wsg/lib/examples

WSG Examples

Each example is self-contained and demonstrates one effect or feature of the library. All use the declarative API (AppBuilder + AppHandler).

Running an example

cargo run -p wsg-lib --example <name>

Example	Effect demonstrated
demo	Full showcase (all effects combined)
bloom	Post-process bloom (glow around bright areas)
hdr	HDR + Tone Mapping (ACES) + exposure control
emissive	Emissive materials (increasing intensities 0 → 4.0)
shadow	Shadow mapping (directional shadow)
culling	GPU-driven culling (15×15 grid, off-frustum objects skipped)
msaa	MSAA 4× (multisample anti-aliasing, smooth edges)
fog	Distance fog (3 modes: linear, exp, exp²)
dof	Depth of Field (cinematic bokeh, focus presets)
pbr	PBR metallic/roughness + normal mapping
manual	Low-level workflow (Context + Renderer + PipelineCache)
import	OBJ file import (non-graphical, stdout)

---

demo — Full Showcase

Combines all effects: LOD primitives, procedural textures, lights (directional + point + spot), shadows, HDR/ACES, exposure, emissive, bloom, culling.

cargo run -p wsg-lib --example demo

Keys

Key	Action
Drag (LMB)	Orbit camera
Wheel	Zoom
R	Reset camera
1 / 2 / 3	Presets: front / side / top
+ / -	Exposure ×1.3 / ÷1.3
0	Reset exposure

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bloom — Post-process Bloom

Two emissive spheres (orange intensity 2.0, blue intensity 3.0) produce a visible halo. The cube and floor serve as reference (non-emissive).

Bloom is a 4-pass GPU pipeline: threshold → blur H → blur V → composite.

cargo run -p wsg-lib --example bloom

Keys

Key	Action
Drag (LMB)	Orbit camera
Wheel	Zoom
R	Reset camera
+ / -	Bloom threshold +0.1 / −0.1
[ / ]	Bloom intensity +0.1 / −0.1
I / O	Bloom radius +0.5 / −0.5
E / Q	Exposure ×1.3 / ÷1.3
0	Reset exposure

What to observe

• Low threshold (0.0): the entire image "blooms" (very diffuse effect).
• High threshold (2.0+): only the bright emissive spheres produce glow.
• Intensity 0.0: no visible glow (even though the threshold extracts pixels).
• Large radius (10+): the glow spreads over a large area.

---

hdr — HDR + Tone Mapping

Demonstrates HDR rendering with the ACES Filmic curve. Three objects:

• Cube: normal lighting (no emissive) — LDR reference.
• Bright sphere (emissive 3.0): without HDR, it would be clamped to white. With ACES, highlights "roll off" smoothly toward white.
• Dark sphere (emissive 0.3): stays dark even at high exposure.

cargo run -p wsg-lib --example hdr

Keys

Key	Action
Drag (LMB)	Orbit camera
Wheel	Zoom
R	Reset camera
E	Exposure ×1.3 (brighter)
Q	Exposure ÷1.3 (darker)
0	Reset exposure to 1.0

What to observe

• At exposure 1.0: the bright sphere is white but with detail (ACES rolloff).
• At high exposure (E×E×E): the scene brightens, the bright sphere stays white (saturated), but the cube gains detail.
• At low exposure (Q×Q): everything darkens, the bright sphere becomes orange (HDR values > 1.0 are compressed).

Note

: the tone mapper is compiled into the pipeline at build time. To compare ACES vs Reinhard, change ToneMapper::Aces → ToneMapper::Reinhard in the source.

---

emissive — Emissive Materials

Five spheres in a row with increasing emissive intensities:

Sphere	Color	Intensity	Effect
1	Gray	0.0	No glow (reference)
2	Orange	0.5	Slight glow
3	Yellow	1.0	Visible glow
4	Green	2.0	HDR glow (beyond 1.0)
5	Blue	4.0	Intense glow (saturation)

With HDR, intensities > 1.0 produce a true "glow" (values exceed [0,1] in linear space). Without HDR, they would be clamped to white.

cargo run -p wsg-lib --example emissive

Keys

Key	Action
Drag (LMB)	Orbit camera
Wheel	Zoom
R	Reset camera
E / Q	Exposure ×1.3 / ÷1.3
0	Reset exposure
C	Cycle emissive multiplier (1× → 2× → 0.5× → ...)

What to observe

• Sphere 1 (intensity 0) is simply lit by the directional light.
• Spheres 2-5 glow with their own light, independent of scene lighting.
• C doubles or halves all intensities simultaneously (to see the HDR effect).

