Android Development

Updated to be Android 2.0.1 compatible.

You are new to this series? Please start with the first part.

The sixth part of this series will show you how you create the correct perspective because 3D is nothing without the correct perspective.

Before we start we should discuss the two possible “views” OpenGL offers: orthographic and perspective.
(continue reading…)

Updated to be Android 2.0.1 compatible.

You are new to this series? Please start with the first part.

The fifth part of this series will show you how you can create your first full 3d object. In this case a 4 sided pyramid.

Some preparation will be needed to make our future development much easier.
We have to be more dynamic in calculating our buffers and creating arrays with the correct size. (continue reading…)

Updated to be Android 2.0.1 compatible.

You are new to this series? Please start with the first part.

The fourth part of this series will show you how to add some colors to you triangle.

In the last part we created a second static triangle to prove the rotation of the triangle and not the entire scene. We will now get rid of this static triangle by removing the function initStaticTriangle(), removing both buffers, _indexBufferStatic and _vertexBufferStatic, used for it. We also have to remove the last 4 lines of code of our onDrawFrame() where we initialized the static triangle. (continue reading…)

Updated to be Android 2.0.1 compatible.

You are new to this series? Please start with the first part.

The third part of this series will show you how to stop the rotation of the triangle and that the rotation really just work on the triangle and not the “camera”.

We want to have more control over the rotation. To get that, we reset the matrix on every call of the onDrawFrame() method. This will reset the angle of our triangle so it always it stays rotated at the given angle on initialization. (continue reading…)

Updated to be Android 2.0.1 compatible.

You are new to this series? Please start with the first part.

The second part of this series will show you how to add a triangle and how to rotate it a bit.

The first thing we have to do is to initialize the triangle we want to display. We have to create a function named initTriangle() in our VortexRenderer class.

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// new object variables we need
// a raw buffer to hold indices
private ShortBuffer _indexBuffer;
 
// a raw buffer to hold the vertices
private FloatBuffer _vertexBuffer;
 
private short[] _indicesArray = {0, 1, 2};
private int _nrOfVertices = 3;
 
// code snipped
 
private void initTriangle() {
    // float has 4 bytes
    ByteBuffer vbb = ByteBuffer.allocateDirect(_nrOfVertices * 3 * 4);
    vbb.order(ByteOrder.nativeOrder());
    _vertexBuffer = vbb.asFloatBuffer();
 
    // short has 2 bytes
    ByteBuffer ibb = ByteBuffer.allocateDirect(_nrOfVertices * 2);
    ibb.order(ByteOrder.nativeOrder());
    _indexBuffer = ibb.asShortBuffer();
 
    float[] coords = {
        -0.5f, -0.5f, 0f, // (x1, y1, z1)
        0.5f, -0.5f, 0f, // (x2, y2, z2)
        0f, 0.5f, 0f // (x3, y3, z3)
    };
 
    _vertexBuffer.put(coords);
    _indexBuffer.put(_indicesArray);
 
    _vertexBuffer.position(0);
    _indexBuffer.position(0);
}

(continue reading…)

Updated to be Android 2.0.1 compatible.

The first part of this series will give you a short introduction to the OpenGL terminology and the first step in your 3D programming.

The series itself will be about a 3D game called Vortex.
The tutorial will focus on 3D programming, stuff like menu or life cycle may be part of the code but will not be introduced.

Lets start with the terminology of OpenGL.
(continue reading…)