Renderive/render_3D/datoviz/spec/scene/examples/FIXTURES.md

Datoviz v0.4 Feature Fixture Matrix

Status: Informative planning Scope: minimal one-feature C examples, generated fixtures, and advanced low-level examples Goal: maintain one small example idea per implemented or planned Datoviz feature

This matrix is an implementation guide for building a compact example suite. It does not define runtime semantics. It records what each fixture should demonstrate, what layer it should use, and which optional capabilities it requires.

Scene/app rows are owned here. Low-level vk, vklite, canvas, stream, video, DRP2, WebGPU, CUDA, and interop rows are included only as a cross-stack coverage index. Their behavior belongs in the owning subsystem specs.

Release staging is not decided in this file. Use PLANNING.md to decide whether a fixture or worked example is v0.4 required, v0.4 experimental, v0.4 fixture-only, v0.5, later, or external/GSP. This matrix should stay focused on small, one-feature validation artifacts.

Principles

1. One feature per fixture. Avoid combining multiple visual families, controllers, effects, GUI panels, and data loaders in one file unless the feature is the combination itself.
2. Prefer deterministic offscreen output. A PNG, JSON stream, DVZR directory, or stdout assertion is better than a live window when the feature does not require live interaction.
3. Use tiny synthetic data. Prefer three points, one triangle, a 4x4 image, or a tiny 3D scalar field over external datasets.
4. Make optional dependencies explicit. GLFW, GUI/cimgui, CUDA/NVENC, Kvazaar, WebGPU, and external-memory fixtures should be gated in CMake and documented in the fixture row.
5. Separate fixtures from showcases. Fixtures prove one API shape; showcase examples may combine features into richer applications. A fixture can be release-critical without becoming a gallery example.
6. Keep low-level examples in their own track. Direct vk, vklite, canvas, stream, and drp2 examples are useful, but they target power users and should not obscure the scene examples.

Output classes

Output	Use
PNG	deterministic visual smoke for offscreen scene/canvas fixtures
JSON	scene JSON, DRP2 fixture JSON, or WebGPU-compatible stream fixture
DVZR	recording/replay examples and regression inputs
MP4/raw video	video encoder/sink fixtures
stdout	non-rendering low-level setup, config, and validation examples
bounded GLFW window	interaction, GUI, present, or live-sink examples only

