psychopy.tools.gltools.createUVSphere

psychopy.tools.gltools.createUVSphere(radius=0.5, sectors=16, stacks=16, flipFaces=False)[source]

Create a UV sphere.

Procedurally generate a UV sphere by specifying its radius, and number of stacks and sectors. The poles of the resulting sphere will be aligned with the Z-axis.

Surface normals and texture coordinates are automatically generated. The returned normals are computed to produce smooth shading.

Parameters
  • radius (float, optional) – Radius of the sphere in scene units (usually meters). Default is 0.5.

  • sectors (int, optional) – Number of longitudinal and latitudinal sub-divisions. Default is 16 for both.

  • stacks (int, optional) – Number of longitudinal and latitudinal sub-divisions. Default is 16 for both.

  • flipFaces (bool, optional) – If True, normals and face windings will be set to point inward towards the center of the sphere. Texture coordinates will remain the same. Default is False.

Returns

Vertex attribute arrays (position, texture coordinates, and normals) and triangle indices.

Return type

tuple

Examples

Create a UV sphere and VAO to render it:

vertices, textureCoords, normals, faces =             gltools.createUVSphere(sectors=32, stacks=32)

vertexVBO = gltools.createVBO(vertices)
texCoordVBO = gltools.createVBO(textureCoords)
normalsVBO = gltools.createVBO(normals)
indexBuffer = gltools.createVBO(
    faces.flatten(),
    target=GL.GL_ELEMENT_ARRAY_BUFFER,
    dataType=GL.GL_UNSIGNED_INT)

vao = gltools.createVAO({0: vertexVBO, 8: texCoordVBO, 2: normalsVBO},
    indexBuffer=indexBuffer)

# in the rendering loop
gltools.drawVAO(vao, GL.GL_TRIANGLES)

The color of the sphere can be changed by calling glColor*:

glColor4f(1.0, 0.0, 0.0, 1.0)  # red
gltools.drawVAO(vao, GL.GL_TRIANGLES)

Raw coordinates can be transformed prior to uploading to VBOs. Here we can rotate vertex positions and normals so the equator rests on Z-axis:

r = mt.rotationMatrix(90.0, (1.0, 0, 0.0))  # 90 degrees about +X axis
vertices = mt.applyMatrix(r, vertices)
normals = mt.applyMatrix(r, normals)

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