meta4d-me/catdogengine

A cross-platform game engine/editor written in modern C++ (WIP)

catdogengine's Issues

[Terrain] Create Terrain Rendering Path

Currently we do not have a way to render terrain other than a demo one. This task captures all the effort to bring Terrain related rendering to this engine.

[shaderc] Not same standard for optimization

So a bgfx shader converted hlsl may fail to compile while converted glsl succeed to compile.

[PBR-Sky] The rest part of sky rendering

Atmospheric scattering is complete in #36 and i gathered informations from #2 and #39 to render the rest part of sky.

[Andriod] Automate android build

https://github.com/Nodrev/bgfx-android-activity

[Editor] SceneView is not correct after resizing window

[PBR-Sky] Rendering atmospheric light scattering

Light scattering is the basic thing to describe the color of the sky.

• Light scattering
  • elastic type - No energy lose. This is the type what we focus on.
  • Rayleigh scattering
    • particles diameter smaller than a value to simulate O2, NO2, CO2
    • affected by the light wavelength
    • blue skylight
  • MIE scattering
    • fog, halos around the sun, gray tones around the cloud
• Combine Rayleigh and MIE
  • Single Scattering
  • Multiple Scattering
• Precomputed atmospheric scattering
  • LUT generate tool
  • https://ebruneton.github.io/precomputed_atmospheric_scattering/demo.html
  • https://github.com/ebruneton/precomputed_atmospheric_scattering
• God Rays
  • halos from the sky to camera. Seems that only a simple post effect.
  • https://www.shadertoy.com/view/4dyXWy
• Reference
  • https://media.contentapi.ea.com/content/dam/eacom/frostbite/files/s2016-pbs-frostbite-sky-clouds-new.pdf
  • https://github.com/sebh/UnrealEngineSkyAtmosphere

[Mac] Build a mac version

[Editor] Create project file

A project should have a config file about:

• Working directory
• Project settings
• Serialization files about the whole world
  • SceneDatabase : done
  • Entities and Components : TBD

[Android] Modify makefile to build and test if it runs well

Based on my experience,

• make a build is OK as codes are almost 99% cross platform.
• shader may run differently.
• some features may not support in low end device, such as mrt.

If you are not familiar with CatDogEngine, build bgfx + sdl in android maybe easier for you to learn.

[Same code styles] ClangFormat

Codes/Performance/Memory Improvement

To improve coding details:

• define FORCEINLINE macro explicitly to force some methods to compile as inline.
• force all string hash to be executed in the compile time.
  • Only init logics will use runtime hash now.
• std::move -> MoveTemp similar to UE so that we can get static_assert if the parameter is a const or already rvalue.
  • Engine side needs to replace. But it will include many header files?

To adopt modern cpp features:

• C++ 20 std::span helps to reduce code size

To add basic infrastructure:

• add allocator classes to improve memory layout.
  • std::unique_ptr needs to write a customized deleter class for it to free memory by ourselves
• JobSystem to support multiple threads
• SIMD Math

[FrameGraph] Improve high level rendering usages

1.A resource manager holds every resource handles in bgfx. Any renderers can use string to find the expected one.
2.As RenderGraph talk said, I need to split resource compile stage away from render logic!

[PBRShader] add EmissiveMap calculation

[Particle System]

[Editor] Inspector

• Draw UI for different components
  • Camera/Light now
  • Property Data
    • [Min, Max]
    • Update intermediately after changes.
    • User friendly. For example, use angles to present quaternion for Transform::Rotation.
    • Accesses for ReadOnly / ReadWrite.

[Terrain] PBR Shader integration

Description

Integrate terrain with PBR shading as pointed out by Issue-47.

Success Criteria

• Terrain gets rendered with PBR lighting outlined in Issue-47

[Editor] Simple architexture editor to build door/wall/floor/...

[shaderc] error: initial value must be a literal expression

When compiling as hlsl, variables cannot be initialized outside the function with expressions that contain other variables.
For example:
float test = 0.5 is ok to compile in every case, but float test2 = test * test will cause an compile error in hlsl case.
I haven't tested all cases, but float test2 = test * test is ok to compile in glsl, spirv and pssl case.
What's worse is that even write float test = 0.5 and compile it to hlsl, the value of test is actually 0.

