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POC#: 2D sub-Tile Line intersection
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copied!<p>I have some problems getting an algorithm for my game to work and hope someone here can help me. Google didn't seem to be a good help as most solutions just work for full tiles.</p> <p>In the game units can occupy different positions inside a tile, i.e. they can be in the upper left corner, center, bottom right, ... position of tile (2/3), i.e. (2.2/3.1), (2.5/3.5), (2.8/3.9).</p> <p>If they move from position (2.2/3.1) to (5.7/4.1) i require a check to see if there is an obstacle in the path.</p> <p>My current algorithm is:</p> <ol> <li>Starting from (2.2/3.1)</li> <li>Calculate the angle of the movement (i.e. 70 degree)</li> <li>Move 0.1 steps in that direction</li> <li>Check which tile i'm on (floor(p.X)/floor(p.Y))</li> <li>Repeat from 2</li> </ol> <p>This algorithm works but to me it doesn't look very efficient as an obstacle can be only a full tile, not a part of a tile (units don't collide). If i increase the step size i begin to miss tiles that are only crossed slightly (i.e. you only cross the lowest left corner). Even with a step size of 0.1 it's still possible to miss an obstacle.</p> <p>I tried to find a solution to take the sub map (all tiles with the corners (floor(start.X)/floor(start.Y)) and (ceil(start.X)/ceil(start.Y)), move through every tile and check mathmatically if it gets crossed. Sadly i seem to lack the required math knowledge for this check.</p> <p>My last idea was to take all 4 borders of a tile as a line and do line-intersection but that seems to be slower than my original approach.</p> <p>Any hints?</p> <p>Thanks.</p>

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