Modularize Shaders about gllara HOT 3 OPEN

Very rough concept for the runtime classes (names TBD):

• Class ShaderModule: Contains defines, uniforms that are colors, that are floats, and textures, all identified by string ids. Several modules can share their uniforms. E.g. if two modules used at the same time both use baseTexture or shininess, then both get the same value set by the user.
  • Can have children, which are just ShaderModules themselves. Nested arbitrarily deep. Activating a child means necessarily activating the parent.
  • Can have requirements for specific vertex attributes. Such modules will be activated by loading code directly.
  • Can be marked as non-UI; used by the engine depending on scene settings (this might be used for light settings or cube maps or what have you)
• Class ShaderBase inherits from ShaderModule
  • Adds the actual shader files to use.
• Class ShaderInstance consists of a ShaderBase and set of ShaderModules (that must all be descendants of that ShaderBase). Calculates effective used set of uniforms, vertex attributes, and preprocessor defines.
• XNALara Shader specifically for loading XNALara files:
  • Contains a ShaderInstance to use
  • Contains mesh groups to which this ShaderInstance applies
  • Contains mapping from generic_mesh parameter values to shader parameters
  • Used only during loading, ignored by rest of system.

Possible expansion if necessary:

• ShaderModuleGroup: Can be a child of a ShaderModule. Has a name and a set of ShaderModules. The shader modules are considered mutually exclusive by default.

from gllara.

Loading from existing scene files:

• Use the XNALara Shader data to map the existing shader string

Saving scene files:

• Add array of selected shader modules to GLLItemMesh; use existing shader name as shader base (or new field for this?)

Actually not that difficult.

UI needs to be adapted for this, but having nicer UI is part of the point of all of this.

from gllara.

Should probably also add a way for models to specify which texture coordinate goes with which texture while we're at it.

from gllara.