Refactor UI code

src/kekengine/cpp/common/defaults.cpp

@@ -1,11 +1,15 @@
+#include "constants.h"
 #include "defaultplayercontroller.h"
 #include "input.h"
 #include "internal.h"
+#include "internal/input.h"
 #include "internal/physics.h"
 #include "internal/ui.h"
 #include "noclipplayercontroller.h"
+#include "types.h"
 #include "ui.h"
 #include "uielements.h"
+#include <GLFW/glfw3.h>
 
 namespace kek::Defaults {
 
@@ -25,17 +29,10 @@ static void defaultPeriodic(PeriodicEvent event, void *data) {
 }
 
 static void doUIMouseHover(double x, double y) {
-	UIElement *hoveredElement = nullptr;
+	if(Input::getMouseButtonState(GLFWMouseButton::LEFT) == GLFWMouseButtonState::PRESSED) return;
 
-	for(UIElement *element : kekData.ui->elements) {
+	IntPoint2 mousePosition = IntPoint2((int) x, (int) y);
-		UIPoint childPos = element->getPosition();
+	UIElement *hoveredElement = UI::findElementAt(mousePosition);
-		UIPoint hoveredAt = UIPoint((int) x - childPos.x, (int) y - childPos.y);
-
-		UIBounds bounds = element->getBounds();
-		if(!bounds.containsOffset(hoveredAt)) continue;
-
-		hoveredElement = element;
-	}
 
 	for(UIElement *element : kekData.ui->elements) {
 		if(element->hovering && element != hoveredElement) {
@@ -44,36 +41,54 @@ static void doUIMouseHover(double x, double y) {
 	}
 
 	if(hoveredElement) {
-		UIPoint childPos = hoveredElement->getPosition();
+		IntPoint2 childPos = hoveredElement->getPosition();
-		UIPoint hoveredAt = UIPoint((int) x - childPos.x, (int) y - childPos.y);
+		hoveredElement->hoverAll(mousePosition - childPos, mousePosition);
-		hoveredElement->hoverAll(hoveredAt, UIPoint((int) x, (int) y));
 	}
 }
 
+static void doUIMouseDrag(double x, double y) {
+	if(Input::getMouseButtonState(GLFWMouseButton::LEFT) != GLFWMouseButtonState::PRESSED) {
+		kekData.input->mouseDown = false;
+		return;
+	}
+
+	if(!kekData.input->mouseDown) {
+		kekData.input->mouseDownPosition = IntPoint2((int) x, (int) y);
+	}
+
+	int deltaX = (int) x - kekData.input->mouseDownPosition.x;
+	int deltaY = (int) y - kekData.input->mouseDownPosition.y;
+	if(deltaX * deltaX + deltaY * deltaY >= KEK_UI_MIN_DRAG_DISTANCE_SQUARED) {
+		// Initiate drag
+		IntPoint2 mousePosition = IntPoint2((int) x, (int) y);
+		UIElement *draggedElement = UI::findElementAt(mousePosition);
+
+		if(draggedElement) {
+			IntPoint2 childPos = draggedElement->getPosition();
+			draggedElement->dragEnterAll(mousePosition - childPos, mousePosition);
+		}
+	}
+
+	// TODO: drag dragged element, exit drag
+
+	kekData.input->mouseDown = true;
+}
+
 static void doUIMouseClick(double x, double y, GLFWMouseButton button) {
-	UIElement *clickedElement = nullptr;
+	IntPoint2 mousePosition = IntPoint2((int) x, (int) y);
-
+	UIElement *clickedElement = UI::findElementAt(mousePosition);
-	for(UIElement *element : kekData.ui->elements) {
-		UIPoint childPos = element->getPosition();
-		UIPoint clickedAt = UIPoint((int) x - childPos.x, (int) y - childPos.y);
-
-		UIBounds bounds = element->getBounds();
-		if(!bounds.containsOffset(clickedAt)) continue;
-
-		clickedElement = element;
-	}
 
 	if(clickedElement) {
-		UIPoint childPos = clickedElement->getPosition();
+		IntPoint2 childPos = clickedElement->getPosition();
-		UIPoint clickedAt = UIPoint((int) x - childPos.x, (int) y - childPos.y);
+		IntPoint2 clickedAt = mousePosition - childPos;
 
 		if(button == GLFWMouseButton::LEFT) {
-			if(!clickedElement->focusEnterAll(clickedAt, UIPoint((int) x, (int) y))) {
+			if(!clickedElement->focusEnterAll(clickedAt, IntPoint2((int) x, (int) y))) {
 				UI::unfocusElement(kekData.ui->focusedElement);
 			}
 		}
 
