1/*
2 * Copyright (C) 2008 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
17package com.example.android.apis.graphics;
18
19import java.io.IOException;
20import java.io.InputStream;
21import java.nio.ByteBuffer;
22import java.nio.ByteOrder;
23import java.nio.FloatBuffer;
24import java.nio.ShortBuffer;
25
26import javax.microedition.khronos.egl.EGLConfig;
27import javax.microedition.khronos.opengles.GL10;
28
29import android.content.Context;
30import android.graphics.Bitmap;
31import android.graphics.BitmapFactory;
32import android.opengl.GLSurfaceView;
33import android.opengl.GLU;
34import android.opengl.GLUtils;
35import android.os.SystemClock;
36
37import com.example.android.apis.R;
38
39public class TriangleRenderer implements GLSurfaceView.Renderer{
40
41    public TriangleRenderer(Context context) {
42        mContext = context;
43        mTriangle = new Triangle();
44    }
45
46    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
47        /*
48         * By default, OpenGL enables features that improve quality
49         * but reduce performance. One might want to tweak that
50         * especially on software renderer.
51         */
52        gl.glDisable(GL10.GL_DITHER);
53
54        /*
55         * Some one-time OpenGL initialization can be made here
56         * probably based on features of this particular context
57         */
58        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,
59                GL10.GL_FASTEST);
60
61        gl.glClearColor(.5f, .5f, .5f, 1);
62        gl.glShadeModel(GL10.GL_SMOOTH);
63        gl.glEnable(GL10.GL_DEPTH_TEST);
64        gl.glEnable(GL10.GL_TEXTURE_2D);
65
66        /*
67         * Create our texture. This has to be done each time the
68         * surface is created.
69         */
70
71        int[] textures = new int[1];
72        gl.glGenTextures(1, textures, 0);
73
74        mTextureID = textures[0];
75        gl.glBindTexture(GL10.GL_TEXTURE_2D, mTextureID);
76
77        gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
78                GL10.GL_NEAREST);
79        gl.glTexParameterf(GL10.GL_TEXTURE_2D,
80                GL10.GL_TEXTURE_MAG_FILTER,
81                GL10.GL_LINEAR);
82
83        gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
84                GL10.GL_CLAMP_TO_EDGE);
85        gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
86                GL10.GL_CLAMP_TO_EDGE);
87
88        gl.glTexEnvf(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,
89                GL10.GL_REPLACE);
90
91        InputStream is = mContext.getResources()
92                .openRawResource(R.raw.robot);
93        Bitmap bitmap;
94        try {
95            bitmap = BitmapFactory.decodeStream(is);
96        } finally {
97            try {
98                is.close();
99            } catch(IOException e) {
100                // Ignore.
101            }
102        }
103
104        GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
105        bitmap.recycle();
106    }
107
108    public void onDrawFrame(GL10 gl) {
109        /*
110         * By default, OpenGL enables features that improve quality
111         * but reduce performance. One might want to tweak that
112         * especially on software renderer.
113         */
114        gl.glDisable(GL10.GL_DITHER);
115
116        gl.glTexEnvx(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,
117                GL10.GL_MODULATE);
118
119        /*
120         * Usually, the first thing one might want to do is to clear
121         * the screen. The most efficient way of doing this is to use
122         * glClear().
123         */
124
125        gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
126
127        /*
128         * Now we're ready to draw some 3D objects
129         */
130
131        gl.glMatrixMode(GL10.GL_MODELVIEW);
132        gl.glLoadIdentity();
133
134        GLU.gluLookAt(gl, 0, 0, -5, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
135
136        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
137        gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
138
139        gl.glActiveTexture(GL10.GL_TEXTURE0);
140        gl.glBindTexture(GL10.GL_TEXTURE_2D, mTextureID);
141        gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
142                GL10.GL_REPEAT);
143        gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
144                GL10.GL_REPEAT);
145
146        long time = SystemClock.uptimeMillis() % 4000L;
147        float angle = 0.090f * ((int) time);
148
149        gl.glRotatef(angle, 0, 0, 1.0f);
150
151        mTriangle.draw(gl);
152    }
153
154    public void onSurfaceChanged(GL10 gl, int w, int h) {
155        gl.glViewport(0, 0, w, h);
156
157        /*
158        * Set our projection matrix. This doesn't have to be done
159        * each time we draw, but usually a new projection needs to
160        * be set when the viewport is resized.
161        */
162
163        float ratio = (float) w / h;
164        gl.glMatrixMode(GL10.GL_PROJECTION);
165        gl.glLoadIdentity();
166        gl.glFrustumf(-ratio, ratio, -1, 1, 3, 7);
167
168    }
169
170    private Context mContext;
171    private Triangle mTriangle;
172    private int mTextureID;
173}
174
175class Triangle {
176    public Triangle() {
177
178        // Buffers to be passed to gl*Pointer() functions
179        // must be direct, i.e., they must be placed on the
180        // native heap where the garbage collector cannot
181        // move them.
182        //
183        // Buffers with multi-byte datatypes (e.g., short, int, float)
184        // must have their byte order set to native order
185
186        ByteBuffer vbb = ByteBuffer.allocateDirect(VERTS * 3 * 4);
187        vbb.order(ByteOrder.nativeOrder());
188        mFVertexBuffer = vbb.asFloatBuffer();
189
190        ByteBuffer tbb = ByteBuffer.allocateDirect(VERTS * 2 * 4);
191        tbb.order(ByteOrder.nativeOrder());
192        mTexBuffer = tbb.asFloatBuffer();
193
194        ByteBuffer ibb = ByteBuffer.allocateDirect(VERTS * 2);
195        ibb.order(ByteOrder.nativeOrder());
196        mIndexBuffer = ibb.asShortBuffer();
197
198        // A unit-sided equalateral triangle centered on the origin.
199        float[] coords = {
200                // X, Y, Z
201                -0.5f, -0.25f, 0,
202                 0.5f, -0.25f, 0,
203                 0.0f,  0.559016994f, 0
204        };
205
206        for (int i = 0; i < VERTS; i++) {
207            for(int j = 0; j < 3; j++) {
208                mFVertexBuffer.put(coords[i*3+j] * 2.0f);
209            }
210        }
211
212        for (int i = 0; i < VERTS; i++) {
213            for(int j = 0; j < 2; j++) {
214                mTexBuffer.put(coords[i*3+j] * 2.0f + 0.5f);
215            }
216        }
217
218        for(int i = 0; i < VERTS; i++) {
219            mIndexBuffer.put((short) i);
220        }
221
222        mFVertexBuffer.position(0);
223        mTexBuffer.position(0);
224        mIndexBuffer.position(0);
225    }
226
227    public void draw(GL10 gl) {
228        gl.glFrontFace(GL10.GL_CCW);
229        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mFVertexBuffer);
230        gl.glEnable(GL10.GL_TEXTURE_2D);
231        gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, mTexBuffer);
232        gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, VERTS,
233                GL10.GL_UNSIGNED_SHORT, mIndexBuffer);
234    }
235
236    private final static int VERTS = 3;
237
238    private FloatBuffer mFVertexBuffer;
239    private FloatBuffer mTexBuffer;
240    private ShortBuffer mIndexBuffer;
241}
242