Alliance Engine

This project is a very basic 3D graphics engine with component based system for learning OpenGL and 3D computer graphics contents.

Controls

Camera Movement

W - Forward | LShift - Up

A - Left | LCtrl - Down

S - Right | WheelScrollY - Look Up/Down

D - Back | WheelScrollX - Look Left/Right

Toogle Polygon Mode

P - Toogles between Fill and Line PolygonMode

UI Display

Mouse Right Click - Toggles between displaying and not displaying the Hierarchy UI.

Architecture

Engine

Engine is the main class of the program, it controls the flow of the application.

Scene

The scene class has a list of all the active GameObjects and handles the components callbacks.

RenderPipeline

The RenderPipeline class maintains a reference to all the Renderers on the scene to draw them every frame.

ModelManager

ModelManager return references to Meshes and instantiates new ones only when needed (avoiding memory duplication on the GPU).

Component System

GameObject

Every object on the scene is a GameObject that can have components attached to it.

GameObjects have a transform, used to calculate translation, rotation and scale transformations and the model matrix.

Component

Components create behaviour through 3 callbacks:

• Start: Called when window is first loaded
• Update: Called Every frame before renderering
• Destroy: Called at window close

UI

We used Dear ImGUI dotnet wrapper to display and change the GameObject's transform data.

Supported Files

Shader

This engine supports only glsl shaders and they must be divided into two files (vertex and fragment).

3D Models

This engine supports only Wavefront (.obj) files and requires a .mtl file. You can have multiple objects in the same .obj with different materials, but they will share the same Mesh and model matrix.

Folder structure

Models

All the models must be included in this folder and must have a separate folder each in the following hierarchy:

Models/modelName/textures/ -> contains all the texture files

Models/modelName/modelName.mtl

Models/modelName/modelName.obj

Scripts

This folder contains all scripts in the project. The component classes are stored at /Component folder and the Alliance Engine code is stored at /Engine

Dependencies

• Silk.NET for window, input, OpenGL and dear ImGui.
• SixLabors ImageSharp for reading image files.