samples/ApiDemos/src/com/example/android/apis/graphics/spritetext/SpriteTextRenderer.java

/*
 * Copyright (C) 2008 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.apis.graphics.spritetext;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Paint;
import android.opengl.GLSurfaceView;
import android.opengl.GLU;
import android.opengl.GLUtils;
import android.os.SystemClock;

import com.example.android.apis.R;

public class SpriteTextRenderer implements GLSurfaceView.Renderer{

    public SpriteTextRenderer(Context context) {
        mContext = context;
        mTriangle = new Triangle();
        mProjector = new Projector();
        mLabelPaint = new Paint();
        mLabelPaint.setTextSize(32);
        mLabelPaint.setAntiAlias(true);
        mLabelPaint.setARGB(0xff, 0x00, 0x00, 0x00);
    }

    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
        /*
         * By default, OpenGL enables features that improve quality
         * but reduce performance. One might want to tweak that
         * especially on software renderer.
         */
        gl.glDisable(GL10.GL_DITHER);

        /*
         * Some one-time OpenGL initialization can be made here
         * probably based on features of this particular context
         */
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,
                GL10.GL_FASTEST);

        gl.glClearColor(.5f, .5f, .5f, 1);
        gl.glShadeModel(GL10.GL_SMOOTH);
        gl.glEnable(GL10.GL_DEPTH_TEST);
        gl.glEnable(GL10.GL_TEXTURE_2D);

        /*
         * Create our texture. This has to be done each time the
         * surface is created.
         */

        int[] textures = new int[1];
        gl.glGenTextures(1, textures, 0);

        mTextureID = textures[0];
        gl.glBindTexture(GL10.GL_TEXTURE_2D, mTextureID);

        gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
                GL10.GL_NEAREST);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D,
                GL10.GL_TEXTURE_MAG_FILTER,
                GL10.GL_LINEAR);

        gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
                GL10.GL_CLAMP_TO_EDGE);
        gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
                GL10.GL_CLAMP_TO_EDGE);

        gl.glTexEnvf(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,
                GL10.GL_REPLACE);

        InputStream is = mContext.getResources()
                .openRawResource(R.drawable.robot);
        Bitmap bitmap;
        try {
            bitmap = BitmapFactory.decodeStream(is);
        } finally {
            try {
                is.close();
            } catch(IOException e) {
                // Ignore.
            }
        }

        GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
        bitmap.recycle();

        if (mLabels != null) {
            mLabels.shutdown(gl);
        } else {
            mLabels = new LabelMaker(true, 256, 64);
        }
        mLabels.initialize(gl);
        mLabels.beginAdding(gl);
        mLabelA = mLabels.add(gl, "A", mLabelPaint);
        mLabelB = mLabels.add(gl, "B", mLabelPaint);
        mLabelC = mLabels.add(gl, "C", mLabelPaint);
        mLabelMsPF = mLabels.add(gl, "ms/f", mLabelPaint);
        mLabels.endAdding(gl);

        if (mNumericSprite != null) {
            mNumericSprite.shutdown(gl);
        } else {
            mNumericSprite = new NumericSprite();
        }
        mNumericSprite.initialize(gl, mLabelPaint);
    }

    public void onDrawFrame(GL10 gl) {
        /*
         * By default, OpenGL enables features that improve quality
         * but reduce performance. One might want to tweak that
         * especially on software renderer.
         */
        gl.glDisable(GL10.GL_DITHER);

        gl.glTexEnvx(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE,
                GL10.GL_MODULATE);

        /*
         * Usually, the first thing one might want to do is to clear
         * the screen. The most efficient way of doing this is to use
         * glClear().
         */

        gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

        /*
         * Now we're ready to draw some 3D objects
         */

        gl.glMatrixMode(GL10.GL_MODELVIEW);
        gl.glLoadIdentity();

        GLU.gluLookAt(gl, 0.0f, 0.0f, -2.5f,
                0.0f, 0.0f, 0.0f,
                0.0f, 1.0f, 0.0f);

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

        gl.glActiveTexture(GL10.GL_TEXTURE0);
        gl.glBindTexture(GL10.GL_TEXTURE_2D, mTextureID);
        gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
                GL10.GL_REPEAT);
        gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
                GL10.GL_REPEAT);

        long time = SystemClock.uptimeMillis() % 4000L;
        float angle = 0.090f * ((int) time);

        gl.glRotatef(angle, 0, 0, 1.0f);
        gl.glScalef(2.0f, 2.0f, 2.0f);

        mTriangle.draw(gl);

        mProjector.getCurrentModelView(gl);
        mLabels.beginDrawing(gl, mWidth, mHeight);
        drawLabel(gl, 0, mLabelA);
        drawLabel(gl, 1, mLabelB);
        drawLabel(gl, 2, mLabelC);
        float msPFX = mWidth - mLabels.getWidth(mLabelMsPF) - 1;
        mLabels.draw(gl, msPFX, 0, mLabelMsPF);
        mLabels.endDrawing(gl);

