/*
* 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 com.android.globaltime;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;
import java.nio.ShortBuffer;
import javax.microedition.khronos.opengles.GL10;
/**
* An abstract superclass for various three-dimensional objects to be drawn
* using OpenGL ES. Each subclass is responsible for setting up NIO buffers
* containing vertices, texture coordinates, colors, normals, and indices.
* The {@link #draw(GL10)} method draws the object to the given OpenGL context.
*/
public abstract class Shape {
public static final int INT_BYTES = 4;
public static final int SHORT_BYTES = 2;
public static final float DEGREES_TO_RADIANS = (float) Math.PI / 180.0f;
public static final float PI = (float) Math.PI;
public static final float TWO_PI = (float) (2.0 * Math.PI);
public static final float PI_OVER_TWO = (float) (Math.PI / 2.0);
protected int mPrimitive;
protected int mIndexDatatype;
protected boolean mEmitTextureCoordinates;
protected boolean mEmitNormals;
protected boolean mEmitColors;
protected IntBuffer mVertexBuffer;
protected IntBuffer mTexcoordBuffer;
protected IntBuffer mColorBuffer;
protected IntBuffer mNormalBuffer;
protected Buffer mIndexBuffer;
protected int mNumIndices = -1;
/**
* Constructs a Shape.
*
* @param primitive a GL primitive type understood by glDrawElements,
* such as GL10.GL_TRIANGLES
* @param indexDatatype the GL datatype for the index buffer, such as
* GL10.GL_UNSIGNED_SHORT
* @param emitTextureCoordinates true to enable use of the texture
* coordinate buffer
* @param emitNormals true to enable use of the normal buffer
* @param emitColors true to enable use of the color buffer
*/
protected Shape(int primitive,
int indexDatatype,
boolean emitTextureCoordinates,
boolean emitNormals,
boolean emitColors) {
mPrimitive = primitive;
mIndexDatatype = indexDatatype;
mEmitTextureCoordinates = emitTextureCoordinates;
mEmitNormals = emitNormals;
mEmitColors = emitColors;
}
/**
* Converts the given floating-point value to fixed-point.
*/
public static int toFixed(float x) {
return (int) (x * 65536.0);
}
/**
* Converts the given fixed-point value to floating-point.
*/
public static float toFloat(int x) {
return (float) (x / 65536.0);
}
/**
* Computes the cross-product of two vectors p and q and places
* the result in out.
*/
public static void cross(float[] p, float[] q, float[] out) {
out[0] = p[1] * q[2] - p[2] * q[1];
out[1] = p[2] * q[0] - p[0] * q[2];
out[2] = p[0] * q[1] - p[1] * q[0];
}
/**
* Returns the length of a vector, given as three floats.
*/
public static float length(float vx, float vy, float vz) {
return (float) Math.sqrt(vx * vx + vy * vy + vz * vz);
}
/**
* Returns the length of a vector, given as an array of three floats.
*/
public static float length(float[] v) {
return length(v[0], v[1], v[2]);
}
/**
* Normalizes the given vector of three floats to have length == 1.0.
* Vectors with length zero are unaffected.
*/
public static void normalize(float[] v) {
float length = length(v);
if (length != 0.0f) {
float norm = 1.0f / length;
v[0] *= norm;
v[1] *= norm;
v[2] *= norm;
}
}
/**
* Returns the number of triangles associated with this shape.
*/
public int getNumTriangles() {
if (mPrimitive == GL10.GL_TRIANGLES) {
return mIndexBuffer.capacity() / 3;
} else if (mPrimitive == GL10.GL_TRIANGLE_STRIP) {
return mIndexBuffer.capacity() - 2;
}
return 0;
}
/**
* Copies the given data into the instance
* variables mVertexBuffer, mTexcoordBuffer, mNormalBuffer, mColorBuffer,
* and mIndexBuffer.
