4.3.2.1 Loading a Material in Memory

To make this example a little more interesting the material is going to be loaded after the other set-up of the texture manager has been performed. This is not really needed but it illustrates how a game might load materials dynamically after the application is already running. So, first we edit `simple.h':

...
class Simple
{
private:
  ...
  void CreateSprites ();
  ...

Then, we edit `simple.cpp' and add the following in Simple::Application() and Simple::CreateSprites() (before `return true'):

bool Simple::Application()
{
  ...
  CreateSprites();
  ...
  return true;
}

...

void Simple::CreateSprites()
{
  // Load a texture for our sprite.
  iTextureManager* txtmgr = g3d->GetTextureManager ();
  iTextureWrapper* txt = loader->LoadTexture ("spark",
        "/lib/std/spark.png", CS_TEXTURE_3D, txtmgr, true);
  if (txt == 0)
    ReportError("Error loading texture!");
}

This code first loads a texture with iLoader::LoadTexture(). The second argument is the file name for our texture (VFS path) and the first argument is how that texture should be named in the engine. In this case we use "spark" for that because that's how the `sprite1' definition wants it. The third parameter indicates for what we want to use this texture. In this case we want to use it to texture map a model for the 3D engine, so the texture must be prepared for 3D. The fourth parameter is the texture manager which will be used to register and prepare the texture and material. This is done automatically by this function because the fifth parameter is set to 'true'. In the previous tutorial we also used this function to load a texture but there we didn't specify the last three parameters. `CS_TEXTURE_3D' is default so that doesn't have to be specified and because we were going to call engine->Prepare() later we also didn't specify the texture manager and the last boolean parameter because Prepare() automatically registers and prepares all textures and materials that are loaded.

If loading succeeds this function will register our texture with the texture manager. As mentioned above this is needed because we are loading this texture after engine->Prepare(). So, this is an easy way to dynamically add textures and materials even when the engine is already running. Note that if you plan to load many new textures and materials, it is more efficient to not let this function register automatically but instead register them manually and then call txtmgr->PrepareTextures() to prepare them all at once.

Further note that when you load a texture like this, there will also be an associated material with the same name. The engine itself works with materials and doesn't directly use textures. The material in this case is simply a wrapper on top of the texture. But you could also add detail textures.

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