Game Development Reference
In-Depth Information
if
(hasTexCoords) {
gl.glEnableClientState(GL10.
GL_TEXTURE_COORD_ARRAY
);
vertices.position(hasColor ? 7 : 3);
gl.glTexCoordPointer(2, GL10.
GL_FLOAT
, vertexSize, vertices);
}
}
public void
draw(
int
primitiveType,
int
offset,
int
numVertices) {
GL10 gl = glGraphics.getGL();
if
(indices !=
null
) {
indices.position(offset);
gl.glDrawElements(primitiveType, numVertices,
GL10.
GL_UNSIGNED_SHORT
, indices);
}
else
{
gl.glDrawArrays(primitiveType, offset, numVertices);
}
}
public void
unbind() {
GL10 gl = glGraphics.getGL();
if
(hasTexCoords)
gl.glDisableClientState(GL10.
GL_TEXTURE_COORD_ARRAY
);
if
(hasColor)
gl.glDisableClientState(GL10.
GL_COLOR_ARRAY
);
}
}
Everything stays the same compared to
Vertices
, except for a few small things:
In the constructor, we calculate
vertexSize
differently since the vertex
position now takes three floats instead of two floats.
ï?®
ï?®
bind()
method, we tell OpenGL ES that our vertices have three rather
than two coordinates in the call to
glVertexPointer()
(first argument).
We have to adjust the offsets that we set in the calls to
In the
ï?®
vertices.position()
for the optional color and texture coordinate components.
That's all we need to do. Using the
Vertices3
class, we now have to specify the x, y, and z
coordinates for each vertex when we call the
Vertices3.setVertices()
method. Everything else
stays the same in terms of usage. We can have per-vertex colors, texture coordinates, indices,
and so on.
An Example
Let's write a simple example called
Vertices3Test
. We want to draw two triangles, one with z
being −3 for each vertex and one with z being −5 for each vertex. We'll also use per-vertex color.
Since we haven't discussed how to use a perspective projection, we'll just use an orthographic
projection with appropriate near and far clipping planes so that the triangles are in the view
frustum (that is, near is 10 and far is −10). Figure
10-1
shows the scene.
