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renderpass [2020/01/09 13:50] – [Rendering Method] adminrenderpass [2020/01/09 14:24] – [How to use] admin
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   * FrameBufferObject (FBO)   * FrameBufferObject (FBO)
  
-While the Context (also main texture or Default-FBO) is the default texture used for final rendering output, the FrameBufferObject (FBO) is a buffer created for each renderpass instance. +While the context (aka. main texture or Default-FBO) is the default texture used for final rendering output, the FrameBufferObject (FBO) is a buffer created for each render pass instance. 
-The FrameBufferObject (FBO) can be used to temporarily store your rendering result and push it to another renderpass.+The FrameBufferObject (FBO) can be used to temporarily store your rendering result and push it to another render pass.
 For further information read down below. For further information read down below.
  
 ^ Type ^ Description ^ ^ Type ^ Description ^
-| TRenderPassMethod.RenderListToContext | Will render all 3D objects in rendering list to the context. If a render pass material exists it will apply it, otherwise it will use the element specific material shader. | +| TRenderPassMethod.RenderListToContext | Will render all 3D objects in rendering list to context. If a render pass material exists it will be applied, otherwise it will use the 3D object specific material shader. | 
-| TRenderPassMethod.RenderListToFBO | Will render all 3D objects in rendering list to the render pass specific FrameBufferObject (FBO) and attached textures. | +| TRenderPassMethod.RenderListToFBO | Will render all 3D objects in rendering list to render pass specific FrameBufferObject (FBO) and its attached textures. | 
-| TRenderPassMethod.RectToContext | Will render a rectangle to context. The render pass need to have an individual material applied, otherwise an error occurs. Use this method for rendering post effects. The shader program will render to default FBO / context / main texture. | +| TRenderPassMethod.RectToContext | Will render a rectangle to context. The render pass need to have an individual material applied, otherwise an error occurs. Use this method for rendering //post effects//. | 
-| TRenderPassMethod.RectToFBO | Will render a rectangle to the render pass specific FrameBufferObject (FBO). he render pass need to have an individual material applied, otherwise an error occurs. Use this method for rendering post effects before applying to main texture / context / default FBO. |+| TRenderPassMethod.RectToFBO | Will render a rectangle to the render pass specific FrameBufferObject (FBO). The render pass need to have an individual material applied, otherwise an error occurs. Use this method for rendering //post effects// in a chain of post effects. |
  
