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AnimalBuster Part 2 - Create a Bullet

Overview​

You will build an interactive VR shooting game using XRCC in this tutorial. Please go through Animal Buster part 1 before this tutorial.

Step 1: Spawn the Bullet​

  1. Open the Asset Panel:
    • Navigate to the 3D Model category.
  2. Find the Bullet Model:
    • Locate the Bullet model and spawn it at the World Center.
  3. Set Bullet Attributes:
    • Enable the following attributes:
      • Interactable
      • Physics
      • Use Gravity
    • Lock the bullet's rotations.

Step 2: Define Variables​

  1. Open the Behavior Tab:
    • Click on the Variable Panel.
  2. Create a Boolean Variable:
    • Define a boolean variable named Load.
    • Set the default value to false.

Step 3: Create Bullet Actions​

  1. Go to the Groups Tab:
    • Define two new actions:
      • Load Bullet
      • Shoot Bullet
  2. Load Bullet Action:
    • Click on the Load Bullet action to open its behavior.
    • Drag the following nodes:
      • Set Position (from Motion section)
      • Vector3 (from Math section)
    • Set the bullet position to 0, 1.2, 1 (the position of the slingshot pad).
    • Drag the following nodes:
      • Set Static (from Physics section)
      • Wait for (from Flow Control section)
    • Set the wait time to 0.1 seconds.
    • Change the bullet state to static, then non-static after 0.1 seconds.
    • Drag a Set Boolean node from the Variable section to set the Load variable to true.

Step 4: Setup Slingshot Pad Behavior​

  1. Go to the Slingshot Pad Behavior:
    • Define a Position Cache vector variable to store the position of the slingshot pad for distance calculations.

Step 5: Create Shoot Bullet Action​

  1. Return to the Bullet Behavior:
    • Select the Shoot Bullet action.
  2. Set Conditions for Shooting:
    • Use a Branch node (from Flow Control section) and a Get Boolean node (from Variable section) to check if the bullet is loaded.
  3. Add Force to Bullet:
    • Drag an Add Force node from the Physics section and set it to Close Relative.
    • Use Get Vector3 to fetch the PositionCache variable from the Slingshot Pad.
    • Subtract the bullet's position from the slingshot pad's position using Vector3Subtract (from Math section).
    • Scale the resulting force using the Multiply node (from Math section) with a factor of 20.
    • Connect this scaled force to the Force input of the Add Force node.
  4. Reset Load Variable:
    • Drag a Set Boolean node to set the Load variable to false after shooting.

Step 6: Update Position Cache​

  1. Return to the Slingshot Pad Behavior:
    • Select the Release the Slingshot action.
    • Use a Get Position node (from Variable section) to obtain the slingshot pad's position.
    • Update the Position Cache using a Set Vector3 node (from Variable section).
    • Finally, drag a Call Action node (from Flow Control section) and select the Shoot Bullet action.

Step 7: Create Load Bullet Button​

  1. Go to the Edit Tab:
    • In the Asset Panel, find the Special Object category.
  2. Create a Button Object:
    • Create a button object and rename it as Load Bullet Button.
    • Turn on Interactable.
    • Set the button text to Load and text size to 20.
    • Position the button at -1, 1.2, 0.5 and set rotation to 0, 180, 0.
    • Set the Action to Load Bullet.

Step 8: Create Bullet Holder​

  1. Create an Empty Cube:
    • Rename it as Bullet Holder to hold the bullet.
    • Turn on the following attributes:
      • Physics
      • Static
      • IsWall
    • Set the position of the Bullet Holder to 0, 0.3, 0.4.
    • Set the scale to 1, 1, 0.5.
    • Set the offset to 0, 0, 0.5.

Conclusion​

Congratulations! You've successfully created the bullet mechanics for the Animal Buster game. You can now load and shoot the bullet using the slingshot. Stay tuned for more tutorials!