        drawMsPF(gl, msPFX);
    }

    private void drawMsPF(GL10 gl, float rightMargin) {
        long time = SystemClock.uptimeMillis();
        if (mStartTime == 0) {
            mStartTime = time;
        }
        if (mFrames++ == SAMPLE_PERIOD_FRAMES) {
            mFrames = 0;
            long delta = time - mStartTime;
            mStartTime = time;
            mMsPerFrame = (int) (delta * SAMPLE_FACTOR);
        }
        if (mMsPerFrame > 0) {
            mNumericSprite.setValue(mMsPerFrame);
            float numWidth = mNumericSprite.width();
            float x = rightMargin - numWidth;
            mNumericSprite.draw(gl, x, 0, mWidth, mHeight);
        }
    }

    private void drawLabel(GL10 gl, int triangleVertex, int labelId) {
        float x = mTriangle.getX(triangleVertex);
        float y = mTriangle.getY(triangleVertex);
        mScratch[0] = x;
        mScratch[1] = y;
        mScratch[2] = 0.0f;
        mScratch[3] = 1.0f;
        mProjector.project(mScratch, 0, mScratch, 4);
        float sx = mScratch[4];
        float sy = mScratch[5];
        float height = mLabels.getHeight(labelId);
        float width = mLabels.getWidth(labelId);
        float tx = sx - width * 0.5f;
        float ty = sy - height * 0.5f;
        mLabels.draw(gl, tx, ty, labelId);
    }

    public void onSurfaceChanged(GL10 gl, int w, int h) {
        mWidth = w;
        mHeight = h;
        gl.glViewport(0, 0, w, h);
        mProjector.setCurrentView(0, 0, w, h);

        /*
        * Set our projection matrix. This doesn't have to be done
        * each time we draw, but usually a new projection needs to
        * be set when the viewport is resized.
        */

        float ratio = (float) w / h;
        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
        mProjector.getCurrentProjection(gl);
    }

    private int mWidth;
    private int mHeight;
    private Context mContext;
    private Triangle mTriangle;
    private int mTextureID;
    private int mFrames;
    private int mMsPerFrame;
    private final static int SAMPLE_PERIOD_FRAMES = 12;
    private final static float SAMPLE_FACTOR = 1.0f / SAMPLE_PERIOD_FRAMES;
    private long mStartTime;
    private LabelMaker mLabels;
    private Paint mLabelPaint;
    private int mLabelA;
    private int mLabelB;
    private int mLabelC;
    private int mLabelMsPF;
    private Projector mProjector;
    private NumericSprite mNumericSprite;
    private float[] mScratch = new float[8];
}

class Triangle {
    public Triangle() {

        // Buffers to be passed to gl*Pointer() functions
        // must be direct, i.e., they must be placed on the
        // native heap where the garbage collector cannot
        // move them.
        //
        // Buffers with multi-byte datatypes (e.g., short, int, float)
        // must have their byte order set to native order

        ByteBuffer vbb = ByteBuffer.allocateDirect(VERTS * 3 * 4);
        vbb.order(ByteOrder.nativeOrder());
        mFVertexBuffer = vbb.asFloatBuffer();

        ByteBuffer tbb = ByteBuffer.allocateDirect(VERTS * 2 * 4);
        tbb.order(ByteOrder.nativeOrder());
        mTexBuffer = tbb.asFloatBuffer();

        ByteBuffer ibb = ByteBuffer.allocateDirect(VERTS * 2);
        ibb.order(ByteOrder.nativeOrder());
        mIndexBuffer = ibb.asShortBuffer();

        for (int i = 0; i < VERTS; i++) {
            for(int j = 0; j < 3; j++) {
                mFVertexBuffer.put(sCoords[i*3+j]);
            }
        }

        for (int i = 0; i < VERTS; i++) {
            for(int j = 0; j < 2; j++) {
                mTexBuffer.put(sCoords[i*3+j] * 2.0f + 0.5f);
            }
        }

        for(int i = 0; i < VERTS; i++) {
            mIndexBuffer.put((short) i);
        }

        mFVertexBuffer.position(0);
        mTexBuffer.position(0);
        mIndexBuffer.position(0);
    }

    public void draw(GL10 gl) {
        gl.glFrontFace(GL10.GL_CCW);
        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mFVertexBuffer);
        gl.glEnable(GL10.GL_TEXTURE_2D);
        gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, mTexBuffer);
        gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, VERTS,
                GL10.GL_UNSIGNED_SHORT, mIndexBuffer);
    }

    public float getX(int vertex) {
        return sCoords[3*vertex];
    }

    public float getY(int vertex) {
        return sCoords[3*vertex+1];
    }

    private final static int VERTS = 3;

    private FloatBuffer mFVertexBuffer;
    private FloatBuffer mTexBuffer;
    private ShortBuffer mIndexBuffer;
    // A unit-sided equalateral triangle centered on the origin.
    private final static float[] sCoords = {
            // X, Y, Z
            -0.5f, -0.25f, 0,
             0.5f, -0.25f, 0,
             0.0f,  0.559016994f, 0
    };
}