Game Engine Architecture, 2nd Edition Overview Ch.1 part 2

Runtime Engine Architecture (section 1.6)?

This is where it delve into the different layers of systems and libraries that comprise the game engine, in my case, Unity.

Here’s a link to Figure 1.15 from the book:

http://www.gameenginebook.com/figures.html

The bottom four layers are dependent on the platforms your game will be running on.  Unity supports multiple platforms – meaning that under the hood, they use the drivers/SDKs so you can deploy your game on any of the platforms.

There isn’t much documentation regarding these layers from Unity.  I did read that Unity uses PhysX by NVIDIA for collision and physics.   It uses OpenGL for graphics…  Everything is nicely wrapped up in the Unity API.

https://docs.unity3d.com/ScriptReference/index.html

In Unity, the rendering engine is broken out into:

Camera: Cameras are components that display what a player will see.  It’s an imaging rectangle floating in your game scene.

Particle Systems: Particle Systems simulate motion using a lot of small 2D images, ie. clouds, fire, liquid.

Meshes: 3D Meshes are the main graphics primitive in Unity.  Unity doesn’t have a built-in modeling tool, but it supports .FBX, .dae, .3DS, .dxf and .obj files.  You can also import files directly from tools like Maya, 3D Studio Max,  Blender, …

For more details:

https://docs.unity3d.com/Manual/class-Mesh.html

Textures:  Textures are images (or movie files) that sit over your mesh.  Think of it as a vinyl wrapper over your car.

https://docs.unity3d.com/Manual/class-TextureImporter.html

Shaders: Shaders are scripts that have the math behind calculating the where and the color of each pixel rendered to your camera.  Unity provides built-in shaders and also lets you create custom shaders.

Here’s a great example of how you can use shaders to manipulate the color and vertices of your texture:

https://docs.unity3d.com/Manual/SL-SurfaceShaderExamples.html

Lighting:  In order to calculate the shading on a 3D object, Unity needs to know the intensity, direction, and color of the light that hits it.

I will be adding links to my posts detailing each topic here:

• Profiling and Debugging
• Collision and Physics
• Animation
• IO Devices
• Audio
• Networking
• Game Play (AI, Scripting…)