create opengl Rectangle Buffer - Android android.opengl

Android examples for android.opengl:OpenGL Buffer

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Description

create opengl Rectangle Buffer

Demo Code


import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;
import android.opengl.GLES20;

public class Main{
    private static final int TYPE_SIZE = 4;
    private static final int SHORT_SIZE = Short.SIZE / 8;
    public static int createRectangleBuffer(float w, float h) {
        float arr[] = { 0, 0, w, 0, 0, h, w, h };

        return copyToBuffer(arr);
    }/* www  . j  ava 2s  .co m*/
    public static int copyToBuffer(float[] arr) {
        return copyToBuffer(arr, arr.length);
    }
    public static int copyToBuffer(float[] arr, int len) {
        // allocate a buffer of the right size...

        // size of float = 4 bytes so size of buffer = 4 * length of float array
        FloatBuffer floatBuf = ByteBuffer.allocateDirect(len * TYPE_SIZE)
                .order(ByteOrder.nativeOrder()) // use the device hardware's native byte order
                .asFloatBuffer(); // create a floating point buffer from the ByteBuffer

        floatBuf.put(arr, 0, len) // copy the array into the buffer
                .position(0); // set the buffer to read the first coordinate

        int err;
        if ((err = GLES20.glGetError()) != 0) {
            DebugLog.e("buff", "err " + err);
        }

        int[] buffer = new int[1];
        GLES20.glGenBuffers(1, buffer, 0);
        int handle = buffer[0];
        GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, handle);
        GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, len * TYPE_SIZE,
                floatBuf, GLES20.GL_STATIC_DRAW);

        if ((err = GLES20.glGetError()) != 0) {
            DebugLog.e("buff", "err " + err);
        }

        return handle;
    }
    public static int copyToBuffer(int target, short[] arr, int len) {
        // allocate a buffer of the right size...

        // size of float = 4 bytes so size of buffer = 4 * length of float array
        ShortBuffer buf = ByteBuffer.allocateDirect(len * SHORT_SIZE)
                .order(ByteOrder.nativeOrder()) // use the device hardware's native byte order
                .asShortBuffer(); // create a floating point buffer from the ByteBuffer

        buf.put(arr, 0, len) // copy the array into the buffer
                .position(0); // set the buffer to read the first coordinate

        int[] buffer = new int[1];
        GLES20.glGenBuffers(1, buffer, 0);
        int handle = buffer[0];
        GLES20.glBindBuffer(target, handle);
        GLES20.glBufferData(target, len * SHORT_SIZE, buf,
                GLES20.GL_STATIC_DRAW);

        return handle;
    }
}

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