-		clickedElement->clickAll(clickedAt, UIPoint((int) x, (int) y), button);
+		clickedElement->clickAll(clickedAt, IntPoint2((int) x, (int) y), button);
 	} else {
 		UI::unfocusElement(kekData.ui->focusedElement);
 	}
@@ -94,6 +109,7 @@ static void defaultKeyCallback(KeyEvent event, void *data) {
 			double x, y;
 			glfwGetCursorPos(kekData.window, &x, &y);
 			doUIMouseHover(x, y);
+			doUIMouseDrag(x, y);
 		} else {
 			Input::setCursorMode(GLFWCursorMode::CAPTURE);
 
@@ -138,6 +154,7 @@ static void defaultMouseCallback(MouseEvent event, void *data) {
 		case GLFWCursorMode::FREE:
 		case GLFWCursorMode::HIDDEN: {
 			doUIMouseHover(event.x, event.y);
+			doUIMouseDrag(event.x, event.y);
 			break;
 		}
 	}

src/kekengine/cpp/common/engine.cpp

@@ -301,7 +301,7 @@ int start() {
 		prevTime = time;
 
 		for(UIElement *uiEl : kekData.ui->elements) {
-			UIPoint pos = uiEl->getScreenPosition();
+			IntPoint2 pos = uiEl->getScreenPosition();
 			uiEl->drawAll(pos, uiProjection);
 		}
 

src/kekengine/cpp/input/input.cpp

@@ -147,8 +147,12 @@ KeyBindingData getKeyBinding(KeyBinding binding) {
 
 GLFWKeyState getKeyState(KeyBinding binding) {
 	auto it = kekData.input->keyBindings.find(binding);
-	if(it == kekData.input->keyBindings.end()) return -1;
+	if(it == kekData.input->keyBindings.end()) return GLFWKeyState::ERROR_INVALID_KEY_BINDING;
-	return glfwGetKey(kekData.window, it->second.key);
+	return (GLFWKeyState) glfwGetKey(kekData.window, it->second.key);
+}
+
+GLFWMouseButtonState getMouseButtonState(GLFWMouseButton mouseButton) {
+	return (GLFWMouseButtonState) glfwGetMouseButton(kekData.window, (int) mouseButton);
 }
 
 void setCursorMode(GLFWCursorMode mode) {

src/kekengine/cpp/player/defaultplayercontroller.cpp

@@ -105,23 +105,23 @@ void DefaultPlayerController::update() {
 	glm::vec3 direction = glm::vec3(0);
 
 	if(!Input::isKeyboardCaptured()) {
-		if(Input::getKeyState(keyForward) == GLFW_PRESS) {
+		if(Input::getKeyState(keyForward) == GLFWKeyState::PRESSED) {
 			direction += kekData.activeCamera->direction;
 		}
 
-		if(Input::getKeyState(keyBackward) == GLFW_PRESS) {
+		if(Input::getKeyState(keyBackward) == GLFWKeyState::PRESSED) {
 			direction += -kekData.activeCamera->direction;
 		}
 
-		if(Input::getKeyState(keyLeft) == GLFW_PRESS) {
+		if(Input::getKeyState(keyLeft) == GLFWKeyState::PRESSED) {
 			direction += -glm::normalize(glm::cross(kekData.activeCamera->direction, glm::vec3(0.0f, 1.0f, 0.0f)));
 		}
 
-		if(Input::getKeyState(keyRight) == GLFW_PRESS) {
+		if(Input::getKeyState(keyRight) == GLFWKeyState::PRESSED) {
 			direction += glm::normalize(glm::cross(kekData.activeCamera->direction, glm::vec3(0.0f, 1.0f, 0.0f)));
 		}
 
-		if(Input::getKeyState(keyJump) == GLFW_PRESS && kekData.player->onGround) {
+		if(Input::getKeyState(keyJump) == GLFWKeyState::PRESSED && kekData.player->onGround) {
 			velocity += glm::vec3(0, jumpVelocity, 0);
 		}
 

src/kekengine/cpp/player/noclipplayercontroller.cpp

@@ -21,27 +21,27 @@ void NoclipPlayerController::update() {
 
 	glm::vec3 direction = glm::vec3(0);
 
-	if(Input::getKeyState(keyForward) == GLFW_PRESS) {
+	if(Input::getKeyState(keyForward) == GLFWKeyState::PRESSED) {
 		direction += kekData.activeCamera->direction;
 	}
 
