Jorijn van der Graaf
48aa9be5ce
Device::Initialize required twelve device extensions with no capability check. Mesa Turnip (Adreno) lacks six of them: VK_EXT_descriptor_heap, VK_KHR_shader_untyped_pointers, VK_EXT_device_fault and the three ray tracing extensions. vkCreateDevice failed there, so not even a UI-only program could start, although the UI path is compute-only and needs nothing else that Turnip is missing. The descriptor heap, ray tracing and device fault are now optional groups, detected at start-up from the extension list and the feature bits (Device::descriptorHeapSupported, rayTracingSupported, deviceFaultSupported). Ray tracing needs the heap; on a device without it the ray tracing entry points throw a message naming the cause. Without the heap the same bindless slots live in one update-after-bind descriptor set per frame, owned by DescriptorHeapVulkan: binding 0 storage images, 1 sampled images, 2 samplers, 3 storage buffers. Slot allocation, the slot handles, UIDispatchHeader and the UIRenderer API are unchanged; buffer slots simply stop being offset. Window::Render binds that frame's set where it binds the heap, every compute pipeline shares the heap object's pipeline layout, and push data travels as push constants. Each UI kernel is built twice from one source. ui-shared.glsl declares its resources through UI_HEAP_* macros that expand to descriptor_heap or, with CRAFTER_GRAPHICS_DESCRIPTOR_SETS defined, to set/binding. <name>.comp.spv and <name>.comp.sets.spv ship side by side and ComputeShader::Load picks one. The heap build of every shader is byte-identical to before. Breaking: - ComputeShader::Load takes the heap as a second argument. - DescriptorHeapVulkan is no longer copyable or movable. - Custom UI shaders declare heap resources with the UI_HEAP_* macros and are registered twice in project.cpp (see the README). - project.cpp uses Shader::defines and Shader::variant, so it needs a crafter-build that has them (Crafter.Build master, fe38cc1 or later). Also: - maintenance5 is enabled as a feature, not only as an extension: every VulkanBuffer already relied on VkBufferUsageFlags2CreateInfo. - Barrier stage masks drop RAY_TRACING_SHADER on devices without ray tracing, and ImageVulkan::Create resolves its default consumer stage to COMPUTE_SHADER there. - Window refuses a swapchain whose image count is not numFrames instead of writing past images[]. The limitation itself is #160. - CRAFTER_GRAPHICS_NO_DESCRIPTOR_HEAP forces the fallback on a driver that has the heap, so it can be exercised on a desktop GPU. Verified on an RTX 4090 in both modes under the validation layer, and on a Fairphone 6 (Turnip, Adreno 810, postmarketOS), where the fallback is the only path. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
285 lines
15 KiB
Markdown
285 lines
15 KiB
Markdown
# Crafter.Graphics
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Vulkan + WebGPU graphics library built around C++20 modules and
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bindless heaps. Provides window management, ray tracing, and a
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compute-shader-driven UI on a single, opinionated stack. Native
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builds use Vulkan with `VK_EXT_descriptor_heap` (the compute/UI path
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also runs without it, see
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[below](#drivers-without-vk_ext_descriptor_heap)); `wasm32-*` builds
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target the browser via WebGPU and a DOM window backend.
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## Backends
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Backends are chosen at build time by the target triple:
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| Target | Window | Renderer | Shaders |
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|---------------------|------------------------|---------------------|---------|
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| native Linux | Wayland | Vulkan (heap-bound) | GLSL → SPIR-V |
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| native Windows | Win32 | Vulkan (heap-bound) | GLSL → SPIR-V |
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| `wasm32-*` (any) | DOM (canvas + JS env) | WebGPU | WGSL (loaded at runtime) |
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The two backends share the same C++ surface for the high-level pieces
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(`UIRenderer`, `Mesh`, `RenderingElement3D`, `RTPass`, item structs,
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`FontAtlas`, `Image2D`, `ComputeShader`). Backend-typed pieces
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(`*Vulkan` vs `*WebGPU`) live behind `#ifdef CRAFTER_GRAPHICS_WINDOW_DOM`.
