3D Programming Tricks - Beginning Android Games - page 570

static int getIndex(String index, int size) {
int idx = Integer. parseInt (index);
if (idx < 0)
return size + idx;
else
return idx - 1;
}
The getIndex() method takes one of the indices given for an attribute of a vertex in a triangle
definition, as well as the number of attributes loaded so far, and returns an index suitable to
reference the attribute in one of our working arrays.
static List<String>readLines(InputStream in) throws IOException {
List<String>lines = new ArrayList<String>();
BufferedReader reader = new BufferedReader( new InputStreamReader(in));
String line = null ;
while ((line = reader.readLine()) != null )
lines.add(line);
return lines;
}
}
Finally, there's the readLines() method, which just reads in each line of a file and returns all
these lines as a List of strings.
To load an OBJ file from an asset, we can use the ObjLoader as follows:
Vertices3 model = ObjLoader.load(game, "mymodel.obj");
Pretty straightforward after all of this index juggling, right? To render this Vertices3 instance,
we need to know how many vertices it has, though. Let's extend the Vertices3 class one more
time, adding two methods to return the number of vertices and the number of indices currently
defined in the instance. Listing 11-13 shows the code.
Listing 11-13. Excerpt from Vertices3.java; Fetching the Number of Vertices and Indices
public int getNumIndices() {
return indices.limit();
}
public int getNumVertices() {
return vertices.limit()/ (vertexSize / 4);
}
For the number of indices, we just return the limit of the ShortBuffer storing the indices. For the
number of vertices, we do the same. However, since the limit is reported in the number of floats
defined in the FloatBuffer , we have to divide it by the vertex size. Since we store that in number
of bytes in vertexSize , we divide that member by 4.