ShaderSystemDemo

The ShaderSystemDemo is a prototype in C++, which can dynamically compile any shader language into any renderer api.

The demo just displays a 2D quad on the screen, but with different colors for each vertex of the quad. More complex demos might follow soon.

Getting started

To start the demo application, you just need python and Visual Studio 2022. The VS solution is automatically generated by premake.

Clone the repo

git clone https://github.com/Cankar001/ShaderSystemDemo

Generate the VS solution

cd ShaderSystemDemo/Scripts && python Setup.py

Now you should see the solution file in the root directory of the project. Just open it and build either the Debug or Release build.

Supported platforms

Windows	Linux	MacOS	Android	IOS	Web
✓	X	X	X	X	X

Supported rendering APIs

OpenGL	Vulkan	DirectX 11	DirectX 12	Metal
✓	X	✓	X	X

How it works

By default, the demo will use OpenGL in combination with the GLSL demo shader. If you go into the Main.cpp file, you should see this function call:

Renderer::SelectRenderingBackend(RenderingAPIType::OpenGL);

If you change the enumeration, the shader system will automatically build the shader binary for the respective rendering backend in the background, this is the current mapping:

OpenGL:

• Shader source -> SPIRV binary
• Reflection on the SPIRV binary
• SPIRV binary can be used by OpenGL

Vulkan:

• Shader source -> SPIRV binary
• Reflection on the SPIRV binary
• SPIRV binary can be used by Vulkan

DirectX11/DirectX12:

• Shader source -> SPIRV binary
• Reflection on the SPIRV binary
• SPIRV binary -> HLSL binary
• HLSL binary is compiled again by the DirectX11 api.

Metal:

• Shader source -> SPIRV binary
• Reflection on the SPIRV binary
• SPIRV binary -> MSL binary
• MSL binary can be used by Metal

This pipeline is applied automatically, all you have to do is to select the rendering backend in the Main.cpp file.

Using HLSL instead of GLSL

Currently the default shader language is GLSL, but the system will work with HLSL shaders as well.

The current usage looks like this:

BufferLayout flatColorShaderLayout = {
	BufferElement("a_Position", ShaderDataType::Float3, false),
	BufferElement("a_TexCoord", ShaderDataType::Float2, false),
	BufferElement("a_Color", ShaderDataType::Float4, false)
};

// This loads the GLSL shader and the system knows the language based on the file extension
s_Data->Library->Load("assets/shaders/FlatColorShader.glsl", flatColorShaderLayout, true);

// So this would load the HLSL shader version
s_Data->Library->Load("assets/shaders/FlatColorShader.hlsl", flatColorShaderLayout, true);

The above example can be found in ShaderSystem/src/Renderer/Renderer.cpp.

Future improvements

If you take a look into the Main.cpp file, there you can see that the uniform buffers and also the vertex attribute layout are hardcoded.

This will also improve in the near future, as the current implementation already does a reflection on the shader source, so in the future there shouldn't be a manual creation of uniform buffers necessary.