Captain07 3 Posted February 2 Share Posted February 2 Hello, I'm working with circles (dxDrawCircle) recently and I need a function to check if the player's cursor is within a circle's sector (a button). Is there a function to do this? I found the isMouseInCircle function, but it's not enough. Any ideas? Link to post

MRmihailZH 1 Posted February 2 Share Posted February 2 (edited) use a triple check, first whether the cursor is in a large circle, then whether the cursor is in a small circle, and whether the cursor is in a triangle x, y - cursor coordinates x1, y1, x2, y2, x3, y3 - coordinates of the angles of the triangle the function returns true if the point x, y belongs to a triangle function getPosition(x, y, x1, y1, x2, y2, x3, y3) local k = (x1 - x) * (y2 - y1) - (x2 - x1) * (y1 - y) local m = (x2 - x) * (y3 - y2) - (x3 - x2) * (y2 - y) local n = (x3 - x) * (y1 - y3) - (x1 - x3) * (y3 - y) return ((k >= 0 and m >= 0 and n >= 0) or (k <= 0 and m <= 0 and n <= 0)) end Edited February 2 by MRmihailZH 1 Link to post

Zango 35 Posted February 2 Share Posted February 2 If you only want to see if the point is inside one of the circle's quadrants, it can be done really simple. If you want to check for any sector, I have made the following, where you define the sector from two angles. It would also be possible to define the sectors from vectors instead. local sx, sy = guiGetScreenSize( ) function isMouseInCircleSector(cx, cy, r, angleStart, angleEnd) local mx, my = getCursorPosition() if not mx then return end -- Relativise mouse position to circle center mx = mx * sx - cx my = my * sy - cy -- Convert angles to vectors local x1, y1 = r * math.cos(angleStart), r * math.sin(angleStart) local x2, y2 = r * math.cos(angleEnd), r * math.sin(angleEnd) return mx^2 + my^2 <= r^2 and -- Check if within radius -x1*my + y1*mx <= 0 and -- Check if counterclockwise to angleStart -x2*my + y2*mx > 0 -- Check if clockwise to angleEnd end Where: cx, cy = Circle center r = Circle radius angleStart = start of sector, in radians angleEnd = end of sector, in radians So as an example, here are the angleStart and angleEnd values for each quadrant 270, 0 - First quadrant 180, 270 - Second quadrant 90, 180 - Third quadrant 0, 90 - Fourth quadrant Hope it's useful 1 Link to post

Captain07 3 Posted February 2 Author Share Posted February 2 Thank you! I tested it and for some reason it's not working properly, did I mess something up? I wanted make it green when it's within the sector, otherwise red. -- 1st test if isMouseInCircleSector(sx/2, sy/2, 330, 0, 90) then dxDrawCircle(sx/2, sy/2, 330, 0, 90, tocolor(0, 255, 0, 255)) else dxDrawCircle(sx/2, sy/2, 330, 0, 90, tocolor(255, 0, 0, 255)) end -- 2nd test if isMouseInCircleSector(sx/2, sy/2, 330, 0, 180) then dxDrawCircle(sx/2, sy/2, 330, 0, 180, tocolor(0, 255, 0, 255)) else dxDrawCircle(sx/2, sy/2, 330, 0, 180, tocolor(255, 0, 0, 255)) end https://imgur.com/a/g6udD5L Link to post

Zango 35 Posted February 2 Share Posted February 2 You need to parse radians to it, like this isMouseInCircleSector(sx/2, sy/2, 330, math.rad(0), math.rad(90)) 1 Link to post

Captain07 3 Posted February 2 Author Share Posted February 2 Oops... thanks! Now it's working like a charm! 1 Link to post

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