edu.mines.jtk.sgl.StateSet Maven / Gradle / Ivy

Go to download
/****************************************************************************
Copyright 2004, Colorado School of Mines and others.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
****************************************************************************/
package edu.mines.jtk.sgl;

import java.awt.Color;
import java.util.*;

import static edu.mines.jtk.ogl.Gl.*;

/**
 * A set of OpenGL states. State sets can be associated with nodes in
 * a scene graph. During the draw process for a node, these states are 
 * applied in the method {@link Node#drawBegin(DrawContext)}, before
 * the method {@link Node#draw(DrawContext)} is called.
 * 
 * If two states of the same class with the same attributes are added
 * to a state set, then the order in which those states are applied
 * is undefined. Generally, 
 * Nothing prevents two states of the same class from being added to
 * the same state set. Howev
 * @author Dave Hale, Colorado School of Mines
 * @version 2005.05.31
 */
public class StateSet implements State {

  /**
   * Returns a new state set with color, light model, and material states.
   * The specified color is used only when per-vertex colors are not used.
   * The light model state is set for two-sided lighting. The material 
   * state is set with color material ambient and diffuse, specular color 
   * white, and shininess set to 100.
   * 
   * This method exists only to provide a simple way to construct a commonly 
   * used state set. It does nothing that cannot be accomplished (more 
   * tediously) by constructing a state set and adding each of its states 
   * using other methods.
   * @param color the color to be set.
   * @return the state set.
   */
  public static StateSet forTwoSidedShinySurface(Color color) {
    StateSet ss = new StateSet();
    if (color!=null) {
      ColorState cs = new ColorState();
      cs.setColor(color);
      ss.add(cs);
    }
    LightModelState lms = new LightModelState();
    lms.setTwoSide(true);
    ss.add(lms);
    MaterialState ms = new MaterialState();
    ms.setColorMaterial(GL_AMBIENT_AND_DIFFUSE);
    ms.setSpecular(Color.white);
    ms.setShininess(100.0f);
    ss.add(ms);
    return ss;
  }

  /**
   * Adds the specified state to this set.
   * @param state the state.
   */
  public void add(State state) {
    _states.add(state);
  }

  /**
   * Removes the specified state from this set.
   * @param state the state.
   */
  public void remove(State state) {
    _states.remove(state);
  }

  /**
   * Determines whether this set contains a state of the specified class.
   * @param stateClass the state class.
   * @return true; if this state contains such a state; false, otherwise.
   */
  public boolean contains(Class stateClass) {
    return find(stateClass)!=null;
  }

  /**
   * Finds a state in this set of the specified class.
   * @param stateClass the state class.
   * @return the state; null, if the set contains no such state.
   */
  public State find(Class stateClass) {
    for (State s : _states) {
      if (s.getClass().equals(stateClass))
        return s;
    }
    return null;
  }

  /**
   * Gets an iterator for all states in this set.
   * @return the iterator.
   */
  public Iterator getStates() {
    return _states.iterator();
  }

  /**
   * Gets the blend state in this set, if present.
   * @return the blend state; null, if none.
   */
  public BlendState getBlendState() {
    return (BlendState)find(BlendState.class);
  }

  /**
   * Gets the color state in this set, if present.
   * @return the color state; null, if none.
   */
  public ColorState getColorState() {
    return (ColorState)find(ColorState.class);
  }

  /**
   * Gets the light model state in this set, if present.
   * @return the light model state; null, if none.
   */
  public LightModelState getLightModelState() {
    return (LightModelState)find(LightModelState.class);
  }

  /**
   * Gets the line state in this set, if present.
   * @return the line state; null, if none.
   */
  public LineState getLineState() {
    return (LineState)find(LineState.class);
  }

  /**
   * Gets the material state in this set, if present.
   * @return the material state; null, if none.
   */
  public MaterialState getMaterialState() {
    return (MaterialState)find(MaterialState.class);
  }

  /**
   * Gets the point state in this set, if present.
   * @return the point state; null, if none.
   */
  public PointState getPointState() {
    return (PointState)find(PointState.class);
  }

  /**
   * Gets the polygon state in this set, if present.
   * @return the polygon state; null, if none.
   */
  public PolygonState getPolygonState() {
    return (PolygonState)find(PolygonState.class);
  }

  /**
   * Applies all states in this set.
   */
  public void apply() {
    for (State s : _states)
      s.apply();
  }

  /**
   * Gets the combined attribute bits for all states in this set.
   * @return the attribute bits.
   */
  public int getAttributeBits() {
    int attributeBits = 0;
    for (State state : _states)
      attributeBits |= state.getAttributeBits();
    return attributeBits;
  }

  ///////////////////////////////////////////////////////////////////////////
  // private

  private Set _states = new HashSet();
}