I am new to Unity and programming in general, however, I wanted to know how to change a sprite's shape. I want to do this while the game is running, so I was thinking about removing a set of pixels given some condition after an event has happened and then adjusting the collider around the object. However, I don't know how to do this. I have searched in YouTube and Google but so far I have not found anything that is useful to me.
My first thoughts were to make the pixels in a sprite's texture transparent given a condition, and I was able to achieve this, but when the time came to translate the texture into the shape of the sprite I failed miserably. Then I thought about using meshes, but I think that meshes might be too hard on the engine and cause some slowdown. I want to make a digging game where I can dig through many different objects and those are my ideas thus far. If you think there are better ways or know of a place where I can learn or, ideally, were willing to give me some coding techniques in C# for achieving the above, I would be very grateful.

  • \$\begingroup\$ Have you considered using block based digging, in other words when you dig it removes some blocks from the scene (like Terraria or Starbound). \$\endgroup\$ Commented Feb 11, 2016 at 1:17
  • \$\begingroup\$ Yes :D, but i'd like it to be smoother, I don't like those blocky aspects, I'd like to make the terrain continuous. :) \$\endgroup\$
    – GuPe
    Commented Feb 11, 2016 at 1:21
  • \$\begingroup\$ Do you only ever dig open pits, or can the player tunnel horizontally? \$\endgroup\$
    – DMGregory
    Commented Feb 11, 2016 at 1:23
  • \$\begingroup\$ @DMGregory, he can tunnel horizontally, but I think that maybe if there is a script for digging open pits, maybe we could rotate the terrain ninety degrees and do it horizontally (?) I am not sure :P. \$\endgroup\$
    – GuPe
    Commented Feb 11, 2016 at 2:51
  • 1
    \$\begingroup\$ Are you sure you wanted to ask about modifying the shape of a sprite not "destructible obstacles/terrain in 2D game"? I think the title is misleading - you dont care how you achieve it, right? \$\endgroup\$
    – wondra
    Commented Feb 11, 2016 at 11:36

1 Answer 1


Then I thought about using meshes, but I think that meshes might be too hard on the engine and cause some slowdown.

Let me check my clock...yes, it is 2016, having 1 mesh shouldn't slow down anything.

What you need here is a tile based terrain (e.g. terraria) with marching squares. Marching squares is an algorithm, wich is made to smooth out 2d tile based terrain.

  • \$\begingroup\$ I researched Marching Squares, a really nice solution, but how do I make the mesh take on the form of an initial terrain image? Would I not need to subdivide the mesh into many different squares? \$\endgroup\$
    – GuPe
    Commented Feb 11, 2016 at 22:19
  • \$\begingroup\$ @GuachoPerez Yeah, you do need to have squares. I have found somewhere a nice tutorial about this, I try to find it. \$\endgroup\$
    – Bálint
    Commented Feb 12, 2016 at 6:46
  • \$\begingroup\$ Found it unity3d.com/learn/tutorials/projects/… \$\endgroup\$
    – Bálint
    Commented Feb 12, 2016 at 6:48
  • \$\begingroup\$ Alright, I implemented the code in the first and second videos but instead of randomly generating the cave, I used an image as a blueprint for the map(copying pixel by pixel into the integer map), it kind of slows down the game by a tiny bit, it is only a 100×100 image, is there a way around this? \$\endgroup\$
    – GuPe
    Commented Feb 12, 2016 at 23:37
  • \$\begingroup\$ @GuachoPerez Make sure to have as few I/O as possible. I'm not a unity progranner btw, I only like to go around and give tips for people about different algorithms. \$\endgroup\$
    – Bálint
    Commented Feb 13, 2016 at 1:18

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