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--- billboard [2019/03/12 17:54] – [Billboard] admin
+++ billboard [Unknown date] (current) – removed - external edit (Unknown date) 127.0.0.1
@@ Line 1: / Line 1: @@
-====== Billboard ======
-A billboard controls proxy instances of a basis mesh (source object).
-The billboard component is a mesh itself, into which proxies are merged. Much faster rendering is possible if proxy meshes are merge into one mesh, instead of rendering each mesh.
-We typically use this technique for grass or trees.
-It is not suitable for animated meshes.
-===== Example: Grass Billboard =====
-In this example we will display grass on multiplied planes inside of the billboard component.
-After applying the TGorillaGrassMaterial we are able to render different textures onto those planes and to manipulate vertices.
-The result should be a varying grass landscape with waving grass.
-<file pascal Form1.pas>
-procedure TForm1.FormCreate(Sender: TObject);
-var LBillboard : TPlane;
-    LPoolE : TGorillaBitmapPoolEntry;
-    LGrassMat : TGorillaGrassMaterialSource;
-    LAlg : TGorillaBillboardRectFilling;
-begin
-  // creating the source object - here a plane
-  LBillboard := TPlane.Create(fGorilla);
-  LBillboard.Scale.Point := Point3D(4, 4, 4);
-  // creating the grass material source
-  FGrassMat := TGorillaGrassMaterialSource.Create(FGorilla);
-  FGrassMat.Parent := FGorilla;
-  // now we load a pool of grass textures, the material shader
-  // randomly chooses from
-  with FGrassMat do
-  begin
-    LPoolE := Bitmaps.Add() as TGorillaBitmapPoolEntry;
-    LPoolE.Bitmap.LoadFromFile('grass1.png');
-    LPoolE := Bitmaps.Add() as TGorillaBitmapPoolEntry;
-    LPoolE.Bitmap.LoadFromFile('grass2.png');
-    LPoolE := Bitmaps.Add() as TGorillaBitmapPoolEntry;
-    LPoolE.Bitmap.LoadFromFile('grass3.png');
-    LPoolE := Bitmaps.Add() as TGorillaBitmapPoolEntry;
-    LPoolE.Bitmap.LoadFromFile('grass4.png');
-  end;
-  // creating the billboard control
-  FGrass := TGorillaBillboard.Create(FGorilla);
-  FGrass .Parent := FGorilla;
-  FGrass.SourceObject := LBillboard;
-  FGrass.MaterialSource := LGrassMat;
-  FGrass.SetSize(GORILLA_BILLBOARD_SIZE, GORILLA_BILLBOARD_SIZE, GORILLA_BILLBOARD_SIZE);
-  // create an individual filling algorithm to multiply the grass planes
-  LAlg := TGorillaBillboardRectFilling.Create(FGrass);
-  try
-    FGrass.Fill(LAlg, true);
-  finally
-    FreeAndNil(LAlg);
-  end;
-</file>
-==== Interact with grass shader ====
-The default grass shader provides functionality to bend the grass planes at a certain point.
-To enable interaction, f.e. at mouse position, we can simply configure the TGorillaGrassMaterialSource:
-<file pascal Form1.pas>
-  FGrassMat.SpotRadius := 0.5;
-  FGrassMat.SpotEnabled := true;
-</file>
-And in the OnMouseMove event we can set the current interaction point like this:
-<file pascal Form1.pas>
-procedure TForm1.DoOnViewportMouseMove(ASender : TObject; AShiftState : TShiftState;
-  X, Y : Single);
-var LPt3D : TPoint3D;
-    LRayPos, LRayDir : TVector3D;
-begin
-  if FMove then
-  begin
-    if (ssLeft in AShiftState) then
-    begin
-      FGorilla.BeginUpdate();
-      try
-        LPt3D := FGorilla.ScreenToWorld(PointF(X, Y));
-        FGorilla.Context.Pick(X, Y, TProjection.Camera, LRayPos, LRayDir);
-        FGrass.RayCastIntersect(LRayPos, LRayDir, LPt3D);
-        // apply scaled light position
-        FGrassMat.Spot := TPoint3D(LPt3D);
-      finally
-        FGorilla.EndUpdate();
-      end;
-    end;
-    FLatest := PointF(X, Y);
-  end;
-end;
-</file>
-Next step: [[inventory|Inventory]]