Back to General and Gameplay Programming

2D tile based collision

Jordan Singh · 2012-10-28T00:02:01

I have been seriously trying at this for just about a day now. Such as simple thing is creating big problems. I am trying to implement 2D tile based collision. All have failed. Should I create a algorithm that calculates the velocity to apply to the position (the velocity calculated by the algorithm will insure that the non-static (moving) entity will not hit solid tiles) or create a algorithm that calculates the position of the entity after the velocity has been applied to it (resulting in directly changing the position to ensure that it will not collide with another tile). All in all this is a generic question, how can this be done properly? (A real example of what I want to do is terraria's character movement). All replies are appriciated. Thanks, Xanather. Edit: One of the algorithms ive tried to implemented checks each velocity axis negativity/positivity and works along that. Edit 2: Entities have the same axis scale as the tiles (1, 1) would mean the player would be drawn at (16, 16) on the screen). [source lang="csharp"] Vector2 result = position + velocity; Vector2 nposition = new Vector2(position.X + velocity.X, position.Y); Vector2 topleft = new Vector2(nposition.X - (width / 2), nposition.Y - (height / 2)); Vector2 topright = new Vector2(nposition.X + (width / 2), nposition.Y - (height / 2)); Vector2 bottomleft = new Vector2(nposition.X - (width / 2), nposition.Y + (height / 2)); Vector2 bottomright = new Vector2(nposition.X + (width / 2), nposition.Y + (height / 2)); if (velocity.X > 0) { for (int y = (int)topright.Y; y < (int)bottomright.Y + 1; y++) { if (engine.main.tiles[(int)topright.X, y].solid) { result.X = (int)topright.X - (width / 2); break; } } } else if (velocity.X < 0) { for (int y = (int)topleft.Y; y < (int)bottomleft.Y + 1; y++) { if (engine.main.tiles[(int)topleft.X, y].solid) { result.X = (int)topleft.X + 1 + (width / 2); break; } } } nposition = new Vector2(position.X, position.Y + velocity.Y); topleft = new Vector2(nposition.X - (width / 2), nposition.Y - (height / 2)); topright = new Vector2(nposition.X + (width / 2), nposition.Y - (height / 2)); bottomleft = new Vector2(nposition.X - (width / 2), nposition.Y + (height / 2)); bottomright = new Vector2(nposition.X + (width / 2), nposition.Y + (height / 2)); if (velocity.Y > 0) { for (int x = (int)bottomleft.X; x < bottomright.X + 1; x++) { if (engine.main.tiles[x, (int)bottomleft.Y].solid) { result.Y = (int)bottomleft.Y - (height / 2); } } } else if (velocity.Y < 0) { for (int x = (int)topleft.X; x < topright.X + 1; x++) { if (engine.main.tiles[x, (int)topleft.Y].solid) { result.Y = (int)topleft.Y + 1 + (height / 2); } } } return result;[/source]

General and Gameplay Programming Programming

Started by Xanather October 21, 2012 08:29 AM

9 comments, last by Inferiarum 11 years, 5 months ago

Inferiarum

739

October 28, 2012 12:02 AM

There is an article describing a relatively simple collision detection technique which can deal with high speed objects:

http://www.wildbunny.co.uk/blog/2011/03/25/speculative-contacts-an-continuous-collision-engine-approach-part-1/

There is also code which i guess uses this method but I did not look into it:

http://www.wildbunny.co.uk/blog/how-to-make-a-platform-game-source-code-options/

2D tile based collision

This topic is closed to new replies.

Popular Topics

Recommended Tutorials

2D tile based collision

This topic is closed to new replies.

Popular Topics

Recommended Tutorials

Reticulating splines