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POCalculate circle coordinates in a sequential fashion
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  1. POCalculate circle coordinates in a sequential fashion
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    copied!<p>I need to have all point coordinates for a given circle one after another, so I can make an object go in circles by hopping from one point to the next. I tried the Midpoint circle algorithm, but the version I found is meant to draw and the coordinates are not sequential. They are produced simultaneously for 8 quadrants and in opposing directions on top of that. If at least they were in the same direction, I could make a separate array for every quadrant and append them to one another at the end. This is the JavaScript adapted code I have now:</p> <pre><code> function calcCircle(centerCoordinates, radius) { var coordinatesArray = new Array(); // Translate coordinates var x0 = centerCoordinates.left; var y0 = centerCoordinates.top; // Define variables var f = 1 - radius; var ddFx = 1; var ddFy = -radius &lt;&lt; 1; var x = 0; var y = radius; coordinatesArray.push(new Coordinates(x0, y0 + radius)); coordinatesArray.push(new Coordinates(x0, y0 - radius)); coordinatesArray.push(new Coordinates(x0 + radius, y0)); coordinatesArray.push(new Coordinates(x0 - radius, y0)); // Main loop while (x &lt; y) { if (f &gt;= 0) { y--; ddFy += 2; f += ddFy; } x++; ddFx += 2; f += ddFx; coordinatesArray.push(new Coordinates(x0 + x, y0 + y)); coordinatesArray.push(new Coordinates(x0 - x, y0 + y)); coordinatesArray.push(new Coordinates(x0 + x, y0 - y)); coordinatesArray.push(new Coordinates(x0 - x, y0 - y)); coordinatesArray.push(new Coordinates(x0 + y, y0 + x)); coordinatesArray.push(new Coordinates(x0 - y, y0 + x)); coordinatesArray.push(new Coordinates(x0 + y, y0 - x)); coordinatesArray.push(new Coordinates(x0 - y, y0 - x)); } // Return the result return coordinatesArray; } </code></pre> <p>I prefer some fast algorithm without trigonometry, but any help is appreciated!</p> <p><strong>EDIT</strong></p> <p>This is the final solution. Thanks everybody!</p> <pre><code> function calcCircle(centerCoordinates, radius) { var coordinatesArray = new Array(); var octantArrays = {oct1: new Array(), oct2: new Array(), oct3: new Array(), oct4: new Array(), oct5: new Array(), oct6: new Array(), oct7: new Array(), oct8: new Array()}; // Translate coordinates var xp = centerCoordinates.left; var yp = centerCoordinates.top; // Define add coordinates to array var setCrd = function (targetArray, xC, yC) { targetArray.push(new Coordinates(yC, xC)); }; // Define variables var xoff = 0; var yoff = radius; var balance = -radius; // Main loop while (xoff &lt;= yoff) { // Quadrant 7 - Reverse setCrd(octantArrays.oct7, xp + xoff, yp + yoff); // Quadrant 6 - Straight setCrd(octantArrays.oct6, xp - xoff, yp + yoff); // Quadrant 3 - Reverse setCrd(octantArrays.oct3, xp - xoff, yp - yoff); // Quadrant 2 - Straight setCrd(octantArrays.oct2, xp + xoff, yp - yoff); // Avoid duplicates if (xoff != yoff) { // Quadrant 8 - Straight setCrd(octantArrays.oct8, xp + yoff, yp + xoff); // Quadrant 5 - Reverse setCrd(octantArrays.oct5, xp - yoff, yp + xoff); // Quadrant 4 - Straight setCrd(octantArrays.oct4, xp - yoff, yp - xoff); // Quadrant 1 - Reverse setCrd(octantArrays.oct1, xp + yoff, yp - xoff); } // Some weird stuff balance += xoff++ + xoff; if (balance &gt;= 0) { balance -= --yoff + yoff; } } // Reverse counter clockwise octant arrays octantArrays.oct7.reverse(); octantArrays.oct3.reverse(); octantArrays.oct5.reverse(); octantArrays.oct1.reverse(); // Remove counter clockwise octant arrays last element (avoid duplicates) octantArrays.oct7.pop(); octantArrays.oct3.pop(); octantArrays.oct5.pop(); octantArrays.oct1.pop(); // Append all arrays together coordinatesArray = octantArrays.oct4.concat(octantArrays.oct3).concat(octantArrays.oct2).concat(octantArrays.oct1). concat(octantArrays.oct8).concat(octantArrays.oct7).concat(octantArrays.oct6).concat(octantArrays.oct5); // Return the result return coordinatesArray; } </code></pre>
 

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