From this image you can see that if a convex polygon is colliding then at least 1 of the corners (vertices) is inside the other polygon.
How to edit a polygon in ArcGIS Desktop?
1 Select the polygon. 2 Set the task to Cut Polygon Features. 3 Click the Sketch tool . 4 Right-click the line and click Replace Sketch. This lets you see the line’s vertices and segments as an edit sketch. 5 Finish the sketch (you can press F2 so you don’t inadvertently add more segments to the sketch when you finish it). The… More