unit ulibShaderFile;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils;

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const
  LSF_LOGLEVEL_DEBUG                      = 0;
  LSF_LOGLEVEL_INFO                       = 1;
  LSF_LOGLEVEL_WARNING                    = 2;
  LSF_LOGLEVEL_ERROR                      = 3;

  LSF_ERR_NONE                            = $00000000;
  LSF_ERR_NOT_INIT                        = $00000001;
  LSF_ERR_INVALID_HANDLE_SHADER_FILE      = $00000010;
  LSF_ERR_INVALID_HANDLE_SHADER_GENERATOR = $00000011;
  LSF_ERR_INVALID_GENERATOR_NAME          = $00000020;
  LSF_ERR_INVALID_PROPERTY_INDEX          = $00000021;
  LSF_ERR_UNKNOWN_IDENTFIFIER             = $00001000;
  LSF_ERR_DUPLICATE_IDENTIFIER            = $00001001;
  LSF_ERR_OUT_OF_RANGE                    = $00001002;
  LSF_ERR_INVALID_IDENTIFIER              = $00001003;
  LSF_ERR_INVALID_PARAMTER_COUNT          = $00001004;
  LSF_ERR_INVALID_PARAMTER                = $00001005;
  LSF_ERR_UNEXPECTED_TOKEN                = $00001006;
  LSF_ERR_INVALID_TOKEN                   = $00001007;
  LSF_ERR_EXPRESSION_INTERNAL             = $00001008;
  LSF_ERR_EXPRESSION                      = $00001009;
  LSF_ERR_SHADER_PART_INTERNAL            = $0000100A;
  LSF_ERR_SHADER_PART                     = $0000100B;
  LSF_ERR_UNKNOWN                         = $FFFFFFFF;

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
type
  TlsfErrorCode = Cardinal;
  TlsfLogLevel = Cardinal;
  TlsfShaderFileHandle = Pointer;
  TlsfShaderGeneratorHandle = Pointer;
  TlsfShaderFileLogEvent = procedure(const aLogLevel: TlsfLogLevel; const aMsg: PAnsiChar; const aUserArgs: Pointer);

  Tlsf_ShaderFile_create            = function: TlsfShaderFileHandle; stdcall;
  Tlsf_ShaderFile_setLogCallback    = function(const aHandle: TlsfShaderFileHandle; const aCallback: TlsfShaderFileLogEvent; const aUserArgs: Pointer): TlsfErrorCode; stdcall;
  Tlsf_ShaderFile_loadFromFile      = function(const aHandle: TlsfShaderFileHandle; const aFilename: PAnsiChar): TlsfErrorCode; stdcall;
  Tlsf_ShaderFile_saveToFile        = function(const aHandle: TlsfShaderFileHandle; const aFilename: PAnsiChar): TlsfErrorCode; stdcall;
  Tlsf_ShaderFile_getGeneratorNames = function(const aHandle: TlsfShaderFileHandle): PAnsiChar; stdcall;
  Tlsf_ShaderFile_destroy           = function(const aHandle: TlsfShaderFileHandle): TlsfErrorCode; stdcall;

  Tlsf_Generator_create             = function(const aHandle: TlsfShaderFileHandle; const aName: PAnsiChar): TlsfShaderGeneratorHandle; stdcall;
  Tlsf_Generator_getPropertyNames   = function(const aHandle: TlsfShaderGeneratorHandle): PAnsiChar; stdcall;
  Tlsf_Generator_getProperty        = function(const aHandle: TlsfShaderGeneratorHandle; const aIndex: Integer): PAnsiChar; stdcall;
  Tlsf_Generator_setProperty        = function(const aHandle: TlsfShaderGeneratorHandle; const aIndex: Integer; const aValue: PAnsiChar): TlsfErrorCode; stdcall;
  Tlsf_Generator_generateCode       = function(const aHandle: TlsfShaderGeneratorHandle): PAnsiChar; stdcall;
  Tlsf_Generator_destroy            = function(const aHandle: TlsfShaderGeneratorHandle): TlsfErrorCode; stdcall;

  Tlsf_init                         = function : TlsfErrorCode; stdcall;
  Tlsf_getLastErrorCode             = function : TlsfErrorCode; stdcall;
  Tlsf_getLastErrorMsg              = function : PAnsiChar; stdcall;
  Tlsf_getLastErrorTrace            = function : PAnsiChar; stdcall;
  Tlsf_finish                       = function: TlsfErrorCode; stdcall;

var
  lsf_ShaderFile_create:            Tlsf_ShaderFile_create;
  lsf_ShaderFile_setLogCallback:    Tlsf_ShaderFile_setLogCallback;
  lsf_ShaderFile_loadFromFile:      Tlsf_ShaderFile_loadFromFile;
  lsf_ShaderFile_saveToFile:        Tlsf_ShaderFile_saveToFile;
  lsf_ShaderFile_getGeneratorNames: Tlsf_ShaderFile_getGeneratorNames;
  lsf_ShaderFile_destroy:           Tlsf_ShaderFile_destroy;

