From f465b26a8aeac95cf7e0186a86ab1262dc771fb4 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Mon, 17 Dec 2018 19:31:38 +0100
Subject: Keep track of window size in its wrapper class

---
 src/glfw/window.cc | 10 ++++++++++
 src/glfw/window.h  | 10 ++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

(limited to 'src/glfw')

diff --git a/src/glfw/window.cc b/src/glfw/window.cc
index 0e57a65..9e76b57 100644
--- a/src/glfw/window.cc
+++ b/src/glfw/window.cc
@@ -1,5 +1,15 @@
 #include "window.h"
 
+bool Window::updateSize() {
+	const int old_width  = _width;
+	const int old_height = _height;
+
+	glfwGetWindowSize(_handle, &_width, &_height);
+
+	return old_width  != _width
+	    || old_height != _height;
+}
+
 Window::Window(const std::string& title):
 	_handle(glfwCreateWindow(_width, _height, title.c_str(), NULL, NULL)) {
 	if ( _handle != nullptr ) {
diff --git a/src/glfw/window.h b/src/glfw/window.h
index 92a1b56..ea6075b 100644
--- a/src/glfw/window.h
+++ b/src/glfw/window.h
@@ -15,6 +15,8 @@ private:
 
 	GLFWwindow* const _handle;
 
+	bool updateSize();
+
 public:
 	Window(const std::string& title);
 	~Window();
@@ -46,9 +48,13 @@ void Window::render(F loop) {
 
 	while ( glfwGetKey(_handle, GLFW_KEY_ESCAPE) != GLFW_PRESS &&
 	        glfwWindowShouldClose(_handle)       == 0 ) {
-		glfwGetWindowSize(_handle, &_width, &_height);
+		const bool window_size_changed = updateSize();
+
+		if ( window_size_changed ) {
+			glViewport(0, 0, getWidth(), getHeight());
+		}
 
-		loop();
+		loop(window_size_changed);
 
 		glfwSwapBuffers(_handle);
 		glfwPollEvents();
-- 
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