LZScene

GLPhongShader.pas
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//
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// This unit is part of the GLScene Engine https://github.com/glscene
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//
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{
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   An ARBvp1.0 + ARBfp1.0 shader that implements phong shading.
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    History :  
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       23/08/10 - Yar - Added OpenGLTokens to uses, replaced OpenGL1x functions to OpenGLAdapter
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       22/04/10 - Yar - Fixes after GLState revision
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       05/03/10 - DanB - More state added to TGLStateCache
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       28/07/09 - DaStr - Small changes and simplifications  
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       24/07/09 - DaStr - TGLShader.DoInitialize() now passes rci
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                              (BugTracker ID = 2826217)   
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       20/03/07 - DaStr - Moved some of the stuff from TGLCustomAsmShader back here
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       25/02/07 - DaStr - Completely replaced with a descendant of TGLCustomAsmShader.
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       11/10/04 - SG - Creation.
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}
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unit GLPhongShader;
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interface
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{$I GLScene.inc }
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uses
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  // VCL
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  Classes, SysUtils,
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  GLTexture, GLVectorGeometry, GLVectorLists, OpenGLTokens, GLContext,
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  GLAsmShader, GLRenderContextInfo, GLCustomShader, GLState;
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type
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  TGLPhongShader = class(TGLCustomAsmShader)
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  private
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    FLightIDs: TIntegerList;
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    FDesignTimeEnabled: Boolean;
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    FAmbientPass: Boolean;
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    procedure SetDesignTimeEnabled(const Value: Boolean);
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  protected
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    procedure DoLightPass(lightID: Cardinal); virtual;
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    procedure DoAmbientPass(var rci: TGLRenderContextInfo); virtual;
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    procedure UnApplyLights(var rci: TGLRenderContextInfo); virtual;
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    procedure DoApply(var rci: TGLRenderContextInfo; Sender: TObject); override;
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    function DoUnApply(var rci: TGLRenderContextInfo): Boolean; override;
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    procedure DoInitialize(var rci : TGLRenderContextInfo; Sender : TObject); override;
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  public
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    constructor Create(AOwner: TComponent); override;
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    destructor Destroy; override;
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    function ShaderSupported: Boolean; override;
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  published
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    property DesignTimeEnabled: Boolean read FDesignTimeEnabled write SetDesignTimeEnabled default False;
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  end;
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implementation
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// DoApply
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//
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procedure TGLPhongShader.DoApply(var rci: TGLRenderContextInfo; Sender: TObject);
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begin
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  if (csDesigning in ComponentState) and not DesignTimeEnabled then Exit;
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  GetActiveLightsList(FLightIDs);
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  FAmbientPass := False;
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  if FLightIDs.Count > 0 then
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  begin
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    rci.GLStates.DepthFunc := cfLEqual;
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    rci.GLStates.Disable(stBlend);
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    DoLightPass(FLightIDs[0]);
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    FLightIDs.Delete(0);
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  end
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  else
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  begin
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    DoAmbientPass(rci);
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    FAmbientPass := True;
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  end;
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end;
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// DoUnApply
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//
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function TGLPhongShader.DoUnApply(var rci: TGLRenderContextInfo): Boolean;
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begin
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  Result := False;
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  if (csDesigning in ComponentState) and not DesignTimeEnabled then Exit;
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  if FLightIDs.Count > 0 then
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  begin
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    UnApplyLights(rci);
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    Result := True;
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    Exit;
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  end
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  else
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  if not FAmbientPass then
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  begin
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    Self.UnApplyShaderPrograms();
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    rci.GLStates.Enable(stBlend);
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    rci.GLStates.SetBlendFunc(bfOne, bfOne);
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    DoAmbientPass(rci);
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    FAmbientPass := True;
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    Result := True;
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    Exit;
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  end;
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  rci.GLStates.DepthFunc := cfLEqual;
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end;
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// DoInitialize
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//
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procedure TGLPhongShader.DoInitialize(var rci : TGLRenderContextInfo; Sender : TObject);
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begin
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  if (csDesigning in ComponentState) and not DesignTimeEnabled then Exit;
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  inherited;
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end;
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// SetDesignTimeEnabled
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//
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procedure TGLPhongShader.SetDesignTimeEnabled(const Value: Boolean);
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begin
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  if Value <> FDesignTimeEnabled then
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  begin
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    FDesignTimeEnabled := Value;
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    NotifyChange(Self);
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  end;
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end;
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// Create
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//
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constructor TGLPhongShader.Create(AOwner: TComponent);
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begin
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  inherited;
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  with VertexProgram.Code do
