Roar

Roar is my personal rendering engine. Hopefully it will support GL/GLES, Vulkan and Metal at some point :)

What is this about

A playground, where I have freedom of getting dirty and creative.

Platforms

• GLFW
  • MacOS
  • Linux
  • Windows (Eventually)
• Android
• iOS

Build

Roar can be built using CMake minimum version 3.6.

git clone --recurse-submodules https://github.com/abbaswasim/roar.git && cd roar && mkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Debug
make -j8

Roar conventions

Roar uses colum major matrices this means the following Matrix4 = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15] has 0, 1, 2, 3 as the first colum of the matrix and 3, 4, 5, 6 as the second. Origin of the matrix is at 12, 13, 14 which is also translation.

| 0 | 4 | 8 | 12 | | 1 | 5 | 9 | 13 | | 2 | 6 | 10 | 14 | | 3 | 7 | 11 | 15 |

To transform a vector using this matrix you have to post-multiply it

Matrix4 mvp;
Vector3 pos;

auto new_pos = mvp * pos;

If you pre-multiply position you will need to transpose the matrix to get the same result

auto same_as_new_pos = pos * mvpT;

Degrees vs Radians

There is no concept of degrees in Roar. You can only use radians. If any method is called with degrees the result will be wrong.

Order of euler angles

Roar uses NASA standard aeroplane conventions as described on page: Euler angles

• Coordinate System: right hand
• Positive angle: right hand
• Order of euler angles: heading first, then attitude, then bank (YZX)
  • heading=Y
  • attitude=Z
  • bank=X

To replicate a github actions build error locally

# First pull the Image where the issue is, something like
$ docker pull ghcr.io/catthehacker/ubuntu:runner-22.04

# Create a container from the image and run bash in it
$ docker run --rm -it --entrypoint bash <image_id_from_the_pulled_images>

# Install the required things:
$ sudo apt-get update && sudo apt install xorg-dev libglu1-mesa-dev cmake vim

# Build normally
$ cmake -H"." -B"build/ubuntu/Vulkan/Debug" -DCMAKE_BUILD_TYPE="Debug" -DROAR_RENDER_TYPE="Vulkan" -DROAR_BUILD_TESTS=1 -DROAR_BUILD_EDITOR=1
$ cmake --build "build/ubuntu/Vulkan/Debug" --config Debug -- -j4

Third party

Roar uses the following third party software as submodules. These come with their own licenses.

• [glfw] (https://github.com/glfw/glfw)
• [spdlog] (https://github.com/gabime/spdlog)
• [nlohmann] (https://github.com/nlohmann/json)
• [xxHash] (https://github.com/Cyan4973/xxHash)
• [CImg] (http://www.cimg.eu)
• [stb] (https://github.com/nothings/stb)
• [Vulkan Headers] (https://github.com/KhronosGroup/Vulkan-Headers)
• [MetalCPP] (https://developer.apple.com/metal/cpp/)
• [glslang] (https://github.com/KhronosGroup/glslang)
• [basis_universal] (https://github.com/BinomialLLC/basis_universal)
• [par] (https://github.com/prideout/par.git)
• [cgltf] (https://github.com/jkuhlmann/cgltf.git)
• [CTPL] (https://github.com/vit-vit/CTPL.git)
• [Dear ImGui] (https://github.com/ocornut/imgui.git)
• [SPIRV-Cross] (https://github.com/KhronosGroup/SPIRV-Cross.git)
• [gtest] (https://github.com/google/googletest.git)

License

The code is licensed under MIT.

Project web sites:

www.waZim.com