rotating a 3x3 array
BlitzMax Forums/BlitzMax Programming/rotating a 3x3 array
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I have a 3x3 array which holds various templates for some level data:block[3, 3] The array just holds integers to represent wall, floor etc. which are copied into my level map. Before I copy the data into my level, I want to rotate it in increments of 90 degrees. I'm pretty sure there is a simple way of doing this but my maths is a little rusty. Does anyone know how to do this? |
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| I did this for a 15x15 grid array in my Guru Logic Remake. I had two arrays - one that held the data (map[]), and the other I used to actually rotate and display it (cmap[]). This is just a small portion of the code. There are probably a lot more efficient ways of doing it (bit-shifting? etc.) but it worked for me, first time. Every time you rotate by 90 degrees, update the "ROTATE" variable (+ or -). For x=0 To 15 For y=0 To 15 If rotated=0 cmap[x,y]=map[x,y] EndIf If rotated=1 cmap[x,y]=map[y,15-x] EndIf If rotated=2 cmap[x,y]=map[15-x,15-y] EndIf If rotated=3 cmap[x,y]=map[15-y,x] EndIf Next Next |
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This should work, although I don't have blitz with me to test.
n:int = 3 'dimension of square array
for x:int = 0 to n-1
for y:int = 0 to n-1
newArray[n-1-y, x] = block[x, y]
next
next
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| Thanks to you both - that's exactly what I was after :) |
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