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  begin
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    Add('!!ARBvp1.0');
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    Add('OPTION ARB_position_invariant;');
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    Add('PARAM mvinv[4] = { state.matrix.modelview.inverse };');
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    Add('PARAM mvit[4] = { state.matrix.modelview.invtrans };');
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    Add('PARAM lightPos = program.local[0];');
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    Add('TEMP light, normal, eye;');
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    Add('   ADD eye, mvit[3], -vertex.position;');
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    Add('   MOV eye.w, 0.0;');
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    Add('   DP4 light.x, mvinv[0], lightPos;');
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    Add('   DP4 light.y, mvinv[1], lightPos;');
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    Add('   DP4 light.z, mvinv[2], lightPos;');
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    Add('   ADD light, light, -vertex.position;');
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    Add('   MOV light.w, 0.0;');
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    Add('   MOV result.texcoord[0], vertex.normal;');
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    Add('   MOV result.texcoord[1], light;');
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    Add('   MOV result.texcoord[2], eye;');
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    Add('END');
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  end;
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  with FragmentProgram.Code do
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  begin
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    Add('!!ARBfp1.0');
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    Add('PARAM lightDiff = program.local[0];');
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    Add('PARAM lightSpec = program.local[1];');
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    Add('PARAM materialDiff = state.material.diffuse;');
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    Add('PARAM materialSpec = state.material.specular;');
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    Add('PARAM shininess = state.material.shininess;');
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    Add('TEMP temp, light, normal, eye, R, diff, spec;');
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    Add('   DP3 temp, fragment.texcoord[0], fragment.texcoord[0];');
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    Add('   RSQ temp, temp.x;');
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    Add('   MUL normal, temp.x, fragment.texcoord[0];');
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    Add('   DP3 temp, fragment.texcoord[1], fragment.texcoord[1];');
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    Add('   RSQ temp, temp.x;');
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    Add('   MUL light, temp.x, fragment.texcoord[1];');
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    Add('   DP3 temp, fragment.texcoord[2], fragment.texcoord[2];');
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    Add('   RSQ temp, temp.x;');
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    Add('   MUL eye, temp.x, fragment.texcoord[2];');
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    Add('   DP3_SAT diff, normal, light;');
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    Add('   MUL diff, diff, lightDiff;');
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    Add('   MUL diff, diff, materialDiff;');
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    Add('   DP3 R, normal, light;');
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    Add('   MUL R, R.x, normal;');
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    Add('   MUL R, 2.0, R;');
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    Add('   ADD R, R, -light;');
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    Add('   DP3_SAT spec, R, eye;');
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    Add('   POW spec, spec.x, shininess.x;');
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    Add('   MUL spec, spec, lightDiff;');
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    Add('   MUL spec, spec, materialDiff;');
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    Add('   ADD_SAT result.color, diff, spec;');
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    Add('   MOV result.color.w, 1.0;');
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    Add('END');
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  end;
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  FLightIDs := TIntegerList.Create;
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end;
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// ShaderSupported
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//
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function TGLPhongShader.ShaderSupported: Boolean;
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var
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  MaxTextures: Integer;
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begin
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  Result := inherited ShaderSupported and GL.ARB_multitexture;
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  GL.GetIntegerv(GL_MAX_TEXTURE_UNITS_ARB, @MaxTextures);
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  Result := Result and (maxTextures > 2);
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end;
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// UnApplyLights
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//
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procedure TGLPhongShader.UnApplyLights(var rci: TGLRenderContextInfo);
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begin
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  rci.GLStates.DepthFunc := cfLEqual;
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  rci.GLStates.Enable(stBlend);
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  rci.GLStates.SetBlendFunc(bfOne, bfOne);
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  DoLightPass(FLightIDs[0]);
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  FLightIDs.Delete(0);
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end;
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destructor TGLPhongShader.Destroy;
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begin
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  FLightIDs.Free;
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  inherited;
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end;
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procedure TGLPhongShader.DoAmbientPass(var rci: TGLRenderContextInfo);
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var
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  ambient, materialAmbient: TVector;
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begin
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  rci.GLStates.Disable(stLighting);
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  GL.GetFloatv(GL_LIGHT_MODEL_AMBIENT, @ambient);
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  GL.GetMaterialfv(GL_FRONT, GL_AMBIENT, @materialAmbient);
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  ScaleVector(ambient, materialAmbient);
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  GL.Color3fv(@ambient);
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end;
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procedure TGLPhongShader.DoLightPass(lightID: Cardinal);
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var
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  LightParam: TVector;
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begin
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  Self.ApplyShaderPrograms();
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  with CurrentGLContext.GLStates do
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  begin
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    GL.GetLightfv(GL_LIGHT0+lightID, GL_POSITION, @LightParam);
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    LightParam := LightParam;
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    GL.ProgramLocalParameter4fv(GL_VERTEX_PROGRAM_ARB, 0, @LightParam);
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    LightParam := LightDiffuse[lightID];
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    GL.ProgramLocalParameter4fv(GL_FRAGMENT_PROGRAM_ARB, 0, @LightParam);
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    LightParam := LightSpecular[lightID];
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    GL.ProgramLocalParameter4fv(GL_FRAGMENT_PROGRAM_ARB, 1, @LightParam);
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  end;
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end;
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initialization
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  RegisterClasses([TGLPhongShader]);
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end.
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