Scene and app fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
Scene lifecycle	Empty scene	Implemented	fixture_scene_empty.c	PNG	scene+app	Create one scene, figure, panel, and offscreen view; capture an empty frame.
Figure	Resize	Implemented	fixture_figure_resize.c	PNG x2	scene+app	Render at one size, resize the figure/window, render again.
Panel	Layout	Implemented	fixture_panel_layout.c	PNG	scene+app	Two panels with different background colors.
Panel	Background color	Implemented	fixture_panel_background.c	PNG	scene+app	One panel filled by dvz_panel_set_background_color().
Visual	Point	Implemented	fixture_point.c	PNG	scene+app	Three colored points with different sizes.
Visual	Pixel	Implemented	fixture_pixel.c	PNG	scene+app	Three screen-space square sprites.
Visual	Splat	Planned v0.4 experimental	fixture_splat.c	PNG	scene+app	One deterministic dense splat cloud with center, radius, color, opacity, depth policy, and nonblank capture.
Visual	Sphere impostor	Implemented	fixture_sphere.c	PNG	scene+app	Three lit spheres with different radii.
Visual	Primitive triangle	Implemented	fixture_primitive_triangle.c	PNG	scene+app	One RGB triangle with DVZ_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST.
Visual	Primitive line	Implemented	fixture_primitive_line.c	PNG	scene+app	One line strip or line list.
Visual	Mesh	Implemented	fixture_mesh.c	PNG	scene+app	One indexed tetrahedron or cube.
Visual	Textured mesh	Implemented / needs fixture promotion	fixture_mesh_textured.c	PNG	scene+app	One UV-mapped quad or small terrain grid with a 4x4 RGBA texture sampled by the mesh shader and lit; current broad proof is examples/c/visuals/textured_mesh.c.
Visual	Path	Implemented	fixture_path.c	PNG	scene+app	One five-point polyline.
Visual	Image	Implemented	fixture_image.c	PNG	scene+app	One 4x4 RGBA checkerboard on a quad.
Visual	Volume slice	Implemented	fixture_volume_slice.c	PNG	scene+app	One tiny 3D scalar field rendered as a slice.
Visual data	Initial attributes	Implemented	fixture_visual_data.c	PNG	scene+app	Set position, color, and size on one point visual.
Visual data	Partial range update	Implemented	fixture_visual_update_range.c	PNG x2	scene+app	Render points, update one item's color/size, render again.
Visual data	Many-attribute upload	Implemented	fixture_visual_data_many.c	PNG	scene+app	Upload several attributes through the compact multi-data path.
Visual data	Mutability hints	Implemented	fixture_visual_attr_mutability.c	stdout/PNG	scene+app	Mark size dynamic and position static, then emit one frame.
Visual state	Visibility	Implemented	fixture_visual_visibility.c	PNG x2	scene+app	Capture the same scene with a visual hidden and visible.
Visual state	Depth test	Implemented	fixture_depth_test.c	PNG x2	scene+app	Two overlapping triangles with depth testing enabled and disabled.
Controller	Panzoom	Implemented	fixture_panzoom.c	PNG	scene+app	Apply a preset panzoom transform to a 2D path.
Controller	Arcball	Implemented	fixture_arcball.c	PNG	scene+app	Apply a preset arcball orientation to a cube.
Controller	Fly camera	Implemented	fixture_fly_camera.c	PNG/live	scene+app	Show a fixed fly-camera pose in a simple 3D scene.
Controller	Turntable	Implemented	fixture_turntable.c	PNG/live	scene+app	Show a fixed turntable pose around a mesh.
Attachment	Fixed overlay	Implemented	fixture_fixed_overlay.c	PNG	scene+app	Combine a controlled data visual with a fixed overlay/background.
Field	2D RGBA sampled field	Implemented	fixture_field_rgba2d.c	PNG	scene+app	Bind a small RGBA sampled field to an image visual.
Field	Scalar field colormap	Implemented	fixture_field_scalar_colormap.c	PNG	scene+app	Render an 8x8 float gradient through a continuous scale/colormap.
Field	Region update	Implemented	fixture_field_update_region.c	PNG x2	scene+app	Update a 2x2 subregion in an image field.
Field	3D scalar field	Implemented	fixture_field_scalar3d.c	PNG	scene+app	Bind a tiny 3D scalar field to a volume visual.
Scale	Domain clipping	Implemented	fixture_scale_domain.c	PNG	scene+app	Render the same scalar image with a clipped scale domain.
Scale	Categorical colormap	Implemented	fixture_scale_categorical.c	PNG	scene+app	Render a small label image through a categorical scale.
Colorbar	Retained bookkeeping	Implemented	fixture_colorbar_bookkeeping.c	stdout/JSON	scene	Create a colorbar object and serialize/inspect it.
Colorbar	Frame-plan contributions	Implemented in scene tests	fixture_colorbar_frame_plan.c	JSON	scene	Verify ramp, ticks, tick labels, title, anchor, orientation, and auto-reserve metadata.
Colorbar	Rendered vertical colorbar	Implemented app/offscreen smoke	fixture_colorbar_vertical.c	PNG	scene+app	Render scalar image plus a right-anchored continuous colorbar with title and tick labels.
Colorbar	Rendered horizontal colorbar	Scene-tested; PNG fixture pending	fixture_colorbar_horizontal.c	PNG	scene+app	Render scalar image plus a bottom-anchored continuous colorbar and deterministic tick labels.
Colorbar	Unsupported scale/anchor diagnostics	Implemented in scene tests	fixture_colorbar_diagnostics.c	stdout/JSON	scene	Check categorical scale and non-edge anchor diagnostics without silent fallback.
Material	Unlit	Implemented	fixture_material_unlit.c	PNG	scene+app	One triangle/mesh using unlit material state.
Material	Phong/lit	Implemented	fixture_material_phong.c	PNG	scene+app	One lit cube or sphere with normals.
Effect	Depth cue points	Implemented	fixture_depth_cue_points.c	PNG	scene+app	Points at different z values fade/darken with depth.
Effect	Depth cue mesh	Implemented	fixture_depth_cue_mesh.c	PNG	scene+app	One slanted mesh with depth cue enabled.
Technique	MSAA	Implemented	fixture_msaa.c	PNG	scene+app	Diagonal line/triangle edges with panel MSAA enabled.
Technique	Eye-Dome Lighting	Implemented	fixture_edl.c	PNG	scene+app	Dense point cloud with EDL enabled and no GUI panel.
Technique	SSAO	Implemented/active	fixture_ssao_spheres.c	PNG	scene+app	A few lit spheres with SSAO enabled.
Technique	Volume occlusion	Implemented	fixture_volume_occlusion.c	PNG	scene+app	Volume plus embedded points/spheres.
Transparency	Alpha blending	Implemented	fixture_alpha_blend.c	PNG	scene+app	Two overlapping translucent quads.
Transparency/stress	Dense splat blending	Planned v0.4 experimental	fixture_splat_blending.c	PNG	scene+app	Overlapping splats at several depths to validate the selected blend/depth policy.
Transparency	WBOIT	Implemented	fixture_wboit.c	PNG/live	scene+app	One translucent cube between opaque cards.
Transparency	Depth peeling	Implemented	fixture_depth_peel.c	PNG/live	scene+app	Two translucent crossing layers.
Transparency	Alpha mask	Draft/API-shaped	fixture_alpha_mask.c	PNG	scene+app	Checkerboard alpha mask when runtime path is active.
Interaction	Point picking	Implemented narrow GPU path	fixture_point_pick.c	stdout	scene+app	Queue a pick at a known pixel and print/verify selected item.
Interaction	Image probing	Implemented narrow GPU path	fixture_image_probe.c	stdout	scene+app	Probe a known texel in a 4x4 scalar image.
Interaction	Request coalescing	Implemented	fixture_request_coalesce.c	stdout	scene+app	Queue several picks/probes and verify latest-result semantics.
Interaction	Selection object	Implemented bookkeeping	fixture_selection.c	stdout	scene	Apply a synthetic pick result to a selection and print count.
Interaction	Link channel	Implemented bookkeeping	fixture_link_channel.c	stdout	scene	Link two panel ranges through a channel with synthetic state.
Interaction	Pinned readout	Implemented bookkeeping	fixture_pinned_readout.c	stdout	scene	Create a pinned readout from a synthetic probe result.
Interaction	Hover picking	Implemented live example	fixture_pick_hover_glfw.c	bounded GLFW	scene+app+GLFW	Minimal live hover-pick point scene.
Text	Font resource	Implemented	fixture_font_resource.c	stdout	scene	Create/destroy a scene-owned font resource.
Text	Retained text	Implemented	fixture_text_bookkeeping.c	JSON/stdout	scene	Create text, update string/style/placement.
Text	Rendered text	Implemented example/app smoke	fixture_text_rendered.c	PNG	scene+app	Promote examples/c/visuals/text.c behavior into a deterministic offscreen fixture.
Annotation	Retained label	Implemented	fixture_annotation_bookkeeping.c	JSON/stdout	scene	Create a label annotation and update format.
Annotation	Rendered label	Implemented first slice	fixture_annotation_rendered.c	PNG	scene+app	One point with one label overlay; callouts remain separate.
App	Offscreen render	Implemented	fixture_app_offscreen.c	PNG	scene+app	Render one point scene offscreen.
App	PNG capture	Implemented	fixture_capture_png.c	PNG	scene+app	Render and save a PNG through app/canvas capture.
App	High-resolution capture	Planned practical fixture	fixture_capture_high_res.c	PNG	scene+app	Render the same tiny scene at a larger output size and verify dimensions/nonblank pixels.
App	Transparent-background capture	Planned/deferred	fixture_capture_transparent_bg.c	PNG	scene+app	Render one alpha-enabled scene and verify exported alpha where the runtime supports it.
App	Batch parameter sweep	Planned practical fixture	fixture_batch_capture_sweep.c	PNG set	scene+app	Render a small deterministic scene across a few parameter values without opening a window.
App	GLFW live window	Implemented	fixture_glfw_window.c	bounded GLFW	scene+app+GLFW	One point scene, auto-close after N frames.
App	Fullscreen window	Planned runtime fixture	fixture_glfw_fullscreen.c	bounded GLFW	scene+app+GLFW	Open a fullscreen or borderless view when supported, render one scene, then auto-close.
App	Multi-window	Planned runtime fixture	fixture_glfw_multi_window.c	bounded GLFW	scene+app+GLFW	Two small windows render independent or synchronized tiny scenes.
App	HiDPI resize	Planned runtime fixture	fixture_hidpi_window.c	stdout/PNG	scene+app+GLFW	Report logical/physical sizes and render a crisp text/line smoke when content scale is available.
App	Frame callback	Implemented	fixture_frame_callback.c	PNG	scene+app	Mutate point color on frame 2 and capture frame 3.
Animation/stress	CPU fluid or particle advection	v0.4 experimental/stretch	fixture_cpu_fluid_particles.c	PNG/live	scene+app	Update a small scalar image plus particle points or short trails over bounded frames without scene-level GPU compute.
Controller	Camera bookmarks	Planned	fixture_camera_bookmarks.c	PNG x2	scene+app	Save or define two named camera/controller states and render both deterministically.
Coordinates	Coordinate-space debug	Planned diagnostic fixture	fixture_coordinate_spaces.c	PNG/stdout	scene+app	Show or print screen, panel, data, world, and NDC coordinate mappings for one point/probe.
App	Hosted window	Implemented smoke	fixture_hosted_window.c	bounded GLFW	app+canvas+GLFW	Minimal hosted-window integration smoke.
Serialization	Scene JSON	Implemented	fixture_scene_json.c	JSON	scene	Serialize one-point scene to JSON.
Emission	Figure DRP2 stream	Implemented	fixture_emit_drp2.c	JSON	scene+drp2	Emit a one-triangle frame plan and save debug JSON.

