update changelog

CHANGELOG.md

@@ -1,5 +1,102 @@
 ## Updates
 
+#### 21-Oct-2023
+
+The major topic of this update is the 'finalized' WebGPU support in sokol_gfx.h and sokol_app.h.
+
+- WebGPU samples are hosted here:
+
+  https://floooh.github.io/sokol-webgpu/
+
+- WebGL2 samples remain hosted here:
+
+  https://floooh.github.io/sokol-html5/
+
+- Please read the following blog post as introduction:
+
+  https://floooh.github.io/2023/10/16/sokol-webgpu.html
+
+- ...and the changelog and updated documentation in the sokol-shdc repository:
+
+  https://github.com/floooh/sokol-tools
+
+- You'll also need to update the sokol-shdc binaries:
+
+  https://github.com/floooh/sokol-tools-bin
+
+- Please also read the following new or updated sections in the embedded   sokol_gfx.h header documentation:
+
+  - `ON SHADER CREATION`
+  - `ON SG_IMAGESAMPLETYPE_UNFILTERABLE_FLOAT AND SG_SAMPLERTYPE_NONFILTERING`
+  - `WEBGPU CAVEATS`
+
+  Please do this especially when using any of the following texture pixel formats, as you will most likely encounter new validation layer errors:
+
+  - `SG_PIXELFORMAT_R32F`
+  - `SG_PIXELFORMAT_RG32F`
+  - `SG_PIXELFORMAT_RGBA32F`
+
+- There is a tiny breaking change in the sokol_gfx.h API (only requires action when not using sokol-shdc):
+
+  - the following `sg_sampler_type` enum items have been renamed to better harmonize with WebGPU:
+    - SG_SAMPLERTYPE_SAMPLE => SG_SAMPLERTYPE_FILTERING
+    - SG_SAMPLERTYPE_COMPARE => SG_SAMPLERTYPE_COMPARISON
+
+  - the enum `sg_image_sample_type` gained a new item:
+    - SG_IMAGESAMPLETYPE_UNFILTERABLE_FLOAT
+
+  - the enum `sg_sampler_type` gained a new item:
+    - SG_SAMPLERTYPE_NONFILTERING
+
+- The sokol_gfx.h struct `sg_desc` has two new items:
+  - `.wgpu_bindgroups_cache_size` - must be power-of-2, default: 1024
+  - `.wgpu_disable_bindgroups_cache` - default: false
+
+- sokol_gfx.h gained the following new public API functions to query per-frame information:
+  - `sg_frame_stats sg_query_frame_stats()`
+  - `void sg_enable_frame_stats(void)`
+  - `void sg_disable_frame_stats(void)`
+  - `bool sg_frame_stats_enabled(void)`
+
+  Frame statistics gathering is enabled after startup, but can be temporarily
+  disabled and enabled again via `sg_disable_frame_stats()` and `sg_enable_frame_stats`.
+
+- The sokol_gfx.h validation layer has new validation checks in `sg_make_shader()`
+  regarding image/sampler pair compatibility (WebGPU is particularly strict about
+  this stuff).
+
+- In sokol_app.h, the old wip WebGPU device and swapchain setup code is now implemented
+  in pure C code (previously this was a mix of Javascript and C).
+
+- Also note that sokol_app.h currently only supports WebGPU setup in the Emscripten backend.
+  If you want to use sokol_gfx.h with the WebGPU backend in a native scenario, you'll have
+  to use a different window system glue library (like GLFW). The sokol-samples directory
+  has a handful of examples for using sokol_gfx.h + Dawn + GLFW.
+
+- The following headers have been made compatible with the sokol_gfx.h WebGPU backend
+  (mainly by embedding WGSL shader code):
+  - sokol_debugtext.h
+  - sokol_fontstash.h
+  - sokol_gl.h
+  - sokol_spine.h
+  - sokol_imgui.h (also required some more changes for embedding `unfilterable-float`
+    textures, since these now require separate shader and pipeline objects)
+  - sokol_nuklear.h (works in WebGPU, but doesn't contain the work from sokol_imgui.h
+    to support `unfilterable-float` user textures)
+
+- sokol_gfx_imgui.h gained a new function `sg_imgui_draw_menu()` which renders a
+  menu panel to show/hide all debug windows. Previously this had to be done
+  outside the header.
+
+- sokol_gfx_imgui.h gained a new 'frame stats' window, which allows to peak into
+  sokol_gfx.h frame-rendering internals. This basically visualizes the struct
+  `sg_frame_stats` returned by the new sokol_gfx.h function `sg_query_frame_stats()`.
+
+- The sokol-samples repository gained 3 new samples:
+  - cubemap-jpeg-sapp.c (load a cubemap from seperate JPEG files)
+  - cubemaprt-sapp.c (render into cubemap faces - this demo actually existed a while but wasn't "official" so far)
+  - drawcallperf-sapp.c (a sample to explore the performance overhead of sg_apply_bindings, sg_apply_uniforms and sg_draw)
+
 #### 03-Oct-2023
 
 - sokol_app.h win/gl: PR https://github.com/floooh/sokol/pull/886 has been merged, this makes