-	if(Input::getKeyState(keyBackward) == GLFW_PRESS) {
+	if(Input::getKeyState(keyBackward) == GLFWKeyState::PRESSED) {
 		direction += -kekData.activeCamera->direction;
 	}
 
-	if(Input::getKeyState(keyLeft) == GLFW_PRESS) {
+	if(Input::getKeyState(keyLeft) == GLFWKeyState::PRESSED) {
 		direction += -glm::normalize(glm::cross(kekData.activeCamera->direction, glm::vec3(0.0f, 1.0f, 0.0f)));
 	}
 
-	if(Input::getKeyState(keyRight) == GLFW_PRESS) {
+	if(Input::getKeyState(keyRight) == GLFWKeyState::PRESSED) {
 		direction += glm::normalize(glm::cross(kekData.activeCamera->direction, glm::vec3(0.0f, 1.0f, 0.0f)));
 	}
 
-	if(Input::getKeyState(keyUp) == GLFW_PRESS) {
+	if(Input::getKeyState(keyUp) == GLFWKeyState::PRESSED) {
 		direction += glm::vec3(0, 1, 0);
 	}
 
-	if(Input::getKeyState(keyDown) == GLFW_PRESS) {
+	if(Input::getKeyState(keyDown) == GLFWKeyState::PRESSED) {
 		direction += glm::vec3(0, -1, 0);
 	}
 

src/kekengine/cpp/ui/ui.cpp

@@ -8,6 +8,7 @@
 #include "input.h"
 #include "internal.h"
 #include "internal/ui.h"
+#include "types.h"
 
 namespace kek {
 
@@ -21,21 +22,21 @@ UIElement::~UIElement() {
 }
 
 // Returns the element's origin position relative to its parent in pixels (not offset by getBounds())
-UIPoint UIElement::getOriginPosition() {
+IntPoint2 UIElement::getOriginPosition() {
-	return UIPoint(uiToScreen(x), uiToScreen(y));
+	return IntPoint2(uiToScreen(x), uiToScreen(y));
 }
 
-// Returns the element's position relative to its parent in pixels (offset by getBounds())
+// Returns the element's position relative to its parent in pixels (offset by getBounds(), aka. the position of the top-left of the element)
-UIPoint UIElement::getPosition() {
+IntPoint2 UIElement::getPosition() {
 	UIBounds bounds = getBounds();
-	return UIPoint(uiToScreen(x) + bounds.x, uiToScreen(y) + bounds.y);
+	return IntPoint2(uiToScreen(x) + bounds.x, uiToScreen(y) + bounds.y);
 }
 
 // Returns the element's origin position on the screen in pixels (not offset by getBounds())
-UIPoint UIElement::getScreenOriginPosition() {
+IntPoint2 UIElement::getScreenOriginPosition() {
-	UIPoint pos = getOriginPosition();
+	IntPoint2 pos = getOriginPosition();
 	if(parent) {
-		UIPoint parentPos = parent->getScreenPosition();
+		IntPoint2 parentPos = parent->getScreenPosition();
 		pos.x += parentPos.x;
 		pos.y += parentPos.y;
 	}
@@ -43,11 +44,18 @@ UIPoint UIElement::getScreenOriginPosition() {
 	return pos;
 }
 
-// Returns the element's position on the screen in pixels (offset by getBounds())
+// Returns the element's position on the screen in pixels (offset by getBounds(), aka. the position of the top-left of the element)
-UIPoint UIElement::getScreenPosition() {
+IntPoint2 UIElement::getScreenPosition() {
-	UIPoint pos = getScreenOriginPosition();
+	IntPoint2 pos = getScreenOriginPosition();
 	UIBounds bounds = getBounds();
-	return UIPoint(pos.x + bounds.x, pos.y + bounds.y);
+	return IntPoint2(pos.x + bounds.x, pos.y + bounds.y);
+}
+
+// Returns the bounds of the element on the screen
+UIBounds UIElement::getScreenBounds() {
+	IntPoint2 pos = getScreenOriginPosition();
+	UIBounds bounds = getBounds();
+	return UIBounds(pos.x + bounds.x, pos.y + bounds.y, bounds.w, bounds.h);
 }
 
 std::vector<UIElement *> UIElement::getChildren() {
@@ -122,7 +130,7 @@ UIBounds UIElement::offsetUIBounds(int w, int h, Origin origin) {
 	return UIBounds(offsetX(w, origin), offsetY(h, origin), w, h);
 }
 
