From 0f73e8f83b89eb7eaed973dd8559511e1f9ccb93 Mon Sep 17 00:00:00 2001
From: Kyle Pelham <kylepelham9000@gmail.com>
Date: Sun, 15 Sep 2024 01:42:22 +0100
Subject: [PATCH] implement resizing + added delta time

---
 include/prism/window.h | 16 +++++++++----
 src/prism.cpp          |  9 ++++----
 src/window.cpp         | 51 +++++++++++++++++++++++++++++++++++-------
 3 files changed, 60 insertions(+), 16 deletions(-)

diff --git a/include/prism/window.h b/include/prism/window.h
index 9769b08..366e613 100644
--- a/include/prism/window.h
+++ b/include/prism/window.h
@@ -73,8 +73,6 @@ class PRISM_EXPORT Window
 
 private:
     GLFWwindow* windowHandle = nullptr;                            ///< Handle to the GLFW window. (NOT NATIVE HANDLE)
-    float lastFrameTime = 0.0f;                                    ///< Time of the last frame.
-    float deltaTime = 0.0f;                                        ///< Delta between frame end and start.
 
 public:
     /// Construct a new Window object.
@@ -177,6 +175,16 @@ class PRISM_EXPORT Window
     */
     void setDefaultTheme();
 
+    // rebuildSwapchain
+    /**
+     * Rebuilds the swapchain for the window.
+     *
+     * This method is called when the swapchain needs to be rebuilt due to a window resize or other event.
+     * It will recreate the swapchain and associated resources.
+     * @note This method is called automatically inside the render() method.
+    */
+    void rebuildSwapchain();
+
     /**
      * Renders ImGui's content to command buffers.
      * @param drawData The ImGui draw data to render.
@@ -304,14 +312,14 @@ class PRISM_EXPORT Window
      * Override this method to implement custom update logic before rendering.
      * @note The ImGui context will be CORRECT during this callback.
     */
-    virtual void onUpdate() {}
+    virtual void onUpdate(float deltaTime) {}
 
     /**
      * Called when the window is rendering.
      * Override this method to implement custom rendering logic.
      * @note The ImGui context will be CORRECT during this callback.
     */
-    virtual void onRender() {}
+    virtual void onRender(float deltaTime) {}
 };
 
 } // namespace Prism
\ No newline at end of file
diff --git a/src/prism.cpp b/src/prism.cpp
index 346cc3f..5afe26b 100644
--- a/src/prism.cpp
+++ b/src/prism.cpp
@@ -27,9 +27,10 @@ Application::Application(std::string name)
 
 Application::~Application()
 {
-    stop();                 // Stop the application
-    appWindows.clear();     // Destroy the windows
-    renderer.reset();       // Destroy the renderer
+    stop();
+    for (auto& window : std::ranges::reverse_view(appWindows))
+        window.reset();
+    renderer.reset();
 }
 
 void Application::run()
@@ -62,7 +63,7 @@ void Application::cullClosedWindowsExitOnMainDeath()
             }
 
             // Remove the window
-            appWindows.erase(appWindows.begin() + i);
+            appWindows.erase(appWindows.begin() + (int64_t)i);
         }
     }
 }
diff --git a/src/window.cpp b/src/window.cpp
index 17bc50a..4526d09 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -159,7 +159,6 @@ Window::Window(WindowSettings settings) :
     ImGui_ImplVulkan_CreateFontsTexture();
 
     // Restore the previous contexts
-    // TODO: Is this really doing what I'm expecting? I'll have to come back to this.
     if (backupImGuiContext) ImGui::SetCurrentContext(backupImGuiContext);
 }
 
@@ -203,17 +202,22 @@ void Window::render()
     // Swap contexts
     ImGuiContext* backupContext = ImGui::GetCurrentContext();
     ImGui::SetCurrentContext(imguiContext);
-
-    // TODO: Resize swap chain
+    
+    // Update the swapchain if needed
+    if (swapchainNeedRebuild)
+        rebuildSwapchain();
 
     // Start ImGui Frame
     ImGui_ImplVulkan_NewFrame();
     ImGui_ImplGlfw_NewFrame();
     ImGui::NewFrame();
 
+    // Get delta time from imgui
+    ImGuiIO& io = ImGui::GetIO();
+    
     // Run update logic, then render ImGui
-    onUpdate();
-    onRender();
+    onUpdate(io.DeltaTime);
+    onRender(io.DeltaTime);
 
     // Render
     ImGui::Render();
@@ -232,8 +236,6 @@ void Window::render()
     else
         std::this_thread::sleep_for(std::chrono::milliseconds(5));
 
-    // TODO: Do delta time here
-
     // Restore the previous context
     if (backupContext) ImGui::SetCurrentContext(backupContext);
 }
@@ -395,6 +397,39 @@ void Window::installGlfwCallbacks()
     glfwSetMonitorCallback(MonitorCallback);
 }
 
+void Window::rebuildSwapchain()
+{
+    // Get the new window size
+    int width, height;
+    glfwGetFramebufferSize(windowHandle, &width, &height);
+
+    // If valid size, rebuild the swapchain
+    if (width > 0 && height > 0) {
+        // Wait for the device to be idle
+        auto renderer = Application::Get().getRenderer();
+        vkDeviceWaitIdle(renderer->getDevice());
+
+        // Rebuild the swapchain
+        ImGui_ImplVulkan_SetMinImageCount(minImageCount);
+        ImGui_ImplVulkanH_CreateOrResizeWindow(
+            renderer->getInstance(),
+            renderer->getPhysicalDevice(),
+            renderer->getDevice(),
+            imguiWindow,
+            renderer->getQueueFamilyIndex(),
+            renderer->getAllocator(),
+            width, height, minImageCount
+        );
+
+        // Reallocate the command buffers
+        allocatedCommandBuffers.clear();
+        allocatedCommandBuffers.resize(imguiWindow->ImageCount);
+
+        // Reset the swapchain flag
+        swapchainNeedRebuild = false;
+    }
+}
+
 void Window::frameRender(ImDrawData* drawData)
 {
     VkResult err;
@@ -430,7 +465,7 @@ void Window::frameRender(ImDrawData* drawData)
 
     auto& cmdBuf = allocatedCommandBuffers[imguiWindow->FrameIndex];
     if (!cmdBuf.empty()) {
-        vkFreeCommandBuffers(renderer->getDevice(), fd->CommandPool, static_cast<uint32_t>(cmdBuf.size()), cmdBuf.data());
+        vkFreeCommandBuffers(renderer->getDevice(), fd->CommandPool, (uint32_t)cmdBuf.size(), cmdBuf.data());
         cmdBuf.clear();
     }