Added my 2 widget classes, with some notes. They are not in the build yet either.

core/widgets/button.cpp

@@ -0,0 +1,89 @@
+#include "button.h"
+
+#include "math.h"
+
+void Button::_event(const SDL_Event &ev) {
+	if (state == BUTTON_STATE_OFF) {
+		return;
+	}
+
+	switch (ev.type) {
+		case SDL_MOUSEMOTION: {
+			int x = ev.motion.x;
+			int y = ev.motion.y;
+
+			if (rect.x < x && rect.x + rect.w > x && rect.y < y && rect.y + rect.w > y) {
+				state = BUTTON_STATE_HOVER;
+			} else {
+				state = BUTTON_STATE_UP;
+			}
+
+			break;
+		}
+		case SDL_MOUSEBUTTONDOWN: {
+			int x = ev.motion.x;
+			int y = ev.motion.y;
+
+			if (rect.x < x && rect.x + rect.w > x && rect.y < y && rect.y + rect.w > y) {
+				state = BUTTON_STATE_DOWN;
+			}
+
+			break;
+		}
+		case SDL_MOUSEBUTTONUP: {
+			int x = ev.motion.x;
+			int y = ev.motion.y;
+
+			if (rect.x < x && rect.x + rect.w > x && rect.y < y && rect.y + rect.w > y) {
+				state = BUTTON_STATE_HOVER;
+
+				if (on_click) {
+					on_click();
+				}
+			} else {
+				state = BUTTON_STATE_UP;
+			}
+
+			break;
+		}
+	}
+}
+
+void Button::_update(float delta) {
+}
+
+void Button::_render() {
+	if (state == BUTTON_STATE_UP) {
+		if (up) {
+			up->set_transform(rect);
+			up->draw();
+		}
+	} else if (state == BUTTON_STATE_HOVER) {
+		if (hover) {
+			hover->set_transform(rect);
+			hover->draw();
+		}
+	} else if (state == BUTTON_STATE_DOWN) {
+		if (down) {
+			down->set_transform(rect);
+			down->draw();
+		}
+	} else if (state == BUTTON_STATE_OFF) {
+		if (off) {
+			off->set_transform(rect);
+			off->draw();
+		}
+	}
+}
+
+Button::Button() : Widget() {
+	state = BUTTON_STATE_UP;
+
+	up = nullptr;
+	down = nullptr;
+	hover = nullptr;
+	off = nullptr;
+}
+
+Button::~Button() {
+}

core/widgets/button.h

@@ -0,0 +1,40 @@
+
+#ifndef BUTTON_H
+#define BUTTON_H
+
+#include "widget.h"
+
+#include <SDL.h>
+
+#include "core/rect2.h"
+#include "renderer/sprite.h"
+
+#include <functional>
+
+class Button : public Widget {
+public:
+	enum ButtonState {
+		BUTTON_STATE_UP,
+		BUTTON_STATE_HOVER,
+		BUTTON_STATE_DOWN,
+		BUTTON_STATE_OFF,
+	};
+
+	void _event(const SDL_Event &ev);
+	void _update(float delta);
+	void _render();
+
+	std::function<void(void)> on_click;
+
+	Button();
+	virtual ~Button();
+
+	ButtonState state;
+
+	Sprite *up;
+	Sprite *down;
+	Sprite *hover;
+	Sprite *off;
+};
+
+#endif

core/widgets/widget.cpp

@@ -0,0 +1,26 @@
+#include "widget.h"
+
+void Widget::event(const SDL_Event &ev) {
+	_event(ev);
+}
+void Widget::update(float delta) {
+	_update(delta);
+}
+void Widget::render() {
+	_render();
+}
+
+void Widget::_event(const SDL_Event &ev) {
+}
+void Widget::_update(float delta) {
+}
+void Widget::_render() {
+}
+
+Widget::Widget() {
+	min_size = 0;
+	stretch_flags = STRETCH_OFF;
+	stretch_ratio = 1;
+}
+Widget::~Widget() {
+}

core/widgets/widget.h

@@ -0,0 +1,52 @@
+
+#ifndef WIDGET_H
+#define WIDGET_H
+
+#include <SDL.h>
+
+#include "core/rect2.h"
+#include "core/vector.h"
+
+//remove sdl dependency
+//should use my own events
+//render should have a parameter for the current renderer
+//it couls store state in a different class -> it could be a mix between an immediate mode gui and normal oop gui
+//Or maybe the state could be stored separately? Or have support for storing the state in widgets, and also in a separate data object. Also needs to be fast.
+//Or just support using state from (also adding a deafult state to) an HTTPRequest
+//it sould do it's layout in a normalized coordinate system 
+//the renderer can turn it to what it needs
+//Shold probably have a widget renderer that encapsulates a normal renderer
+//could have 2 type of renderers -> one for httprequests and a normal one
+
+class Widget {
+public:
+	enum StretchFlags {
+		STRETCH_HORIZONTAL = 1 << 0,
+		STRETCH_VERTICAL = 1 << 1,
+
+		STRETCH_OFF = 0,
+		STRETCH_BOTH = STRETCH_HORIZONTAL | STRETCH_VERTICAL,
+	};
+
+	void event(const SDL_Event &ev);
+	void update(float delta);
+	void render();
+
+	virtual void _event(const SDL_Event &ev);
+	virtual void _update(float delta);
+	virtual void _render();
+
+	Widget();
+	virtual ~Widget();
+
+	float min_size;
+	int stretch_flags;
+	float stretch_ratio;
+
+	Rect2 rect;
+
+private:
+	Vector<Widget *> _children;
+};
+
+#endif