Drawing on 2D Textures using SetPixel: Drawing on left edge - also appears on right edge

Hey,

In my Project, I am trying to draw (inGame) on a Plane with this method:

Spoiler: Circle Method

Code (CSharp):

1. public void Circle(Texture2D tex, int cx, int cy, int r, Color col)
2.     {
3.         int x, y, px, nx, py, ny, d;
4.  
5.         for (x = 0; x <= r; x++)
6.         {
7.             d = (int)Mathf.Ceil(Mathf.Sqrt(r * r - x * x));
8.             for (y = 0; y <= d; y++)
9.             {
10.                 px = cx + x;
11.                 nx = cx - x;
12.                 py = cy + y;
13.                 ny = cy - y;
14.                 try
15.                 {
16.                     pixelArray[py * paper_width + px] = col;
17.                     pixelArray[py * paper_width + nx] = col;
18.                 }
19.                 catch (Exception e) { }
20.                 try
21.                 {
22.                     pixelArray[ny * paper_width + px] = col;
23.                     pixelArray[ny * paper_width + nx] = col;
24.                 }
25.                 catch (Exception e) { }
26.             }
27.         }
28.         tex.SetPixels32(pixelArray);
29.         tex.Apply();
30.     }

(with pixelArray = paper.getPixels32)

Now, when I draw a line (of Circles) to the left or right edge of the paper, the bit of the Circle that doesnt fit on the Paper appears on the right/left edge of the paper.
How can I stop that from happening?



When I draw to the upper/lower edges, it just gives an IndexOutOfBoundsException which is why I used try/catch and which is what I also want to happen for the left/right edges.

Any help is appreciated.

Regards, Claas M.

 

have you tried changing the clamping?

 

I tried

Code (CSharp):

1. paper.wrapMode = TextureWrapMode.Clamp;

, with no success.

 

well if there is no other easy solution suggested by others then I guess you are going to have to update your code which builds up the pixel array to perform this clamping

 

i briefly looked at you code and just noticed you redraw the entire texture array every time? Why are you not drawing only the area required for updating? ( unless its something ive overlooked and proves to be way to difficult or less optimal?)

 

i would think its better to cache the brush textures array and simply blit it onto the area concerned of the paper texture

 

I solved it using

Code (CSharp):

1. cx = Mathf.Clamp(cx, r, paper_width - r);

in line 3 of the method.
The problem is that the radius of the circle differs a lot so that wouldn't bring much performance. But maybe I will take a look at that. Anyway thanks for your help

 

glad you came right

 

Yah was going to say, because you are drwing to main memory, you were just drawing past the right edge of a row and the memory simply wraps around to the start of the next row, so you just needed to not draw outside the bounds of the image.