Differences

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--- 1.1.0:picking [2024/04/09 15:42] – created admin
+++ 1.1.0:picking [2024/04/09 15:59] (current) – admin
@@ Line 12: / Line 12: @@
 |function PickTriangle(const ARayPos, ARayDir: TVector3D; var AIntersection, ANormal: TPoint3D; out A, B, C : TPoint3D) : Boolean;|Detects an intersected triangle by an absolute raypos and raydir! If intersection was successful, the method returns the intersection 3D coordinate and the normal vector at this position. Otherwise those values are undefined. If intersection was successful, the method returns the absolute triangle corner coordinates. Otherwise A, B and C are zero.|
 |function PickTriangle(const ARayPos, ARayDir: TVector3D; var AResult : TTriangleRayCastResult) : Boolean;|Detects an intersected triangle by an absolute raypos and raydir! If intersection was successful, the method returns the TTriangleRayCastResult structure containing the intersection point, the normal at this position, the 3 corner vertex positions and if a object could be detected the instance those data belongs to. Otherwise this structure is undefined.|
+Use the extended calls with the **TTriangleRayCastResult** result for detailed information about the picked data.
+The TTriangleRayCastResult record has the following structure:
+<file Pascal>
+  TTriangleRayCastResult = record
+    T            : Single;
+    Normal       : TPoint3D;
+    Hit          : Boolean;
+    Intersection : TPoint3D;
+    Instance     : TObject; // TCustomMeshDef/TMeshDef/TGorillaMesh
+    Triangle     : Array[0..2] of TPoint3D;
+  end;
+</file>
+As example, you can register an OnMouseUp event on your specific mesh/model or sub-mesh.
+Within your OnMouseUp event you can then perform the raycasting or triangle picking:
+<file Pascal>
+procedure TForm1.MyMeshMouseUp(Sender: TObject; Button: TMouseButton;
+  Shift: TShiftState; X, Y: Single; RayPos, RayDir: TVector3D);
+var LAbsRayPos, LAbsRayDir : TVector3D;
+    LIntersect, LNormal : TPoint3D;
+    LMesh : TGorillaMesh;
+    LTriResult  : TTriangleRayCastResult;
+begin
+  LMesh := Sender as TGorillaMesh;
+  if not Assigned(LMesh) then
+    Exit;
+  // Convert from local vector to absolute, because we're currently in object space
+  LAbsRayPos := LMesh.LocalToAbsoluteVector(ARayPos);
+  LAbsRayDir := LMesh.LocalToAbsoluteDirection(ARayDir);
+  // Perform a raycast intersection test and if it hits the mesh, show a message
+  if LMesh.RayCastIntersect(LAbsRayPos, LAbsRayDir, LIntersect, LNormal) then
+    ShowMessage(Format('Intersection-Point = (%n, %n, %n)', [LIntersect.X, LIntersect.Y, LIntersect.Z]));
+  // Or perform a triangle pick and output the triangle points and the instance pointer too
+  if LMesh.PickTriangle(LAbsRayPos, LAbsRayDir, LTriResult) then
+    ShowMessage(Format('instance=%d, Intersection-Point = (%n, %n, %n), triangle-P1=(%n,%n,%n), triangle-P2=(%n,%n,%n), triangle-P3=(%n,%n,%n)',
+      [
+      NativeUInt(LTriResult.Instance),
+      LTriResult.Intersection.X, LTriResult.Intersection.Y, LTriResult.Intersection.Z,
+      LTriResult.Triangle[0].X, LTriResult.Triangle[0].Y, LTriResult.Triangle[0].Z,
+      LTriResult.Triangle[1].X, LTriResult.Triangle[1].Y, LTriResult.Triangle[1].Z,
+      LTriResult.Triangle[2].X, LTriResult.Triangle[2].Y, LTriResult.Triangle[2].Z
+      ]));
+end;
+</file>
+Next step: [[charactercontrolling|CharacterControlling]]