[Editor] Features overview

TODO:

• Settings
  • read/write/apply localization settings
  • keyboard hot key settings
  • editor user settings
• Styles
  • splash
  • dpi aware GUI to fit 2K, 4K, ...
  • multiple viewports
• Scene Edit
  • camera control in the scene view
  • select and pick mesh in the scene view
  • switch wireframe/shading without texture/shading with texture
• Rendering
  • optimize drawcalls -> one drawcall UI

[Light System]

[GI] Prepare for parsing GI probe data in a standalone render pass

[Animation System] Overview

• Asset Data

  • assimp has some animation data bugs on fbx file format : assimp/assimp#4620

• Runtime

  • Camera Animation
  • Vertex based Animation for Static Mesh
  • Morph Animation
  • Skeleton Animation for Skin Mesh

• References

  • OpenGEX SceneGraph
  • Skeleton Animation Basics
  • GDC 2017 Animation Bootcamp: The First Person Animation of Overwatch

[Editor] Adopt the need of LevelEditor APIs and standalone launch

Do it later as it has more work to do than I thought.

[GI] Research about integrations different GI SDKs

What we need to do in the engine side?
As bgfx doesn't support RTX, can we have another way to integrate them? And have a look at bgfx's status on RTX.

[Visual Studio] Natvis

I remember there is a way to describe what should show in the watch list. Forget its name...

[ECS] manage registered entites

How to manage them effeciently? If you just store all entites in the array, then you need to loop through its components by n * O(1) hashmap query to decide how it looks like?
Entt has a class Registry design which we can have a look.

[Editor] ResourceBuilder in multiple processes

#99

[Terrain] Sectorized train generation and rendering

Description

Current we only have one large terrain that's generated with the following parameters:

• Number of rectangles in the X-axis
• Number of rectangles in the Y-axis
• Width of each rectangle
• Depth of each rectangle
• Max depth for the entire terrain
• Up to 6 frequency parameters and their seeds for the Simplex2D function

With these parameters, we will generate a single mesh composed of many triangles with varying heights samples from Simplex2D noise function. This issue focuses on breaking these up into individual mesh with no seams in between. These sectors will only be sent to render if it's within the range of the viewing frustum.

Success Criteria

• Terrain generation is able to specify the dimension and the number of sectors.
• Each sector will retain the same number of parameters as the initial description.
• The TerrainRenderer will only send near-by meshes to render. Specifically it should be the ones intersecting with the view frustum.

[Terrain] Support CLOD Terrain

Description

Given the generated terrain meshes with their LOD, we need to support the picking of the right LOD at render time.

Success Criteria

• Terrain meshes have their LODs swapped in when they are far and swapped in when they are near.

[Build System] Remove cmake.exe from repo

It is for convenience to include cmake.exe and other things. Looks strange in the homepage about cmake 95%.

[Editor] ImGui multiple viewports

In general, it is a two direction conversion feature about ImGuiWindow <-> Window.

• ImGuiWindow
  • No hwnd. Just rendered quads.
  • No standalone SwapChain/RenderTarget. Shared by all ImGuiWindows.
  • Hard to process input preciously. SceneView logic is a mass.
• Window
  • Sure has hwnd.
  • Sure has standalone SwapChain/RenderTarget
  • Input logic is easy to handle. But take care focus/device get/lose cases.