-In the next step you have to decide, if the element materials (only in RenderList) or an especially for the render-pass created material should be used.+In the next step you have to decide, if a **one-for-all material shader** should be used //or// the **object specific material shaders**.
 Because sometimes you want the full scene just to be rendered from another perspective (like reflection) or you want to store a specific value (like the depth-value in shadow mapping) in the FBO. Because sometimes you want the full scene just to be rendered from another perspective (like reflection) or you want to store a specific value (like the depth-value in shadow mapping) in the FBO.
 +
 +===== Render-Pass Material =====
 +
 +To create an individual material shader for your render-pass you need to extend **TGorillaRenderPassMaterialSource** and **TGorillaRenderPassMaterial**.
 +
 +<file pascal>
 +uses
 +  FMX.Types3D,
 +  FMX.Materials,
 +  FMX.MaterialSources,
 +  Gorilla.Controller;
 +  
 +  TMyRenderPassMaterial = class(TGorillaRenderPassMaterial)
 +    protected
 +      procedure DoApply(const Context: TContext3D); override;
 +      procedure DoInitialize(); override;
 +    public
 +  end;
 +
 +  TMyRenderPassMaterialSource = class(TGorillaRenderPassMaterialSource)
 +    protected
 +      function CreateMaterial() : TMaterial; override;
 +    public
 +  end;
 +</file>
 +
 +Here you can have a look at this example of a render-pass material implementation.
 +
 +Notice: No multiple targets used here. We just write to default output buffer by gl_FragColor.
 +
 +<file pascal>
 +uses
 +  Gorilla.Context.GLES;
 +  
 +  ResourceString SOURCE_VS =
 +    'attribute vec3 a_Position;' +
 +    '' +
 +    'uniform mat4 _ModelViewProjMatrix;' +
 +    '' +
 +    'varying vec4 v_position;' +
 +    '' +
 +    'void main( void ){' +
 +    '  vec4 fvPosition = vec4(a_Position.x, a_Position.y, a_Position.z, 1.0);' +
 +    '  v_position = _ModelViewProjMatrix * fvPosition;' +
 +    '  gl_Position = v_position;' +
 +    '}';
 +
 +  ResourceString SOURCE_FS =
 +    'varying vec4 v_position;' +
 +    '' +
 +    'void main( void ){' +
 +    '  gl_FragColor = v_position;' +
 +    '}';
 +
 +procedure TMyRenderPassMaterial.DoInitialize();
 +var LOGLBytes : TArray<Byte>;
 +begin
 +  LOGLBytes := TEncoding.ASCII.GetBytes(SOURCE_VS);
 +  FVertexShader := TShaderManager.RegisterShaderFromData('MyRenderPass.fvs', TContextShaderKind.VertexShader, '', [
 +    TContextShaderSource.Create(TContextShaderArch.GLSL,
 +      LOGLBytes,
 +      [
 +      TContextShaderVariable.Create('ModelViewProjMatrix', TContextShaderVariableKind.Matrix, 0, 4)
 +      ]
 +    )
 +  ]);
 +
 +  LOGLBytes := TEncoding.ASCII.GetBytes(SOURCE_FS);
 +  FPixelShader := TShaderManager.RegisterShaderFromData('MyRenderPass.fps', TContextShaderKind.PixelShader, '', [
 +    TContextShaderSource.Create(TContextShaderArch.GLSL,
 +      LOGLBytes,
 +      []
 +    )
 +  ]);
 +end;
 +
 +{ TMyRenderPassMaterial }
 +
 +procedure TMyRenderPassMaterial.DoApply(const Context: TContext3D);
 +begin
 +  // activate shaders
 +  Context.SetShaders(FVertexShader, FPixelShader);
 +  // set model view projection matrix
 +  TCustomContextOpenGL(Context).SetShaderVariable('ModelViewProjMatrix', Context.CurrentModelViewProjectionMatrix, true);
 +end;
 +
 +{ TMyRenderPassMaterialSource }
 +
 +function TMyRenderPassMaterialSource.CreateMaterial() : TMaterial;
 +begin
 +  Result := TMyRenderPassMaterial.Create(Self);
 +end;
 +</file>
 +
 +You than have to overwrite the CreateMaterialSource() method and create your material source.
 +In case you'd like to use the element specific material shaders, return nil in the CreateMaterialSource() method.
 +
 +<file pascal>
 +function TMyRenderPass.CreateMaterialSource() : TGorillaRenderPassMaterialSource;
 +begin
 +  result := TMyRenderPassMaterialSource.Create(Self);
 +end;
 +</file>
  
 ===== Start / End ===== ===== Start / End =====
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           [TRenderTarget.Color_0, TRenderTarget.Depth],            [TRenderTarget.Color_0, TRenderTarget.Depth], 
           TAlphaColorF.Create(0, 0, 0, 0), 0, 0);           TAlphaColorF.Create(0, 0, 0, 0), 0, 0);
-        FFBO.Bind();+           
 +        // prepare framebufferobject for multiple render targets
         FFBO.Prepare([TRenderTarget.Color_0, TRenderTarget.Depth]);                 FFBO.Prepare([TRenderTarget.Color_0, TRenderTarget.Depth]);        
       end;       end;
Line 73: Line 177:
     OnPassEnd:     OnPassEnd:
       begin               begin        
-        AContext.SetCameraMatrix(FPrevCamView); +        AContext.SetCameraMatrix(FPrevCamView);   
-         +
-        FFBO.Unbind();        +
       end;       end;
   end;   end;
Line 203: Line 305:
 To use a render target from the framebuffer object, we need to clear it on each rendering step. To use a render target from the framebuffer object, we need to clear it on each rendering step.
 After that, we have to activate it for shader usage by the Prepare() method. After that, we have to activate it for shader usage by the Prepare() method.
 +The prepare method will activate all supplied render targets for shader computation.
 +If you forget to execute prepare() only the default target Color_0 will be available for computation.
  
 We do this all in the render-pass callback method (DoOnRenderPass), when state is "TRenderPassEventState.OnPassBegin": We do this all in the render-pass callback method (DoOnRenderPass), when state is "TRenderPassEventState.OnPassBegin":
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       FFBO.Clear(Point(AContext.Width, AContext.Height),        FFBO.Clear(Point(AContext.Width, AContext.Height), 
         LTarget, TAlphaColorF.Create(0, 0, 0, 0), 0, 0);         LTarget, TAlphaColorF.Create(0, 0, 0, 0), 0, 0);
-       
-      // bind again the framebuffer object 
-      FFBO.Bind(); 
              
