Collision detection bouncing problem c#

Question

So I got my collision detection working, but for some reason the player seems to go intro the ground 1 frame then jump out of it in the next frame and then fall down as its supposed to.

Code I use for the collision detection

        void DoCollisions()
    {
        onGround = false;
        Position.Y += Velocity.Y;
        Vector2 tileCollision = GetTileCollision();
        if (tileCollision.X != -1 || tileCollision.Y != -1)
        {
            onGround = true;
            Vector2 collisionDepth = CollisionRectangle.DepthIntersection(
                new Rectangle(
                    tileCollision.X * World.tileEngine.TileWidth,
                    tileCollision.Y * World.tileEngine.TileHeight,
                    World.tileEngine.TileWidth,
                    World.tileEngine.TileHeight
                )
            );
            Position.Y -= Velocity.Y;
            Velocity.Y = 0;
            Position.Y += collisionDepth.Y;

        }

        Position.X += Velocity.X;
        tileCollision = GetTileCollision();
        if (tileCollision.X != -1 || tileCollision.Y != -1)
        {
            Vector2 collisionDepth = CollisionRectangle.DepthIntersection(
                new Rectangle(
                    tileCollision.X * World.tileEngine.TileWidth,
                    tileCollision.Y * World.tileEngine.TileHeight,
                    World.tileEngine.TileWidth,
                    World.tileEngine.TileHeight
                )
            );
            Position.X -= Velocity.X;
            Velocity.X = 0;
            Position.X += collisionDepth.X;

        }
    }

    Vector2 GetTileCollision()
    {
        int topLeftTileX = (int)(CollisionRectangle.TopLeft.X / World.tileEngine.TileWidth);
        int topLeftTileY = (int)(CollisionRectangle.TopLeft.Y / World.tileEngine.TileHeight);
        int BottomRightTileX = (int)(CollisionRectangle.DownRight.X / World.tileEngine.TileWidth);
        int BottomRightTileY = (int)(CollisionRectangle.DownRight.Y / World.tileEngine.TileHeight);

        for (int i = topLeftTileX; i <= BottomRightTileX; i++)
        {
            for (int j = topLeftTileY; j <= BottomRightTileY; j++)
            {
                if (World.tileEngine.TileIsSolid(i, j))
                {
                    return new Vector2(i,j);
                }
            }
        }

        return new Vector2(-1,-1);
    }

Answer 1

Using just the Y direction as an example, at first glance it seems that you are adjusting Y twice, once before the collision check, then when you get a collision you revert the Y and push the object out by collisionDepth

You should probably not be reverting the Y , if the collisionDepth.Y indicates that you are intersecting the ground you should just push your object back by the depth amount, which would put you flush against the ground.

        if (tileCollision.X != -1 || tileCollision.Y != -1)
        {
            onGround = true;
            Vector2 collisionDepth = CollisionRectangle.DepthIntersection(
                new Rectangle(
                    tileCollision.X * World.tileEngine.TileWidth,
                    tileCollision.Y * World.tileEngine.TileHeight,
                    World.tileEngine.TileWidth,
                    World.tileEngine.TileHeight
                )
            );
            Velocity.Y = 0;
            // Depending on your coordinate system this should
            // be either + or - collisionDepth.Y
            Position.Y += collisionDepth.Y;
        }