GUI and cimgui fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
GUI	Overlay attach	Implemented	fixture_gui_overlay.c	bounded GLFW	GUI+GLFW	Attach DvzGui to a GLFW view and show one tiny window.
GUI	Callback	Implemented	fixture_gui_callback.c	bounded GLFW	GUI+GLFW	Register a GUI callback that increments and displays a counter.
GUI	Curated controls	Implemented	fixture_gui_controls.c	bounded GLFW	GUI+GLFW	One panel with text, button, checkbox, combo, and slider.
GUI	Text widget	Implemented	fixture_gui_text.c	bounded GLFW	GUI+GLFW	Show one dvz_gui_text() item.
GUI	Button	Implemented	fixture_gui_button.c	bounded GLFW	GUI+GLFW	Button toggles a visual or background color.
GUI	Checkbox	Implemented	fixture_gui_checkbox.c	bounded GLFW	GUI+GLFW	Checkbox toggles point visibility.
GUI	Combo	Implemented	fixture_gui_combo.c	bounded GLFW	GUI+GLFW	Combo switches background or alpha mode.
GUI	Slider	Implemented	fixture_gui_slider_float.c	bounded GLFW	GUI+GLFW	Slider controls point size.
GUI	Formatted slider	Implemented	fixture_gui_slider_float_format.c	bounded GLFW	GUI+GLFW	Slider controls mesh alpha with custom display format.
GUI	Monospace font	Implemented	fixture_gui_mono_font.c	bounded GLFW	GUI+GLFW	Display one normal and one monospace line.
GUI	Demo window	Implemented	fixture_gui_demo.c	bounded GLFW	GUI+GLFW	Show the Dear ImGui demo window; developer-only.
GUI	Docking/dockspace	Implemented	fixture_gui_docking.c	bounded GLFW	GUI+GLFW	Enable docking and show a small dockable control panel.
GUI viewport	Datoviz image viewport	Implemented	fixture_gui_viewport.c	bounded GLFW	GUI+GLFW	Render a point figure into a dockable ImGui viewport image.
GUI viewport	Input forwarding	Implemented	fixture_gui_viewport_input.c	bounded GLFW	GUI+GLFW	Forward viewport input to a panzoom or arcball controller.
GUI viewport	Multi-viewport	Implemented	fixture_gui_multi_viewport.c	bounded GLFW	GUI+GLFW	Two tiny offscreen figures shown in two GUI viewport windows.
cimgui	Raw ig* calls	Implemented	fixture_cimgui_raw.c	bounded GLFW	GUI+cimgui+GLFW	Include datoviz/imgui.h and call one raw cimgui function in a GUI callback.

