Game Development Reference
In-Depth Information
In OpenGL ES, we have to use a vertex array to define a group of vertices. So, you will:
1.
Define the (x, y, z) location of the vertices in a Java array.
2.
Allocate the vertex-array buffer, and transfer the data into the buffer.
To render from the vertex-array, you need to enable the client-state vertex-array, which is
done in
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
and then render the triangle in
the
draw()
method by doing the following:
1. Enable vertex-array client states:
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
2. Define the location of the buffers:
gl.glVertexPointer
(3, GL10.GL_FLOAT, 0, vertexBuffer)
3. Render the primitives using
glDrawElements()
, using the index array
to reference the vertex and color arrays.
gl.glDrawElements
(GL10.GL_TRIANGLES, numIndices, GL10.GL_UNSIGNED_BYTE,
indexBuffer)
Now you can run the project and see the result in Figure
3-2
.
Figure 3-2.
Triangle OpenGL sample
