uproc.c

利用VC++和OpenGVS结合编的一个关于火车运行的三维模拟程序。是OpenGVS三维初学者的应该参考的好范例。

/****************************************************************************** *
*  uproc.c --
*
*	OpenGVS run-time code for the Train demo
*
*******************************************************************************/
#include <g_sys.h>
#include <stdio.h>
#include <stdlib.h>

#include <g_timer.h>
#include <g_consts.h>
#include <g_timer.h>
#include <gv_cam.h>
#include <gv_chn.h>
#include <gv_fbf.h>
#include <gv_user.h>
#include <gvu_path.h>
#include <tgifts.h>

#include "train.h"
#include "hostdata.h"

/* Global throughout this module only */
static G_Boolean debug = G_FALSE;
static TParse_data * tdata = NULL;
static GV_Obi owntrain = NULL;

/*************************************************************************** 
*
*  path_proc--
*
*	Update the specified object every frame based upon the path
*
****************************************************************************/
static void path_proc( GVU_Path path, GV_Obi object )
{
    G_Position position;
    G_Rotation rotation;

    GVU_path_inq_position_current( path, &position );
    GVU_path_inq_rotation_current( path, &rotation );

    GV_obi_set_position( object, &position );
    GV_obi_set_rotation( object, &rotation );
}


/*************************************************************************** 
*
*  GV_user_proc --
*
*	OpenGVS callback function;
*	called every frame to handle graphics updates
*
****************************************************************************/
int GV_user_proc( void )
{
    static G_Boolean first_time = G_TRUE;
    static GV_Obi train_town = NULL;
    static GV_Obi skydome = NULL;
    GV_Channel chnhdl;
    GV_Camera camera;
    G_State state;

    GV_chn_inq_input_focus( &chnhdl );
    GV_chn_inq_camera( chnhdl, &camera );

    if( pcf_timing ) 
        ttiming_uproc_pre() ;

    if( first_time )
    {
        /* Save pointer to command line data */
        tparse_inq_data( &tdata );

        GV_obi_inq_by_name( "SKYDOME", &skydome );
        GV_obi_inq_by_name( "TRAIN_TOWN", &train_town );
        GV_obi_inq_by_name( "OWNTRAIN", &owntrain );

        if( debug )
        {
            GV_Scene scene;
            GV_Fog fogmodel;
            float clipnear, clipfar, visibility;

            GV_chn_inq_clip_far( chnhdl, &clipfar );
            GV_chn_inq_clip_near( chnhdl, &clipnear );
            GV_chn_inq_scene( chnhdl, &scene );
            GV_scn_inq_fog( scene, &fogmodel );
            GV_fog_inq_opaque_distance( fogmodel, &visibility );

            fprintf( stdout, "GV_user_proc: channel near=%.2f, far=%.2f, "
            "fog range=%.2f\n", clipnear, clipfar, visibility );
        }
        first_time = G_FALSE;
    }

    if( tdata && tdata->network_duties != NETWORK_DUTIES_SLAVE )
    {
        static G_Boolean last_pause = G_FALSE;
        static G_Boolean sleep_while_paused = G_FALSE;
        static float elapsed_time = 0.0;
        int inx;

        if( !path_owntrain )
            GVU_path_inq_by_name( "OWNTRAIN", &path_owntrain );

        if( pcf_pause )
        {
            /* We are paused... skipping equations of motion and path updates*/
            if( last_pause == G_FALSE )
            {
                /* Transition from unpaused to paused */
                if( path_owntrain )
                GVU_path_inq_time( path_owntrain, &elapsed_time );
            }
            last_pause = G_TRUE;
            if( sleep_while_paused )
            G_sleep( 100 );	/* Milliseconds */

            return G_SUCCESS;
        }
        else if( (pcf_pause == G_FALSE) && (last_pause == G_TRUE) )
        {
            /* Transition from paused to unpaused; 
            restart all active path logic if any @ the time when we 
            initially paused */
            GVU_Path path;
            GVU_path_inq_first( &path );
            while( path )
            {
                GVU_path_reset( path );
                GVU_path_set_time( path, elapsed_time );
                GVU_path_inq_next( path, &path );
            }
        }
        last_pause = pcf_pause;

        /* We are not paused... do normal processing */
        if( path_owntrain && owntrain )
            path_proc( path_owntrain, owntrain );

        for( inx=0; inx<NUM_VEHICLES; inx++ )
            path_proc( path_other[inx], vobi[inx] );

        if( pcf_record && !pcf_pause )
        {
            static int period = 15;
            trecord_frame( owntrain, period );
        }
    }

    GV_obi_inq_state( skydome, &state );
    if( state == G_ON )
    {
        /* The skydome will be translated in x and z with the current
        camera world position to remain fully visible with the eyepoint */
        G_Position position;
        G_Rotation rotation;

        GV_cam_inq_pos_rot_world( camera, GV_CAM_PLATFORM_LAST,
        &position, &rotation );

        GV_obi_set_position_x( skydome, position.x );
        GV_obi_set_position_z( skydome, position.z );
    }

    if( tdata && tdata->network_duties == NETWORK_DUTIES_SLAVE )
    {
        int status;
        /* Get raw data from master */
        status = dnet_slave_get_data( sizeof (host_data),
            &host_data_length, &host_data );
        if( status == G_SUCCESS )
            host_slave_get( owntrain, camera );
    }

    /* Perform any spotlight special effects processing as required */
    tspotlight_proc( owntrain );

    return G_SUCCESS;
}


/*************************************************************************** 
*
*  GV_user_proc_post --
*
*	OpenGVS callback function;
*	called every frame at end of *all* callbacks (cameras, users,
*	objects, ...) and right before graphics commands from OpenGVS to
*	the hardware start for this frame
*
****************************************************************************/
int GV_user_proc_post( void )
{
    GV_Channel chnhdl;
    GV_chn_inq_input_focus( &chnhdl );
    if( chnhdl )
    {
        GV_Camera camera;
        GV_chn_inq_camera( chnhdl, &camera );

        if( tdata && tdata->network_duties == NETWORK_DUTIES_MASTER )
        {
            /* Update "raw" network data */
            host_master_put( owntrain, camera );

            /* Send raw data to slaves */
            dnet_master_send_data( host_data_length, &host_data );
        }
    }

    if( pcf_timing ) 
    {
        static int frame = 0 ;
        ttiming_uproc_post() ;
        ttiming_frame_count( frame++ ) ;
    }
    
    return G_SUCCESS;
}