3D Shooters for Quake II - Pro Android Games - page 247

where width and height are references that will store the size of the screen, and mode
is the gl_mode argument sent in the command line. Note that ri.Vid_GetModeInfo is
nothing more than a function pointer that references the real Vid_GetModeInfo function
declared in vid_so.c .
ri.Vid_GetModeInfo = Vid_GetModeInfo
This is done because, as mentioned at the beginning of the chapter, Quake II has been
greatly modularized. In the default configuration (where the client, game, and renderer
are compiled in separate libraries) functions can be called across libraries. This makes
the code very complex, but the benefits are well worth it: it's very easy to maintain and
enhance. Vid_GetModeInfo simply uses the value of mode to look up the video modes
table ( vid_modes ) and obtain the size of the screen.
*width = vid_modes[mode].width;
*height = vid_modes[mode].height;
Once the screen size is received, GLimp_SetMode sends the information back to the parent
and tells the other subsystems that a new window has been created.
*pwidth = width;
*pheight = height;
// let the sound and input subsystems know about the new window
ri.Vid_NewWindow (width, height);
In Android, VID_NewWindow updates the video definition with the screen values and calls the
C-to-Java callback jni_init_video .
viddef.width = width;
viddef.height = height;
//tell Java about it
jni_init_video (width, height);
jni_init_video invokes the Java static method OnInitVideo declared in quake.jni.Natives.
java with the width and height of the screen.
// jni_quake.c
jmethodID mid = (*env)->GetStaticMethodID(env, jNativesCls
, "OnInitVideo"
, "(II)V");
if (mid) {
(*env)->CallStaticVoidMethod(env, jNativesCls, mid, width, height);
}
Note that the jni_init_video implementation is the same as Quake I in Chapter 6.