Video fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
Video	Encoder defaults	Implemented	fixture_video_config.c	stdout	video	Print/default-check codec, mux, backend, size, and fps settings.
Video	Sink defaults	Implemented	fixture_video_sink_config.c	stdout	video	Build a DvzVideoSinkConfig from defaults and print fields.
Video	CPU readback config	Implemented	fixture_video_cpu_readback_config.c	stdout	video	Configure CPU callbacks for synthetic RGBA frames.
Video	Offline/headless encode	Implemented	fixture_video_offline_encode.c	MP4	video backend	Encode 8-16 synthetic RGBA frames to MP4.
Video	Builtin stream sink	Implemented	fixture_video_sink.c	MP4	stream+video backend	Register/use dvz_stream_sink_video() and feed a few frames.
Video	Offscreen scene capture	Planned practical fixture	fixture_video_scene_offscreen.c	MP4	scene+app+video backend	Render a simple offscreen point scene for N frames and encode it.
Video	Canvas video sink	Implemented API	advanced_canvas_video_sink.c	MP4	canvas+video backend	Enable dvz_canvas_configure_video_sink() on a manual canvas.
Video	MP4 streaming mux	Implemented	fixture_video_mp4_streaming.c	MP4	video backend	Encode tiny synthetic frames with streaming MP4 mux.
Video	MP4 post mux	Implemented/backend-dependent	fixture_video_mp4_post.c	MP4+raw	video backend	Encode to temporary raw stream and post-mux.
Video	Raw H.26x stream	Implemented/backend-dependent	fixture_video_raw_h26x.c	.h264/.h265	video backend	Disable MP4 mux and write elementary stream.
Video	H.264	Implemented enum/backend-dependent	fixture_video_h264.c	MP4/raw	video backend	Tiny synthetic frames with H.264 codec.
Video	HEVC	Implemented enum/backend-dependent	fixture_video_hevc.c	MP4/raw	video backend	Tiny synthetic frames with HEVC codec.
Video backend	NVENC external capture	Optional	fixture_video_nvenc_external.c	MP4	CUDA+NVENC+Vulkan external memory	Developer-only external image/semaphore encode smoke.
Video backend	Kvazaar CPU fallback	Optional	fixture_video_kvazaar_cpu.c	MP4	Kvazaar	Encode CPU RGBA frames through Kvazaar.
Video backend	Missing-backend fallback	Implemented internally	fixture_video_backend_fallback.c	stdout	video	Request a missing backend and verify graceful fallback/failure.

