Android Open Source - ExpertAndroid Animated Simple Triangle Renderer

• Back to Development/book  ↑

From Project

Back to project page ExpertAndroid.

License

The source code is released under:

MIT License

Java Source Code

package com.iuriio.demos.expertandroid.ch9openglexperiments;
//ww w. ja va2s  . c om
import android.content.Context;
import android.os.SystemClock;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;

import javax.microedition.khronos.opengles.GL10;

/**
 * Created by iuriio on 10/26/13.
 */
public class AnimatedSimpleTriangleRenderer extends AbstractRenderer {
    private static final int VERTS = 3;
    private FloatBuffer vertexBuffer;
    private ShortBuffer indexBuffer;

    public AnimatedSimpleTriangleRenderer(Context context) {
        ByteBuffer vbb = ByteBuffer.allocateDirect(VERTS * 3 * 4);
        vbb.order(ByteOrder.nativeOrder());
        this.vertexBuffer = vbb.asFloatBuffer();

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

        float[] coords = {
                -0.5f, -0.5f, 0, // (x1,y1,z1)
                0.5f, -0.5f, 0,
                0.0f,  0.5f, 0
        };

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

        final short[] indecesArray = { 0, 1, 2 };
        for (int i = 0; i < 3; i++) {
            this.indexBuffer.put(indecesArray[i]);
        }

        this.vertexBuffer.position(0);
        this.indexBuffer.position(0);
    }

    @Override
    protected void draw(GL10 gl) {
        long time = SystemClock.uptimeMillis();
        float angle = 0.090f * ((int) time);

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

        gl.glColor4f(1.0f, 0.0f, 0.0f, 0.5f);
        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, this.vertexBuffer);
        gl.glDrawElements(
                GL10.GL_TRIANGLES,
                VERTS,
                GL10.GL_UNSIGNED_SHORT,
                this.indexBuffer);
    }
}

Java Source Code List

• Back to Development/book  ↑