File	Doc	Category	Size	Date	Package
Visibility.java	API Doc	Android 1.5 API	5871	Wed May 06 22:42:00 BST 2009	android.opengl

Visibility

• java.lang.Object

Fields Summary

Constructors Summary

Methods Summary
public static native void	computeBoundingSphere(float[] positions, int positionsOffset, int positionsCount, float[] sphere, int sphereOffset) Compute a bounding sphere for a set of points. It is approximately the minimal bounding sphere of an axis-aligned box that bounds the points. param positions positions in x, y, z triples param positionsOffset offset into positions array param positionsCount number of position triples to process param sphere array containing the output as (x, y, z, r) param sphereOffset offset where the sphere data will be written throws IllegalArgumentException if positions is null, positionsOffset < 0, positionsOffset > positions.length - positionsCount, sphere is null, sphereOffset < 0, sphereOffset > sphere.length - 4.
public static native int	frustumCullSpheres(float[] mvp, int mvpOffset, float[] spheres, int spheresOffset, int spheresCount, int[] results, int resultsOffset, int resultsCapacity) Given an OpenGL ES ModelView-Projection matrix (which implicitly describes a frustum) and a list of spheres, determine which spheres intersect the frustum. A ModelView-Projection matrix can be computed by multiplying the a Projection matrix by the a ModelView matrix (in that order.). There are several possible ways to obtain the current ModelView and Projection matrices. The most generally applicable way is to keep track of the current matrices in application code. If that is not convenient, there are two optional OpenGL ES extensions which may be used to read the current matrices from OpenGL ES: GL10Ext.glQueryMatrixxOES GL11.GL_MODELVIEW_MATRIX_FLOAT_AS_INT_BITS_OES and GL_PROJECTION_MATRIX_FLOAT_AS_INT_BITS_OES The problem with reading back the matrices is that your application will only work with devices that support the extension(s) that it uses. A frustum is a six-sided truncated pyramid that defines the portion of world space that is visible in the view. Spheres are described as four floating point values: x, y, z, and r, in world-space coordinates. R is the radius of the sphere. param mvp a float array containing the mode-view-projection matrix param mvpOffset The offset of the mvp data within the mvp array. param spheres a float array containing the sphere data. param spheresOffset an offset into the sphere array where the sphere data starts param spheresCount the number of spheres to cull. param results an integer array containing the indices of the spheres that are either contained entirely within or intersect the frustum. param resultsOffset an offset into the results array where the results start. param resultsCapacity the number of array elements available for storing results. return the number of spheres that intersected the frustum. Can be larger than resultsCapacity, in which case only the first resultsCapacity results are written into the results array. throws IllegalArgumentException if mvp is null, mvpOffset < 0, mvpOffset > mvp.length - 16, spheres is null, spheresOffset < 0, spheresOffset > spheres.length - sphereCount, results is null, resultsOffset < 0, resultsOffset > results.length - resultsCapacity.
public static native int	visibilityTest(float[] ws, int wsOffset, float[] positions, int positionsOffset, char[] indices, int indicesOffset, int indexCount) Test whether a given triangle mesh is visible on the screen. The mesh is specified as an indexed triangle list. param ws the world space to screen space transform matrix, as an OpenGL column matrix. param wsOffset an index into the ws array where the data starts. param positions the vertex positions (x, y, z). param positionsOffset the index in the positions array where the data starts. param indices the indices of the triangle list. The indices are expressed as chars because they are unsigned 16-bit values. param indicesOffset the index in the indices array where the index data starts. param indexCount the number of indices in use. Typically a multiple of three. If not a multiple of three, the remaining one or two indices will be ignored. return 2 if all of the mesh is visible, 1 if some part of the mesh is visible, 0 if no part is visible. throws IllegalArgumentException if ws is null, wsOffset < 0, positions is null, positionsOffset < 0, indices is null, indicesOffset < 0, indicesOffset > indices.length - indexCount