/*
 * $Header: /home/barad-dur/vision/forsyth/schenney/sced-0.94/elk/RCS/view.c,v 1.0 1997/05/06 20:44:49 schenney Exp $
 *
 * $Log: view.c,v $
 * Revision 1.0  1997/05/06 20:44:49  schenney
 * Initial revision
 *
 */
#include "elk_private.h"
#include <View.h>


/***********************************************************************
 *
 * Description: viewport_destroy() is used to destroy a Viewport that
 *      was previously created with viewport_create().
 *
 * Parameter:   viewport - Viewport object to destroy.
 *
 ***********************************************************************/
static void
Viewport_Destroy(Viewport *viewport)
{
    if (viewport) {
        free(viewport);
    }
    return;
}


/***********************************************************************
 *
 * Description: elk_viewport_print() is used internally by the scheme
 *      interpreter. This function is called whenever a user
 *      tries to print out the viewport from scheme.
 *
 * Scheme example: (display (viewport-create)) => #[viewport 0x1a4c00]
 *
 ***********************************************************************/
int
Elk_Viewport_Print(Object w, Object port, int raw, int depth, int len)
{
    Viewport *viewport = (Viewport *) ELKVIEWPORT(w)->viewport;
    
    Printf(port, "#[viewport 0x%x]\n", viewport);
    return 0;
}

/***********************************************************************
 *
 * Description: elk_viewport_equal() is used internally by the scheme
 *      interpreter. This function is called whenever two viewports
 *      are compared in scheme using the "equal?" operator.
 *
 * Scheme example: (equal? (viewport-create) (viewport-create))
 *
 ***********************************************************************/
int
Elk_Viewport_Equal(Object a, Object b)
{
    return (ELKVIEWPORT(a)->viewport == ELKVIEWPORT(b)->viewport);
}

/***********************************************************************
 *
 * Description: elk_viewport_equiv() is used internally by the scheme
 *      interpreter. This function is called whenever two viewports
 *      are compared in scheme using the "eqv?" operator.
 *
 * Scheme example: (eqv? (viewport-create) (viewport-create))
 *
 ***********************************************************************/
int
Elk_Viewport_Equiv(Object a, Object b)
{
    return (ELKVIEWPORT(a)->viewport == ELKVIEWPORT(b)->viewport);
}

/***********************************************************************
 *
 * Description: elk_viewport_create() is the C callback for the scheme
 *      function "viewport-create". This function is used to
 *      create a new viewport object from scheme.
 *
 * Scheme example: (viewport-create)
 *
 * Return value: Returns a new viewport object
 *
 ***********************************************************************/
Object
Elk_Viewport_Create()
{
    Object obj;
    
    /*
     * First we allocate an Elk object to save the viewport in.
     */
    obj = Alloc_Object(sizeof(Elkviewport), T_Viewport, 0);
    ELKVIEWPORT(obj)->viewport = New(Viewport, 1);

    Viewport_Init(ELKVIEWPORT(obj)->viewport);
    ELKVIEWPORT(obj)->viewport->scr_width = camera.scr_width;
    ELKVIEWPORT(obj)->viewport->scr_height = camera.scr_height;

    return obj;
}

/***********************************************************************
 *
 * Description: elk_camera_destroy() is the C callback for the scheme
 *      function "viewport-destroy". This function is used to
 *      destroy a viewport object that was previously created
 *      with "viewport-create".
 *
 * Parameter:   viewportobj - viewport to be destroyed.
 *
 * Scheme example: (viewport-destroy (viewport-create))
 *
 * Return value: Returns the Void object.
 *
 ***********************************************************************/
Object
Elk_Viewport_Destroy(Object viewportobj)
{
    Check_Type(viewportobj, T_Viewport);
    if (ELKVIEWPORT(viewportobj)->viewport)
        Viewport_Destroy(ELKVIEWPORT(viewportobj)->viewport);
    return Void;
}

/***********************************************************************
 *
 * Description: elk_viewport_lookat() is the C callback for the scheme
 *      function "viewport-lookat". This function is used to
 *      set a new look point for the viewport.
 *
 * Parameter:   xobj - new look point's X coordinate
 *      yobj - new look point's Y coordinate
 *      zobj - new look point's Z coordinate
 *      viewportobj - viewport to change
 *
 * Scheme example: (viewport-lookat 1.0 1.0 1.0 (viewport-create))
 *
 * Return value: Returns the viewport object passed in.
 *
 ***********************************************************************/
Object
Elk_Viewport_Lookat(Object xobj, Object yobj, Object zobj, Object viewportobj)
{
    Viewport *viewport;

    Check_Type(viewportobj, T_Viewport);
    Check_Type(xobj, T_Flonum);
    Check_Type(yobj, T_Flonum);
    Check_Type(zobj, T_Flonum);
    viewport = ELKVIEWPORT(viewportobj)->viewport;
    viewport->view_at.x = FLONUM(xobj)->val;
    viewport->view_at.y = FLONUM(yobj)->val;
    viewport->view_at.z = FLONUM(zobj)->val;

    return viewportobj;
}

/***********************************************************************
 *
 * Description: elk_viewport_position() is the C callback for the scheme
 *      function "viewport-position". This function is used to
 *      change the current "view from" position of a viewport.
 *
 * Parameter:   xobj - new X coordinate
 *      yobj - new Y coordinate
 *      zobj - new Z coordinate
 *      viewportobj - viewport to change
 *
 * Scheme example: (viewport-position 1.0 1.0 1.0 (viewport-create))
 *
 * Return value: Returns the viewport object passed in.
 *
 ***********************************************************************/
Object
Elk_Viewport_Position(Object xobj, Object yobj, Object zobj, Object viewportobj)
{
    Viewport *viewport;