-void UIElement::drawAll(UIPoint screenPos, glm::mat4 projection) {
+void UIElement::drawAll(IntPoint2 screenPos, glm::mat4 projection) {
 	if(!visible) return;
 
 	UIBounds bounds = getBounds();
@@ -135,8 +143,8 @@ void UIElement::drawAll(UIPoint screenPos, glm::mat4 projection) {
 	draw(screenPos, projection);
 
 	for(UIElement *child : children) {
-		UIPoint pos = child->getPosition();
+		IntPoint2 pos = child->getPosition();
-		child->drawAll(UIPoint(screenPos.x + pos.x, screenPos.y + pos.y), projection);
+		child->drawAll(IntPoint2(screenPos.x + pos.x, screenPos.y + pos.y), projection);
 	}
 
 	if(enableClipping) {
@@ -144,24 +152,30 @@ void UIElement::drawAll(UIPoint screenPos, glm::mat4 projection) {
 	}
 }
 
-void UIElement::hoverAll(UIPoint pos, UIPoint screenPos) {
+static UIElement *findChildAtRelativePos(UIElement *element, IntPoint2 pos) {
-	UIElement *hoveredChild = nullptr;
+	UIElement *foundChild = nullptr;
-	for(UIElement *child : children) {
+
-		UIPoint childPos = child->getPosition();
+	for(UIElement *child : element->getChildren()) {
-		int relX = pos.x - childPos.x;
+		IntPoint2 childPos = child->getPosition();
-		int relY = pos.y - childPos.y;
+		IntPoint2 relativeChildPos = pos - childPos;
 		UIBounds b = child->getBounds();
-		if(!b.containsOffset(UIPoint(relX, relY))) continue;
+		if(!b.containsOffset(relativeChildPos)) continue;
-		hoveredChild = child;
+		foundChild = child;
 	}
 
+	return foundChild;
+}
+
+void UIElement::hoverAll(IntPoint2 pos, IntPoint2 screenPos) {
+	UIElement *hoveredChild = findChildAtRelativePos(this, pos);
+
 	for(UIElement *child : children) {
 		if(child != hoveredChild && child->hovering) child->hoverExitAll();
 	}
 
 	if(hoveredChild) {
-		UIPoint childPos = hoveredChild->getPosition();
+		IntPoint2 childPos = hoveredChild->getPosition();
-		hoveredChild->hoverAll(UIPoint(pos.x - childPos.x, pos.y - childPos.y), screenPos);
+		hoveredChild->hoverAll(pos - childPos, screenPos);
 	}
 
 	if(!hovering) hoverEnter(pos, screenPos);
@@ -178,20 +192,12 @@ void UIElement::hoverExitAll() {
 	hoverExit();
 }
 
-bool UIElement::clickAll(UIPoint pos, UIPoint screenPos, GLFWMouseButton button) {
+bool UIElement::clickAll(IntPoint2 pos, IntPoint2 screenPos, GLFWMouseButton button) {
-	UIElement *clickedChild = nullptr;
+	UIElement *clickedChild = findChildAtRelativePos(this, pos);
-	for(UIElement *child : children) {
-		UIPoint childPos = child->getPosition();
-		int relX = pos.x - childPos.x;
-		int relY = pos.y - childPos.y;
-		UIBounds b = child->getBounds();
-		if(!b.containsOffset(UIPoint(relX, relY))) continue;
-		clickedChild = child;
-	}
 
 	if(clickedChild != nullptr) {
-		UIPoint childPos = clickedChild->getPosition();
+		IntPoint2 childPos = clickedChild->getPosition();
-		if(clickedChild->clickAll(UIPoint(pos.x - childPos.x, pos.y - childPos.y), screenPos, button)) return true;
+		if(clickedChild->clickAll(pos - childPos, screenPos, button)) return true;
 	}
 
 	if(clickable) {
@@ -202,20 +208,12 @@ bool UIElement::clickAll(UIPoint pos, UIPoint screenPos, GLFWMouseButton button)
 	return false;
 }
 