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Vulkan ray tracing is hardware (`VK_KHR_ray_tracing_pipeline`); WebGPU
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ray tracing is a library-built software path (BVH + traceRay in a
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compute pipeline composed from user-supplied WGSL stages). The WebGPU
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path supports triangle and AABB (procedural, `VK_GEOMETRY_TYPE_AABBS_KHR`)
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geometry, closest-hit / miss / any-hit / intersection shaders — see
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[examples/RTVolume](examples/RTVolume/README.md) for procedural spheres
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shaded through an intersection shader with an any-hit cut-out.
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> **Native RT status:** reading an acceleration structure through
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> `VK_EXT_descriptor_heap` aborts with `VK_ERROR_DEVICE_LOST` on NVIDIA
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> driver `610.43.02` — a driver-side fault in the brand-new descriptor-heap
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> acceleration-structure path, not an engine bug (the setup is correct and
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> validation-clean; images/buffers through the same heap work). The engine
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> **works around it transparently** (issue #15): on the NVIDIA driver only,
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> `VulkanShader` rewrites the compiled SPIR-V so heap AS reads become a
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> TLAS-device-address + `OpConvertUToAccelerationStructureKHR` path (which
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> reads no descriptor), and `RTPass` supplies the address as push data.
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> Shaders and example code are unchanged, and it's a single fenced block
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> gated on `Device::workaroundDescriptorHeapAS`, removable once a fixed
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> driver ships. See
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> [examples/VulkanTriangle/README.md](examples/VulkanTriangle/README.md)
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> for the full investigation. WebGPU RT is unaffected.
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> **Native RT limitation — dynamic `descriptor_heap` indexing in hit
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> shaders:** on the same NVIDIA driver, indexing a `descriptor_heap`
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> array with a **runtime (non-constant)** index inside a ray-tracing
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> **hit** shader also device-losts (`VK_ERROR_DEVICE_LOST`), for plain
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> SSBO **and** sampled-image descriptors. A **constant / spec-constant**
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> index is fine (that's why [Sponza](examples/Sponza/README.md)'s
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> closest-hit reads `albedo[albedoSlot]` through a spec constant), and
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> the identical dynamic pattern works in fragment shaders (the UI
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> renderer indexes `uiTextures[]` by per-item runtime slots) — so this
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> is **RT-stage-specific**, not a general heap problem. Unlike the
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> AS-read fault above this **cannot** be worked around transparently:
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> sampled images have no device-address escape hatch the way an
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> acceleration structure does (`OpConvertUToAccelerationStructureKHR`).
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> The recommended pattern for bindless per-mesh geometry/material is to
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> **bind one resource and index *within* it dynamically** rather than
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> selecting a descriptor dynamically: pack geometry into a single SSBO
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> (or reach it via `buffer_reference`) at a spec-constant slot and index
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> by element offset, and put materials in one `texture2DArray` indexed
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> by layer. Dynamic addressing *inside* a bound resource is ordinary
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> memory/layer addressing and is unaffected; only dynamic selection of a
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> *descriptor* faults. This is exactly what the WebGPU path already does
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> (bucketed texture arrays + a single buffer). Full investigation and
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> GLSL in [examples/Sponza/README.md](examples/Sponza/README.md) (issue
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> #23). WebGPU RT is unaffected.
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## What's in here
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- **Window** — Wayland, Win32, and DOM backends, swapchain ring / canvas
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framing, input events. Pick a backend at build time via the target
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triple. The DOM backend routes every dynamic symbol through
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[additional/dom-env.js](additional/dom-env.js) and
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[additional/dom-webgpu.js](additional/dom-webgpu.js).
