Changelog

- 0.6.0
  - Updated versioning system and build process. Each library now maintains its own version (and potentially changelog at some point).
    - New version format is MAJOR.MINOR.PATCH.BUILD-REVISION. This will allow for greater versioning control and patching to minor versions.
    - Only 0.6+ will follow this, older versioning will stay as it is.
  - Removed a trace warning about early memory allocations.
  - Branching strategy is changing. 
    - Branch names will be based on version using the format "vMAJOR.MINOR.PATCH". Ex: v0.6.0
    - Development will continue to happen in feature branches, but those will be branched from version branches. 
    - When complete, feature branches will merge into version branches.
      - Ex: feature/terrain_chunking is branched from v0.6.0. When complete, feature/terrain_chunking is merged into v0.6.0. feature/terrain_chunking is then deleted.
    - Version branches will be merged into main as they are completed. A tag is then created on the main branch. 
      - Release cycles (when they happen) will follow this.
    - Changelog will list all changes under a minor version (i.e. 0.6.0) unless a later patch is made.
      - If a patch update is made, new notes would appear under that patch version (i.e. 0.6.1, 0.6.2, etc.).
  - All libraries (as of now, engine, plugin_audio_openal, standard_ui, testbed_lib and vulkan_renderer) now maintain their own versions.
    - NOTE: The engine version is the one used to denote primary releases, this changelog, etc. since plugins, etc. may not have updates between versions.
    - The build process now generates a file for each library: <assembly-folder>/src/<assembly-name>_version.h. Ex: engine/src/engine_version.h.
    - Each library includes its version file and now reports version to the console during its initialization.
  - versiongen utility has been updated to accept a filename parameter instead of major/minor versions. The build process passes "<assembly-folder>/version.txt".
    - version.txt is read in its entirety (up to 10 characters) and is used to define the major, minor, and patch. Ex: "0.6.0". This is then prepended to the generated build-revision to complete the format listed above.
  - Added terrain chunking support.
  - Fixed an issue with darrays that could cause invalid header data in certain scenarios.
  - Updated simple scene query functions to take pointers to arrays of geometry render data to account for array resizes if needed.
  - Fixed extents generation for terrain chunks, which fixes improper frustum culling issue.
  - Fixed a bug where shader scopes weren't being bound properly in the scene pass, causing debug objects to render all over the place.
  - The scene is now only queried once for geometry to be used with all shadow map cascades, as opposed to once per cascade.
  - Removed "wireframe" shader config property and replaced it with "supports_wireframe". See next entry for details.
  - Added the ability to have a wireframe mode, if supported, in a shader. This creates a separate set of pipelines that are used when this 
    mode is selected.
  - Added a RENDERER_MODE_WIREFRAME, which will enable wireframe for certain shaders when swapped to.
    - macOS: Note that, in order to support wireframe mode in macOS the newest (at the time) Vulkan SDK 
      must be used (1.3.275).
  - Fixed an issue where ksort would segfault while trying to access a negative array index.
  - Added "skirt" geometry to terrain sides in an effort to plug holes in transitions between chunks.
  - Vulkan Renderer performance updates (see Vulkan Plugin Changelog).
  - To facilitate the above, several areas of logic that previously required a separate command buffer and queue wait have had thier work offloaded
    to the beginning of the next frame. This reduces waits and more efficiently batches workload to the GPU.
  - The core engine frame lifecycle now has a slightly altered sequence of events. The new cycle is as follows (only changed section is listed):
    - After resize detection, renderer_prepare is called, which can cause the renderer to wait for resource regeneration if needed. Otherwise:
    - renderer_begin is now called in the main engine loop instead of by the application. This makes the renderer begin its current command buffer.
    - systems_manager_renderer_frame_prepare is called. All systems can now have a "frame_prepare" phase, which is optional. Only standard_ui uses this for now. This is to allow updates which need GPU uploads to occur before the rest of the frame workload begins.
    - The application instance recieves a call to its prepare_frame.
      - In testbed, this calls a new function in simple_scene for prepare_frame, which handles any GPU uploads before the rest of the frame workload begins.
    - renderer_end ends the renderer's current command buffer. This is now called from the main engine loop instead of the application.
    - renderer_present presents the current drawn-to attachment to the screen. This is now called from the main engine loop instead of the application.
  - Added missing "peek" function to stack container.
  - Fixed an issue with the sui_label_control where pending data didn't include new vertex/index buffer offsets during an update.
  - Created specialized rendergraphs for Forward rendering, one for the Editor (currently lives in TestBed) and one for Standard UI.
  - Added job ids, and job dependencies that can be used to link jobs one after another.
  - Added semaphores.
  - Updated job system to use semaphores to block worker threads until there is work to be done. Semaphores are signaled when work is deployed to a job thread.
  - Added threadpool, worker threads and setup layered texture loading to use them.

