Module: GeometryPipeline

Content pipeline functions for geometries.
Source:
See:

Methods

(static) compressVertices(geometry) → {Geometry}

Compresses and packs geometry normal attribute values to save memory.
Parameters:
Name Type Description
geometry Geometry The geometry to modify.
Source:
Returns:
The modified geometry argument, with its normals compressed and packed.
Type
Geometry
Example
geometry = Cesium.GeometryPipeline.compressVertices(geometry);

(static) computeBinormalAndTangent(geometry) → {Geometry}

Computes per-vertex binormals and tangents for a geometry containing TRIANGLES. The result is new binormal and tangent attributes added to the geometry. This assumes a counter-clockwise winding order.

Based on Computing Tangent Space Basis Vectors for an Arbitrary Mesh by Eric Lengyel.

Parameters:
Name Type Description
geometry Geometry The geometry to modify.
Source:
Throws:
  • geometry.indices length must be greater than 0 and be a multiple of 3.
    Type
    DeveloperError
  • geometry.primitiveType must be PrimitiveType.TRIANGLES.
    Type
    DeveloperError
Returns:
The modified geometry argument with the computed binormal and tangent attributes.
Type
Geometry
Example
Cesium.GeometryPipeline.computeBinormalAndTangent(geometry);

(static) computeNormal(geometry) → {Geometry}

Computes per-vertex normals for a geometry containing TRIANGLES by averaging the normals of all triangles incident to the vertex. The result is a new normal attribute added to the geometry. This assumes a counter-clockwise winding order.
Parameters:
Name Type Description
geometry Geometry The geometry to modify.
Source:
Throws:
  • geometry.indices length must be greater than 0 and be a multiple of 3.
    Type
    DeveloperError
  • geometry.primitiveType must be PrimitiveType.TRIANGLES.
    Type
    DeveloperError
Returns:
The modified geometry argument with the computed normal attribute.
Type
Geometry
Example
Cesium.GeometryPipeline.computeNormal(geometry);

(static) createAttributeLocations(geometry) → {Object}

Creates an object that maps attribute names to unique locations (indices) for matching vertex attributes and shader programs.
Parameters:
Name Type Description
geometry Geometry The geometry, which is not modified, to create the object for.
Source:
Returns:
An object with attribute name / index pairs.
Type
Object
Example
var attributeLocations = Cesium.GeometryPipeline.createAttributeLocations(geometry);
// Example output
// {
//   'position' : 0,
//   'normal' : 1
// }

(static) createLineSegmentsForVectors(geometry, attributeNameopt, lengthopt) → {Geometry}

Creates a new Geometry with LINES representing the provided attribute (attributeName) for the provided geometry. This is used to visualize vector attributes like normals, binormals, and tangents.
Parameters:
Name Type Attributes Default Description
geometry Geometry The Geometry instance with the attribute.
attributeName String <optional>
 'normal' The name of the attribute.
length Number <optional>
 10000.0 The length of each line segment in meters. This can be negative to point the vector in the opposite direction.
Source:
Throws:
geometry.attributes must have an attribute with the same name as the attributeName parameter.
Type
DeveloperError
Returns:
A new Geometry instance with line segments for the vector.
Type
Geometry
Example
var geometry = Cesium.GeometryPipeline.createLineSegmentsForVectors(instance.geometry, 'binormal', 100000.0);

(static) encodeAttribute(geometry, attributeName, attributeHighName, attributeLowName) → {Geometry}

Encodes floating-point geometry attribute values as two separate attributes to improve rendering precision.

This is commonly used to create high-precision position vertex attributes.

Parameters:
Name Type Description
geometry Geometry The geometry to modify.
attributeName String The name of the attribute.
attributeHighName String The name of the attribute for the encoded high bits.
attributeLowName String The name of the attribute for the encoded low bits.
Source:
Throws:
  • geometry must have attribute matching the attributeName argument.
    Type
    DeveloperError
  • The attribute componentDatatype must be ComponentDatatype.DOUBLE.
    Type
    DeveloperError
Returns:
The modified geometry argument, with its encoded attribute.
Type
Geometry
Example
geometry = Cesium.GeometryPipeline.encodeAttribute(geometry, 'position3D', 'position3DHigh', 'position3DLow');

(static) fitToUnsignedShortIndices(geometry) → {Array.<Geometry>}

Splits a geometry into multiple geometries, if necessary, to ensure that indices in the indices fit into unsigned shorts. This is used to meet the WebGL requirements when unsigned int indices are not supported.

