wippatern_preview: Adding patern preview

This adds a preview of the patern placement, checking out of bound

CMakeLists.txt

@@ -76,6 +76,7 @@ set(SRC_CXX_FILES "./src/main.cpp"
                   "./src/selection.cpp"
                   "./src/paterns_menu.cpp"
                   "./src/patern_preview.cpp"
+                  "./src/snapping.cpp"
                   "${rlImGui_SOURCE_DIR}/rlImGui.cpp"
                   "${imgui_SOURCE_DIR}/imgui.cpp"
                   "${imgui_SOURCE_DIR}/imgui_draw.cpp"

README.md

@@ -6,7 +6,7 @@ This is a simple Game Of Life editor written in C++ with raylib & dearImGUI
 
 ## How to compile the project
 
-Ensure you have g++, cmake and the thendependencies of raylib
+Ensure you have g++, cmake and the dependencies of raylib
 
 ```shell
 mkdir build

includes/patern_preview.hpp

@@ -10,6 +10,8 @@
 
 #include <memory>
 
+#include <raylib.h>
+
 #include <context.hpp>
 
 namespace gol {
@@ -24,6 +26,7 @@ public:
 private:
   bool is_started = false;
   std::shared_ptr<ctx> context_;
+  Vector2 mouse_pos_ = {0, 0};
 };
 
 } // namespace gol

includes/paterns_menu.hpp

@@ -30,6 +30,7 @@ private:
   std::shared_ptr<ctx> context_ = nullptr;
   std::map<std::string,std::string> paterns_paths_list_;
   std::vector<std::string> paterns_name_list_;
+public:
   int patern_width_ = 0;
   int patern_height_ = 0;
   std::vector<uint32_t> loaded_patern_;

includes/snapping.hpp

@@ -1,5 +1,5 @@
 /*
-* File name: selection.cpp
+* File name: snapping.hpp
 * Author: lejulien
 * Date created: 01-01-1970 00:59:59
 // Date modified: 12-01-2026 21:30:10
@@ -13,12 +13,6 @@
 #include <raylib.h>
 #include <cmath>
 
-Vector2 snapToGrid(Vector2 screen, int cell_size) {
+Vector2 snapToGrid(Vector2 screen, int cell_size);
-  return {static_cast<float>(round(screen.x / cell_size) * cell_size),
-          static_cast<float>(round(screen.y / cell_size) * cell_size)};
-}
 
-Vector2i screenToGrid(Vector2 screen, int cell_size) {
+Vector2i screenToGrid(Vector2 screen, int cell_size);
-  return {static_cast<int>(round(screen.x / cell_size)),
-          static_cast<int>(round(screen.y / cell_size))};
-}

src/main.cpp

@@ -25,6 +25,7 @@
 #include <selection_menu.hpp>
 #include <selection.hpp>
 #include <paterns_menu.hpp>
+#include <patern_preview.hpp>
 
 int main(int ac, char **av) {
   std::shared_ptr<gol::ctx> context = std::make_shared<gol::ctx>();
@@ -107,6 +108,7 @@ int main(int ac, char **av) {
   context->selection_menu = std::make_shared<gol::SelectionMenu>(context);
   context->selection = std::make_shared<gol::Selection>(context);
   context->paterns_menu = std::make_shared<gol::PaternsMenu>(context);
+  context->patern_preview = std::make_shared<gol::PaternPreview>(context);
 
   // Speed handling values
   float sim_speed = 1.0f;
@@ -136,6 +138,7 @@ int main(int ac, char **av) {
 
     // Selection behaviour
     context->selection->update();
+    context->patern_preview->update();
     context->selection_menu->update();
     context->settings_menu->update();
 
@@ -154,6 +157,7 @@ int main(int ac, char **av) {
     ClearBackground(BLACK);
     context->render->display(context->world);
     context->selection->display();
+    context->patern_preview->display();
     // Start ImGui frame
     rlImGuiBegin();
     context->control_menu->display();

src/patern_preview.cpp

@@ -6,27 +6,60 @@
 * ------
 */
 
+#include <imgui.h>
+#include <raylib.h>
+#include <rlImGui.h>
+
 #include <patern_preview.hpp>
+#include <paterns_menu.hpp>
+#include <settings_menu.hpp>
+#include <snapping.hpp>
+#include <world.hpp>
 
 namespace gol {
 
-PaternPreview::PaternPreview(std::shared_ptr<ctx> context): context_(context) {}
+PaternPreview::PaternPreview(std::shared_ptr<ctx> context)
+    : context_(context) {}
 
-void PaternPreview::start() {
+void PaternPreview::start() { is_started = true; }
-  // TODO: load patern from pater menu
-  is_started = true;
-}
 
 void PaternPreview::update() {
   if (!is_started) return;
-  // gather mousePos
+  mouse_pos_ = GetMousePosition();
+  if (ImGui::IsMouseClicked(1)) {
+    is_started = false;
+    return;
+  }
   // if right click stop the preview
   // if left click, apply patern to current world
   // mouse should pass through any present windows
 }
 
 void PaternPreview::display() {
-
+  if (!is_started) return;
+  std::cout << "preview display started " << std::endl;
+  auto cell_size = context_->settings_menu->getCellSize();
+  auto mouse_in_grid =
+      screenToGrid(mouse_pos_, context_->settings_menu->getCellSize());
+  bool is_unplacable =
+      ((mouse_in_grid.x + context_->paterns_menu->patern_width_ >
+        context_->world->getWidth()) ||
+       (mouse_in_grid.y + context_->paterns_menu->patern_height_ >
+        context_->world->getHeight()));
+  std::cout << "mx:" << mouse_in_grid.x << ", my:" << mouse_in_grid.y
+            << ", cs:" << context_->settings_menu->getCellSize() << std::endl;
+  for (int j = 0; j < context_->paterns_menu->patern_height_; j++) {
+    for (int i = 0; i < context_->paterns_menu->patern_width_; i++) {
+      auto cell =
+          context_->paterns_menu
+              ->loaded_patern_[i + (j * context_->paterns_menu->patern_width_)];
+      if (cell) {
+        DrawRectangle((i + mouse_in_grid.x) * cell_size,
+                      (j + mouse_in_grid.y) * cell_size, cell_size, cell_size,
+                      (is_unplacable) ? RED : BLUE);
+      }
+    }
+  }
 }
 
-};
+};  // namespace gol

src/paterns_menu.cpp

@@ -64,7 +64,7 @@ bool PaternsMenu::loadPatern(std::string &path) {
     }
   } catch (std::exception &e) {
     std::cerr << "Failure in loading patern : " << path << std::endl;
-    return 1;
+    return false;
   }
   return true;
 }

src/snapping.cpp

@@ -0,0 +1,19 @@
+/*
+* File name: snapping.hpp
+* Author: lejulien
+* Date created: 01-01-1970 00:59:59
+// Date modified: 12-01-2026 21:30:10
+* ------
+*/
+
+#include <snapping.hpp>
+
+Vector2 snapToGrid(Vector2 screen, int cell_size) {
+  return {static_cast<float>(round(screen.x / cell_size) * cell_size),
+          static_cast<float>(round(screen.y / cell_size) * cell_size)};
+}
+
+Vector2i screenToGrid(Vector2 screen, int cell_size) {
+  return {static_cast<int>(round(screen.x / cell_size)),
+          static_cast<int>(round(screen.y / cell_size))};
+}