Ogre Lexicon  »  -Material

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Material - A material determines how the surface of a mesh will appear after being rendered. You can e.g. assign textures, set colours, enable lighting or shadow-receiving as well as assigning shaders.

Transparency

 
If you have problems with transparency, look for some important material options.

• Use the correct value for alpha (0.0 is completely transparent and 1.0 is fully opaque)
• Set scene blend to alpha blend
• Disable depth write

 
Depth write can be turned off when rendering static backgrounds or when rendering a collection of transparent objects at the end of a scene so that they overlap each other correctly.

Apply in material script:

material TransparencyExample
{
    technique
    {
        pass
        {
            //...
            scene_blend alpha_blend
            depth_write off
        }
    }
}

 

Apply by code:

myMaterialPtr->getTechnique(0)->getPass(0)->setSceneBlending(Ogre::SBT_TRANSPARENT_ALPHA);
myMaterialPtr->getTechnique(0)->getPass(0)->setDepthWriteEnabled(false);

 

Apply by code (C# example for Mogre):

myMaterialPtr.GetTechnique(0).GetPass(0).SetSceneBlending(SceneBlendType.SBT_TRANSPARENT_ALPHA);
myMaterialPtr.GetTechnique(0).GetPass(0).DepthWriteEnabled = false;

Both-side visibility

 
By default a material is only visible from one side.
This is usable for volumetric bodies. (e.g. an (unripped) monster you don't need to see from inside).
For flat surfaces (e.g. a water surface or billboards) often there is a whish to have a both-side visibility.

Enable both-side visibility by a *.material file:
(For details look to this section of the Ogre manual.)

material TransparencyExample
{
    technique
    {
        pass
        {
            //...
            cull_hardware none
            cull_software none 
        }
    }
}

 
To enable both-side visibility by code call the material related method Pass::setCullingMode().
Example:

myMaterialPtr::getTechnique(0)::getPass(0)::setCullingMode(CullingMode::CULL_NONE);

Apply to Mesh

 
Apply a material to a (sub)mesh by code:

entity::getSubEntity(0)::setMaterialName("myMaterialName");

Dynamic usage

It's possible to update a MaterialObject to change it's shape or properties. For this you need to set the dynamic flag:

ManualObject::setDynamic(true);

Then you can update its content:

manObj->beginUpdate();
...
// Recreate object
...
manObj->end();

When you are going to be changing the number of vertices, you additionally should call this:

ManualObject::estimateVertexCount();
ManualObject::estimateIndexCount()

 
Alternatively you can use the low level class DynamicRenderable. A usage example is on page DynamicGrowingBuffers.

See also

• Ogre::Material Class Reference
• Texture
• Collection of Ogre material templates
• Displaying 2D Backgrounds
• Line 3D / MOGRE Line 3D - includes some code how to create a material by code
• Projective Decals - dynamic texture projection on top of a terrain texture
• Reloading materials and parsing material scripts
• MadMarx Tutorial 7 - Basic Material (part 1)
• MadMarx Tutorial 8 - Basic Material (part 2), about transparency, decals, environment map, mix percentage
• Yaose - Editor for material script files, including syntax highlighting and code suggestion

 

Ogre Manual:

• Materials
• Material Scripts
  • Techniques
  • Passes - Definition of colours, transparency, blending types, etc.
  • Texture Units
  • Script Inheritance
  • Script Variables

See also

• Ogre::Material Class Reference
• Texture
• Collection of Ogre material templates
• Displaying 2D Backgrounds
• Line 3D / MOGRE Line 3D - includes some code how to create a material by code
• Projective Decals - dynamic texture projection on top of a terrain texture
• Reloading materials and parsing material scripts
• MadMarx Tutorial 7 - Basic Material (part 1)
• MadMarx Tutorial 8 - Basic Material (part 2), about transparency, decals, environment map, mix percentage

 

Ogre Manual:

• Materials
• Material Scripts
  • Techniques
  • Passes - Definition of colours, transparency, blending types, etc.
  • Texture Units
  • Script Inheritance
  • Script Variables