| /* |
| * Copyright (C) 2011 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.example.android.opengl; |
| |
| import java.nio.ByteBuffer; |
| import java.nio.ByteOrder; |
| import java.nio.FloatBuffer; |
| |
| import javax.microedition.khronos.opengles.GL10; |
| |
| /** |
| * A two-dimensional triangle for use as a drawn object in OpenGL ES 1.0/1.1. |
| */ |
| public class Triangle { |
| |
| private final FloatBuffer vertexBuffer; |
| |
| // number of coordinates per vertex in this array |
| static final int COORDS_PER_VERTEX = 3; |
| static float triangleCoords[] = { |
| // in counterclockwise order: |
| 0.0f, 0.622008459f, 0.0f,// top |
| -0.5f, -0.311004243f, 0.0f,// bottom left |
| 0.5f, -0.311004243f, 0.0f // bottom right |
| }; |
| |
| float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 0.0f }; |
| |
| /** |
| * Sets up the drawing object data for use in an OpenGL ES context. |
| */ |
| public Triangle() { |
| // initialize vertex byte buffer for shape coordinates |
| ByteBuffer bb = ByteBuffer.allocateDirect( |
| // (number of coordinate values * 4 bytes per float) |
| triangleCoords.length * 4); |
| // use the device hardware's native byte order |
| bb.order(ByteOrder.nativeOrder()); |
| |
| // create a floating point buffer from the ByteBuffer |
| vertexBuffer = bb.asFloatBuffer(); |
| // add the coordinates to the FloatBuffer |
| vertexBuffer.put(triangleCoords); |
| // set the buffer to read the first coordinate |
| vertexBuffer.position(0); |
| } |
| |
| /** |
| * Encapsulates the OpenGL ES instructions for drawing this shape. |
| * |
| * @param gl - The OpenGL ES context in which to draw this shape. |
| */ |
| public void draw(GL10 gl) { |
| // Since this shape uses vertex arrays, enable them |
| gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); |
| |
| // draw the shape |
| gl.glColor4f( // set color: |
| color[0], color[1], |
| color[2], color[3]); |
| gl.glVertexPointer( // point to vertex data: |
| COORDS_PER_VERTEX, |
| GL10.GL_FLOAT, 0, vertexBuffer); |
| gl.glDrawArrays( // draw shape: |
| GL10.GL_TRIANGLES, 0, |
| triangleCoords.length / COORDS_PER_VERTEX); |
| |
| // Disable vertex array drawing to avoid |
| // conflicts with shapes that don't use it |
| gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); |
| } |
| } |