---

shadow — Shadow Mapping

Four objects (cube, sphere, cone, cylinder) on a floor, lit by a directional light that casts shadows. Shadow quality is controlled by ShadowConfig (map size, anti-acne bias).

cargo run -p wsg-lib --example shadow

Keys

Key	Action
Drag (LMB)	Orbit camera
Wheel	Zoom
R	Reset camera
1	Front view
2	Side view
3	Top view (see shadow shapes clearly)
L	Change light direction (3 presets)

What to observe

• The cube rotates slowly → its shadow moves on the floor.
• The sphere has a smooth shadow/light transition (soft terminator).
• The cone produces a distinct triangular shadow.
• In top view (3), you see the exact shape of projected shadows.
• Shadow map size (1024 default) determines resolution: modify SHADOW_MAP_SIZE at the top of the file to test 256 (pixelated) or 2048 (sharp).

---

culling — GPU Frustum Culling

A grid of 15×15 = 225 cubes is placed on a large floor. The GPU-driven culling (compute shader) determines which cubes are visible in the camera frustum and zeros their indirect draw args — zero CPU cost.

cargo run -p wsg-lib --example culling

Keys

Key	Action
Drag (LMB)	Orbit camera (look around)
Wheel	Zoom in/out
R	Reset (top view)
1	Front view (cubes behind are culled)
2	Side view
3	Top view (see the full grid)

What to observe

• In top view (3): the entire grid is visible.
• Orbit to 90°: cubes behind the camera are not drawn (culled).
• Zoom very close: only cubes near the near plane are rendered.
• Cubes rotate slowly (staggered phases) → culling is dynamic (a cube can enter/leave the frustum during a frame).

Note

: culling is enabled via AppBuilder::with_culling(true). Changing it to false in the source disables culling (all cubes are always drawn, even off-screen).

---

msaa — MSAA 4× (Anti-aliasing)

Demonstrates multisample anti-aliasing: object edges (cube, sphere) are smooth instead of "stair-stepped". The scene contains a cube (sharp edges), a sphere (curved silhouette), and a small cube near the camera (maximum aliasing).

cargo run -p wsg-lib --example msaa

Keys

Key	Action
Drag (LMB)	Orbit camera
Wheel	Zoom
R	Reset camera
M	Show sample count

To compare with/without MSAA

Remove the .with_msaa(4) line in the source and recompile: the scene is identical, only the edges differ (stair-stepped vs smooth).

Note

: MSAA is a build-time setting (multisample texture allocation). It works independently of HDR: with HDR, the MSAA texture is Rgba16Float and resolves into the HDR texture before bloom/TM.

---

fog — Distance Fog

Demonstrates the 3 fog modes: linear, exponential, exponential². The scene contains a row of cubes receding into the distance and scattered spheres on a large floor plane. Fog blends objects toward a background color, creating the illusion of an infinite world.

cargo run -p wsg-lib --example fog --features "all-prims"

Keys: 1 = linear, 2 = exp, 3 = exp², 4 = off, R = reset.

Fog is applied in the main fragment shader (after lighting, before tone mapping). It uses the Euclidean distance from the fragment to the camera.

---

dof — Depth of Field (cinematic bokeh)

Demonstrates depth of field blur: an object at the focus plane stays sharp while foreground and background blur according to their distance from the focus plane. Creates a natural attention effect (cinematic style).

The scene contains 20 cubes in a row along Z (z=3 to z=-25.5) and 5 spheres to the sides, on a floor plane. Focus presets at 3m / 8m / 15m.

cargo run -p wsg-lib --example dof --features "all-prims"

Keys: 1 = cinematic, 2 = subtle, 3 = focus 3m, 4 = focus 15m, 5 = off, R = reset.

DoF operates in linear HDR (after bloom, before tone mapping). Two passes: CoC (depth → per-pixel blur radius) then 12-tap disc blur with variable radius.

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pbr — PBR Metallic/Roughness + Normal Mapping

Demonstrates the Cook-Torrance PBR workflow: GGX distribution + Smith geometry + Schlick Fresnel + hemispheric IBL + normal mapping.

cargo run -p wsg-lib --example pbr

Key	Action
Drag (LMB)	Orbit camera
Wheel	Zoom
R	Reset camera

Scene: 6 PBR materials (mirror metal, smooth plastic, rusty metal, ceramic, bump map, matte floor). The bump-map cube shows procedural sin-wave surface detail.

---

manual — Low-level Workflow

Demonstrates the API without the App facade: direct use of Context, Renderer, PipelineCache, Mesh, Material. Renders a colored quad (unlit).

Useful for understanding what the App facade encapsulates.

cargo run -p wsg-lib --example manual

No keys — static render (unlit quad, 4 colors).

---

import — OBJ File Import

Non-graphical example: parses a .obj file and prints statistics (vertex count, normals, UVs, indices, bounding box) to stdout.

# With a file:
cargo run -p wsg-lib --example import --features import-obj -- /path/to/model.obj

# Without argument (demo triangle):
cargo run -p wsg-lib --example import --features import-obj

No keys — runs and exits.