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GLSL Tutorial
Index
Introduction
The Graphics Pipeline
Pipeline Overview
Vertex Processor
Fragment Processor
OpenGL Setup for GLSL
Overview
Creating a Shader
Creating a Program
Source Code
Trouble Shooting: the InfoLog
Cleaning Up
Comm. OpenGL=> GLSL
Comm. Introduction
Uniform Variables
Attribute Variables
Shader Basics
Data Types and Variables
Statments and Functions
Varying Variables
Shader Examples
Shader Examples List
GLSL Hello World
Color Shader
Flatten Shader
Toon Shader
Toon Shader - Version I
Toon Shader - Version II
Toon Shader - Version III
Lighting
OpenGL Directional Light I
OpenGL Directional Light II
Directional Light per Pixel
Point Light Per Pixel
Spot Light Per Pixel
Simple Texture
Combine Texture + Fragment
Multitexturing
Notes
The gl_NormalMatrix
Normalization Issues
OpenGLTutorials @ Lighthouse3d.com
Led Shader
View Frustum Culling
GLSL Tutorial
Maths Tutorial
Billboarding Tutorial
Picking Tutorial
Terrain Tutorial
Display Lists Tutorial
GLUT Tutorial
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GLSL Tutorial
Toon Shading
Toon shading is probably the simplest non-photorealistic shader we can write. It uses very few colors, usually tones, hence it changes abruptly from tone to tone, yet it provides a sense of 3D to the model. The following image shows what we're trying to achieve.
The tones in the teapot above are selected based on the angle, actually on the cosine of the angle, between a virtual light's direction and the normal of the surface.
So if we have a normal that is close to the light's direction, then we'll use the brightest tone. As the angle between the normal and the light's direction increases darker tones will be used. In other words, the cosine of the angle provides an intensity for the tone.
In this tutorial we'll start with a version that computes the intensity per vertex. Then we will move this computation to the fragment shader. It will also be shown how to access OpenGL light's position.
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