Resolve Issues

Release 0.13.11

World pipeline double buffering (#37)

• Implement a double buffering mechanism for STPWorldPipeline. Generation is done in the back buffer while the renderer can still read from the front buffer. Therefore sync before rendering is no longer necessary.
• Fix the splatmap border seams by delaying splatmap generation until all chunks are loaded.
• Add a memory manager for STPWorldPipeline.
• Revamp the specification of STPWorldPipeline. See the documentation in source code for more details.

Configurable specular power (#38)

Now the scene pipeline allows user to specify specularity for Phong shading model. As Phong does not model roughness very well, our implementation simply linear interpolates between a user-specified range of shininess based on the roughness read from G-Buffer.

To reserve spaces for supporting more shading model in the future, the scene pipeline now allows specifying shading model at initialisation.

Automatic resource download (#42)

• Simplify the process of downloading additional resources not included in the commit, and provide a better way of tracking resource changes.
• Update README build instruction to reflect this.
• Remove unused functions from GLAD and only retain ARB and NV extensions.
• Bump stb_image.h to nothings/stb@5ba0baa.

General fixes and improvement

• Add two issue templates. (#46)
• Add version checking for SQLite library.
• Remove some unnecessary ${} for variables in if condition in CMake.
• Add a default constructor for STPBindlessTexture and STPBindlessBuffer.
• Replace use of std::optional<STPBindlessTexture> with STPBindlessTexture as now it can be constructed by default.
  • The same applies to use of STPBindlessBuffer.
• Make bindless texture and bindless buffer object default constructible.
• Make STPSceneLight and STPLightShadow default move constructible.
• STPDirectionalLight now take the shadow instance as an optional rather than a unique pointer, to avoid dynamic memory allocation.
• Improve STPCascadedShadowMap for better handling of move construction.
  • STPCascadedShadowMap can now be moved, and it will properly deregister the old instance from camera status callback and register the new one.
• Remove unnecessary buffer unmap call in destructor since GL does it automatically upon deletion of object.
• Add a clang-format document.
• Break some super super long codes into two lines.
• Change variable BaseVertex in STPIndirectCommand::STPDrawElement from uint to int to match the GL specification.
• Avoid repetitive evaluation of end iteration in STPWorldPipeline.
• Remove unused typedef STPLightIdentifier from STPScenePipeline.
• Add STPPitchedDeviceMemory as another smart device memory object.
• Convert encoding for README to UTF-8.