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Posted: **Wed Dec 02, 2015 1:48 am**

Disclaimer: This is all (PSEUDOCODE)

I have a Tile Map in an array like so

{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}

I then use a for loop to create an individual tile for each element in the array like so

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newTile(x,y)

Every tile has the same width and height and none of the tiles are moving.

While the player can move freely throughout the map without any fixed movement.

Now that I have covered some background I can continue with my actual problem. I'm having no issues detecting if there is a collision but with actually solving the collision and determining which side the collision was detected.

My current approach is similar to as follows

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if(colliding(player, tile))
    if(playerX + playerW >= tileX)
        return rightSide
    if(playerX <= tileX + tileW)
        return leftSide
    if(playerY + playerH >= tileY)
        return bottomSide
    if(playerY <= tileY + tileH)
        return topSide

Then I use what is returned and proceed to actually solve the collision.

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 if(checkSide() == rightSide)
     // What now???

The method that returns what side is being intersected doesn't work as intended. I also do not know how to resolve the collision. Which is why I ask How to resolve a collision between two rectangles in a 2D grid?

http://stackoverflow.com/questions/3403 ... -a-2d-grid

Posted: **Wed Dec 02, 2015 4:53 am**

I see you got this working according to Stack Overflow. But just in case I wanted to mention an alternative method, since checking x/y seems a messy approach.

All about the angles

Calculate the angle between your player character and the centre of the tile - let us assume XY

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angleInDegrees = math.atan2(TileY - PlayerY, TileX - PlayerX) * 180 / math.pi + 180

Then you can simply check

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if angleInDegrees > 30 and angleInDegrees < 130 then
    'TOP'
elseif angleInDegrees > 130 and angleInDegrees < 220 then
    'RIGHT'
...

The angle should range 0 - 360. You can take it from there

Posted: **Wed Dec 02, 2015 6:01 am**

You can try to resolve collisions by using the velocity of the player. For example, if the player collides with a wall and the player is currently moving to the right, then you have to resolve the collision to the left.

Posted: **Wed Dec 02, 2015 7:55 am**

If you only have rectangular collisions, look into Bump 3.0.

Posted: **Wed Dec 02, 2015 8:07 pm**

kbmonkey wrote:I see you got this working according to Stack Overflow. But just in case I wanted to mention an alternative method, since checking x/y seems a messy approach.

All about the angles

Calculate the angle between your player character and the centre of the tile - let us assume XY
Code: Select all
angleInDegrees = math.atan2(TileY - PlayerY, TileX - PlayerX) * 180 / math.pi + 180
Then you can simply check
Code: Select all
if angleInDegrees > 30 and angleInDegrees < 130 then
    'TOP'
elseif angleInDegrees > 130 and angleInDegrees < 220 then
    'RIGHT'
...
The angle should range 0 - 360. You can take it from there

I'm very intriqued by this approach and I'll try it later. Thank you!

Posted: **Wed Dec 02, 2015 8:08 pm**

micha wrote:You can try to resolve collisions by using the velocity of the player. For example, if the player collides with a wall and the player is currently moving to the right, then you have to resolve the collision to the left.

I also like that. I suck at thinking outside the box.

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