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- **Device** *(Vulkan only)* — single-instance bring-up targeting
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`VK_EXT_descriptor_heap`; pipelines are created with
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`VK_PIPELINE_CREATE_2_DESCRIPTOR_HEAP_BIT_EXT` so there are no
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descriptor-set layouts and push constants travel via
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`vkCmdPushDataEXT`. The heap, ray tracing and device-fault extensions
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are optional groups, detected at start-up
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(`Device::descriptorHeapSupported`, `rayTracingSupported`,
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`deviceFaultSupported`).
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- **DescriptorHeapVulkan / DescriptorHeapWebGPU** — bindless slot
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allocators. Vulkan side allocates image/buffer/sampler slots in a
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`VK_EXT_descriptor_heap`; WebGPU side resolves slots to JS-side
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handle-table cookies that the dispatch bridge binds per pass.
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- **VulkanBuffer\<T, Mapped\> / WebGPUBuffer\<T\>** — typed buffer.
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Vulkan variant has optional host mapping and a `FlushDevice` that
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issues the right host-write barrier; WebGPU variant goes through
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`queue.writeBuffer` over the JS bridge.
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- **ImageVulkan\<Pixel\> / Image2D\<Pixel\> / Image2DArray\<Pixel\>** —
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image + staging buffer with mip-chain support on Vulkan; on WebGPU,
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`rgba8unorm` 2D / 2D-array textures created and written via the
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bridge. Atlas (`r8unorm`, sub-region writes) is a separate path.
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- **PipelineRTVulkan / PipelineRTWebGPU / ShaderBindingTableVulkan /
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ShaderBindingTableWebGPU / RTPass** — ray-tracing pipelines. Vulkan
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uses native RT pipelines + SBTs; WebGPU compiles a **wavefront /
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streaming** software tracer — five `@compute` kernels
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(`GENERATE → PREP → TRACE → SHADE → RESOLVE`) sharing one module,
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connected by GPU ray/hit/payload buffers and a GPU-driven indirect
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bounce loop (`dispatchWorkgroupsIndirect`). TRACE carries zero user
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code (traversal + intersection only); user raygen calls
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`rtEmitPrimaryRay`, and closesthit / miss run in SHADE where they
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`rtEmitRay` continuation/shadow rays and `rtAccumulate` radiance
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(atomic — any number of rays per pixel per bounce, e.g. one shadow
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ray per light). An
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optional Resolve shader tonemaps the linear accumulator. See
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[WAVEFRONT-DESIGN.md](WAVEFRONT-DESIGN.md).
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- **ComputeShader / WebGPUComputeShader** — Tier 1 wrapper used by the
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UI system. Vulkan loads a `.spv` and dispatches with
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`vkCmdPushDataEXT` (or the `.sets.spv` build and `vkCmdPushConstants`
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without the heap); WebGPU loads a user-supplied `.wgsl` blob at
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runtime via `wgpuLoadCustomShader`. Use it directly for any custom
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compute.
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- **UI** — three-tier UI system; see below. The standard shaders (four
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kernels plus the fused one) ship as `.spv` / `.sets.spv` pairs on
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native and as WGSL strings baked into the WebGPU dispatcher.
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- **FontAtlas** — single-channel SDF atlas (1024×1024, 32pt base,
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shelf-packed, lazy `Ensure` per codepoint, dirty-flush via `Update`).
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Backend-agnostic.
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- **Mesh / RenderingElement3D / Animation** — BLAS/TLAS construction
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and 3D scene plumbing. Vulkan calls `vkCmdBuildAccelerationStructures`;
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WebGPU registers BLAS data (verts, idx, BVH nodes, primRemap, optional
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per-vertex attribs) into global mesh heaps and builds the TLAS in a
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library compute pass.
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- **Clipboard / Input / Gamepad / Router / Dom** — input plumbing.
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Gamepad uses libudev+libevdev on Linux and WGI on Windows; the DOM
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backend exposes the host page DOM (`Dom::HtmlElement`) and a router
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for hash-routed wasm apps.
