From 029f753bbf193eea2fcbe8a62c0b26f28929ebfa Mon Sep 17 00:00:00 2001
From: Teo-CD <teocd.perso@outlook.fr>
Date: Mon, 29 Jan 2024 00:25:54 +0000
Subject: [PATCH] World: Re-use RectangleShapes for rendering

sf::RectangleShapes were created brand new each frame, which takes a lot of time.
Instead, keep an array of them available and update them instead of creating new ones.

This also allows a nice optimization of only updating them if needed, by checking their
previous value.

Update the available number of rects when the window resizes.
---
 World.cpp | 22 ++++++++++++++++------
 World.h   |  6 ++++--
 main.cpp  |  3 +++
 3 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/World.cpp b/World.cpp
index b8a8eb6..a7f7bf1 100644
--- a/World.cpp
+++ b/World.cpp
@@ -27,6 +27,12 @@ int World::getH() const
 	return h;
 }
 
+void World::resizeWindow(const sf::FloatRect& resizedView) {
+	sf::RectangleShape defaultRectangle(sf::Vector2f(1,2));
+	defaultRectangle.setFillColor(Colors::Wall);
+	renderColumns.resize(static_cast<long>(resizedView.width), defaultRectangle);
+}
+
 BlockType World::getBlock(int x, int y) const
 {
 	return map[x + w*y];
@@ -212,18 +218,22 @@ float World::castRay(float originX, float originY, float orientation) const
 }
 
 void World::fillColumn(sf::RenderWindow& window, unsigned int column,
-					   float scale, sf::Color fillColor) const
+					   float scale, sf::Color fillColor)
 {
 	float columnHeight = static_cast<float>(window.getSize().y)*scale;
-	sf::RectangleShape pixelColumn(sf::Vector2f(1,columnHeight));
-	pixelColumn.setPosition(static_cast<float>(column),
-							(static_cast<float>(window.getSize().y)-columnHeight)/2.0f);
-	pixelColumn.setFillColor(fillColor);
+	sf::RectangleShape& pixelColumn = renderColumns[column];
+	if (pixelColumn.getSize().y != columnHeight) {
+		pixelColumn.setSize({1, columnHeight});
+		pixelColumn.setPosition(static_cast<float>(column),
+								(static_cast<float>(window.getSize().y) - columnHeight) / 2.0f);
+	}
+	if (pixelColumn.getFillColor() != fillColor)
+		pixelColumn.setFillColor(fillColor);
 
 	window.draw(pixelColumn);
 }
 
-void World::render(sf::RenderWindow& window) const
+void World::render(sf::RenderWindow& window)
 {
 	float windowX = static_cast<float>(window.getSize().x);
 	float windowY = static_cast<float>(window.getSize().y);
diff --git a/World.h b/World.h
index 43b4b1e..7b24d70 100644
--- a/World.h
+++ b/World.h
@@ -30,12 +30,13 @@ public:
 		  std::vector<BlockType> worldMap = {});
 	int getW() const;
 	int getH() const;
+	void resizeWindow(const sf::FloatRect& resizedView);
 
 	inline BlockType getBlock(int x, int y) const;
 	inline BlockType getBlock(float x, float y) const;
 	void setBlock(BlockType block, int x, int y, int width = 1, int height = 1);
 
-	void render(sf::RenderWindow&) const;
+	void render(sf::RenderWindow&);
 
 	/**
 	 * Move the world one step forward.
@@ -47,13 +48,14 @@ public:
 private:
 	int w;
 	int h;
+	std::vector<sf::RectangleShape> renderColumns;
 	std::vector<BlockType> map;
 
 	sf::Color groundColor;
 	sf::Color ceilingColor;
 
 	void fillColumn(sf::RenderWindow&, unsigned int column, float scale,
-					sf::Color fillColor = Colors::Wall) const;
+					sf::Color fillColor = Colors::Wall);
 	/**
 	 * Cast a ray from a given position and return its distance to the origin.
 	 * @param originX Ray X origin, strictly positive
diff --git a/main.cpp b/main.cpp
index 0aedcd7..83ef919 100644
--- a/main.cpp
+++ b/main.cpp
@@ -15,10 +15,12 @@ int main()
 	World world(32,32);
 	world.setBlock(BlockType::AIR,1,1,30,30);
 	world.setBlock(BlockType::WALL,4,4,2,2);
+	world.setBlock(BlockType::WALL, 4, 6, 1, 10);
 	world.player.move(2,2);
 	std::cout << world << std::endl;
 
 	sf::RenderWindow window(sf::VideoMode(1000,1000),"Da raycasting");
+	world.resizeWindow(sf::FloatRect(0,0, 1000, 1000));
 #ifdef IMGUI
 	if (!ImGui::SFML::Init(window)) {
 		std::cout << "Failed to init Dear ImGui SFML" << std::endl;
@@ -47,6 +49,7 @@ int main()
 									  static_cast<float>(event.size.width),
 									  static_cast<float>(event.size.height));
 				window.setView(sf::View(newView));
+				world.resizeWindow(newView);
 				continue;
 			}
 #ifdef IMGUI