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/*
*
* Copyright (C) 2000 Silicon Graphics, Inc. All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* Further, this software is distributed without any warranty that it is
* free of the rightful claim of any third person regarding infringement
* or the like. Any license provided herein, whether implied or
* otherwise, applies only to this software file. Patent licenses, if
* any, provided herein do not apply to combinations of this program with
* other software, or any other product whatsoever.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
* Mountain View, CA 94043, or:
*
* http://www.sgi.com
*
* For further information regarding this notice, see:
*
* http://oss.sgi.com/projects/GenInfo/NoticeExplan/
*
*/
// -*- C++ -*-
/*
* Copyright (C) 1990,91 Silicon Graphics, Inc.
*
_______________________________________________________________________
______________ S I L I C O N G R A P H I C S I N C . ____________
|
| $Revision $
|
| Description:
| This file defines the SoEnvironment node class.
|
| Author(s) : Paul S. Strauss
|
______________ S I L I C O N G R A P H I C S I N C . ____________
_______________________________________________________________________
*/
#ifndef _SO_ENVIRONMENT_
#define _SO_ENVIRONMENT_
#include <Inventor/fields/SoSFColor.h>
#include <Inventor/fields/SoSFEnum.h>
#include <Inventor/fields/SoSFFloat.h>
#include <Inventor/fields/SoSFVec3f.h>
#include <Inventor/nodes/SoSubNode.h>
//////////////////////////////////////////////////////////////////////////////
//
// Class: SoEnvironment
//
// Node that describes global environmental attributes such as
// ambient lighting, light attenuation, and fog.
//
// Ambient lighting is the amount of extra light impinging on each
// surface point when computing Phong lighting.
//
// Light attenuation affects all subsequent lights in a scene. It is
// a quadratic function of distance from a light source to a surface
// point. The three coefficients are specified in the attenuation
// field. Attenuation works only for light sources with a fixed
// location, such as point and spot lights.
//
// Fog has one of four types, each of which blends each surface point
// with the specified fog color. Each type interprets the visibility
// field to be the distance at which fog totally obscures objects. A
// visibility value of 0 (the default) causes the SoEnvironment node
// to set up fog so that the visibility is the distance to the far
// clipping plane of the current camera.
//
// Note that this node has effect only during rendering, and that it
// does not inherit field values from other SoEnvironment nodes.
//
//////////////////////////////////////////////////////////////////////////////
// C-api: prefix=SoEnv
// C-api: public= ambientIntensity, ambientColor, attenuation
// C-api: public= fogType, fogColor, fogVisibility
class SoEnvironment : public SoNode {
SO_NODE_HEADER(SoEnvironment);
public:
enum FogType { // Type of fog:
NONE, // No fog
HAZE, // Linear increase in opacity with distance
FOG, // Exponential increase in opacity
SMOKE // Exponential squared increase in opacity
};
// Fields
// Intensity and RGB color of ambient lighting
SoSFFloat ambientIntensity;
SoSFColor ambientColor;
// Squared, linear, and constant light attenuation coefficients
// (in order) with respect to distance of light from surface (for
// Phong lighting)
SoSFVec3f attenuation;
// Type of fog, color of fog, and visibility factor.
SoSFEnum fogType;
SoSFColor fogColor;
SoSFFloat fogVisibility;
// Constructor
SoEnvironment();
SoEXTENDER public:
virtual void GLRender(SoGLRenderAction *action);
virtual void callback(SoCallbackAction *action);
SoINTERNAL public:
static void initClass();
protected:
virtual ~SoEnvironment();
private:
// Computes fog density based on visibility
static float computeDensity(float visibility, SbBool squared);
};
#endif /* _SO_ENVIRONMENT_ */
|