- 0.5x
  - Added Physically-Based Rendering (PBR) material type support.
  - Fixed an issue with pulling the default checkerboard texture when already using a default texture (i.e normal, spec, ao, etc.).
  - Added in partial descriptor binding support in Vulkan backend to allow for uniform descriptor aliasing.
  - Modified material system to handle PBR properties.
  - PBR materials are now required on terrains. Phong will not work.
  - Added default cubemap, metallic, roughness and AO textures to texture system.
  - Added query to texture system to indicate if a given texture is a one of the default textures.
  - Adjusted material system to globally track an irradiance cubemap for IBL.
  - Renamed clock to kclock to avoid collisions with standard library types.
  - Added function pointers to rendergraph_passes to get attachment textures and regenerate textures for self-owned attachments.
  - Added shadow maps with optional PCF filtering. A KVAR called "use_pcf" can be toggled 1/0 to turn this on/off.
  - Added dynamic shadow frustum generation.
  - Implemented generic quick-sort (see ksort.h).
  - Added queries to simple scene for getting mesh and terrain geometries using frustums.
  - Fixed various math bugs as they relate to frustum generation and use.
  - Added per-frame tracking of shadow map draw calls.
  - Added cascading shadow maps (right now limited to 4 cascades).
  - Fixed a bug in the Vulkan allocator where memory was not properly freed from a call to vulkan_alloc_reallocation if the reported size was 0, as per the spec.
  - Moved uniform sampler counts logic to renderer frontend to facilitate queries.
  - Removed all traces of defunct UI material type.
  - Removed Phong material type, shaders, etc. Entire material pipeline is now PBR.
  - Changed the way samplers work on the frontend and backend to allow for arrayed uniforms.
    - Shader config now requires specification of sampler type (sampler2D, samplerCube, sampler2DArray, etc.)
    - Shader config now allows for arrays of uniform types. Ex: sampler2D[4] specifies an array of 4 sampler2Ds.
  - Added array_index argument to shader uniform-setting functions to allow for setting arrayed uniforms. array_index is ignored for non-arrayed uniforms.
  - Changed nomenclature of "uniform index" to "uniform location".
  - Moved shader file parsing logic to frontend in preparation for #include directive logic.
  - Vulkan backend changes to allow not having any global/instance (one or the other) UBO and/or samplers.
  - Updated the API around local uniforms to require a bind/set/apply flow similar to the other scopes. 
  - Refactored Vulkan push constant logic to handle the above.
  - Added support for array textures. Converted shadow map pass to use them as attachments.
  - Changed PBR and terrain materials to use a "combined" map containing metallic in R, roughness in G and AO in B. Also wrote a conversion utility in tools for this.
    - As a result, explicit metallic, roughness and AO maps have been removed.
  - Terrains now combine maps from materials into a single array texture. This comes with the requirement that all terrain material maps be of the same size.
  - Refactored various Vulkan image loading logic to properly handle layered images.
  - Added ability to load layered textures in the texture system by passing a series of texture names and a layer count to a new function.
  - Fixed an issue with parsing directory from string where the resulting string was not zero terminated.
  - Fixed various obj/mtl loading issues and added conversions for new PBR map types.
  - Fixed an issue in the shadow map shader/pass where albedo textures were not being sampled (thus transparent materials weren't being taken into account).
  - Added a test tree model resource.
  - Point lights are now unaffected by directional shadow maps.

- 0.4x
  - Added first pass of Standard UI system, including panel, button, label, and textbox controls.
  - Removed ui_text and replaced with sui_label_control as part of the Standard UI system.
  - Moved DebugConsole to Standard UI.
  - Resolved several DebugConsole bugs, in particular ones involving commands and command history.
  - Modified the Windows build process to use incremental linking to speed things up.
  - Added cursor to textbox control. Fixed typing, backspace, delete and left/right navigation.
  - Added support for stencil buffers/stencil testing.
  - Added support for toggling keyboard key repeats on/off.
  - Added Standard UI clip masks.
  - Fixed various issues around Vulkan dynamic state feature detection.
  - Changed Vulkan backend to require dynamic pipeline state either natively (Vulkan 1.3+) or via extension (VK_EXT_extended_dynamic_state). If this plugin is not available, this backend won't work. This is because the engine requires several forms of dynamic state, potentially all at once, which would mean having a pipeline for each state _on top of_ per topology category, which was becoming unweildy.
  - Updated readme with build instructions and updated prerequisites.
  - Updated VSCode configuration to include new libraries' include paths.
  - Various tweaks to debug console to make it look/act nicer.

- 0.3x - Changelog started at this point to track change list. The major changes here are:
  - Fixed build process for both debug _and_ release builds, including a few required code changes.
  - Release builds now properly make no-ops out of KTRACE and KDEBUG log messages.
  - Release builds are now set to use O2 level compiler optimizations.
  - Debug builds are now set to use O0 level compiler optimizations explicitly (although -g did this informally already).
  - Removed all geometry logic and tracking from the renderer backend and correctly handle this in the frontend.
  - Moved geometry vertex and index buffers to the renderer frontend.
  - Removed the concept of geometry internal data, since it no longer has graphics API-specific data (and really never did).
  - Geometry itself now manages the concept of vertex/index buffer offsets.
  - Moved version console output to systems_manager, right after logging is instantiated so it appears at the top of the logs.
  - Overhauled the implementation of identifiers to now be a struct which holds a u64, generated by a newly Mersenne Twister random number generator. This new refactoring will also ease the process of (de)serialization.
  - Anything using a form of "unique id" should now be using the refactored identifiers.
  - Fixed scene unloading by handling this state in application_prepare_frame in testbed_lib.
  - Fixed a state checking issue in simple scene updates to trigger an unload and return if an unload has been requested.
  - Added device pixel ratio logic for Windows and macOS.
  - Added event handler for monitor changing on macOS. This helps capture DPI changes when switching monitors.
    
- 0.2x - Added audio plugin. Build versioning wasn't fixed yet, though, so this wasn't a readily visible
    change in version number. Also recieved a plethora of nondescript bugfixes and performance tweaks.

- 0.1x - Initial versions of the engine including all changes up to ~October 2023. Includes 
    basic functionality and some basic engine sub-systems.