cesium/Specs/Data/Models/glTF-2.0/unitSquare

UnitSquare

A unit square, in different flavors.

All files describe a square (0,0,0)-(1,1,0), with positions, normals, and texture coordinates. The normals are always (0,0,1). The texture coordinates are the (x,1-y) components of the vertex positions (i.e. the (x,y) coordinates, but flipped vertically). The texture is a simple 128x128 pixel dummy PNG texture.

The files that start with unitSquare11x11 consist of a regular grid of 11x11 = 121 vertices, representing and 200 triangles, stored with mode=GL_TRIANGLES.

The flavors of this file are

• unitSquare11x11_plain.glb: Just the plain glTF, without compression or quantization, storing all attributes in their floating point representation, in non-interleaved accessors
• unitSquare11x11_plain_interleaved.glb: The same as plain, but storing the data in interleaved accessors
• unitSquare11x11_draco.glb: The plain version, draco-compressed
• unitSquare11x11_meshopt.glb: The plain version, meshopt-compressed
• unitSquare11x11_quantized.glb: The plain file, with quantization, storing the result in non-interleaved accessors
• unitSquare11x11_quantized_interleaved.glb: The same as quantized, but storing the result in interleaved accessors
• unitSquare11x11_unsignedShortTexCoords.glb: The same as plain, but with the texture coordinates stored as a GL_UNSIGNED_SHORT (normalized) accessor, in non-interleaved accessors
• unitSquare11x11_unsignedShortTexCoords_interleaved.glb: The same as unsignedShortTexCoords, stored with interleaved accessors
• unitSquare11x11_unsignedShortTexCoords_quantized.glb: The same as unsignedShortTexCoords, with additional quantization, stored in non-interleaved accessors
• unitSquare11x11_unsignedShortTexCoords_quantized_interleaved.glb: The same as unsignedShortTexCoords_quantized, but stored with interleaved accessors

The other representations aim at different primitive modes:

• unitSquare11x2_triangleStrip.glb: Contains 11x2 vertices, 11 in x-direction and 2 in y-direction, storing the triangles in mode=GL_TRIANGLE_STRIP
• unitSquare5_triangleFan.glb: Contains 5 vertices, one at (0.5, 0.5) and one at each corner of the unit square, representing the triangles in mode=GL_TRIANGLE_FAN

Other representations aim at further structural tests

• unitSquare_fourPrimitives_plain.glb: A unit square given as a single mesh that consists of four primitives, each with 3x3 vertices.

Most basic versions of the files have been created with a custom snippet based on JglTF. The compressed, interleaved, and quantized versions have been created with glTF-Transform (via https://gltf.report/). The quantization in all cases was { quantizePosition: 14, quantizeNormal: 10 }.