Height Fields Using Shaders

Overview

This project involves creating an interactive 3D terrain visualization using OpenGL, derived from grayscale image data. Height fields are widely used in computer graphics for terrain rendering in simulations, video games, and data visualization. The program allows users to manipulate the terrain in real-time through rotations, translations, and scaling while offering various rendering modes and custom shader effects.

Key Features:

• Height Field Generation: Reads a grayscale JPEG image specified by the user, where pixel intensity values determine the terrain height.
• Real-Time Manipulation: Users can rotate, translate, and scale the terrain interactively using mouse and keyboard inputs.
• Multiple Rendering Modes: Supports rendering as points, lines, or solid triangles, each mode providing a unique way to visualize the terrain.
• Shader-Based Smoothing and Coloring: Implements a custom vertex shader that smooths the geometry and adjusts colors based on height, enhancing the visual quality.

Technical Details

Rendering Techniques

• Height Field Representation: Models the terrain using a 2D grid of points with height values derived from image pixel intensities.
• Rendering Options:
  • Points (key "1")
  • Wireframe lines (key "2")
  • Solid triangles (key "3")
• Smooth Terrain Rendering: A specialized mode (key "4") that smooths the terrain by averaging vertex positions with their neighbors directly within the vertex shader.

Vertex Shader Functionality

The custom vertex shader operates in two modes:

1. Basic Mode (`keys "1", "2", "3"): Handles standard vertex transformations without modifying the color, allowing for point, line, and triangle rendering.
2. Enhanced Smoothing Mode (`key "4"): Smooths the terrain by averaging vertex positions with their neighboring points and dynamically adjusts the terrain height and color using shader uniform variables.

Interactive Controls

• Keyboard Inputs:

  • 1: Render terrain as points.
  • 2: Render terrain as wireframe lines.
  • 3: Render terrain as solid triangles.
  • 4: Apply smoothing and adjust terrain color.
  • +/-: Adjust the height scaling factor.
  • 9/0: Adjust the exponent factor for height adjustment.

• Mouse Inputs:

  • Enables real-time interaction to rotate, move, and scale the terrain.

Additional Features

• Camera and Perspective: Supports dynamic perspective views and seamless camera control.
• Dynamic Vertex Coloring: Colors the terrain vertices proportionally based on their height, creating a visually striking representation of the landscape.
• Frame Capture for Animation: Captures frames to create animations showcasing the terrain transformations.

Getting Started

Prerequisites

• OpenGL Core Profile: Version 3.2 or higher is required for shader-based rendering.
• Platform Support:
  • Windows: Includes Visual Studio solution files.
  • MacOS: Requires Xcode command line tools.
  • Linux: Dependencies include libjpeg62-dev and libglew-dev.

Compilation and Execution

• Compile the code using the provided Makefiles or Visual Studio project files.
• Run the program by specifying the heightmap image, for example:

  ./hw1 heightmap/spiral.jpg