102 lines
3.9 KiB
Java
102 lines
3.9 KiB
Java
/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.globaltime;
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import javax.microedition.khronos.opengles.GL10;
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/**
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* A class that draws a ring with a given center and inner and outer radii.
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* The inner and outer rings each have a color and the remaining pixels are
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* colored by interpolation. GlobalTime uses this class to simulate an
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* "atmosphere" around the earth.
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*/
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public class Annulus extends Shape {
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/**
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* Constructs an annulus.
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*
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* @param centerX the X coordinate of the center point
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* @param centerY the Y coordinate of the center point
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* @param Z the fixed Z for the entire ring
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* @param innerRadius the inner radius
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* @param outerRadius the outer radius
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* @param rInner the red channel of the color of the inner ring
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* @param gInner the green channel of the color of the inner ring
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* @param bInner the blue channel of the color of the inner ring
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* @param aInner the alpha channel of the color of the inner ring
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* @param rOuter the red channel of the color of the outer ring
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* @param gOuter the green channel of the color of the outer ring
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* @param bOuter the blue channel of the color of the outer ring
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* @param aOuter the alpha channel of the color of the outer ring
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* @param sectors the number of sectors used to approximate curvature
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*/
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public Annulus(float centerX, float centerY, float Z,
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float innerRadius, float outerRadius,
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float rInner, float gInner, float bInner, float aInner,
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float rOuter, float gOuter, float bOuter, float aOuter,
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int sectors) {
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super(GL10.GL_TRIANGLES, GL10.GL_UNSIGNED_SHORT,
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false, false, true);
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int radii = sectors + 1;
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int[] vertices = new int[2 * 3 * radii];
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int[] colors = new int[2 * 4 * radii];
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short[] indices = new short[2 * 3 * radii];
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int vidx = 0;
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int cidx = 0;
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int iidx = 0;
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for (int i = 0; i < radii; i++) {
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float theta = (i * TWO_PI) / (radii - 1);
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float cosTheta = (float) Math.cos(theta);
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float sinTheta = (float) Math.sin(theta);
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vertices[vidx++] = toFixed(centerX + innerRadius * cosTheta);
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vertices[vidx++] = toFixed(centerY + innerRadius * sinTheta);
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vertices[vidx++] = toFixed(Z);
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vertices[vidx++] = toFixed(centerX + outerRadius * cosTheta);
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vertices[vidx++] = toFixed(centerY + outerRadius * sinTheta);
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vertices[vidx++] = toFixed(Z);
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colors[cidx++] = toFixed(rInner);
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colors[cidx++] = toFixed(gInner);
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colors[cidx++] = toFixed(bInner);
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colors[cidx++] = toFixed(aInner);
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colors[cidx++] = toFixed(rOuter);
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colors[cidx++] = toFixed(gOuter);
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colors[cidx++] = toFixed(bOuter);
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colors[cidx++] = toFixed(aOuter);
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}
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for (int i = 0; i < sectors; i++) {
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indices[iidx++] = (short) (2 * i);
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indices[iidx++] = (short) (2 * i + 1);
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indices[iidx++] = (short) (2 * i + 2);
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indices[iidx++] = (short) (2 * i + 1);
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indices[iidx++] = (short) (2 * i + 3);
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indices[iidx++] = (short) (2 * i + 2);
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}
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allocateBuffers(vertices, null, null, colors, indices);
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}
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}
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