Shaders

Table of Contents

• Introduction
• How it works
• Available Uniforms
• Apply on a material

Introduction

In computer rendering, shaders provides a great way to customize rendering and make many special effects

This chapter will give general informations about how shaders work in Oxygen Engine

Readers are assumed to have fairly comfortable with the GLSL language (to use complex shaders)

Note

If you prefer to write simple shaders with minimal amount of code, take a look at the surface shaders chapter

How it works

Features:

• GLSL Compile time #defines with the define() functions
• On compilation error, the line and complete faulty shader source code are sent to the standard error

As Oxygen Engine is based on OpenGL, all shaders should be written using the GLSL language

However, there are some additional rule about shader:

• Your shader should not contain any version string #version xxx
  • The GLSL version will be chosen based on the OpenGL version used by the renderer

Apart those, your shader should be exactly like a standard GLSL one 🙂

Available Uniforms

• All uniforms filled from camera data
• All uniforms filled from material standard properties
• Any custom properties filled in the oe::scene::Material

Apply on a material

To apply the shader on a material, you need first to fill content of the Vertex and fragment stages then apply it on the material

oe::scene::Material& material = some_node.getMaterial();
auto shader = std::make_shared<oe::render::Shader>();
 
shader->setVertexShader("...");
shader->setFragmentShader("...");
 
shader->compile();
 
material.shader = shader;
 
// When running the shader, the uniform "my_uniform" will be available (if declared in the shader)
material.setProperty<glm::vec3>("my_uniform", glm::vec3(8.f, 3.f, 3.f));