text: //========= Copyright Valve Corporation, All rights reserved. ============//
  //
  // Purpose: 
  //
  // $Workfile:     $
  // $Date:         $
  // $NoKeywords: $
  //=============================================================================//
  
  #ifndef IDISPINFO_H
  #define IDISPINFO_H
  
  #ifdef _WIN32
  #pragma once
  #endif
  
  
  //=============================================================================
  
  #include <assert.h>
  #include "bspfile.h"
  #include "mathlib/vmatrix.h"
  #include "dispnode.h"
  #include "builddisp.h"
  #include "utlvector.h"
  #include "engine/ishadowmgr.h"
  #include "getintersectingsurfaces_struct.h"
  #include "surfacehandle.h"
  #include "ivrenderview.h"
  
  struct model_t;
  struct Ray_t;
  struct RayDispOutput_t;
  struct decal_t;
  class CMeshBuilder;
  
  
  //-----------------------------------------------------------------------------
  // Handle to decals + shadows on displacements
  //-----------------------------------------------------------------------------
  typedef unsigned short DispDecalHandle_t;
  
  enum
  {
  	DISP_DECAL_HANDLE_INVALID = (DispDecalHandle_t)~0
  };
  
  typedef unsigned short DispShadowHandle_t;
  
  enum
  {
  	DISP_SHADOW_HANDLE_INVALID = (DispShadowHandle_t)~0
  };
  
  
  //-----------------------------------------------------------------------------
  // Displacement interface to the engine (and WorldCraft?)
  //-----------------------------------------------------------------------------
  abstract_class IDispInfo
  {
  public:
  
  	virtual				~IDispInfo() {}
  
  	// Builds a list of displacement triangles intersecting the sphere.
  	virtual void		GetIntersectingSurfaces( GetIntersectingSurfaces_Struct *pStruct ) = 0;
  
  	virtual void		RenderWireframeInLightmapPage( int pageId ) = 0;
  	
  	virtual void		GetBoundingBox( Vector &bbMin, Vector &bbMax ) = 0;
  
  	// Get and set the parent surfaces.
  	virtual void		SetParent( SurfaceHandle_t surfID ) = 0;
  	virtual SurfaceHandle_t	GetParent() = 0;
  
  	// Add dynamic lights to the lightmap for this surface.
  	virtual void AddDynamicLights( struct dlight_t *pLights, unsigned int lightMask ) = 0;
  	// Compute the mask for the lights hitting this surface.
  	virtual unsigned int ComputeDynamicLightMask( struct dlight_t *pLights ) = 0;
  
  	// Add and remove decals.
  	// flSize is like the radius of the decal so the decal isn't put on any disp faces it's too far away from.
  	virtual DispDecalHandle_t	NotifyAddDecal( decal_t *pDecal, float flSize ) = 0;
  	virtual void				NotifyRemoveDecal( DispDecalHandle_t h ) = 0;
  	
  	virtual DispShadowHandle_t	AddShadowDecal( ShadowHandle_t shadowHandle ) = 0;
  	virtual void				RemoveShadowDecal( DispShadowHandle_t handle ) = 0;
  
  	// Compute shadow fragments for a particular shadow, return the vertex + index count of all fragments
  	virtual bool		ComputeShadowFragments( DispShadowHandle_t h, int& vertexCount, int& indexCount ) = 0;
  
  	// Tag the surface and check if it's tagged. You can untag all the surfaces
  	// with DispInfo_ClearAllTags. Note: it just uses a frame counter to track the
  	// tag state so it's really really fast to call ClearAllTags (just increments
  	// a variable 99.999% of the time).
  	virtual bool		GetTag() = 0;
  	virtual void		SetTag() = 0;
  
  	// Cast a ray against this surface
  	virtual	bool	TestRay( Ray_t const& ray, float start, float end, float& dist, Vector2D* lightmapUV, Vector2D* textureUV ) = 0;
  
  	// Computes the texture + lightmap coordinate given a displacement uv
  	virtual void	ComputeLightmapAndTextureCoordinate( RayDispOutput_t const& uv, Vector2D* luv, Vector2D* tuv ) = 0;
  };
  
  
  // ----------------------------------------------------------------------------- //
  // Adds shadow rendering data to a particular mesh builder
  // The function will return the new base index
  // ----------------------------------------------------------------------------- //
  int				DispInfo_AddShadowsToMeshBuilder( CMeshBuilder& meshBuilder, 
  										DispShadowHandle_t h, int baseIndex );
  
  
  typedef void* HDISPINFOARRAY;
  
  
  // Init and shutdown for the material system (references global, materials).
  void			DispInfo_InitMaterialSystem();
  void			DispInfo_ShutdownMaterialSystem();
  
  
  // Use these to manage a list of IDispInfos.
  HDISPINFOARRAY	DispInfo_CreateArray( int nElements );
  void			DispInfo_DeleteArray( HDISPINFOARRAY hArray );
  IDispInfo*		DispInfo_IndexArray( HDISPINFOARRAY hArray, int iElement );
  int				DispInfo_ComputeIndex( HDISPINFOARRAY hArray, IDispInfo* pInfo );
  
  // Clear the tags for all displacements in the array.
  void			DispInfo_ClearAllTags( HDISPINFOARRAY hArray );
  
  // Call this to render a list of displacements.
  // If bOrtho is true, then no backface removal is done on dispinfos.
  void			DispInfo_RenderList( int nSortGroup, SurfaceHandle_t *pList, int listCount, bool bOrtho, unsigned long flags, ERenderDepthMode DepthMode );
  
  
  // This should be called from Map_LoadDisplacements (while the map file is open).
  // It loads the displacement data from the file and prepares the displacements for rendering.
  //
  // bRestoring is set to true when just restoring the data from the mapfile
  // (ie: displacements already are initialized but need new static buffers).
  bool			DispInfo_LoadDisplacements( model_t *pWorld, bool bRestoring );
  
  // Deletes all the static vertex buffers.
  void			DispInfo_ReleaseMaterialSystemObjects( model_t *pWorld );
  
  
  #endif // IDISPINFO_H
  