Add initial prototype.

4-high/gel/applet/demo/sprite/drop_box_on_box/drop_box_on_box.gpr

@@ -0,0 +1,17 @@
+with
+     "gel",
+     "lace_shared";
+
+project drop_Box_on_Box
+is
+   for Object_Dir use "build";
+   for Exec_Dir   use ".";
+   for Main       use ("launch_drop_box_on_box.adb");
+   for Languages  use ("Ada");
+
+   package Ide      renames Lace_shared.Ide;
+   package Builder  renames Lace_shared.Builder;
+   package Compiler renames Lace_shared.Compiler;
+   package Binder   renames Lace_shared.Binder;
+
+end drop_Box_on_Box;

4-high/gel/applet/demo/sprite/drop_box_on_box/launch_drop_box_on_box.adb

@@ -0,0 +1,98 @@
+with
+     gel.Forge,
+     gel.Window.sdl,
+     gel.Applet.gui_world,
+     gel.Camera,
+     gel.Sprite,
+     physics.Model,
+
+     openGL.Model.box.colored,
+     openGL.Palette,
+
+     ada.Text_IO,
+     ada.Exceptions;
+
+pragma unreferenced (gel.window.sdl);
+
+procedure launch_drop_Box_on_Box
+--
+--  Drops a box onto a box 'terrain'.
+--
+is
+   use openGL.Model.box,
+       openGL,
+       opengl.Palette,
+       ada.Text_IO;
+
+   the_Applet : constant gel.Applet.gui_World.view
+     := gel.Forge.new_gui_Applet ("drop Ball on Box");
+
+
+   the_ground_graphics_Model : constant openGL.Model.box.colored.view
+     := openGL.Model.box.colored.new_Box (Size  => [10.0, 0.5, 10.0],
+                                          Faces => [Front => (Colors => [others => (Red,     Opaque)]),
+                                                    Rear  => (Colors => [others => (Blue,    Opaque)]),
+                                                    Upper => (Colors => [others => (Green,   Opaque)]),
+                                                    Lower => (Colors => [others => (Yellow,  Opaque)]),
+                                                    Left  => (Colors => [others => (Cyan,    Opaque)]),
+                                                    Right => (Colors => [others => (Magenta, Opaque)])]);
+   the_ground_physics_Model : constant physics.Model.view
+     := physics.Model.Forge.new_physics_Model (shape_Info => (Kind         => physics.Model.cube,
+                                                              half_Extents => [5.0, 0.25, 5.0]));
+
+   the_Ground : constant gel.Sprite.view
+     := gel.Sprite.forge.new_Sprite ("demo.Ground",
+                                     gel.Sprite.World_view (the_Applet.gui_World),
+                                     math.Origin_3D,
+                                     the_ground_graphics_Model,
+                                     the_ground_physics_Model);
+
+
+   the_box_physics_Model : constant physics.Model.view
+     := physics.Model.forge.new_physics_Model (shape_Info => (Kind         => physics.Model.cube,
+                                                              half_Extents => [1.0, 0.5, 1.0]),
+                                               Mass => 1.0);
+
+   the_box_graphics_Model : constant openGL.Model.box.colored.view
+     := openGL.Model.box.colored.new_Box (Size => [1.0, 1.0, 1.0],
+                                          Faces => [Front => (Colors => [others => (Red,        Opaque)]),
+                                                    Rear  => (Colors => [others => (Blue,       Opaque)]),
+                                                    Upper => (Colors => [others => (dark_Green, Opaque)]),
+                                                    Lower => (Colors => [others => (Yellow,     Opaque)]),
+                                                    Left  => (Colors => [others => (Cyan,       Opaque)]),
+                                                    Right => (Colors => [others => (Magenta,    Opaque)])]);
+   the_Box : constant gel.Sprite.view
+     := gel.Sprite.forge.new_Sprite ("demo.Box",
+                                     gel.Sprite.World_view (the_Applet.gui_World),
+                                     math.Origin_3D,
+                                     the_box_graphics_Model,
+                                     the_box_physics_Model);
+begin
+   new_Line;
+   put_Line ("Use arrow keys and PgUp/PgDn to move the camera.");
+   new_Line;
+
+   the_Applet.gui_Camera.Site_is ([0.0, 5.0, 15.0]);      -- Position the camera.
+   the_Applet.enable_simple_Dolly (1);                    -- Enable user camera control via keyboards.
+   the_Applet.enable_Mouse (detect_Motion => False);      -- Enable the mouse.
+
+   the_Applet.gui_World.add (the_Ground, and_children => False);               -- Add ground.
+   the_Ground.Site_is (math.Origin_3D);
+
+   the_Applet.gui_World.add (the_Box, and_Children => False);                   -- Add ball.
+   the_Box.Site_is ([0.0, 10.0, 0.0]);
+
+   while the_Applet.is_open
+   loop
+      the_Applet.freshen;                                 -- Handle any new events and update the screen.
+   end loop;
+
+   the_Applet.destroy;
+
+exception
+   when E : others =>
+      new_Line;
+      put_Line ("Unhandled exception in main thread ...");
+      put_Line (ada.Exceptions.exception_Information (E));
+      new_Line;
+end launch_drop_Box_on_Box;