Shader Programming Lecture Notes

Introduction

• Practical and visual approach to understanding shaders.
• Encouraging questions throughout the lesson.

What is a Shader?

• Shaders are code run on the GPU to render graphics.
• Essential for rendering graphics in modern games.
• Shaders define how graphics appear and sometimes how they move.

Basics of Shaders

• Shaders take parameters such as object position, mesh data, and surface appearance.
• They process these inputs to render visuals on the screen.
• Shaders are everywhere in games, performing a variety of functions.

Types of Shaders

• Vertex Shader: Processes each vertex's position in space. Transforms vertices from local space to clip space.
• Fragment Shader: Determines the color of each pixel. Outputs the final color to display on the screen.

Shader Structure

• Shader File: Contains properties and sub-shaders.
• Properties: Input data like colors, textures, and numbers.
• Sub-Shader: Can contain multiple passes; each defines rendering behavior.
• Pass: Contains the actual shader code to process vertex and fragment shaders.

Shader Code Basics

• Vertex Shader: Alters vertex positions and communicates data to the fragment shader.
• Fragment Shader: Outputs color, can blend textures, and apply effects.

Shader Development in Unity

• Unity uses HLSL (High-Level Shading Language) for writing shaders.
• ShaderLab: Unity's syntax for defining shader properties and organizing shader code.

Practical Examples

• Normal Maps: Adds surface detail without additional geometry.
• UV Coordinates: Maps 2D textures onto 3D surfaces.
• Transformations: Adjust color and texture mapping based on UV transformations.

Rendering Techniques

• Blending: Combines the source and destination colors. Examples: additive, multiplicative blending.
• Depth Buffer: Manages which surfaces are visible based on depth.

Advanced Shader Effects

• Refraction: Distorts background based on surface properties.
• Fresnel Effect: Highlights edges of surfaces based on viewing angle.
• Lighting Effects: Simulate realistic lighting and surface interaction.

Using Textures in Shaders

• Texture Sampling: Extracts color data from textures using UV coordinates.
• Mipmaps: Pre-computed texture levels for efficient rendering at various distances.
• Filtering: Blends texture data for smoother visuals.

Practical Assignments

• Create Shaders: Experiment with vertex and fragment shaders to create dynamic visual effects.
• Texture Mapping: Apply and manipulate textures on 3D models.
• Advanced Effects: Combine shaders and textures for effects like ripples, distortion, and patterns.

Conclusion

• Shaders are a powerful tool for creating visually compelling and optimized graphics in games.
• Understanding shaders enhances control over game visuals and can lead to innovative artistic effects.

Note: For further study, experiment with shader code provided during the lecture and explore Unity’s documentation on shaders.