Add scale tool

DECISIONS.md

@@ -845,7 +845,7 @@ If undo/redo is bolted into each feature separately, the project will accumulate
 
 ### Decision
 
-Implement scale before rotate.
+Implement scale before rotate, defer snapping to the grid until we have a better understanding of tools, undo/redo, and inspector behaviour.
 
 ### Why
 

NOTES.md

@@ -130,11 +130,11 @@ Scale fits the current object model because Prune already has width/height and r
 
 Initial scope:
 
-- Single selected authored object
-- Corner or edge handle
-- Minimum size clamp
-- Inspector updates immediately
-- Undo/redo command recorded when the drag completes
+- [x] Single selected authored object
+- [x] Corner or edge handle
+- [x] Minimum size clamp
+- [x] Inspector updates immediately
+- [x] Undo/redo command recorded when the drag completes
 
 ### 7. Basic audio and event hooks
 
@@ -148,22 +148,43 @@ Preferred direction:
 
 Initial scope:
 
-- One or two hard-coded sound resources
-- Fire event
-- Hit/destroy event
-- Global enable/disable toggle
+- [ ] One or two hard-coded sound resources
+- [ ] Fire event
+- [ ] Hit/destroy event
+- [ ] Global enable/disable toggle
 
-## Later
+## Medium term, in no particular order
 
+- Z-Index ordering
 - Rotate tool
-- Grouping
-- Copy/paste
-- Prefabs/templates
+- Delete action and command
+- Background image support
+- Simplified asset management
+- Copy command
+- Text rendering
+- Paste command
+- Behaviour toggles for authored objects
+- Polished sample scenes
 - Asset browser
-- Animation/facing support
+- Animated sprites/facing support
 - Scene file versioning
+- Grid snapping support on all tools and UI option, not in settings
+- Runtime reset and reload, not just pause/resume
+- Object locking and protection
+- More robust collision shapes and collision options
+
+## Later term, in no particular order
+
+- Scene layering, rendering and collision etc.
+- Grouping
+- Input mapping and rebinding
+- Scene settings panel for background, music, and other scene-wide options
+- Game UI panels 
+- Pathfinding support
 - Full audio mixer
-- Many more tools
+- Prefabs/templates
+- Native playable export
+- WebAssembly playable export
 - Card scene
 - Puzzle scene
-- More robust collision shapes and collision options
+- Many more scene tools

README.md

@@ -194,8 +194,8 @@ Current priorities:
 - [x] Command history panel
 - [x] Multi-select
 - [x] Multi-select move/delete
-- [ ] Tool mode state
-- [ ] Scale tool
+- [x] Tool mode state
+- [x] Scale tool
 - [ ] Basic audio hooks
 
 My development plan is tracked in [NOTES.md](NOTES.md), check the file for more details on what each of these points mean as well as what is included - this is what I will be working on in the next development phase.
@@ -204,18 +204,18 @@ My development plan is tracked in [NOTES.md](NOTES.md), check the file for more
 
 I will consider Prune ready for users when the below is ready, this is the minimum I think users expect from a live editor/runtime prototype:
 
-- Open app.
-- Pick a scene type.
-- Select object in viewport.
-- Move with handle.
-- Resize with scale tool.
-- Duplicate it.
-- Delete it.
-- Undo/redo all of that.
-- Save.
-- Load.
-- Behaviour still works.
-- Runtime objects do not get accidentally edited or saved.
+- [x] Open app.
+- [ ] Pick a scene type. (Deferred for now, initial scene type is hardcoded to Platformer, others in new dropdown.)
+- [x] Select object in viewport.
+- [x] Move with handle.
+- [x] Resize with scale tool.
+- [ ] Duplicate it.
+- [ ] Delete it.
+- [x] Undo/redo all of that.
+- [x] Save.
+- [x] Load.
+- [x] Behaviour still works.
+- [x] Runtime objects do not get accidentally edited or saved.
 
 ## Documentation stance
 

src/prune/editor/editor_tool.hpp

@@ -4,7 +4,8 @@ namespace prune {
 
     enum class EditorTool {
         Select = 0,
-        Move
+        Move,
+        Scale
     };
 
     [[nodiscard]] inline constexpr const char* editor_tool_label(EditorTool tool) noexcept
@@ -14,6 +15,8 @@ namespace prune {
             return "Select";
         case EditorTool::Move:
             return "Move";
+        case EditorTool::Scale:
+            return "Scale";
         }
 
         return "Unknown";
@@ -24,4 +27,9 @@ namespace prune {
         return tool == EditorTool::Move;
     }
 