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## UI system (three tiers)
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The UI is *deliberately* layered to balance no-boilerplate against
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no-lock-in:
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- **Tier 1 — `ComputeShader`.** Load any `.spv`, dispatch with push
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constants, library inserts inter-dispatch barriers. The escape hatch:
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if the standard shaders don't fit, write your own compute and
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dispatch it next to them.
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- **Tier 2 — `UIRenderer` + standard shaders.** Four shipped compute
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shaders (`drawQuads`, `drawCircles`, `drawImages`, `drawText`), POD
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item structs (`QuadItem`, `CircleItem`, `ImageItem`, `GlyphItem`), a
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shared GLSL contract in [shaders/ui-shared.glsl](shaders/ui-shared.glsl),
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and helpers (`RegisterBuffer`, `RegisterImage`, `RegisterSampler`,
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`FillHeader`, `Dispatch*`, `ShapeText`). You build your own per-shader
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SSBOs (manual batching) and call one `Dispatch*` per shader type per
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frame. Item array order = draw order.
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- **Tier 3 — stateless presentation functions.** `DrawButton`,
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`DrawCheckbox`, `DrawSlider`, `DrawProgressBar`. Each is a small
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function that *appends* items to your buffers — they don't dispatch.
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Colors come in as small inline `*Colors` aggregates, no library
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`Theme` type. **The source is the customization API**: if a
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component doesn't fit, copy its body and edit it. No virtual hooks,
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no extension points.
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What's *not* in the UI: widget tree, layout engine (just a `Rect::SubRect`
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carving helper), theming, hit-testing, focus management. State for
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interactive components (hover, drag, focus) lives in user-owned POD
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structs, not the library.
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### UI dispatch model
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Standard shaders dispatch one workgroup per 8×8 *screen tile* — each
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thread iterates every item in the SSBO in array order, accumulating
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into a local `dst`, and stores once. Total cost is `O(W·H·N)`; works
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well up to a few hundred items at 1080p. Splitting one buffer into
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multiple dispatches doesn't help — the same total work plus barrier
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overhead. If you need to render thousands of UI items, you want a
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different shader (tile binning, per-item-list resolve), not more
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dispatches.
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### Drivers without `VK_EXT_descriptor_heap`
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The compute/UI path also runs on Vulkan drivers that lack
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`VK_EXT_descriptor_heap` (Mesa Turnip on Qualcomm Adreno, for one).
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`Device::Initialize` detects this and sets
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`Device::descriptorHeapSupported = false`. The same slots then live in
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one bindless descriptor set per frame instead of the heap, and push
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constants go through `vkCmdPushConstants`. Slot handles, item structs,
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`UIDispatchHeader` and the `UIRenderer` API are unchanged, so
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application code does not branch on it. Ray tracing is heap-only: on
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such a driver `Device::rayTracingSupported` is false and the RT entry
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points throw.
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Each compute shader is shipped in two builds of the same source:
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`<name>.spv` for the heap and `<name>.sets.spv` for descriptor sets.
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`ComputeShader::Load(path, heap)` takes the `.spv` path and picks the
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right file itself. For a custom shader that means three things:
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- Declare bindless resources with the `UI_HEAP_*` macros from
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[shaders/ui-shared.glsl](shaders/ui-shared.glsl), not with a literal
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`descriptor_heap`:
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```glsl
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layout(UI_HEAP_BUFFERS, std430) readonly buffer MyBuf { MyItem items[]; } myHeap[];
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```
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- Register the shader twice in `project.cpp`, the second time with the
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define and the variant name:
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```cpp
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cfg.shaders.emplace_back(fs::path("my.comp.glsl"), std::string("main"), ShaderType::Compute);
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Shader& sets = cfg.shaders.emplace_back(fs::path("my.comp.glsl"), std::string("main"), ShaderType::Compute);
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sets.defines = {"CRAFTER_GRAPHICS_DESCRIPTOR_SETS"};
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sets.variant = "sets";
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```
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- Keep the push-constant block within the device's
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`maxPushConstantsSize` (256 bytes on common drivers). Without the
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heap a larger payload throws in `ComputeShader::Dispatch`.
