Class: CustomShader

CustomShader

new CustomShader(options)

A user defined GLSL shader used with Model as well as Cesium3DTileset.

If texture uniforms are used, additional resource management must be done:

  • The update function must be called each frame. When a custom shader is passed to a Model or a Cesium3DTileset, this step is handled automaticaly
  • CustomShader#destroy must be called when the custom shader is no longer needed to clean up GPU resources properly. The application is responsible for calling this method.

See the Custom Shader Guide for more detailed documentation.

Name Type Description
options object

An object with the following options

Name Type Default Description
mode CustomShaderMode CustomShaderMode.MODIFY_MATERIAL 可选

The custom shader mode, which determines how the custom shader code is inserted into the fragment shader.
lightingModel LightingModel 可选

The lighting model (e.g. PBR or unlit). If present, this overrides the default lighting for the model.
translucencyMode CustomShaderTranslucencyMode CustomShaderTranslucencyMode.INHERIT 可选

The translucency mode, which determines how the custom shader will be applied. If the value is CustomShaderTransulcencyMode.OPAQUE or CustomShaderTransulcencyMode.TRANSLUCENT, the custom shader will override settings from the model's material. If the value is CustomShaderTransulcencyMode.INHERIT, the custom shader will render as either opaque or translucent depending on the primitive's material settings.
uniforms Object.<string, UniformSpecifier> 可选

A dictionary for user-defined uniforms. The key is the uniform name that will appear in the GLSL code. The value is an object that describes the uniform type and initial value
varyings Object.<string, VaryingType> 可选

A dictionary for declaring additional GLSL varyings used in the shader. The key is the varying name that will appear in the GLSL code. The value is the data type of the varying. For each varying, the declaration will be added to the top of the shader automatically. The caller is responsible for assigning a value in the vertex shader and using the value in the fragment shader.
vertexShaderText string 可选

The custom vertex shader as a string of GLSL code. It must include a GLSL function called vertexMain. See the example for the expected signature. If not specified, the custom vertex shader step will be skipped in the computed vertex shader.
fragmentShaderText string 可选

The custom fragment shader as a string of GLSL code. It must include a GLSL function called fragmentMain. See the example for the expected signature. If not specified, the custom fragment shader step will be skipped in the computed fragment shader.
Example
const customShader = new CustomShader({
  uniforms: {
    u_colorIndex: {
      type: Cesium.UniformType.FLOAT,
      value: 1.0
    },
    u_normalMap: {
      type: Cesium.UniformType.SAMPLER_2D,
      value: new Cesium.TextureUniform({
        url: "normal.png"
      })
    }
  },
  varyings: {
    v_selectedColor: Cesium.VaryingType.VEC3
  },
  vertexShaderText: `
  void vertexMain(VertexInput vsInput, inout czm_modelVertexOutput vsOutput) {
    v_selectedColor = mix(vsInput.attributes.color_0, vsInput.attributes.color_1, u_colorIndex);
    vsOutput.positionMC += 0.1 * vsInput.attributes.normal;
  }
  `,
  fragmentShaderText: `
  void fragmentMain(FragmentInput fsInput, inout czm_modelMaterial material) {
    material.normal = texture(u_normalMap, fsInput.attributes.texCoord_0);
    material.diffuse = v_selectedColor;
  }
  `
});

Members

readonly fragmentShaderTextstring

The user-defined GLSL code for the fragment shader

readonly lightingModelLightingModel

The lighting model to use when using the custom shader. This is used by CustomShaderPipelineStage

readonly modeCustomShaderMode

A value determining how the custom shader interacts with the overall fragment shader. This is used by CustomShaderPipelineStage

readonly translucencyModeCustomShaderTranslucencyMode

The translucency mode, which determines how the custom shader will be applied. If the value is CustomShaderTransulcencyMode.OPAQUE or CustomShaderTransulcencyMode.TRANSLUCENT, the custom shader will override settings from the model's material. If the value isCustomShaderTransulcencyMode.INHERIT, the custom shader will render as either opaque or translucent depending on the primitive's material settings.

Default Value:
CustomShaderTranslucencyMode.INHERIT

readonly uniformsObject.<string, UniformSpecifier>

Additional uniforms as declared by the user.

readonly varyingsObject.<string, VaryingType>

Additional varyings as declared by the user. This is used by CustomShaderPipelineStage

readonly vertexShaderTextstring

The user-defined GLSL code for the vertex shader

Methods

setUniform(uniformName, value)

Update the value of a uniform declared in the shader

Name Type Description
uniformName string

The GLSL name of the uniform. This must match one of the uniforms declared in the constructor
value boolean | number | Cartesian2 | Cartesian3 | Cartesian4 | Matrix2 | Matrix3 | Matrix4 | string | Resource | TextureUniform

The new value of the uniform.