Differences

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--- 0.8.3:fbo [2021/01/03 18:15] – admin
+++ 0.8.3:fbo [2021/01/03 18:36] (current) – admin
@@ Line 12: / Line 12: @@
 [...]
 // create the buffer and link to a context
-FDefaultFrameBuf := TFrameBufferObject.Create(AContext);
+FFBO := TFrameBufferObject.Create(AContext);
 // in case you need a depth and stencil buffer
-FDefaultFrameBuf.CreateDepthBuffer(Width, Height);
+FFBO.CreateDepthBuffer(Width, Height);
+</file>
+When working with framebuffer objects, you have to bind them before and to unbind afterwards.
+<file pascal>
+  FFBO.Bind(AContext);
+  try
+    FFBO.Clear(TRenderTarget.Color_0, TAlphaColorF.Create(0, 0, 0, 0), 1, 0);
+  finally
+    FFBO.Unbind(AContext);
+  end;
 </file>
@@ Line 69: / Line 79: @@
 __Caution:__ Not all GPU's support all render targets. Some GPU's only support up to 8 targets or less.
-The following snippet shows how to attach a texture / render-target to the default framebuffer object of a render-pass.
+The following snippet shows how to attach the previously created texture to our framebuffer object.
 <file pascal>
 procedure TMyRenderPass.DoSetupTexturesByViewport(const AContext : TContext3D;
   const AWidth, AHeight : Integer);
-var LCtx : TCustomContextOpenGL;
 begin
   [...]
-  LCtx := Renderer.SharedContext as TCustomContextOpenGL;
+  FFBO.AttachTexture(AContext, FMyRenderTargetTexture.GorillaTexture, TRenderTarget.Color_0);
-  LCtx.DefaultFrameBuf.AttachTexture(AContext, FMyRenderTargetTexture.GorillaTexture, TRenderTarget.Color_1);
 end;
 </file>
@@ Line 83: / Line 92: @@
 === Using multiple targets ===
-To use a render target from the framebuffer object, we need to clear it on each rendering step.
+To use the framebuffer object with its attached render-targets, we need to bind, clear and prepare it on each rendering step.
-After that, we have to activate it for shader usage by the Prepare() method.
+If you forget to execute Prepare() only the default target Color_0 will be available for computation.
-The prepare method will activate all supplied render targets for shader computation.
+Only color attachments need to be prepared, not stencil or depth buffers.
-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":
+Notice: when working with render-passes and the embedded TRenderer, this is already done for you.
+But in case you established your own FBO, you enable it the following way.
 <file pascal>
-[...]
+procedure TMyRenderPass.DoOnBeginRenderPassSetup(
-case AState of
+  const ACount : Integer; const APass : TRenderPass);
-  TRenderPassEventState.OnPassBegin :
+begin
-    begin
+  inherited;
-      [...]
-      LTarget := TRenderTarget.Color_1;
+  // bind your framebuffer to use in shaders
+  FFBO.Bind(Renderer.SharedContext);
-      // clear the specific render target buffer
+  // clear the specific render target buffer
-      FFBO.Clear(Point(AContext.Width, AContext.Height),
+  FFBO.Clear([TRenderTarget.Color_0, TRenderTarget.Depth],
-        LTarget, TAlphaColorF.Create(0, 0, 0, 0), 0, 0);
+    TAlphaColorF.Create(0, 0, 0, 1), 1, 0);
-      // activate the specific render target buffer for shader
+  // activate the specific render target buffer for shader
-      FFBO.Prepare([LTarget]);
+  FFBO.Prepare([TRenderTarget.Color_0]);
-    end;
+end;
-    [...]
-</file>
-On "OnPassEnd" state we need to unbind the framebuffer object:
+procedure TMyRenderPass.DoOnEndRenderPassSetup(
+  const ACount : Integer; const APass : TRenderPass);
-<file pascal>
+begin
-TRenderPassEventState.OnPassEnd :
+  FFBO.Unbind(Renderer.SharedContext);
-  begin
-    [...]
+  inherited;
-  end;
+end;
 </file>