  lsf_Generator_create:             Tlsf_Generator_create;
  lsf_Generator_getPropertyNames:   Tlsf_Generator_getPropertyNames;
  lsf_Generator_getProperty:        Tlsf_Generator_getProperty;
  lsf_Generator_setProperty:        Tlsf_Generator_setProperty;
  lsf_Generator_generateCode:       Tlsf_Generator_generateCode;
  lsf_Generator_destroy:            Tlsf_Generator_destroy;

  lsf_getLastErrorCode:             Tlsf_getLastErrorCode;
  lsf_getLastErrorMsg:              Tlsf_getLastErrorMsg;
  lsf_getLastErrorTrace:            Tlsf_getLastErrorTrace;

procedure lsf_init(const aLibName: String);
procedure lsf_finish;

implementation

uses
  dynlibs;

var
  libHandle: TLibHandle;
  lsf_init_intern: Tlsf_init;
  lsf_finish_intern: Tlsf_finish;

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
procedure lsf_init(const aLibName: String);

  function LoadProc(const aName: AnsiString): Pointer;
  begin
    result := GetProcedureAddress(libHandle, aName);
    if not Assigned(result) then
      raise Exception.CreateFmt('unable to load ''%s'' from ''%s''', [aName, aLibName]);
  end;

begin
  libHandle := LoadLibrary(aLibName);
  if (libHandle = 0) then
    raise Exception.CreateFmt('unable to load library: %s', [aLibName]);
  lsf_ShaderFile_create             := Tlsf_ShaderFile_create(            LoadProc('lsf_ShaderFile_create'));
  lsf_ShaderFile_setLogCallback     := Tlsf_ShaderFile_setLogCallback(    LoadProc('lsf_ShaderFile_setLogCallback'));
  lsf_ShaderFile_loadFromFile       := Tlsf_ShaderFile_loadFromFile(      LoadProc('lsf_ShaderFile_loadFromFile'));
  lsf_ShaderFile_saveToFile         := Tlsf_ShaderFile_saveToFile(        LoadProc('lsf_ShaderFile_saveToFile'));
  lsf_ShaderFile_getGeneratorNames  := Tlsf_ShaderFile_getGeneratorNames( LoadProc('lsf_ShaderFile_getGeneratorNames'));
  lsf_ShaderFile_destroy            := Tlsf_ShaderFile_destroy(           LoadProc('lsf_ShaderFile_destroy'));

  lsf_Generator_create              := Tlsf_Generator_create(             LoadProc('lsf_Generator_create'));
  lsf_Generator_getPropertyNames    := Tlsf_Generator_getPropertyNames(   LoadProc('lsf_Generator_getPropertyNames'));
  lsf_Generator_getProperty         := Tlsf_Generator_getProperty(        LoadProc('lsf_Generator_getProperty'));
  lsf_Generator_setProperty         := Tlsf_Generator_setProperty(        LoadProc('lsf_Generator_setProperty'));
  lsf_Generator_generateCode        := Tlsf_Generator_generateCode(       LoadProc('lsf_Generator_generateCode'));
  lsf_Generator_destroy             := Tlsf_Generator_destroy(            LoadProc('lsf_Generator_destroy'));

  lsf_init_intern                   := Tlsf_init(                         LoadProc('lsf_init'));
  lsf_getLastErrorCode              := Tlsf_getLastErrorCode(             LoadProc('lsf_getLastErrorCode'));
  lsf_getLastErrorMsg               := Tlsf_getLastErrorMsg(              LoadProc('lsf_getLastErrorMsg'));
  lsf_getLastErrorTrace             := Tlsf_getLastErrorTrace(            LoadProc('lsf_getLastErrorTrace'));
  lsf_finish_intern                 := Tlsf_finish(                       LoadProc('lsf_finish'));

  if (lsf_init_intern() <> LSF_ERR_NONE) then
    raise Exception.Create('error while initializing library: ' + lsf_getLastErrorMsg());
end;

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
procedure lsf_finish;
begin
  lsf_finish_intern();
  lsf_ShaderFile_create            := nil;
  lsf_ShaderFile_setLogCallback    := nil;
  lsf_ShaderFile_loadFromFile      := nil;
  lsf_ShaderFile_saveToFile        := nil;
  lsf_ShaderFile_getGeneratorNames := nil;
  lsf_ShaderFile_destroy           := nil;
  lsf_getLastErrorCode             := nil;
  lsf_getLastErrorMsg              := nil;
  lsf_getLastErrorTrace            := nil;
  if (libHandle <> 0) then begin
    FreeLibrary(libHandle);
    libHandle := 0;
  end;
end;

end.