[shaderc] variable in fragment shader seems optimized but actually used in bgfx shader language

fs_SingleScattering_RayMarching.sc
void main()
{
	vec3 rayStart = u_cameraPos;
	vec3 rayDir = normalize(v_worldPos.xyz);

        // lightDir was optimized here
	vec3 lightDir = normalize(-u_LightDir);
	
	// We assume that camera always in atmosphere.
	vec2 atmIntersection = RaySphereIntersection(rayStart, rayDir, _PlanetCenter, _PlanetRadius + _AtmosphereHeight);
	float rayLength = atmIntersection.y;

        // It is ok to put here
	// vec3 lightDir = normalize(-u_LightDir);

	// If ray intersect whith the earth.
	vec2 earthIntersection = RaySphereIntersection(rayStart, rayDir, _PlanetCenter, _PlanetRadius);
	if (earthIntersection.x > 0.0) {
		rayLength = earthIntersection.x;
	}
	
	vec3 inscattering = IntegrateInscattering(rayStart, rayDir, rayLength, lightDir);
	
	vec3 color = PostProcssing(inscattering, 0.0);
	gl_FragColor = vec4(color.x, color.y, color.z, 1.0);
}

[Editor] Basic scene edit

• ImGuizmo operations on entites
• Better visual controls
  • Wireframe
  • White color models
  • Switch IBL/PBR sky
• More entites to place in the scene
  • Light
  • Camera
  • ...

[Cloud]

[PBRShader] enable/disable IBL

[ShadowMap]

[Delegates] Support async, thread safe, ...

• CppCon 2017: Alfred Bratterud “Delegate this! Designing with delegates in modern C++”
• https://github.com/Armillus/Delegate
• https://simoncoenen.com/blog/programming/CPP_Delegates

[PBR] Move BgfxConsumer demo here and refine codes

• Review the implementation
• Refine codes in a generic way

[Unit Test] Use a better framework

Write a framework for tests? Or use google-test, ...

[Material System]

• Material template for all material types
  • default values

  Material CreateMaterial() {
      Material material;
      material.albedo = vec3(0.99, 0.98, 0.95);
      material.normal = vec3(0.0, 1.0, 0.0);
      material.occlusion = 1.0;
      material.roughness = 0.8;
      material.metallic = 0.2;
      material.F0 = vec3(0.192, 0.192, 0.192);
      material.opacity = 1.0;
      material.emissive = vec3(0.0, 0.0, 0.0);
      return material;
  }
  

• CatDogEngine PBR
  • Apply CDPBR's rules to Material template.
    • override values when material instance changes its config
      • BaseColor file path applied -> material.baseColor = SampleAlbedoTexture(...)
      • NormalMap file path applied -> material.normal = SampleNormalTexture(...)
      • it uses ORM -> support two cases
        • AO + RM
          • material.ao = SampleORMTexture(...).r
          • material.roughness = SampleORMTexture(...).g
          • material.metallic = SampleORMTexture(...).b
        • RM
          • material.roughness = SampleORMTexture(...).g
          • material.metallic = SampleORMTexture(...).b

[Physx]

[iOS] Build an iOS version

[Profiler] optick looks good. Need to integrate it.

[Make a Game project]

For a game engine, the best testing about performances and features is to make a game.

[Linux] Build a linux version

[Editor] FileSystem for AssetBrowser

• Show folder tree in the UI window
• Show images in the UI window
  • (Optional)Image in disk -> CPU memory -> bgfx::createTexture -> bgfx::TextureHandle -> uint16_t -> ImTextureID -> ImGui::Image
  • Model
    • Need to setup a simple Renderer to draw RTV and save as texture handle.
  • Texture
    • .tga / .png -> bgfx texturec -> .dds
    • .dds -> bgfx::createTexture -> bgfx::TextureHandle -> ...
  • Material
    • Need to setup a simple Renderer and setup a sphere/... to attach textures and save as texture handle.
  • ...

[Editor] Drag and drop support for ImGui child windows

Currently, I only added drag and drop in the SDL level to import assets conveniently.
It is better to drag and drop to different child ImGui windows.

[CubeMap] Import EnvMap workflow based on cmftStudio tool

[Editor] MRT displays its color image in scene view looks not correctly.

[RHI] New RHI except bgfx.

We want to avoid using bgfx as the only one RHI for this game engine. As bgfx is a compatiable RHI, not an advanced one.
So it has some works to remove dependencies from bgfx. And consider to use new RHI with same shaders from bgfx. Also, we are happy to try to reuse some codes in the rendering logic side.