If the geometry does not have any indices, this function has no effect.

Parameters:
Name Type Description
geometry Geometry The geometry to be split into multiple geometries.
Source:
Throws:
  • geometry.primitiveType must equal to PrimitiveType.TRIANGLES, PrimitiveType.LINES, or PrimitiveType.POINTS
    Type
    DeveloperError
  • All geometry attribute lists must have the same number of attributes.
    Type
    DeveloperError
Returns:
An array of geometries, each with indices that fit into unsigned shorts.
Type
Array.<Geometry>
Example
var geometries = Cesium.GeometryPipeline.fitToUnsignedShortIndices(geometry);

(static) projectTo2D(geometry, attributeName, attributeName3D, attributeName2D, projectionopt) → {Geometry}

Projects a geometry's 3D position attribute to 2D, replacing the position attribute with separate position3D and position2D attributes.

If the geometry does not have a position, this function has no effect.

Parameters:
Name Type Attributes Default Description
geometry Geometry The geometry to modify.
attributeName String The name of the attribute.
attributeName3D String The name of the attribute in 3D.
attributeName2D String The name of the attribute in 2D.
projection Object <optional>
 new GeographicProjection() The projection to use.
Source:
Throws:
  • geometry must have attribute matching the attributeName argument.
    Type
    DeveloperError
  • The attribute componentDatatype must be ComponentDatatype.DOUBLE.
    Type
    DeveloperError
  • Could not project a point to 2D.
    Type
    DeveloperError
Returns:
The modified geometry argument with position3D and position2D attributes.
Type
Geometry
Example
geometry = Cesium.GeometryPipeline.projectTo2D(geometry, 'position', 'position3D', 'position2D');

(static) reorderForPostVertexCache(geometry, cacheCapacityopt) → {Geometry}

Reorders a geometry's indices to achieve better performance from the GPU's post vertex-shader cache by using the Tipsify algorithm. If the geometry primitiveType is not TRIANGLES or the geometry does not have an indices, this function has no effect.
Parameters:
Name Type Attributes Default Description
geometry Geometry The geometry to modify.
cacheCapacity Number <optional>
 24 The number of vertices that can be held in the GPU's vertex cache.
Source:
See:
Throws:
cacheCapacity must be greater than two.
Type
DeveloperError
Returns:
The modified geometry argument, with its indices reordered for the post-vertex-shader cache.
Type
Geometry
Example
geometry = Cesium.GeometryPipeline.reorderForPostVertexCache(geometry);

(static) reorderForPreVertexCache(geometry) → {Geometry}

Reorders a geometry's attributes and indices to achieve better performance from the GPU's pre-vertex-shader cache.
Parameters:
Name Type Description
geometry Geometry The geometry to modify.
Source:
See:
  • GeometryPipeline.reorderForPostVertexCache
Throws:
Each attribute array in geometry.attributes must have the same number of attributes.
Type
DeveloperError
Returns:
The modified geometry argument, with its attributes and indices reordered for the GPU's pre-vertex-shader cache.
Type
Geometry
Example
geometry = Cesium.GeometryPipeline.reorderForPreVertexCache(geometry);

(static) toWireframe(geometry) → {Geometry}

Converts a geometry's triangle indices to line indices. If the geometry has an indices and its primitiveType is TRIANGLES, TRIANGLE_STRIP, TRIANGLE_FAN, it is converted to LINES; otherwise, the geometry is not changed.

This is commonly used to create a wireframe geometry for visual debugging.

Parameters:
Name Type Description
geometry Geometry The geometry to modify.
Source:
Throws:
geometry.primitiveType must be TRIANGLES, TRIANGLE_STRIP, or TRIANGLE_FAN.
Type
DeveloperError
Returns:
The modified geometry argument, with its triangle indices converted to lines.
Type
Geometry
Example
geometry = Cesium.GeometryPipeline.toWireframe(geometry);

(static) transformToWorldCoordinates(instance) → {GeometryInstance}

Transforms a geometry instance to world coordinates. This changes the instance's modelMatrix to Matrix4.IDENTITY and transforms the following attributes if they are present: position, normal, binormal, and tangent.
Parameters:
Name Type Description
instance GeometryInstance The geometry instance to modify.
Source:
Returns:
The modified instance argument, with its attributes transforms to world coordinates.
Type
GeometryInstance
Example
Cesium.GeometryPipeline.transformToWorldCoordinates(instance);