OpenGL 4.0 Shading Language Cookbook

OpenGL 4.0 Shading Language Cookbook

Overview of this book

The OpenGL Shading Language (GLSL) is a programming language used for customizing parts of the OpenGL graphics pipeline that were formerly fixed-function, and are executed directly on the GPU. It provides programmers with unprecedented flexibility for implementing effects and optimizations utilizing the power of modern GPUs. With version 4.0, the language has been further refined to provide programmers with greater flexibility, and additional features have been added such as an entirely new stage called the tessellation shader. The OpenGL Shading Language 4.0 Cookbook provides easy-to-follow examples that first walk you through the theory and background behind each technique then go on to provide and explain the GLSL and OpenGL code needed to implement it. Beginning level through to advanced techniques are presented including topics such as texturing, screen-space techniques, lighting, shading, tessellation shaders, geometry shaders, and shadows. The OpenGL Shading Language 4.0 Cookbook is a practical guide that takes you from the basics of programming with GLSL 4.0 and OpenGL 4.0, through basic lighting and shading techniques, to more advanced techniques and effects. It presents techniques for producing basic lighting and shading effects; examples that demonstrate how to make use of textures for a wide variety of effects and as part of other techniques; examples of screen-space techniques, shadowing, tessellation and geometry shaders, noise, and animation. The OpenGL Shading Language 4.0 Cookbook provides examples of modern shading techniques that can be used as a starting point for programmers to expand upon to produce modern, interactive, 3D computer graphics applications.

OpenGL 4.0 Shading Language Cookbook

Credits

About the Author

About the Reviewers

www.PacktPub.com

Preface

Free Chapter

Getting Started with GLSL 4.0

Introduction

Using the GLEW Library to access the latest OpenGL functionality

Using the GLM library for mathematics

Determining the GLSL and OpenGL version

Compiling a shader

Linking a shader program

Sending data to a shader using per-vertex attributes and vertex buffer objects

Getting a list of active vertex input attributes and indices

Sending data to a shader using uniform variables

Getting a list of active uniform variables

Using uniform blocks and uniform buffer objects

Building a C++ shader program class

The Basics of GLSL Shaders

Introduction

Implementing diffuse, per-vertex shading with a single point light source

Implementing per-vertex ambient, diffuse, and specular (ADS) shading

Using functions in shaders

Implementing two-sided shading

Implementing flat shading

Using subroutines to select shader functionality

Discarding fragments to create a perforated look

Lighting, Shading Effects, and Optimizations

Introduction

Shading with multiple positional lights

Shading with a directional light source

Using per-fragment shading for improved realism

Using the halfway vector for improved performance

Simulating a spotlight

Creating a cartoon shading effect

Simulating fog

Using Textures

Introduction

Applying a 2D texture

Applying multiple textures

Using alpha maps to discard pixels

Using normal maps

Simulating reflection with cube maps

Simulating refraction with cube maps

Image-based lighting

Applying a projected texture

Rendering to a texture

Image Processing and Screen Space Techniques

Introduction

Applying an edge detection filter

Applying a Gaussian blur filter

Creating a "bloom" effect

Using gamma correction to improve image quality

Using multisample anti-aliasing

Using deferred shading

Using Geometry and Tessellation Shaders

Introduction

Point sprites with the geometry shader

Drawing a wireframe on top of a shaded mesh

Drawing silhouette lines using the geometry shader

Tessellating a curve

Tessellating a 2D quad

Tessellating a 3D surface

Tessellating based on depth

Shadows

Introduction

Rendering shadows with shadow maps

Anti-aliasing shadow edges with PCF

Creating soft shadow edges with random sampling

Improving realism with prebaked ambient occlusion

Using Noise in Shaders

Introduction

Creating a noise texture using libnoise

Creating a seamless noise texture

Creating a cloud-like effect

Creating a wood grain effect

Creating a disintegration effect

Creating a paint-spatter effect

Creating a night-vision effect

Animation and Particles

Introduction

Animating a surface with vertex displacement

Creating a particle fountain

Creating a particle system using transform feedback

Creating a particle system using instanced particles

Simulating fire with particles

Simulating smoke with particles

Index

Customer Reviews

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Implementing diffuse, per-vertex shading with a single point light source

One of the simplest shading techniques is to assume that the surface exhibits purely diffuse reflection. That is to say that the surface is one that appears to scatter light in all directions equally, regardless of direction. Incoming light strikes the surface and penetrates slightly before being re-radiated in all directions. Of course, the incoming light interacts with the surface before it is scattered, causing some wavelengths to be fully or partially absorbed and others to be scattered. A typical example of a diffuse surface is a surface that has been painted with a matte paint. The surface has a dull look with no shine at all.

The following image shows a torus rendered with diffuse shading.

The mathematical model for diffuse reflection involves two vectors: the direction from the surface point to the light source (s), and the normal vector at the surface point (n). The vectors are represented in the following diagram...

OpenGL 4.0 Shading Language Cookbook

OpenGL 4.0 Shading Language Cookbook

Overview of this book

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OpenGL 4.0 Shading Language Cookbook

Implementing diffuse, per-vertex shading with a single point light source