scrappycocco / scrapengine

A very simple real-time Vulkan 3D game engine

An engine made of scrap code /s

Build command	Status
cppcheck

Description

I have always been passionate about game development and rendering, and I wanted to go deeper into it. With the arrival of Vulkan, I thought it was a good time to start learning how a game engine works. The development of his game engine started on July 2018, and at the beginning of August 2018 it was able to render the basic triangle. Since then I had to slow down for a few months because of University and its projects, but on August 2019 this repository has been made public with the release of the first working small game tagged as demo 1.

I followed mostly Alexander Vulkan tutorial and SaschaWillems Vulkan examples to understand the basics and to develop it.

It is a very simple game engine, made mostly to understand the basics of rendering and how to connect multiple parts between them (input-render-audio-physics).

It is not perfect and is not intended to be used in production, is a personal project made to study Vulkan, feel free to modify it if you want. If you have any question feel free to open an Issue.

How to build the engine

To see how to build the engine from the source code, please read the wiki page.

Known problems

Since it's a engine made from zero, the GameObject-Component structure is not perfect and may lead to bugs or errors involving transformations or rotation. Specially when moving the GameObject with multiple components or a GameObject and its children. This is known when the user try to rotate a RigidbodyComponent.

There may be other parts of the engine that do not work perfectly or as expected.

I will try to make it better and to fix all the issues about it.

What's next

I currently do not plan to keep working/updating this repository. I will not archive it and will leave it open to receive questions, pull requests or similar if anyone is interested in it.

Previous TODO list:

• Directional light and Shadow-Mapping;
• (Should improve Forward Rendering structure or move to Deferred Rendering before adding more lights);
• Omnidirectional light and Shadow-Mapping;
• [...?]

Special thanks

• SaschaWillems for all his Vulkan examples and for his suggestions on Discord;
• Charles for all his support during the whole development, helping me understanding where and what the problem was, and for all his help and suggestions;
• My friends frncscdf and davidepi for their suggestions and support;
• All the people in the Vulkan Discord server.

Vulkan FAQ

• How do you render multiple objects? How do you render the UI?
  • See the discussion on Issue#38.
• Resources to understand the basics of lights/shadows
  • See the discussion on Issue#40.

Download / Example gameplay gif

You can download this example game here.

Version #1 of the game: GIF.

Version #2 of the game:

scrapengine's Issues

Gameobject parent-child rotation have broken values

Every half circle (π) the rotation values change, in a wrong way
This need further investigation, since right now i have no idea where the error come from

Forward declarations

The engine is starting to have way too many includes, everything (possible) should be moved to forward declaration also for a fast compilation

How to link an external git repo as a library in github.

https://github.com/ScrappyCocco/ScrapEngine/tree/master/external

Here you have managed to link external repositories to your library folder. I would like to do the same thing too, could you tell me how you did it?

Assimp with vs2017

f:\projects\github\scrapengine\external\assimp\include\assimp\defs.h(53): fatal error C1083: Cannot open include file: 'assimp/config.h': No such file or directory

Doesn't compile out of the box for debug or release
Can't bulid the sample for obvious reasons - no engine

Use premake to make the engine development compatible across Windows and Linux

Premake can allow you to create setup for VS, CMake and more easily.

The engine may crash because the vector cleanup is not synced

There's a part of code that's not done right:
cleanup_meshes() is called in two different parts of the code: one in a thread and one into another thread, this probably can lead to errors and crashes.
The cleanup of the meshes vector must be checked and fixed to be safe with other parts of code that use this vector.

Port memory allocation to VulkanMemoryAllocator

The memory allocation is self-done and could not be perfect;
It's better to use GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator

The engine will be ported to use VulkanMemoryAllocator soon

How to render multiple objects to one image

I'm a newbie to vulkan, i read your code, but there is so many jump between the functions. The most one i cannot understand is that how to render multiple objects to one image, such as skybox,ball and the light.

Compile failed with VS2017

I followed your wiki, fisrt compile the external modules, it's all ok.But when compile the engine itself, there is too many errors:

It seems cannot find the standark lib of cpp, but i'm not famililar with VS.
There is also some errors like syntax error:

Rotations are broken

The parent-child relative rotation is broken, and must be fixed as soon as possible

About light module

Hello, i'm comeback again : )

Nowadays, i'm studying the light model.
Your engine are using the plane lights with a single light source, is right?
But what the principle to compute the shadow, any document will be helpful, thank you very much!