Low-level vk fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
vk	GPU context	Implemented	advanced_vk_gpu_context.c	stdout	vk	Create DvzGpuCtx, print selected GPU info, destroy.
vk	Validation	Implemented	advanced_vk_validation.c	stdout	vk+validation layers	Enable validation and print validation error count.
vk	GPU selection	Implemented	advanced_vk_select_gpu.c	stdout	vk	Choose GPU index from CLI and print selected device.
vk	Feature request	Implemented	advanced_vk_features.c	stdout	vk	Request selected Vulkan 1.2/1.3 features before context creation.
vk	Instance extension request	Implemented	advanced_vk_instance_extension.c	stdout	vk	Add one instance extension to GPU context config.
vk	Canvas extensions	Implemented	advanced_vk_canvas_extensions.c	stdout	vk+canvas deps	Enable surface/swapchain device extensions for future present canvas use.
vk	External-memory allocator policy	Implemented	advanced_vk_external_memory.c	stdout	vk+platform support	Configure allocator export handle type for interop.
vk	GLSL compilation	Implemented	advanced_vk_compile_glsl.c	stdout/SPIR-V	shaderc available	Compile tiny GLSL vertex/fragment/compute string to SPIR-V.
vk	Queue access	Implemented	advanced_vk_queue.c	stdout	vk	Retrieve graphics/transfer queues from the GPU context.

Low-level vklite fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
vklite	Buffer upload/download	Implemented	advanced_vklite_buffer.c	stdout	vk+vklite	Allocate buffer, upload four floats, download and print them.
vklite	Buffer resize	Implemented	advanced_vklite_buffer_resize.c	stdout	vk+vklite	Create buffer, resize it, verify allocated size.
vklite	Image and view	Implemented	advanced_vklite_image.c	stdout	vk+vklite	Create a 2D RGBA image and image view.
vklite	Image upload	Implemented	advanced_vklite_image_upload.c	PNG/stdout	vk+vklite	Upload a 4x4 checkerboard to an image through staging/copy helpers.
vklite	Sampler	Implemented	advanced_vklite_sampler.c	stdout	vk+vklite	Create nearest and linear samplers.
vklite	Shader module	Implemented	advanced_vklite_shader.c	stdout	vk+vklite	Compile/load SPIR-V and create a shader module.
vklite	Commands	Implemented	advanced_vklite_commands.c	stdout	vk+vklite	Allocate command buffer, begin/end/reset/release.
vklite	Barriers	Implemented	advanced_vklite_barriers.c	stdout	vk+vklite	Record one image layout transition.
vklite	Sync	Implemented	advanced_vklite_sync.c	stdout	vk+vklite	Create fence/semaphore, submit empty command buffer, wait.
vklite	Descriptors	Implemented	advanced_vklite_descriptors.c	stdout	vk+vklite	Create a simple uniform-buffer descriptor set.
vklite	Graphics pipeline	Implemented helpers	advanced_vklite_graphics_triangle.c	PNG	vk+vklite	Draw one triangle without scene or DRP2.
vklite	Compute pipeline	Implemented helpers	advanced_vklite_compute.c	stdout	vk+vklite	Dispatch a tiny compute shader that writes to a buffer.
vklite	Surface wrapping	Implemented	advanced_vklite_surface.c	stdout	vk+vklite+GLFW	Wrap a native window surface and print formats/present modes.
vklite	Swapchain acquire/present	Implemented	advanced_vklite_swapchain.c	bounded GLFW	vk+vklite+GLFW	Create swapchain, acquire one image, present.
vklite	Immediate present	Implemented	advanced_vklite_immediate_present.c	stdout/live	vk+vklite+GLFW	Minimal immediate-present loop for FPS diagnostics.