*
* @param vertices an array of fixed-point vertex coordinates
* @param texcoords an array of fixed-point texture coordinates
* @param normals an array of fixed-point normal vector coordinates
* @param colors an array of fixed-point color channel values
* @param indices an array of short indices
*/
public void allocateBuffers(int[] vertices, int[] texcoords, int[] normals,
int[] colors, short[] indices) {
allocate(vertices, texcoords, normals, colors);
ByteBuffer ibb =
ByteBuffer.allocateDirect(indices.length * SHORT_BYTES);
ibb.order(ByteOrder.nativeOrder());
ShortBuffer shortIndexBuffer = ibb.asShortBuffer();
shortIndexBuffer.put(indices);
shortIndexBuffer.position(0);
this.mIndexBuffer = shortIndexBuffer;
}
/**
* Copies the given data into the instance
* variables mVertexBuffer, mTexcoordBuffer, mNormalBuffer, mColorBuffer,
* and mIndexBuffer.
*
* @param vertices an array of fixed-point vertex coordinates
* @param texcoords an array of fixed-point texture coordinates
* @param normals an array of fixed-point normal vector coordinates
* @param colors an array of fixed-point color channel values
* @param indices an array of int indices
*/
public void allocateBuffers(int[] vertices, int[] texcoords, int[] normals,
int[] colors, int[] indices) {
allocate(vertices, texcoords, normals, colors);
ByteBuffer ibb =
ByteBuffer.allocateDirect(indices.length * INT_BYTES);
ibb.order(ByteOrder.nativeOrder());
IntBuffer intIndexBuffer = ibb.asIntBuffer();
intIndexBuffer.put(indices);
intIndexBuffer.position(0);
this.mIndexBuffer = intIndexBuffer;
}
/**
* Allocate the vertex, texture coordinate, normal, and color buffer.
*/
private void allocate(int[] vertices, int[] texcoords, int[] normals,
int[] colors) {
ByteBuffer vbb =
ByteBuffer.allocateDirect(vertices.length * INT_BYTES);
vbb.order(ByteOrder.nativeOrder());
mVertexBuffer = vbb.asIntBuffer();
mVertexBuffer.put(vertices);
mVertexBuffer.position(0);
if ((texcoords != null) && mEmitTextureCoordinates) {
ByteBuffer tbb =
ByteBuffer.allocateDirect(texcoords.length * INT_BYTES);
tbb.order(ByteOrder.nativeOrder());
mTexcoordBuffer = tbb.asIntBuffer();
mTexcoordBuffer.put(texcoords);
mTexcoordBuffer.position(0);
}
if ((normals != null) && mEmitNormals) {
ByteBuffer nbb =
ByteBuffer.allocateDirect(normals.length * INT_BYTES);
nbb.order(ByteOrder.nativeOrder());
mNormalBuffer = nbb.asIntBuffer();
mNormalBuffer.put(normals);
mNormalBuffer.position(0);
}
if ((colors != null) && mEmitColors) {
ByteBuffer cbb =
ByteBuffer.allocateDirect(colors.length * INT_BYTES);
cbb.order(ByteOrder.nativeOrder());
mColorBuffer = cbb.asIntBuffer();
mColorBuffer.put(colors);
mColorBuffer.position(0);
}
}
/**
* Draws the shape to the given OpenGL ES 1.0 context. Texture coordinates,
* normals, and colors are emitted according the the preferences set for
* this shape.
*/
public void draw(GL10 gl) {
gl.glVertexPointer(3, GL10.GL_FIXED, 0, mVertexBuffer);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
if (mEmitTextureCoordinates) {
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glTexCoordPointer(2, GL10.GL_FIXED, 0, mTexcoordBuffer);
gl.glEnable(GL10.GL_TEXTURE_2D);
} else {
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glDisable(GL10.GL_TEXTURE_2D);
}
if (mEmitNormals) {
gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);
gl.glNormalPointer(GL10.GL_FIXED, 0, mNormalBuffer);
} else {
gl.glDisableClientState(GL10.GL_NORMAL_ARRAY);
}
if (mEmitColors) {
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
gl.glColorPointer(4, GL10.GL_FIXED, 0, mColorBuffer);
} else {
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
}
gl.glDrawElements(mPrimitive,
mNumIndices > 0 ? mNumIndices : mIndexBuffer.capacity(),
mIndexDatatype,
mIndexBuffer);
}
}
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