cesiumjs-materials-shaders

# CesiumJS Materials, Shaders & Post-Processing

Version baseline: CesiumJS 1.142 (June 2026). All imports use ES module style.

## Material System (Fabric JSON)

`Material` defines surface appearance for **Primitives** through a JSON schema called Fabric. Materials compile to GLSL and are consumed by `MaterialAppearance` or `PolylineMaterialAppearance`.

### Built-in Material Types

**Surface:** `Color` (color), `Image` (image, repeat), `DiffuseMap`, `AlphaMap`, `SpecularMap`, `EmissionMap` (image, channel(s), repeat), `BumpMap`, `NormalMap` (image, channel(s), strength, repeat).

**Patterns:** `Grid` (color, cellAlpha, lineCount, lineThickness), `Stripe` (evenColor, oddColor, repeat), `Checkerboard` (lightColor, darkColor, repeat), `Dot` (lightColor, darkColor, repeat).

**Effects:** `Water` (baseWaterColor, normalMap, frequency, animationSpeed), `RimLighting` (color, rimColor, width), `Fade` (fadeInColor, fadeOutColor, maximumDistance).

**Terrain:** `ElevationContour` (color, spacing, width), `ElevationRamp` (image, minimumHeight, maximumHeight).

**Polyline:** `PolylineArrow` (color), `PolylineDash` (color, gapColor, dashLength, dashPattern), `PolylineGlow` (color, glowPower, taperPower), `PolylineOutline` (color, outlineColor, outlineWidth).

### Creating Materials

```js
import { Material, Color, Cartesian2 } from "cesium";

// Shorthand with fromType (preferred for built-in types)
const colorMat = Material.fromType("Color", { color: new Color(1.0, 0.0, 0.0, 0.5) });

// Full Fabric notation
const gridMat = new Material({
  fabric: {
    type: "Grid",
    uniforms: { color: Color.GREEN, cellAlpha: 0.1, lineCount: new Cartesian2(8, 8) },
  },
});

// Async loading -- awaits textures before first frame, no flicker
const imageMat = await Material.fromTypeAsync("Image", { image: "./textures/facade.png" });
```

### Custom Fabric with GLSL Source

Use `source` for inline GLSL. Uniforms declared in `uniforms` are available by name in the shader.

```js
import { Material, Color } from "cesium";

const pulseMaterial = new Material({
  fabric: {
    uniforms: { color: Color.CYAN, speed: 2.0 },
    source: `czm_material czm_getMaterial(czm_materialInput materialInput) {
      czm_material material = czm_getDefaultMaterial(materialInput);
      float pulse = sin(czm_frameNumber * speed * 0.01) * 0.5 + 0.5;
      material.diffuse = color.rgb;
      material.alpha = color.a * pulse;
      return material;
    }`,
  },
  translucent: true,
});
```

### Applying Materials to Primitives

```js
import { Primitive, GeometryInstance, RectangleGeometry, Rectangle,
  MaterialAppearance, Material, Color, Cartesian2 } from "cesium";

viewer.scene.primitives.add(new Primitive({
  geometryInstances: new GeometryInstance({
    geometry: new RectangleGeometry({ rectangle: Rectangle.fromDegrees(-100, 30, -90, 40) }),
  }),
  appearance: new MaterialAppearance({
    material: Material.fromType("Checkerboard", {
      lightColor: Color.WHITE, darkColor: Color.BLACK, repeat: new Cartesian2(4, 4),
    }),
  }),
}));
```

### Compositing Sub-Materials (Fabric `materials` + `components`)

```js
import { Material, Color } from "cesium";

const compositeMat = new Material({ fabric: {
  materials: {
    gridMaterial: { type: "Grid" },
    colorMaterial: { type: "Color", uniforms: { color: Color.BLUE } },
  },
  components: {
    diffuse: "gridMaterial.diffuse + 0.2 * colorMaterial.diffuse",
    alpha: "min(gridMaterial.alpha, colorMaterial.alpha)",
  },
}});
```

## CustomShader

`CustomShader` injects user GLSL into `Model`, `Cesium3DTileset`, and `VoxelPrimitive` rendering, with access to vertex attributes, feature IDs, and `EXT_structural_metadata`.

**For shader authoring — struct reference, metadata access, feature IDs, voxel subset, 1.139 breaking changes, and seven worked examples — see the `cesiumjs-custom-shader` skill.** This skill owns the `CustomShader` integration surface; the authoring depth lives there.

Minimal example:

```js
import { CustomShader, Model } from "cesium";

const shader = new CustomShader({
  fragmentShaderText: `
    void fragmentMain(FragmentInput fsInput, inout czm_modelMaterial material) {
      material.diffuse = vec3(1.0, 0.5, 0.0);
    }
  `,
});
const model = await Model.fromGltfAsync({ url: "./building.glb", customShader: shader });
viewer.scene.primitives.add(model);
```

## ImageBasedLighting

Controls PBR image-based lighting for `Model` and `Cesium3DTileset`. `imageBasedLightingFactor` (Cartesian2) scales diffuse (x) and specular (y) from 0 to 1. Diffuse comes from `sphericalHarmonicCoefficients` (array of 9 Cartesian3, L0-L2). Specular comes from `specularEnvironmentMaps` (URL to KTX2 cube map).

```js
import { ImageBasedLighting, Cartesian2, Cartesian3 } from "cesium";

const coefficients = [ // 9 Cartesian3 values for L0..L2 bands
  new Cartesian3(0.35, 0.35, 0.38), new Cartesian3(0.11, 0.11, 0.11),
  new Cartesian3(0.04, 0.04, 0.04), new Cartesian3(-0.08, -0.08, -0.08),
  new Cartesian3(-0.02, -0.02, -0.02), new Cartesian3(0.04, 0.04, 0.04),
  new Cartesian3(-0.06, -0.06, -0.06), new Cartesian3(0.01, 0.01, 0.01),
  new Cartesian3(-0.03, -0.03, -0.03),
];
const ibl = new ImageBasedLighting({
  imageBasedLightingFactor: new Cartesian2(1.0, 1.0),
  sphericalHarmonicCoefficients: coefficients,
  specularEnvironmentMaps: "./environment/specular.ktx2",
});
const model = await Cesium.Model.fromGltfAsync({ url: "./helmet.glb", imageBasedLighting: ibl });
viewer.scene.primitives.add(model);
// Disable: model.imageBasedLighting.imageBasedLightingFactor = new Cartesian2(0.0, 0.0);
```

## Post-Processing

Screen-space pipeline via `viewer.scene.postProcessStages` (`PostProcessStageCollection`). Stages execute in order; each reads `colorTexture` and `depthTexture`.

### Built-in Effects (PostProcessStageLibrary)

`createBlurStage()` (delta, sigma, stepSize), `createDepthOfFieldStage()` (focalDistance, delta, sigma, stepSize), `createEdgeDetectionStage()` (color, length), `createSi