'How to rotate a bidimensional byte array?

I have the need to rotate the data in a bidimensional square byte matrix in any degree (0~359)

My matrix is composed by a 16x16 byte square like this:

[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][7F][7F][7F][7F][7F][7F][7F][7F][00][00]
[00][00][00][00][00][00][7F][7F][7F][7F][7F][7F][7F][7F][00][00]
[00][00][00][00][00][00][7F][7F][7F][7F][7F][7F][7F][7F][00][00]
[00][00][00][00][00][00][7F][7F][7F][7F][7F][7F][7F][7F][00][00]
[00][00][00][00][00][00][7F][7F][7F][7F][7F][7F][7F][7F][00][00]
[00][00][00][00][00][00][00][00][7F][7F][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]
[00][00][00][00][00][00][00][00][00][00][00][00][00][00][00][00]

This matrix represents a collision map of an item in a game. The numbers in the matrix represents the height of each position in the game world to be used to determine collision with other objects in the game.

I need to be able to rotate this collision map (the matrix data), as the object in the game can be rotated.

Does anyone have any idea how I could accomplish this?

Thank you very much!

mathmatrixrotation


Solution 1:[1]

I was so amazed by Norman's answer that I had to share my badly written Python code here just to show how the calculation works well!

from math import sin,cos,floor
import os,time

height = 16
width = 16
angle = 0
# Because python is weird sometimes - https://stackoverflow.com/questions/2397141/how-to-initialize-a-two-dimensional-array-in-python
tmp= [ [0]*16 for i in range(16)]

#My bitmap is actually a sprite pattern
bitmap=[
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,1,1,1,1,1,1,1,1,1,1,1,1,0,0],
    [0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0],
    [0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0],
    [0,0,1,0,0,0,0,1,1,0,0,0,0,1,0,0],
    [0,0,1,0,0,0,1,1,1,1,0,0,0,1,0,0],
    [0,0,1,0,0,1,1,0,0,1,1,0,0,1,0,0],
    [0,0,1,0,0,1,0,0,0,0,1,0,0,1,0,0],
    [0,0,1,0,0,0,0,1,1,0,0,0,0,1,0,0],
    [0,0,1,0,0,0,0,1,1,0,0,0,0,1,0,0],
    [0,0,1,0,0,0,0,1,1,0,0,0,0,1,0,0],
    [0,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0],
    [0,0,1,1,1,1,1,1,1,1,1,1,1,1,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
    ]

while(angle < 6.2):
    os.system('clear') #replace clear with cls if OS == Windows
    for x in range (0,height):
        for y in range(0,width):
            rx =  cos(-angle) * x + sin(-angle) * y - (+0.5 - (0.5 * height)) * ( 1 - cos(-angle) - sin(-angle))
            ry = -sin(-angle) * x + cos(-angle) * y - (+0.5 - (0.5 * width))  * ( 1 - cos(-angle) + sin(-angle))
            if ( round(rx) >= 0 and round(rx) < width and round(ry) >= 0 and round(ry) < height):
                tmp[x][y]=bitmap[round(rx)][round(ry)]
            else:
                tmp[x][y]=0
        print("\r\n",end='')

    for x in range (0,height):
        for y in range(0,width):
            if (tmp[x][y]) == 0:
                print (".",end='')
            else:
                print ("1",end='')
        print("\r\n", end='')

    print(angle)
    angle = angle + 0.1
    time.sleep(.1)

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1

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