CODEWITHSUNDEEP
androidopengl-es
Mikhail
Mikhail

Reputation: 8028

FloatBuffer.put causes crash?

I have a very simple geometry that makes a few rectangles. For some reason the put method of the float buffer crashes the phone. The code is as follows

private FloatBuffer mFloatVertexBuffer;
public Bars(int numberOf,float widthIn,float heightIn, GL10 gl)
{
    width=widthIn;height=heightIn;

    mCoordinateType= GL10.GL_FLOAT;
    mCoordinateSize = 4;//FLOAT_SIZE =4 ;
    mFloatVertexBuffer = ByteBuffer.allocateDirect(mCoordinateSize * numberOf * 3).order(ByteOrder.nativeOrder()).asFloatBuffer();
    mVertexBuffer = mFloatVertexBuffer;

    mIndexCount = 6 * numberOf;
    final int CHAR_SIZE = 2;
    mIndexBuffer = ByteBuffer.allocateDirect(CHAR_SIZE * mIndexCount).order(ByteOrder.nativeOrder()).asCharBuffer();

    for (int i = 0, j = 0; i < numberOf; i++)
    {
        char a = (char) (j++); char b = (char) (j++);
        char c = (char) (j++);char d = (char) (j++);

        mIndexBuffer.put(a);mIndexBuffer.put(b); mIndexBuffer.put(c);
        mIndexBuffer.put(b); mIndexBuffer.put(c);mIndexBuffer.put(d);
    }
    float stride = widthIn/numberOf;
    for (int i = 0, j = 0; i < numberOf; i++)
    {
        float z = 0;
        float height=  heightIn*((float) Math.random());
        float ax = stride*(i+0);
        float ay = 0;
        float dx = stride*(i+1);
        float dy = 0;
        float bx = stride*(i+0);
        float by = height;
        float cx= stride*(i+1);
        float cy = height;

        mFloatVertexBuffer.put(j++,ax);
        mFloatVertexBuffer.put(j++,ay);
        mFloatVertexBuffer.put(j++,z);

        mFloatVertexBuffer.put(j++,bx);
        mFloatVertexBuffer.put(j++,by);
        mFloatVertexBuffer.put(j++,z);//Still Working

        mFloatVertexBuffer.put(j++,cx);//Throws error at this line (via debugger)
        mFloatVertexBuffer.put(j++,cy);
        mFloatVertexBuffer.put(j++,z);

        mFloatVertexBuffer.put(j++,dx);
        mFloatVertexBuffer.put(j++,dy);
        mFloatVertexBuffer.put(j++,z);
    }

Upvotes: 0

Views: 183

Answers (1)

Bondax
Bondax

Reputation: 3163

mFloatVertexBuffer = ByteBuffer.allocateDirect(mCoordinateSize * numberOf * 3).order(ByteOrder.nativeOrder()).asFloatBuffer();

allocates (4 * numberOf * 3) bytes, but you need (4 * numberOf * 4 * 3) bytes since you want to store 12 floats of size 4 for each of the numberOf items.

Upvotes: 3

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