Computer Graphics: Definitions, Types & Evolution

TAKEAWAYS:

• Computer graphics is the art of creating visual content using computers, divided into 2D (flat images) and 3D (volumetric models).
• The evolution of hardware (GPUs, VR/AR) and software (rendering engines) has revolutionized realism in gaming and simulations.
• Raster graphics (pixel-based) and vector graphics (mathematical paths) are the two primary types, each suited for different applications.
• Graphics systems consist of hardware (DAC, frame buffer) and software (APIs like OpenGL, DirectX).
• Real-world applications include eSewa’s UI design, Daraz’s product visualization, and Ncell’s 3D animations in ads.
• Understanding DAC (Digital-to-Analog Conversion) is crucial for how images are displayed on screens.

1. Definition of Computer Graphics

Computer graphics is the study and practice of generating visual content using computers. It combines mathematics, art, and programming to create images, animations, and simulations.

Types of Computer Graphics

There are two main types:

1. Raster Graphics (Bitmap Graphics)

   • Represented as a grid of pixels (picture elements).
   • Used in photos, digital paintings, and screenshots.
   • Example: A JPEG image on your phone.

2. Vector Graphics

   • Represented using mathematical equations (lines, curves, shapes).
   • Scalable without losing quality.
   • Example: Logos (e.g., Daraz’s logo), SVG files.

graph LR
    A["Computer Graphics"] --> B["Raster Graphics"]
    A --> C["Vector Graphics"]
    B --> D["Pixel-based<br/>(Photos, Screenshots)"]
    C --> E["Math-based<br/>(Logos, Icons)"]

Real-World Example: eSewa’s UI

• eSewa uses vector graphics for its logo and icons (scalable for all devices).
• Raster graphics are used for background images (e.g., payment confirmation screens).

2. Evolution of Computer Graphics Technology

The field has evolved through hardware advancements (GPUs, VR headsets) and software improvements (rendering engines like Unity, Unreal Engine).

Key Milestones

Impact on Gaming (Exam Question Link)

• Realism: Early games (e.g., Pong) used simple 2D sprites, while modern games (Cyberpunk 2077) use ray tracing for lifelike lighting.
• Player Immersion: VR headsets (e.g., Meta Quest) use 3D tracking to simulate real-world interactions.

3. Graphics Systems: Hardware & Software

A graphics system consists of:

1. Hardware Components

   • CPU (Central Processing Unit): Executes instructions.
   • GPU (Graphics Processing Unit): Renders images (parallel processing).
   • DAC (Digital-to-Analog Converter): Converts digital signals to analog for display.
   • Frame Buffer: Stores pixel data before display.

2. Software Components

   • APIs (Application Programming Interfaces): OpenGL, DirectX (used in game engines).
   • Rendering Engines: Unity, Unreal Engine (for 3D animations).

graph TD
    A["Graphics System"] --> B["Hardware"]
    A --> C["Software"]
    B --> D["CPU/GPU"]
    B --> E["DAC & Frame Buffer"]
    C --> F["APIs<br/>(OpenGL, DirectX)"]
    C --> G["Rendering Engines<br/>(Unity, Unreal)"]

How DAC Works (Exam Question Link)

• DAC converts digital pixel values (0-255) into analog signals for monitors.
• Example: A pixel with RGB(255, 0, 0) is converted to a red analog signal.

4. Applications in Nepal & Worldwide

Worked Example: Daraz Order Queue Visualization

• Problem: Daraz needs to show order processing status (e.g., "Shipping," "Delivered").
• Solution: Use a progress bar (vector-based) with animated icons (raster).
• Implementation:
  • Vector: SVG for scalable progress bar.
  • Raster: PNG for delivery truck icon.

sequenceDiagram
    participant User
    participant Daraz
    User->>Daraz: Places order
    Daraz->>User: Shows progress bar (vector)
    Daraz->>User: Updates with raster icons (truck, package)

5. Exam Tip

• Define computer graphics clearly (art + science of visual content).
• Differentiate raster vs. vector (pixels vs. math).
• Explain DAC’s role in display systems (digital → analog conversion).
• Link evolution to gaming/real-world apps (e.g., Ncell ads, eSewa UI).
• For short-answer questions, memorize:
  • Types: 2D (flat), 3D (volumetric).
  • Hardware: CPU, GPU, DAC, frame buffer.
  • Software: OpenGL, DirectX, Unity.

Final Note: Computer graphics is everywhere—from Khalti’s transaction screens to Pathao’s ride animations. Mastering this unit helps in UI/UX design, game development, and simulations.