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Set the environment variable `CRAFTER_GRAPHICS_NO_DESCRIPTOR_HEAP` to
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force the descriptor-set path on a driver that does have the heap; the
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`UIFallbackParity` test uses it to compare the two paths frame for
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frame.
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## Build
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The repository is built with `crafter-build` (a project-config based
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build system; the project description lives in `project.cpp`):
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```bash
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crafter-build # native: Wayland on Linux, Win32 on Windows
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crafter-build --target=wasm32-wasip1 # browser: DOM window + WebGPU renderer
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crafter-build -r # build and run (in an example directory)
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```
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The build picks the window + renderer pair automatically from the
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target triple: any `wasm32-*` triple flips to DOM + WebGPU (no Vulkan
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loader linked), everything else stays on the native Vulkan path. Each
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example with both backends ships GLSL *and* WGSL copies of its shaders
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side-by-side (e.g. [raygen.glsl](examples/Sponza/raygen.glsl) +
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[raygen.wgsl](examples/Sponza/raygen.wgsl)); `project.cpp` selects the
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right set per target.
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## Examples
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See [examples/](examples/). Quick map:
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- [HelloWindow](examples/HelloWindow/) — minimal native window, no rendering.
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- [HelloDom](examples/HelloDom/) — wasm-only smoke test of the DOM
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partition: page-level events, `HtmlElement::CreateInBody`, and
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`Router::PushState`-driven SPA navigation. No GPU work.
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- [VulkanTriangle](examples/VulkanTriangle/) — ray-traced triangle on
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both Vulkan and WebGPU. The smallest test of the bindless + RT path
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on each backend.
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- [RTStress](examples/RTStress/) — wavefront RT benchmark: an N×N×N grid
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of a cube mesh (instance-count knob `kGrid`, 512 → 8000) shaded with
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primary + shadow rays. Prints a GPU timestamp-query per-pass breakdown
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each second. WebGPU/DOM only.
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- [Sponza](examples/Sponza/) — ray-traced Sponza atrium on both
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backends. Exercises `.cmesh` / `.ctex` decompression (GPU
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`VK_EXT_memory_decompression` on Vulkan, CPU on WebGPU) and a
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textured closest-hit. See [its README](examples/Sponza/README.md)
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for asset provenance.
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- [HelloUI](examples/HelloUI/) — UI smoke test using all three tiers
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(background quad, slider, progress bar, button with text label,
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cursor-tracking circle).
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- [CustomShader](examples/CustomShader/) — Tier 1 demo: a user-authored
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compute shader inverting RGB under a list of item-circles, dispatched
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alongside the standard `drawQuads`. Shipped as both
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[`.comp.glsl`](examples/CustomShader/inverse-circle.comp.glsl) and
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[`.comp.wgsl`](examples/CustomShader/inverse-circle.comp.wgsl).
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- [Decompression](examples/Decompression/) — `Crafter::Compression`
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CPU round-trip smoke test (used by the WebGPU asset path).
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- [InputSystem](examples/InputSystem/) — keyboard / mouse / gamepad
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event surface check.
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## License
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This library is licensed under the GNU Lesser General Public License, version 3 only (LGPL-3.0-only). See [LICENSE](LICENSE) for the license text. The LGPL supplements the GNU General Public License version 3, a copy of which is included as [LICENSE.GPL](LICENSE.GPL).
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The example code under [examples/](examples/) is licensed under the MIT license (see [examples/LICENSE](examples/LICENSE)), so it can be freely copied into your own projects.
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The [lib/](lib/) directory contains vendored third-party code (stb, Wayland protocol bindings) that remains under its own permissive licenses; see the headers of those files.
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## Copyright
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Copyright (C) 2026 Catcrafts®
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catcrafts.net
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