1 /*
2  * Copyright (C) 2007 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.example.android.apis.graphics;
18 
19 import java.nio.ByteBuffer;
20 import java.nio.ByteOrder;
21 import java.nio.IntBuffer;
22 
23 import javax.microedition.khronos.opengles.GL10;
24 
25 /**
26  * A vertex shaded cube.
27  */
28 class Cube
29 {
Cube()30     public Cube()
31     {
32         int one = 0x10000;
33         int vertices[] = {
34                 -one, -one, -one,
35                 one, -one, -one,
36                 one,  one, -one,
37                 -one,  one, -one,
38                 -one, -one,  one,
39                 one, -one,  one,
40                 one,  one,  one,
41                 -one,  one,  one,
42         };
43 
44         int colors[] = {
45                 0,    0,    0,  one,
46                 one,    0,    0,  one,
47                 one,  one,    0,  one,
48                 0,  one,    0,  one,
49                 0,    0,  one,  one,
50                 one,    0,  one,  one,
51                 one,  one,  one,  one,
52                 0,  one,  one,  one,
53         };
54 
55         byte indices[] = {
56                 0, 4, 5,    0, 5, 1,
57                 1, 5, 6,    1, 6, 2,
58                 2, 6, 7,    2, 7, 3,
59                 3, 7, 4,    3, 4, 0,
60                 4, 7, 6,    4, 6, 5,
61                 3, 0, 1,    3, 1, 2
62         };
63 
64         // Buffers to be passed to gl*Pointer() functions
65         // must be direct, i.e., they must be placed on the
66         // native heap where the garbage collector cannot
67         // move them.
68         //
69         // Buffers with multi-byte datatypes (e.g., short, int, float)
70         // must have their byte order set to native order
71 
72         ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);
73         vbb.order(ByteOrder.nativeOrder());
74         mVertexBuffer = vbb.asIntBuffer();
75         mVertexBuffer.put(vertices);
76         mVertexBuffer.position(0);
77 
78         ByteBuffer cbb = ByteBuffer.allocateDirect(colors.length*4);
79         cbb.order(ByteOrder.nativeOrder());
80         mColorBuffer = cbb.asIntBuffer();
81         mColorBuffer.put(colors);
82         mColorBuffer.position(0);
83 
84         mIndexBuffer = ByteBuffer.allocateDirect(indices.length);
85         mIndexBuffer.put(indices);
86         mIndexBuffer.position(0);
87     }
88 
draw(GL10 gl)89     public void draw(GL10 gl)
90     {
91         gl.glFrontFace(GL10.GL_CW);
92         gl.glVertexPointer(3, GL10.GL_FIXED, 0, mVertexBuffer);
93         gl.glColorPointer(4, GL10.GL_FIXED, 0, mColorBuffer);
94         gl.glDrawElements(GL10.GL_TRIANGLES, 36, GL10.GL_UNSIGNED_BYTE, mIndexBuffer);
95     }
96 
97     private IntBuffer   mVertexBuffer;
98     private IntBuffer   mColorBuffer;
99     private ByteBuffer  mIndexBuffer;
100 }
101