    Check_Type(viewportobj, T_Viewport);
    Check_Type(xobj, T_Flonum);
    Check_Type(yobj, T_Flonum);
    Check_Type(zobj, T_Flonum);
    viewport = ELKVIEWPORT(viewportobj)->viewport;
    viewport->view_from.x = FLONUM(xobj)->val;
    viewport->view_from.y = FLONUM(yobj)->val;
    viewport->view_from.z = FLONUM(zobj)->val;

    return viewportobj;
}

/***********************************************************************
 *
 * Description: elk_viewport_upvector() is the C callback for the scheme
 *      function "viewport-upvector". This function is used to
 *      change a viewport's notion of what up is.
 *
 * Parameter:   xobj - new X up coordinate
 *      yobj - new Y up coordinate
 *      zobj - new Z up coordinate
 *      viewportobj - viewport to change
 *
 * Scheme example: (viewport-upvector 0.0 1.0 0.0 (viewport-create))
 *
 * Return value: Returns the viewport object passed in.
 *
 ***********************************************************************/
Object
Elk_Viewport_Upvector(Object xobj, Object yobj, Object zobj, Object viewportobj)
{
    Viewport *viewport;

    Check_Type(viewportobj, T_Viewport);
    Check_Type(xobj, T_Flonum);
    Check_Type(yobj, T_Flonum);
    Check_Type(zobj, T_Flonum);
    viewport = ELKVIEWPORT(viewportobj)->viewport;
    viewport->view_up.x = FLONUM(xobj)->val;
    viewport->view_up.y = FLONUM(yobj)->val;
    viewport->view_up.z = FLONUM(zobj)->val;

    return viewportobj;
}


/*************************************************************************
 *
 * Description: elk_viewport_distance() is the C callback for the scheme
 *      function "viewport-distance". This function is used to change the
 *      viewing distance.
 *
 * Parameters: distobj - new distance
 *             viewportobj - viewport to change
 *
 * Scheme example: (viewport-distance 10.0 (viewport-create))
 *
 * Return value: Returns the viewport object passed in.
 *
 *************************************************************************/
Object
Elk_Viewport_Distance(Object distobj, Object viewportobj)
{
    Viewport *viewport;

    Check_Type(viewportobj, T_Viewport);
    Check_Type(distobj, T_Flonum);
    viewport = ELKVIEWPORT(viewportobj)->viewport;
    viewport->view_distance = FLONUM(distobj)->val;
    return viewportobj;
}

/*************************************************************************
 *
 * Description: elk_viewport_eye() is the C callback for the scheme
 *      function "viewport-eye". This function is used to change the
 *      eye distance.
 *
 * Parameters: eyeobj - new eye distance
 *             viewportobj - viewport to change
 *
 * Scheme example: (viewport-eye 10.0 (viewport-create))
 *
 * Return value: Returns the viewport object passed in.
 *
 *************************************************************************/
Object
Elk_Viewport_Eye(Object eyeobj, Object viewportobj)
{
    Viewport *viewport;

    Check_Type(viewportobj, T_Viewport);
    Check_Type(eyeobj, T_Flonum);
    viewport = ELKVIEWPORT(viewportobj)->viewport;
    viewport->eye_distance = FLONUM(eyeobj)->val;
    return viewportobj;
}

Object
Elk_Viewport_Zoom(Object zoomobj, Object viewportobj)
{
    Check_Type(viewportobj, T_Viewport);
    Check_Integer(zoomobj);
    ELKVIEWPORT(viewportobj)->viewport->magnify = Get_Integer(zoomobj);

    return viewportobj;
}

/***********************************************************************
 *
 * Description: elk_viewport_setup() is the C callback for the scheme
 *      function "viewport-setup". This function is used to
 *      set the current viewport to be a new viewport object
 *      or to make changes to the current viewport take effect.
 *
 * Parameter:   viewportobj - new viewport to make into current viewport
 *
 * Scheme example: (let ((view (viewport-create)))
 *          (viewport-setup (viewport->lookat 1.0 1.0 1.0 view)))
 *
 * Return value: Returns the Void object.
 *
 ***********************************************************************/
Object
Elk_Viewport_Setup(Object viewportobj)
{
    Viewport *viewport;

    viewport = ELKVIEWPORT(viewportobj)->viewport;

    elk_window->viewport = *viewport;
    Build_Viewport_Transformation(&(elk_window->viewport));
    if (viewport->scr_width) {
        XtVaSetValues(elk_window->view_widget,
                  XtNwidth, viewport->scr_width,
                  XtNheight, viewport->scr_height,
                  XtNdesiredWidth, viewport->scr_width,
                  XtNdesiredHeight, viewport->scr_height,
                  NULL);
    }

    elk_window->magnify = viewport->magnify;

    View_Update(elk_window, elk_window->all_instances, CalcView);
    Update_Projection_Extents(elk_window->all_instances);
    return Void;
}


Object
Elk_Viewport_To_Camera(Object viewportobj)
{
    Viewport *viewport;

    viewport = ELKVIEWPORT(viewportobj)->viewport;

    camera.defined = TRUE;

    Viewport_To_Camera(viewport, main_window.view_widget, &camera, FALSE);

    return Void;
}