XNA 2D object collision (without Tiles/Grid) - vb.net

Question

First time posting here. Tried to look for topics previously to help.
I'm using Visual Basic, but so far I've been able to follow C# and just translate into VB.
I would like collision without tiles. Smooth movement without any sort of snapping. I already have the movement down, and my sprites stop at the edges of the screen.
I've read I could use Bounds and Intersects, which I have tried. When I apply an IF statement to the arrow keys each time they are pressed, using Bounds and Intersects (I just prevent sprite movement if it is intersecting), it works for ONE key. I move left into an object, and I stop. If I apply the IF to all keys, it will work the first time. Say I move left into an object, the IF statement checks if the Intersects is true or not and acts accordingly.
Now I want to move right, away from the object. I can't since my sprite is ALREADY colliding with the object, since each arrow key is programmed to NOT move if there is Intersection. I see perfectly why this happens.
The code I currently have: (Each arrow key has the same code, altered to it)
If Keyboard.GetState(PlayerIndex.One).IsKeyDown(Keys.Right) And rBlockBounds.X <=
graphics.GraphicsDevice.Viewport.Width - rBlockBounds.Width = True Then
If rBlockBoundBoxBounds.Intersects(rObstructBounds) Then
rBlockBounds.X += 0
rBlockBoundBoxBounds.X = rBlockBounds.X - 1
Else
rBlockBounds.X += 1
rBlockBoundBoxBounds.X = rBlockBounds.X - 1
End If
End If
rBlockBounds is my sprite As Rectangle
rBlockBoundBoxBounds is another Rectangle (1 pixle bigger than rBlockBounds) used as a Hit Box more or less that moves with rBlockBounds, and is the thing doing the collision checking
rObstructBounds is the stationary object that I'm moving my Sprite into.
Anyone have suggestions on how I can make this work?

Answer 1

Since I myself program in C#, not VB I can not code your solution but instead I can explain a better way of approaching it.
What you want to do is prevent the two rectangles from ever intersecting. To do this you will need to implement a move method into your code which can check if the two tiles are colliding. Here is a C# example:
public bool MoveX(float distance) // Move Player Horizontally in this example
{
rBlockBounds.X += distance;
if(rBlockBoundBoxBounds.Intersects(rObstructBounds)
{
rBlockBounds.X -= distance;
return false;
}
return true;
}
Which essentially means that if you run into an object you will be pushed out of it. Since it occurs in one tick you won't get any jutty back-and-front animations.
And that should do what you want. You can test this out and then implement it for y-coordinates as well.
Also, you might notice I've made the function return a bool. This is optional but allows you to check if your player has moved or not.
Note if you teleport an object into another one it will cause problems so remember to implement this every time you move anything.
But that should do what you want.
Edit
Note since your objects are not in a tiled grid, you will need to move lots of time in very small steps.
Something like this:
public bool MoveX(float distance) // Move Player Horizontally in this example
{
rBlockBounds.X += distance;
if(rBlockBoundBoxBounds.Intersects(rObstructBounds)
{
rBlockBounds.X -= distance;
return false;
}
return true;
}
public bool MoveX(float distance, int repeat)
{
for(int i=0; i < repeat; i++)
{
rBlockBounds.X += distance;
if(rBlockBoundBoxBounds.Intersects(rObstructBounds)
{
rBlockBounds.X -= distance;
return false;
}
}
return true;
}
Where the second one will take multiple steps. Here is why you would use it:
MoveX(500); // Will move 500 right. Could easily skip over objects!
MoveX(5, 100); // Will move 5 right one hundred times
// ^ This will take more time but will not skip object
Similarly for yours you could do this:
MoveX(3); // If contact object will be max 3 pixels away
MoveX(1, 3); // If contact object will be max 1 pixels away
MoveX(0.5f, 6); // If contact object will be max 0.5 pixels away
Now I am guessing all your x, y positions are integers. If so you could get away doing the second call and come exactly next to each other. If not you would do the third call.
Hope this helped.