ColorImageAffector.cs :  » Game » RealmForge » Axiom » ParticleFX » C# / CSharp Open Source

#region LGPL License
/*
Axiom Game Engine Library
Copyright (C) 2003  Axiom Project Team

The overall design, and a majority of the core engine and rendering code 
contained within this library is a derivative of the open source Object Oriented 
Graphics Engine OGRE, which can be found at http://ogre.sourceforge.net.  
Many thanks to the OGRE team for maintaining such a high quality project.

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.

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
*/
#endregion

using System;
using Axiom.ParticleSystems;
using Axiom.Scripting;
using Axiom.Media;

namespace Axiom.ParticleFX{
  /// <summary>
  /// Summary description for ColorFaderAffector.
  /// </summary>
  public class ColorImageAffector : ParticleAffector {
    protected Axiom.Media.Image colorImage;
    protected String colorImageName;

    public ColorImageAffector() {
      this.type = "ColourImage";
    }

    public String ColorImageName {
      get { 
        return colorImageName; 
      }
      set { 
        colorImageName = value;
        colorImage = Axiom.Media.Image.FromFile(value);

        PixelFormat  format = colorImage.Format;

        if ( format != PixelFormat.A8R8G8B8 ) {
          throw new NotSupportedException( "Error: Image is not a rgba image.  ColorImageAffector.ColorImageName property set" );
        }
      }
    }

    public override void InitParticle(ref Particle particle) {
      const float div_255 = 1.0f / 255.0f;
    
      particle.Color.r = colorImage.Data[0] * div_255;
      particle.Color.g = colorImage.Data[1] * div_255;
      particle.Color.b = colorImage.Data[2] * div_255;
      particle.Color.a = colorImage.Data[3] * div_255;
    }

    public override void AffectParticles(ParticleSystem system, float timeElapsed) {
      float width = colorImage.Width  - 1;
      float height = colorImage.Height - 1;
      const float div_255 = 1.0f / 255.0f;

      // loop through the particles
      for( int i = 0; i < system.Particles.Count; i++) {
        Particle p = (Particle)system.Particles[i];

        // life_time, float_index, index and position are CONST in OGRE, but errors here

        // We do not have the concept of a total time to live!
        float life_time = p.totalTimeToLive;
        float particle_time  = 1.0f - (p.timeToLive / life_time); 

        if (particle_time > 1.0f) {
          particle_time = 1.0f;
        }
        if (particle_time < 0.0f) {
          particle_time = 0.0f;
        }

        float float_index = particle_time * width;
        int index = (int)float_index;
        int position = index * 4;
        
        if (index <= 0 || index >= width) {
          p.Color.r = (colorImage.Data[position + 0] * div_255);
          p.Color.g = (colorImage.Data[position + 1] * div_255);
          p.Color.b = (colorImage.Data[position + 2] * div_255);
          p.Color.a = (colorImage.Data[position + 3] * div_255);
        } 
        else {
          // fract, to_color and from_color are CONST in OGRE, but errors here
          float fract = float_index - (float)index;
          float toColor = fract * div_255;
          float fromColor = (div_255 - toColor);

          p.Color.r = (colorImage.Data[position + 0] * fromColor) + (colorImage.Data[position + 4] * toColor);
          p.Color.g = (colorImage.Data[position + 1] * fromColor) + (colorImage.Data[position + 5] * toColor);
          p.Color.b = (colorImage.Data[position + 2] * fromColor) + (colorImage.Data[position + 6] * toColor);
          p.Color.a = (colorImage.Data[position + 3] * fromColor) + (colorImage.Data[position + 7] * toColor);
        }
      }
    }

    #region Command definition classes

    [Command("image", "Image for color alterations.", typeof(ParticleAffector))]
    class ImageCommand : ICommand {
      #region ICommand Members

      public string Get(object target) {
        ColorImageAffector affector = target as ColorImageAffector;
        return affector.ColorImageName;
      }
      public void Set(object target, string val) {
        ColorImageAffector affector = target as ColorImageAffector;
        affector.ColorImageName = val;
      }

      #endregion
    }

    #endregion Command definition classes
  }
}