       // activate the specific render target buffer for shader       // activate the specific render target buffer for shader
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   begin   begin
     [...]     [...]
-     
-    // unbind framebuffer object 
-    FFBO.Unbind(); 
   end;   end;
 </file> </file>
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   * function GetProjectionMatrix(const AContext : TContext3D) : TMatrix3D;   * function GetProjectionMatrix(const AContext : TContext3D) : TMatrix3D;
  
-===== Render-Pass Material ===== 
- 
-To create an individual material shader for your render-pass you need to extend **TGorillaRenderPassMaterialSource** and **TGorillaRenderPassMaterial**. 
- 
-<file pascal> 
-uses 
-  FMX.Types3D, 
-  FMX.Materials, 
-  FMX.MaterialSources, 
-  Gorilla.Controller; 
-   
-  TMyRenderPassMaterial = class(TGorillaRenderPassMaterial) 
-    protected 
-      procedure DoApply(const Context: TContext3D); override; 
-      procedure DoInitialize(); override; 
-    public 
-  end; 
- 
-  TMyRenderPassMaterialSource = class(TGorillaRenderPassMaterialSource) 
-    protected 
-      function CreateMaterial() : TMaterial; override; 
-    public 
-  end; 
-</file> 
- 
-Here you can have a look at this example of a render-pass material implementation. 
- 
-Notice: No multiple targets used here. We just write to default output buffer by gl_FragColor. 
- 
-<file pascal> 
-uses 
-  Gorilla.Context.GLES; 
-   
-  ResourceString SOURCE_VS = 
-    'attribute vec3 a_Position;' + 
-    '' + 
-    'uniform mat4 _ModelViewProjMatrix;' + 
-    '' + 
-    'varying vec4 v_position;' + 
-    '' + 
-    'void main( void ){' + 
-    '  vec4 fvPosition = vec4(a_Position.x, a_Position.y, a_Position.z, 1.0);' + 
-    '  v_position = _ModelViewProjMatrix * fvPosition;' + 
-    '  gl_Position = v_position;' + 
-    '}'; 
- 
-  ResourceString SOURCE_FS = 
-    'varying vec4 v_position;' + 
-    '' + 
-    'void main( void ){' + 
-    '  gl_FragColor = v_position;' + 
-    '}'; 
- 
-procedure TMyRenderPassMaterial.DoInitialize(); 
-var LOGLBytes : TArray<Byte>; 
-begin 
-  LOGLBytes := TEncoding.ASCII.GetBytes(SOURCE_VS); 
-  FVertexShader := TShaderManager.RegisterShaderFromData('MyRenderPass.fvs', TContextShaderKind.VertexShader, '', [ 
-    TContextShaderSource.Create(TContextShaderArch.GLSL, 
-      LOGLBytes, 
-      [ 
-      TContextShaderVariable.Create('ModelViewProjMatrix', TContextShaderVariableKind.Matrix, 0, 4) 
-      ] 
-    ) 
-  ]); 
- 
-  LOGLBytes := TEncoding.ASCII.GetBytes(SOURCE_FS); 
-  FPixelShader := TShaderManager.RegisterShaderFromData('MyRenderPass.fps', TContextShaderKind.PixelShader, '', [ 
-    TContextShaderSource.Create(TContextShaderArch.GLSL, 
-      LOGLBytes, 
-      [] 
-    ) 
-  ]); 
-end; 
- 
-{ TMyRenderPassMaterial } 
- 
-procedure TMyRenderPassMaterial.DoApply(const Context: TContext3D); 
-begin 
-  // activate shaders 
-  Context.SetShaders(FVertexShader, FPixelShader); 
-  // set model view projection matrix 
-  TCustomContextOpenGL(Context).SetShaderVariable('ModelViewProjMatrix', Context.CurrentModelViewProjectionMatrix, true); 
-end; 
- 
-{ TMyRenderPassMaterialSource } 
- 
-function TMyRenderPassMaterialSource.CreateMaterial() : TMaterial; 
-begin 
-  Result := TMyRenderPassMaterial.Create(Self); 
-end; 
-</file> 
- 
-You than have to overwrite the CreateMaterialSource() method and create your material source. 
-In case you'd like to use the element specific material shaders, return nil in the CreateMaterialSource() method. 
- 
-<file pascal> 
-function TMyRenderPass.CreateMaterialSource() : TGorillaRenderPassMaterialSource; 
-begin 
-  result := TMyRenderPassMaterialSource.Create(Self); 
-end; 
-</file> 
  
 ===== How to use ===== ===== How to use =====
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 FMyRenderPass.Enabled := true; FMyRenderPass.Enabled := true;
 </file> </file>
 +
 +Next step: [[shadows|Shadows]]
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