Window and input fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
Window	Headless window	Implemented	advanced_window_headless.c	stdout	window	Create a headless window and poll once.
Window	GLFW window	Implemented	advanced_window_glfw.c	bounded GLFW	window+GLFW	Create a GLFW window, poll events, auto-close.
Window	User data	Implemented	advanced_window_user_data.c	stdout	window	Attach a struct pointer to a window and retrieve it.
Window	Request-frame loop	Implemented	advanced_window_request_frame.c	stdout	window	Request frames manually and observe pending state.
Window	Surface query	Implemented	advanced_window_surface.c	stdout	window+GLFW+vk	Print native surface extent/handle availability.
Input	Router callbacks	Implemented	advanced_input_router.c	stdout	input	Attach pointer/key callbacks and emit/observe one synthetic event.

Stream and canvas fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
Stream	Empty stream	Implemented	advanced_stream_empty.c	stdout	stream	Create/start/update/stop a stream with a borrowed dummy frame.
Stream	Custom sink backend	Implemented	advanced_stream_custom_sink.c	stdout	stream	Implement a sink that logs frame ids and timeline values.
Stream	Sink registry	Implemented	advanced_stream_registry.c	stdout	stream	Register custom sink, find by name, pick automatically.
Stream	Multi-sink routing	Implemented	advanced_stream_multi_sink.c	stdout/MP4	stream+optional video	Attach log sink plus video/live sink.
Stream	Borrowed frame descriptor	Implemented	advanced_stream_borrowed_frame.c	stdout	stream+vk	Construct DvzStreamFrame around externally owned Vulkan handles.
Stream	Frame usage flags	Implemented	advanced_stream_usage_flags.c	stdout	stream	Demonstrate render-target/copy-src/copy-dst metadata.
Canvas	Draw callback	Implemented	advanced_canvas_draw_callback.c	PNG/live	canvas+vk	Create canvas, set callback, clear/draw manually.
Canvas	Offscreen capture	Implemented	advanced_canvas_offscreen_capture.c	PNG	canvas+vk	Draw one color/triangle and save PNG.
Canvas	Present	Implemented	advanced_canvas_present.c	bounded GLFW	canvas+GLFW	Create GLFW-backed canvas and present N frames.
Canvas	Immediate FPS	Implemented	advanced_canvas_immediate.c	stdout/live	canvas+GLFW	Present as fast as possible and print timing samples.
Canvas	RGBA capture	Implemented	advanced_canvas_capture_rgba.c	stdout	canvas	Render offscreen, read RGBA, inspect first pixel.
Canvas	PNG capture	Implemented	advanced_canvas_capture_png.c	PNG	canvas	Render and save PNG without scene/app.
Canvas	Video sink	Implemented	advanced_canvas_video_sink.c	MP4	canvas+video backend	Enable canvas video sink and write a short MP4.
Canvas	Live-image sink	Implemented	advanced_canvas_live_image_sink.c	stdout	canvas+platform handles	Enable live-image callback and print Vulkan handles.
Canvas	Underlying stream	Implemented	advanced_canvas_stream.c	stdout	canvas+stream	Retrieve dvz_canvas_stream() and inspect/attach custom sinks.
Canvas	Input router	Implemented	advanced_canvas_input.c	stdout/live	canvas+window	Get dvz_canvas_input() and wire custom controls.
Canvas	Timing diagnostics	Implemented	advanced_canvas_timing.c	stdout	canvas	Render frames and print timing samples.

