ECE433 — Computer Graphics

Coursework repository for ECE433 — Computer Graphics at the University of Thessaly. The repository covers raster graphics, antialiasing, scanline polygon filling, clipping, OpenGL/GLUT, 2D/3D transformations, lighting, texturing, culling, and a substantially extended final 3D scene project.

The main portfolio piece is Homework 3 / Project 3: Visiting a 3D House: a first-person OpenGL scene that grew beyond the assignment into a small modular rendering/game framework with hierarchical objects, hot-reloadable assets, dynamic lighting, textured models, transparent windows, a day/night cycle, NURBS terrain features, and multiple camera/view modes.

Quick overview

Area	What is included
Rasterization	Bresenham-style lines, Xiaolin Wu-style antialiasing, circles, filled circles, interactive drawing tools.
Polygon algorithms	Scanline polygon filling, RGB interpolation, Sutherland-Hodgman clipping, interactive polygon/clipping demos.
Transformations	Written 2D/3D homogeneous-coordinate transformation exercises and worked examples.
OpenGL scene work	Lighting, materials, texture mapping, culling, camera navigation, multi-viewport rendering.
Final project	A furnished, explorable 3D house and outdoor environment with a custom scene/object framework.

Standout project: interactive 3D house

The assignment asked for a 3D house or 3D space with transformations, modeling, hidden-surface removal, lighting, texture mapping, a moving camera, and a separate view-rendering program. This implementation goes much further:

• Hierarchical object system: Object supports parent/child composition, recursive transforms, polymorphic drawing through drawInternal(), and grouped scene objects such as rooms, furniture, lanterns, framed windows, and the full house.
• Display-list optimization: static objects can be compiled into OpenGL display lists, avoiding repeated expensive redraw setup for heavy geometry.
• Transparency pipeline: transparent objects are tracked separately and sorted relative to the camera before rendering, used for glass/window rendering and masked textures.
• Manager-based architecture: separate managers coordinate game state, window setup, input, lighting, materials, textures, assets, and global scene lifecycle.
• First-person camera: WASD movement, mouse-look or keyboard-look modes, optional flight mode, frame-rate-independent motion via delta time, fullscreen toggling, and an attachable flashlight.
• Dynamic lighting: global ambient light, multiple local lights, a camera-following flashlight, lantern/portal lighting, and a time-varying sun/moon system.
• Day/night environment: sun and moon objects orbit the scene while the sky color and light color update over time.
• Textured house and environment: floors, walls, posters, grass, stone, glass, Minecraft-style blocks, and imported/converted texture assets.
• Hot-reloadable assets: many pieces of furniture and scene objects are described in text files and loaded through a custom AssetLoader, so placement can be edited without recompiling.
• OBJ model support: Model loads external .obj geometry, including the detailed car model used in the garage scene.
• Procedural/NURBS geometry: a reusable SplineObject / NurbsCurve / NurbsSurface layer wraps GLU NURBS. It is used for the mountainous horizon and curved objects such as the garden hose.
• Two executable views: visiting3Dhouse provides the navigable first-person experience, while views presents orthographic/perspective floor-plan, roof, exterior, and rotating interior views.

Course contents

Handouts and recovered reports are collected under docs/handouts/ and docs/reports/. Homework 1 and Homework 3 use subfolders because they include multiple handout/supporting PDFs.

Path	Description
homework-1-rasterization-antialiasing/	Rasterization exercises: line drawing, antialiasing, circles, filled circles, OpenGL examples, pseudocode, the project handout, and antialiasing notes.
homework-2-polygon-fill-clipping/	Polygon filling, color interpolation, 2D/3D transformation theory, Sutherland-Hodgman clipping, an interactive gradient polygon filler, and an interactive polygon clipping tool.
homework-3-3d-house/	Lighting/texturing/culling lecture examples plus the final 3D house simulation in final-3d-house/.
docs/images/	Selected final-project screenshots used by this README.

Homework details

Homework 1 — Rasterization and antialiasing

Homework 1 starts with lower-level raster graphics algorithms before moving to interactive OpenGL programs.

Implemented/reported work includes:

• Bresenham-style line drawing.
• Xiaolin Wu-style antialiased line drawing.
• Circle and filled-circle rasterization.
• Object storage for interactive drawing.
• Mouse-driven point/line/circle creation.
• Keyboard-controlled drawing color and mode selection.

Useful paths:

• docs/handouts/homework-1-rasterization-antialiasing/project-handout.pdf
• docs/reports/homework-1-rasterization-antialiasing-report.pdf
• docs/handouts/homework-1-rasterization-antialiasing/antialiasing-notes.pdf
• homework-1-rasterization-antialiasing/exercise-4-antialiased-lines/
• homework-1-rasterization-antialiasing/exercise-5-circle-drawing/

Homework 2 — Polygon filling, transformations, and clipping

Homework 2 combines written transformation/clipping exercises with two interactive OpenGL implementations.

Implemented/reported work includes:

• Scanline polygon filling using an active-edge table/list.
• RGB color interpolation along polygon edges and across scanlines.
• Sutherland-Hodgman polygon clipping pseudocode and worked examples.
• Interactive polygon input with per-vertex colors.
• Interactive clipping-window selection and polygon clipping.
• Optional fill toggling for clipped polygons.

Useful paths:

• docs/handouts/homework-2-polygon-fill-clipping.pdf
• docs/reports/homework-2-polygon-fill-clipping-report.pdf
• homework-2-polygon-fill-clipping/exercise-11-gradient-polygon-fill/
• homework-2-polygon-fill-clipping/exercise-12-interactive-polygon-clipping/

Homework 3 — Visiting a 3D house

Homework 3 is the final project and the deepest implementation in the repository. It contains lecture/lab examples for lighting, texturing, culling, and camera movement, then the full 3D house simulation.

Useful paths:

• docs/handouts/homework-3-3d-house/project-handout.pdf
• docs/reports/homework-3-3d-house-report.pdf
• homework-3-3d-house/final-3d-house/src/
• homework-3-3d-house/final-3d-house/assets/
• homework-3-3d-house/final-3d-house/textures/

Build and run

The final project is a C++/OpenGL/GLUT project. A normal Linux OpenGL/X11 development toolchain is recommended.

On Debian/Ubuntu-like systems:

sudo apt install build-essential freeglut3-dev libglew-dev libgl1-mesa-dev libglu1-mesa-dev libx11-dev

Build the final project:

cd homework-3-3d-house/final-3d-house/src
make clean
make all -j"$(nproc)"

Run the first-person simulation from the final-project root so asset paths resolve correctly:

cd ..
target/linux/visiting3Dhouse .

Run the multi-view renderer:

target/linux/views .

If mouse warping is blocked by your window manager, build with keyboard-only camera rotation:

cd homework-3-3d-house/final-3d-house/src
make clean
make all -j"$(nproc)" USE_MOUSE=0

Controls for visiting3Dhouse

Action	Mouse-look mode	Keyboard-look mode
Move	W, A, S, D	W, A, S, D
Fly up / down	Space / Z	Space / Z
Look around	Mouse movement	I, J, K, L
Toggle flight mode	F	F
Toggle flashlight	E	E
Reload text assets	R	R
Toggle fullscreen	F11	F11
Quit	ESC or Q	ESC or Q