/* * Copyright (C) 2007 Google Inc. * * 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 com.android.globaltime;public class LatLongSphere extends Sphere {    public LatLongSphere(float centerX, float centerY, float centerZ,        float radius, int lats, int longs,        float minLongitude, float maxLongitude,        boolean emitTextureCoordinates,        boolean emitNormals,        boolean emitColors,        boolean flatten) {        super(emitTextureCoordinates, emitNormals, emitColors);        int tris = 2 * (lats - 1) * (longs - 1);        int[] vertices = new int[3 * lats * longs];        int[] texcoords = new int[2 * lats * longs];        int[] colors = new int[4 * lats * longs];        int[] normals = new int[3 * lats * longs];        short[] indices = new short[3 * tris];        int vidx = 0;        int tidx = 0;        int nidx = 0;        int cidx = 0;        int iidx = 0;        minLongitude *= DEGREES_TO_RADIANS;        maxLongitude *= DEGREES_TO_RADIANS;        for (int i = 0; i < longs; i++) {            float fi = (float) i / (longs - 1);            // theta is the longitude            float theta =                (maxLongitude - minLongitude) * (1.0f - fi) + minLongitude;            float sinTheta = (float) Math.sin(theta);            float cosTheta = (float) Math.cos(theta);            for (int j = 0; j < lats; j++) {                float fj = (float) j / (lats - 1);                // phi is the latitude                float phi = PI * fj;                float sinPhi = (float) Math.sin(phi);                float cosPhi = (float) Math.cos(phi);                float x = cosTheta * sinPhi;                float y = cosPhi;                float z = sinTheta * sinPhi;                if (flatten) {                    // Place vertices onto a flat projection                    vertices[vidx++] = toFixed(2.0f * fi - 1.0f);                    vertices[vidx++] = toFixed(0.5f - fj);                    vertices[vidx++] = toFixed(0.0f);                } else {                    // Place vertices onto the surface of a sphere                    // with the given center and radius                    vertices[vidx++] = toFixed(x * radius + centerX);                    vertices[vidx++] = toFixed(y * radius + centerY);                    vertices[vidx++] = toFixed(z * radius + centerZ);                }                if (emitTextureCoordinates) {                    texcoords[tidx++] = toFixed(1.0f - (theta / (TWO_PI)));                    texcoords[tidx++] = toFixed(fj);                }                if (emitNormals) {                    float norm = 1.0f / Shape.length(x, y, z);                    normals[nidx++] = toFixed(x * norm);                    normals[nidx++] = toFixed(y * norm);                    normals[nidx++] = toFixed(z * norm);                }                // 0 == black, 65536 == white                if (emitColors) {                    colors[cidx++] = (i % 2) * 65536;                    colors[cidx++] = 0;                    colors[cidx++] = (j % 2) * 65536;                    colors[cidx++] = 65536;                }            }        }        for (int i = 0; i < longs - 1; i++) {            for (int j = 0; j < lats - 1; j++) {                int base = i * lats + j;                // Ensure both triangles have the same final vertex                // since this vertex carries the color for flat                // shading                indices[iidx++] = (short) (base);                indices[iidx++] = (short) (base + 1);                indices[iidx++] = (short) (base + lats + 1);                indices[iidx++] = (short) (base + lats);                indices[iidx++] = (short) (base);                indices[iidx++] = (short) (base + lats + 1);            }        }                allocateBuffers(vertices, texcoords, normals, colors, indices);    }}