Direct DRP2, DVZR, and WebGPU fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
DRP2	Hello stream	Implemented	advanced_drp2_hello.c	stdout/JSON	drp2	Create stream, append HelloRenderer, print command count.
DRP2	Raw triangle	Implemented	advanced_drp2_triangle.c	PNG/JSON	drp2+runtime	Direct DRP2 triangle without scene.
DRP2	Validation	Implemented	advanced_drp2_validate.c	stdout	drp2	Build valid/invalid streams and print validation results.
DRP2	vklite runtime execution	Implemented	advanced_drp2_runtime.c	PNG/stdout	drp2+vklite	Execute a tiny stream through a vklite runtime.
DRP2	Borrowed canvas frame	Implemented	advanced_drp2_canvas_frame.c	PNG/live	drp2+canvas	Attach a canvas frame target and render into it.
DRP2	Readback	Implemented	advanced_drp2_readback.c	stdout	drp2+vklite	Copy/write into a buffer and read CPU bytes after execution.
DRP2	External buffer	Implemented	advanced_drp2_external_buffer.c	PNG/stdout	drp2+vklite	Register a caller-owned buffer under a DRP2 id.
DRP2	Labels/debug trace	Implemented	advanced_drp2_labels.c	stdout/JSON	drp2	Attach debug labels to ids and serialize/print the stream.
DRP2	Fixture JSON	Implemented	advanced_drp2_fixture_json.c	JSON	drp2	Produce a deterministic DRP2 fixture JSON document.
DVZR	Raw DRP2 recording	Implemented	advanced_drp2_recording.c	DVZR	drp2	Record/replay raw DRP2 frames without scene/app.
DVZR	Scene app recording	Implemented	fixture_dvzr_record_replay.c	DVZR+PNG	scene+app+drp2	Record one offscreen scene frame, replay it, compare/capture output.
DVZR	Raw fallback diagnostics	Implemented	fixture_dvzr_raw_fallback.c	stdout/DVZR	drp2	Developer-only unsupported-command fallback diagnostic.
WebGPU	Clear	Planned feasibility	fixture_webgpu_clear.json	JSON	WebGPU adapter	Clear-only DRP2 subset.
WebGPU	Static point	Planned feasibility	fixture_webgpu_point.json	JSON	WebGPU adapter	One static point stream.
WebGPU	Primitive	Planned feasibility	fixture_webgpu_primitive.json	JSON	WebGPU adapter	One triangle stream.
WebGPU	Image	Planned feasibility	fixture_webgpu_image.json	JSON	WebGPU adapter	One checkerboard image stream.
WebGPU	Depth	Planned after basics	fixture_webgpu_depth.json	JSON	WebGPU adapter	Two overlapping triangles with depth.

Interop and external-consumer fixtures

Area	Feature	Status	Example name	Output	Requirements	Minimal fixture idea
Interop	Live image handoff	Implemented	advanced_interop_live_image.c	stdout	canvas+platform handles	Canvas live-image callback prints image/view/command buffer/FD handles.
Interop	External memory export	Implemented lower-level support	advanced_interop_external_memory.c	stdout	vk+platform support	Create export-capable allocation metadata.
Interop	CUDA-filled external buffer	Implemented test smoke	advanced_interop_cuda_buffer.c	PNG/stdout	CUDA+Vulkan external memory	CUDA fills Vulkan-owned buffer, then render/readback.
Interop	External timeline semaphore	Implemented lower-level support	advanced_interop_timeline_semaphore.c	stdout	CUDA/Vulkan platform support	Demonstrate synchronization metadata and wait/signal path.
Interop	Custom external UI sink	Implemented stream substrate	advanced_interop_custom_sink.c	stdout	stream+canvas	Route frames into a custom sink for embedding applications.

Deferred and planned scene fixtures

These rows should remain planned until the corresponding runtime behavior is landed and validated.

Area	Feature	Example name	Minimal future fixture idea
Axes	2D axes/ticks	fixture_axes_2d.c	One path/point plot with x/y axes and ticks.
Legends	Legend	fixture_legend.c	Two visuals with a simple legend.
Text	Rendered glyph atlas	fixture_text_glyph_atlas.c	One line of text rendered from an atlas.
Annotation	Arrow/callout	fixture_annotation_callout.c	One arrow from text label to a point.
Picking	Mesh face picking	fixture_pick_mesh_face.c	Pick an indexed mesh triangle and report face id.
Picking	Rich payload ids	fixture_pick_payload_ids.c	Verify stable visual/item/group identity payloads.
Technique	Object-id G-buffer	fixture_gbuffer_object_id.c	Render object ids to an auxiliary target.
Technique	Selected outline	fixture_selected_outline.c	Select one object and render an outline.
Technique	Dual depth peeling	fixture_dual_depth_peel.c	Transparent layered geometry after graph-backed path lands.
Technique	Curvature/cavity shading	fixture_cavity_shading.c	One lit mesh/sphere with cavity shading.
Diagnostics	Picking-id view	fixture_diagnostics_picking_ids.c	Render or read a tiny id target and verify stable visual/item ids.
Diagnostics	Bounds/grid overlay	fixture_diagnostics_bounds_grid.c	Show coordinate grid and visual bounds over a tiny scene.
Diagnostics	Draw/update trace	fixture_diagnostics_update_trace.c	Emit a deterministic trace of draw groups or buffer dirty ranges for one update.
Compute	GPU particle simulation	fixture_gpu_particles.c	Scene-level compute writes persistent particle buffers consumed by point/sphere rendering.

