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author | The Android Open Source Project <initial-contribution@android.com> | 2008-10-21 07:00:00 -0700 |
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committer | The Android Open Source Project <initial-contribution@android.com> | 2008-10-21 07:00:00 -0700 |
commit | 54b6cfa9a9e5b861a9930af873580d6dc20f773c (patch) | |
tree | 35051494d2af230dce54d6b31c6af8fc24091316 /opengl/java/android/opengl/Visibility.java | |
download | frameworks_base-54b6cfa9a9e5b861a9930af873580d6dc20f773c.zip frameworks_base-54b6cfa9a9e5b861a9930af873580d6dc20f773c.tar.gz frameworks_base-54b6cfa9a9e5b861a9930af873580d6dc20f773c.tar.bz2 |
Initial Contribution
Diffstat (limited to 'opengl/java/android/opengl/Visibility.java')
-rw-r--r-- | opengl/java/android/opengl/Visibility.java | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/opengl/java/android/opengl/Visibility.java b/opengl/java/android/opengl/Visibility.java new file mode 100644 index 0000000..b802160 --- /dev/null +++ b/opengl/java/android/opengl/Visibility.java @@ -0,0 +1,124 @@ +/* + * Copyright (C) 2007 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package android.opengl; + +/** + * {@hide} + * A collection of utility methods for computing the visibility of triangle + * meshes. + * + */ +public class Visibility { + /** + * 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 + */ + public static native int visibilityTest(float[] ws, int wsOffset, + float[] positions, int positionsOffset, char[] indices, + int indicesOffset, int indexCount); + + /** + * Given an OpenGL ES ModelView-Projection matrix (which implicitly + * describes a frustum) and a list of spheres, determine which spheres + * intersect the frustum. + * <p> + * 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: + * <ul> + * <li>GL10Ext.glQueryMatrixxOES + * <li>GL11.GL_MODELVIEW_MATRIX_FLOAT_AS_INT_BITS_OES and + * GL_PROJECTION_MATRIX_FLOAT_AS_INT_BITS_OES + * </ul> + * The problem with reading back the matrices is that your application + * will only work with devices that support the extension(s) that + * it uses. + * <p> + * A frustum is a six-sided truncated pyramid that defines the portion of + * world space that is visible in the view. + * <p> + * Spheres are described as four floating point values: x, y, z, and r, in + * world-space coordinates. R is the radius of the sphere. + * <p> + * @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 frustumCullSpheres(float[] mvp, int mvpOffset, + float[] spheres, int spheresOffset, int spheresCount, + int[] results, int resultsOffset, int resultsCapacity); + + /** + * 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 void computeBoundingSphere(float[] positions, + int positionsOffset, int positionsCount, float[] sphere, + int sphereOffset); +} |