Book Image

OpenGL 4 Shading Language Cookbook - Second Edition

By : David Wolff
Book Image

OpenGL 4 Shading Language Cookbook - Second Edition

By: David Wolff

Overview of this book

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, the language has been further refined to provide programmers with greater power and flexibility, with new stages such as tessellation and compute. OpenGL 4 Shading Language Cookbook provides easy-to-follow examples that first walk you through the theory and background behind each technique, and then go on to provide and explain the GLSL and OpenGL code needed to implement it. Beginner level through to advanced techniques are presented including topics such as texturing, screen-space techniques, lighting, shading, tessellation shaders, geometry shaders, compute shaders, and shadows. OpenGL Shading Language 4 Cookbook is a practical guide that takes you from the fundamentals of programming with modern GLSL and OpenGL, through to advanced techniques. The recipes build upon each other and take you quickly from novice to advanced level code. You'll see essential lighting and shading techniques; 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 including HDR rendering, bloom, and blur; shadowing techniques; tessellation, geometry, and compute shaders; how to use noise effectively; and animation with particle systems. OpenGL Shading Language 4 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.
Table of Contents (17 chapters)
OpenGL 4 Shading Language Cookbook Second Edition
About the Author
About the Reviewers

Tessellating a curve

In this recipe, we'll take a look at the basics of tessellation shaders by drawing a cubic Bezier curve. A Bezier curve is a parametric curve defined by four control points. The control points define the overall shape of the curve. The first and last of the four points define the start and end of the curve, and the middle points guide the shape of the curve, but do not necessarily lie directly on the curve itself. The curve is defined by interpolating the four control points using a set of blending functions. The blending functions define how much each control point contributes to the curve for a given position along the curve. For Bezier curves, the blending functions are known as the Bernstein polynomials.

In the preceding equation, the first term is the binomial coefficient function (shown in the following equation), n is the degree of the polynomial, i is the polynomial number, and t is the parametric parameter.

The general parametric form for the Bezier curve is then...