Showcase Pressure Tests

These rows are not one-feature fixtures. They record gallery-scale examples that combine several features and should be backed by smaller fixtures for the individual capabilities.

Area	Example	Status	Main pressure	Minimal first slice
Embedding dashboard	IMAGE_EMBEDDING_LOD.md	Planned showcase	PD12M image thumbnails, texture-array LOD, panzoom, picking, retained resource reuse.	<=10,000 PD12M items rendered as mean-color rectangles from preprocessed embedding positions.
Embedding dashboard	SEMANTIC_EMBEDDING_ATLAS.md	Planned showcase	Dense semantic points, label LOD, title search, selection cards, optional query vectors.	<=100,000 Wikivecs articles rendered as colored points with panzoom and stable pick ids.
Terrain/planet	textured_planet.c; historical GRAND_CANYON_FLYOVER.md / EARTH.md notes	v0.4 required showcase slice	Retained textured mesh, UVs, sampler state, lit sphere-like surface, camera/capture.	One deterministic UV-mapped Earth/Mars planet using true mesh texture sampling, not baked vertex colors. Full terrain/DEM workflow follows later.
Dense splats	Splat / Gaussian-like point cloud	v0.4 experimental if visual lands	New splat visual, dense translucent rendering, blend/depth policy, camera/capture.	One synthetic or LiDAR-like splat cloud with deterministic seed, fixed camera, and nonblank PNG.
Physics	CFD_VORTICITY_ADVECTION.md	v0.4 experimental/stretch	Dynamic image updates, particle/path updates, bounded animation loop, optional video capture.	CPU advection updates a small field and point/trail overlay for 64-256 frames.
Frame graph	Debug graph dump	fixture_frame_plan_graph_debug.c	Emit deterministic graph debug output with typed resources/passes.
Descriptor refresh	Resize refresh	fixture_descriptor_refresh_resize.c	Repeated resize with stable resource ids and refreshed descriptors.
CuPy	Python/CuPy external memory	fixture_cupy_external_memory.py	Future Python-facing Vulkan-owned allocation import into CuPy.

Recommended implementation order

Phase 1 — tiny deterministic scene fixtures

1. fixture_point.c
2. fixture_pixel.c
3. fixture_path.c
4. fixture_primitive_triangle.c
5. fixture_mesh.c
6. fixture_image.c
7. fixture_field_scalar_colormap.c
8. fixture_volume_slice.c
9. fixture_sphere.c
10. fixture_panel_layout.c
11. fixture_depth_test.c
12. fixture_alpha_blend.c
13. fixture_scene_json.c
14. fixture_dvzr_record_replay.c

Phase 2 — interaction, effects, and app features

1. fixture_point_pick.c
2. fixture_image_probe.c
3. fixture_frame_callback.c
4. fixture_wboit.c
5. fixture_depth_peel.c
6. fixture_edl.c
7. fixture_ssao_spheres.c
8. fixture_volume_occlusion.c

Phase 3 — GUI and video

1. fixture_gui_controls.c
2. fixture_gui_viewport.c
3. fixture_cimgui_raw.c
4. fixture_video_config.c
5. fixture_video_offline_encode.c
6. fixture_video_scene_offscreen.c

Phase 4 — low-level power-user examples

1. advanced_vk_gpu_context.c
2. advanced_vklite_buffer.c
3. advanced_vklite_image.c
4. advanced_vklite_commands.c
5. advanced_canvas_offscreen_capture.c
6. advanced_canvas_live_image_sink.c
7. advanced_stream_custom_sink.c
8. advanced_drp2_triangle.c
9. advanced_drp2_canvas_frame.c
10. advanced_drp2_recording.c

Phase 5 — backend-gated and future fixtures

1. fixture_video_nvenc_external.c
2. fixture_video_kvazaar_cpu.c
3. advanced_interop_cuda_buffer.c
4. WebGPU JSON fixture set
5. rendered text/annotation fixtures
6. richer picking and frame-graph fixtures