sfml: properly detect nearest object

Makefile

@@ -25,7 +25,8 @@ deps_update:
 deps_opt:
 	@[ -d lib/ ] || make deps
 doc:
-	crystal docs ./src/zero_epsilon.cr ./src/tests/physics_sandbox.cr ./lib/crsfml/src/crsfml.cr ./lib/imgui/src/imgui.cr
+	crystal docs ./src/zero_epsilon.cr ./src/tests/physics_sandbox.cr ./lib/crsfml/src/crsfml.cr ./lib/imgui/src/imgui.cr ./lib/imgui-sfml/src/imgui-sfml.cr
+
 clean:
 	rm $(NAME)
 

src/engine/gravity/body.cr

@@ -11,9 +11,15 @@ module Gravity
     EARTH2 = Gravity::Body(2).new(mass: 5972200000000000000000000.0, position: Vector(Float64, 2).zero)
     EARTH3 = Gravity::Body(3).new(mass: 5972200000000000000000000.0, position: Vector(Float64, 3).zero)
 
-    getter :mass, :position, :g
+    getter :mass, :position, :g, :name
 
-    def initialize(@mass : Float64, @position : Vector(Float64, N) = Vector(Float64, N).zero, @g : Float64 = G)
+    @@name_idx = 0
+    def self.next_name
+      @@name_idx += 1
+      "default~#{@@name_idx}"
+    end
+
+    def initialize(@mass : Float64, @position : Vector(Float64, N) = Vector(Float64, N).zero, @g : Float64 = G, @name : String = next_name)
     end
 
     def acceleration(position : Vector(Float64, N)) : Vector(Float64, N)

src/tests/physics_sandbox.cr

@@ -27,7 +27,7 @@ class Game
   @selected_body : Gravity::Body(2)
 
   SECOND_IN_NANO = 1_000_000_000
-  DEFAULT_ZOOM = 5/16
+  DEFAULT_ZOOM = 3/16
 
   def accuracy_frequency_nano_rate
     ((SECOND_IN_NANO * @timescale) // @framerate).to_u64
@@ -93,11 +93,11 @@ class Game
 
     sun_offset = Vector[3*10.0**11, 3*10.0**11]
     @bodies = {
-      vessel: Gravity::MovingBody(2).new(mass: 1.0, g: 0.1, position: Vector[10.0, 10.0]),
+      vessel: Gravity::MovingBody(2).new(name: "vessel", mass: 1.0, g: 0.1, position: Vector[10.0, 10.0]),
-      star:   Gravity::MovingBody(2).new(mass: 300000.0, g: 0.1, position: Vector[1000.0, 1000.0], speed: Vector[0.0, 0.0]),
+      star:   Gravity::MovingBody(2).new(name: "star", mass: 300000.0, g: 0.1, position: Vector[1000.0, 1000.0], speed: Vector[0.0, 0.0]),
-      pla1:   Gravity::MovingBody(2).new(mass: 15000.0, g: 0.1, position: Vector[500.0, 500.0], speed: Vector[12.0, 0.0]),
+      pla1:   Gravity::MovingBody(2).new(name: "pla1", mass: 15000.0, g: 0.1, position: Vector[500.0, 500.0], speed: Vector[12.0, 0.0]),
-      pla2:   Gravity::MovingBody(2).new(mass: 18000.0, g: 0.1, position: Vector[1000.0, 1500.0], speed: Vector[-6.0, -6.0]),
+      pla2:   Gravity::MovingBody(2).new(name: "pla2", mass: 18000.0, g: 0.1, position: Vector[1000.0, 1500.0], speed: Vector[-6.0, -6.0]),
-      pla3:   Gravity::MovingBody(2).new(mass: 12000.0, g: 0.1, position: Vector[1500.0, 1500.0], speed: Vector[-6.0, 0.0]),
+      pla3:   Gravity::MovingBody(2).new(name: "pla3", mass: 12000.0, g: 0.1, position: Vector[1500.0, 1500.0], speed: Vector[-6.0, 0.0]),
     }
     @gravited = [
       @bodies[:pla1], @bodies[:pla2], @bodies[:pla3], @bodies[:star],
@@ -141,6 +141,8 @@ class Game
     @ui_events_handler = UI::EventHandler.new
   end
 
+  MAX_DISTANCE_TO_SELECT_PROJECTABLE = 15
+
   def handle_events
     joystick_moved_modified = false
 
@@ -154,12 +156,27 @@ class Game
       when SF::Event::KeyPressed
         Log.debug "KeyPressed #{event}"
       when SF::Event::MouseMoved
+      when SF::Event::MouseButtonReleased
+        clicked_on_imgui_item = ImGui.is_any_item_hovered || ImGui.is_any_item_active
+        if !clicked_on_imgui_item
+          # don't match if click on the buttons of ImGui
+          # click_coord = @window.map_pixel_to_coords({event.x, event.y}, @view)
+          # m = (proj.position - Vector[click_coord.x, click_coord.y]).magnitude
+          # mmhhhh it does not work as expected, bugged
+          nearest_proj = @projectables.map do |projectable|
+            pixel = @window.map_coords_to_pixel({projectable.position[0], projectable.position[1]}, @view)
+            {
+              projectable: projectable,
+              distance: (Vector[pixel.x, pixel.y] - Vector[event.x, event.y]).magnitude,
+            }
+          end.sort_by!{ |tuple| tuple[:distance] }.first
+          if nearest_proj[:distance] <= MAX_DISTANCE_TO_SELECT_PROJECTABLE
+            @selected_body = nearest_proj[:projectable].gravity_body
+            pp "Select a new body #{@selected_body.name}"
+          end
+        end
       when SF::Event::MouseButtonEvent
-        click_coord = @window.map_pixel_to_coords({event.x, event.y}, @view)
+        pp "MouseButtonEvent #{event}"
-        # mmhhhh it does not work as expected, bugged
-        nearest_proj = @projectables.sort_by { |proj| (proj.position - Vector[event.x, event.y]).magnitude }.first
-        @selected_body = nearest_proj.gravity_body
-        Log.debug "MouseButtonEvent #{event}"
       when SF::Event::JoystickButtonPressed
         @joystick_moved.zero!              # reset 0
         joystick_moved_modified = :vector # force exact set
@@ -296,4 +313,4 @@ class Game
   end
 end
 
-Game.new(framerate: 120, width: 1200, height: 1000).execute_loop
+Game.new(framerate: 120, width: 800, height: 600).execute_loop

src/tests/physics_sandbox/draw.cr

@@ -309,6 +309,7 @@ module PhysicsSandboxDraw
       draw_table_line "Speed", @vessel.gravity_body.speed[0].round(3).to_s, @vessel.gravity_body.speed[1].round(3).to_s, "m/s"
       draw_table_line "Acceleration", @vessel.gravity_body.acceleration[0].round(3).to_s, @vessel.gravity_body.acceleration[1].round(3).to_s, "m/s²"
       draw_table_line "Selected body", "#{@selected_body.position[0].round(4)}", "#{@selected_body.position[1].round(4)}", "m"
+      draw_table_line "", @selected_body.name, "", ""
       draw_table_line "Relative speed", "#{relative_speed[0].round(4)}", "#{relative_speed[1].round(4)}", "m/s"
     end
     ImGui.text ""