CompilerPreprocessor

Introduction

This compiler is built to work best with the Closure Compiler, especially with ADVANCED_OPTIMIZATIONS turned on.

You'll find an example in the examples/compiler directory. This example utilizes code from the the WebGL framework J3D Preprocessor directives

At the top of Phong.glsl, you'll find a bit of header code for the preprocessor. This code is used to specify the name of the class we're generating as well as to include any library functions. Headers

//! NAMESPACE=J3D //! CLASS=PhongShader //! INCLUDE CommonInclude.glsllib //! INCLUDE VertexInclude.glsllib //! INCLUDE Lights.glsllib //! JSREQUIRE J3D.Constants //! JSCONST POINTSIZE J3D.Constants.PointSize

//! NAMESPACE=

The namespace of the generated class.

//! CLASS=

The name of the class to be generated.

//! SUPERCLASS=

The name of the super class to be generated. This field is optional and would have to taken advantage of by the template.

//! INCLUDE

INCLUDE will splat the code contained in the .glsllib file into this file. The optimization steps will then take care of removing any functions in this file but not used by the shader. By default, the compiler will only look in the same directory as the input glsl file for library files. To specify additional directories to look in, specify the --glsl_include_prefix flag.

NOTE: This doesn't support any sort of smart ordering yet. If you have file A include B which includes A, it will crash the compiler.

//! JSREQUIRE

JSREQUIRE will add a goog.require() statement to the top of the generated file with the class name specified. This is used mostly in conjunction with JSCONST

//! JSCONST

JSCONST allows developers to specify constants in JavaScript and use them from GLSL. Each shader will have

'#define ' + + '\n';

Added to the top of it. This is highly useful when sharing constants between GLSL and JavaScript without having to duplicate them. Sections

Throughout the compiler code, you'll find a few section headers.

//! COMMON, //! VERTEX, and //! FRAGMENT. These are used to change what code goes where between the two shaders.

//! COMMON

Code in the common section will go into both the vertex shader and the fragment shader. The default mode for a file is Common.

//! VERTEX

Code in the Vertex section will only go into the vertex shader.

//! FRAGMENT

Code in the Fragment section will only go into the fragment shader. Inheritance

The shader compiler provides the beginnings of support for inheritance. It supports the ability to override functions specified in libraries.

//! OVERRIDE

This will override the definition of with in all previous instances of the code, including libraries. OVERRIDE should only be used from the .glsl file, and not library files.

For example:

//! OVERRIDE luminance baseLuminance float luminance(vec3 c) { return baseLuminance(c) * 1.1; }

Templated Output

The compiler supports a templated output using mustache templates.

After all of the optimizations are performed, the ShaderProgram is fed into the mustache templating engine using the template specified with the --template flag.

You can find the default template here