+    [[nodiscard]] inline constexpr bool editor_tool_allows_scale(EditorTool tool) noexcept
+    {
+        return tool == EditorTool::Scale;
+    }
+
 }

src/prune/editor/tools/transform_gizmo.hpp

@@ -1,11 +1,37 @@
 #pragma once
 
+#include <array>
+
 #include <SDL2/SDL.h>
 
 namespace prune::editor::tools::transform_gizmo {
 
     constexpr int k_outline_padding = 2;
     constexpr int k_move_handle_size = 12;
+    constexpr int k_scale_handle_size = 8;
+
+    enum class ScaleHandle {
+        None = 0,
+        TopLeft,
+        Top,
+        TopRight,
+        Right,
+        BottomRight,
+        Bottom,
+        BottomLeft,
+        Left
+    };
+
+    inline constexpr std::array<ScaleHandle, 8> k_scale_handles{
+        ScaleHandle::TopLeft,
+        ScaleHandle::Top,
+        ScaleHandle::TopRight,
+        ScaleHandle::Right,
+        ScaleHandle::BottomRight,
+        ScaleHandle::Bottom,
+        ScaleHandle::BottomLeft,
+        ScaleHandle::Left
+    };
 
     [[nodiscard]] inline SDL_Rect selected_outline_rect(const SDL_Rect& object_rect) noexcept
     {
@@ -27,6 +53,38 @@ namespace prune::editor::tools::transform_gizmo {
         };
     }
 
+    [[nodiscard]] inline SDL_Rect scale_handle_rect(const SDL_Rect& selected_outline, ScaleHandle handle) noexcept
+    {
+        const int half_size = k_scale_handle_size / 2;
+        const int center_x = selected_outline.x + (selected_outline.w / 2);
+        const int center_y = selected_outline.y + (selected_outline.h / 2);
+        const int right = selected_outline.x + selected_outline.w;
+        const int bottom = selected_outline.y + selected_outline.h;
+
+        switch (handle) {
+        case ScaleHandle::TopLeft:
+            return SDL_Rect{ selected_outline.x - half_size, selected_outline.y - half_size, k_scale_handle_size, k_scale_handle_size };
+        case ScaleHandle::Top:
+            return SDL_Rect{ center_x - half_size, selected_outline.y - half_size, k_scale_handle_size, k_scale_handle_size };
+        case ScaleHandle::TopRight:
+            return SDL_Rect{ right - half_size, selected_outline.y - half_size, k_scale_handle_size, k_scale_handle_size };
+        case ScaleHandle::Right:
+            return SDL_Rect{ right - half_size, center_y - half_size, k_scale_handle_size, k_scale_handle_size };
+        case ScaleHandle::BottomRight:
+            return SDL_Rect{ right - half_size, bottom - half_size, k_scale_handle_size, k_scale_handle_size };
+        case ScaleHandle::Bottom:
+            return SDL_Rect{ center_x - half_size, bottom - half_size, k_scale_handle_size, k_scale_handle_size };
+        case ScaleHandle::BottomLeft:
+            return SDL_Rect{ selected_outline.x - half_size, bottom - half_size, k_scale_handle_size, k_scale_handle_size };
+        case ScaleHandle::Left:
+            return SDL_Rect{ selected_outline.x - half_size, center_y - half_size, k_scale_handle_size, k_scale_handle_size };
+        case ScaleHandle::None:
+            break;
+        }
+
+        return SDL_Rect{};
+    }
+
     [[nodiscard]] inline bool contains_point(const SDL_Rect& rect, int x, int y) noexcept
     {
         return x >= rect.x &&
@@ -35,4 +93,43 @@ namespace prune::editor::tools::transform_gizmo {
             y < rect.y + rect.h;
     }
 
+    [[nodiscard]] inline ScaleHandle scale_handle_at_point(const SDL_Rect& selected_outline, int x, int y) noexcept
+    {
+        for (const ScaleHandle handle : k_scale_handles) {
+            if (contains_point(scale_handle_rect(selected_outline, handle), x, y)) {
+                return handle;
+            }
+        }
+
+        return ScaleHandle::None;
+    }
+
+    [[nodiscard]] inline bool scale_handle_resizes_left(ScaleHandle handle) noexcept
+    {
+        return handle == ScaleHandle::TopLeft ||
+            handle == ScaleHandle::BottomLeft ||
+            handle == ScaleHandle::Left;
+    }
+
+    [[nodiscard]] inline bool scale_handle_resizes_right(ScaleHandle handle) noexcept
+    {
+        return handle == ScaleHandle::TopRight ||
+            handle == ScaleHandle::BottomRight ||
+            handle == ScaleHandle::Right;
+    }
+
+    [[nodiscard]] inline bool scale_handle_resizes_top(ScaleHandle handle) noexcept
+    {
+        return handle == ScaleHandle::TopLeft ||
+            handle == ScaleHandle::TopRight ||
+            handle == ScaleHandle::Top;
+    }
+
+    [[nodiscard]] inline bool scale_handle_resizes_bottom(ScaleHandle handle) noexcept
+    {
+        return handle == ScaleHandle::BottomLeft ||
+            handle == ScaleHandle::BottomRight ||
+            handle == ScaleHandle::Bottom;
+    }
+
 }

src/prune/scene/scene.hpp

@@ -91,6 +91,11 @@ namespace prune {
                 object.editor.movable;
         }
 
+        [[nodiscard]] virtual bool object_is_scalable(const GameObject& object) const
+        {
+            return object_is_selectable(object) && object_is_editable(object);
+        }
+
         [[nodiscard]] virtual ObjectConcept object_concept_for(const GameObject& object) const
         {
             return object_concepts::fallback_for(object);