Pendulums and More Shooting

Continuing on from last weeks work about shooting, we added a few modifications to the scene. The first addition was adding a cross hair so the player could see where they were going to hit when firing. Using the new Unity 5 UI system makes adding text and images to the UI incredibly easy. Rather than having to code the entire object in a script, you can add a canvas to the scene and place an object upon that canvas. For images just move it into the position you want and for text items, do the same them add the text in and even stylise it if needs be. So I placed the cross hair image dead center of the screen, adjusting my bullet spawner to fire at the same point upon clicking.

Cross hair in scene used to destroy block

The second thing added to my shooter this week was a bullet hole upon impact. In order to do this I had to use Ray Casts for the game to judge on whether an object would be hit upon firing. If this is found to be true then a bullet hole will be instantiated at the point of impact giving a more realistic affect to the scenery. To stop graphical glitches, the bullet hole is not applied directly onto the object it hits, but set as a quad 0.01 units in front of the collision point. This stops the created bullet hole and target object from fighting for the same world space and flickering when looked at by the player.

Bullet hole created by bullet collision

When this was all implemented however, I very quickly found that the holes stacked upon one another. On top of this, since they were just placed where there was a collision, if the object the bullet hits gets moved then the bullet hole is left floating in space. To solve the first problem I needed to destroy the bullet holes after a little while to stop them from filling up space, so created a script which waited for 3 seconds after being created, before destroying it. To stop floating holes I had to set the object getting hit as a parent of the bullet hole. This means wherever the object hit goes, the bullet hole will go with it.

Code to create bullet hole and set object collided with as parent

After we finished with the new shooting mechanics, we moved onto something new: pendulums. Making a pendulum was surprisingly quick and easy, since all you need to add to an object is a Rigidbody and a hinge joint. When applying the hinge joint you add the object that will be the connected body and that causes the two objects to act as a hinge. Adding multiple objects in a row and hinging each to the previous one creates a chain that we added a sphere to the end of. After creating a wrecking ball it only made sense to add a wall to knock down with it, which is exactly what I did.

Pendulums swinging to destroy wall