-bool UIElement::focusEnterAll(UIPoint pos, UIPoint screenPos) {
+bool UIElement::focusEnterAll(IntPoint2 pos, IntPoint2 screenPos) {
-	UIElement *focusedChild = nullptr;
+	UIElement *focusedChild = findChildAtRelativePos(this, pos);
-	for(UIElement *child : children) {
-		UIPoint childPos = child->getPosition();
-		int relX = pos.x - childPos.x;
-		int relY = pos.y - childPos.y;
-		UIBounds b = child->getBounds();
-		if(!b.containsOffset(UIPoint(relX, relY))) continue;
-		focusedChild = child;
-	}
 
 	if(focusedChild != nullptr) {
-		UIPoint childPos = focusedChild->getPosition();
+		IntPoint2 childPos = focusedChild->getPosition();
-		if(focusedChild->focusEnterAll(UIPoint(pos.x - childPos.x, pos.y - childPos.y), screenPos)) return true;
+		if(focusedChild->focusEnterAll(pos - childPos, screenPos)) return true;
 	}
 
 	if(focusable) {
@@ -226,27 +224,19 @@ bool UIElement::focusEnterAll(UIPoint pos, UIPoint screenPos) {
 	return false;
 }
 
-UIElement *UIElement::dragEnterAll(UIPoint pos, UIPoint screenPos) {
+UIElement *UIElement::dragEnterAll(IntPoint2 pos, IntPoint2 screenPos) {
-	UIBounds bounds = getBounds();
+	UIElement *draggedChild = findChildAtRelativePos(this, pos);
-	if(!bounds.contains(pos)) return nullptr; // Only used by topmost parent UIElement
-
-	UIElement *draggedChild = nullptr;
-	for(UIElement *child : children) {
-		UIPoint childPos = child->getPosition();
-		int relX = pos.x - childPos.x;
-		int relY = pos.y - childPos.y;
-		UIBounds b = child->getBounds();
-		if(!b.containsOffset(UIPoint(relX, relY))) continue;
-		draggedChild = child;
-	}
 
 	if(draggedChild) {
-		UIPoint childPos = draggedChild->getPosition();
+		IntPoint2 childPos = draggedChild->getPosition();
-		UIElement *dragged = draggedChild->dragEnterAll(UIPoint(pos.x - childPos.x, pos.y - childPos.y), screenPos);
+		UIElement *dragged = draggedChild->dragEnterAll(pos - childPos, screenPos);
 		if(dragged) return dragged;
 	}
 
-	if(draggable) return this;
+	if(draggable) {
+		// TODO: start drag
+		return this;
+	}
 
 	return nullptr;
 }
@@ -304,4 +294,17 @@ void UI::unfocusElement(UIElement *element) {
 	oldFocus->focusExit();
 }
 
+UIElement *UI::findElementAt(IntPoint2 screenPos) {
+	UIElement *foundElement = nullptr;
+
+	for(UIElement *element : kekData.ui->elements) {
+		UIBounds bounds = element->getScreenBounds();
+		if(!bounds.contains(screenPos)) continue;
+
+		foundElement = element;
+	}
+
+	return foundElement;
+}
+
 }

src/kekengine/cpp/ui/uielements.cpp

@@ -10,6 +10,7 @@
 #include "input.h"
 #include "internal.h"
 #include "internal/ui.h"
+#include "pango/pango-engine.h"
 #include "ui.h"
 #include "unicode.h"
 #include "utils.h"
@@ -68,7 +69,7 @@ std::string TextElement::getText() {
 	return text->getText();
 }
 
-void TextElement::draw(UIPoint screenPos, glm::mat4 projection) {
+void TextElement::draw(IntPoint2 screenPos, glm::mat4 projection) {
 	switch(textMode) {
 		case TextMode::BASELINE:
 			text->getFont()->drawText(text, projection, screenPos.x, screenPos.y, sizePixels, color);
@@ -136,7 +137,7 @@ UIBounds RectangleElement::getBounds() {
 	return offsetUIBounds(uiToScreen(w), uiToScreen(h), origin);
 }
 
-void RectangleElement::draw(UIPoint screenPos, glm::mat4 projection) {
+void RectangleElement::draw(IntPoint2 screenPos, glm::mat4 projection) {
 	kekData.ui->rectangleShader->use();
 
 	UIBounds offset = getBounds();
@@ -170,11 +171,11 @@ UIElementType ButtonElement::getType() {
 	return UIElementType::BUTTON;
 }
 
-void ButtonElement::click(UIPoint pos, UIPoint screenPos, GLFWMouseButton button) {
+void ButtonElement::click(IntPoint2 pos, IntPoint2 screenPos, GLFWMouseButton button) {
 	onClick();
 }
 
-void ButtonElement::draw(UIPoint screenPos, glm::mat4 projection) {
+void ButtonElement::draw(IntPoint2 screenPos, glm::mat4 projection) {
 	RectangleElement::color = hovering ? hoverColor : color;
 	RectangleElement::draw(screenPos, projection);
 }
@@ -318,7 +319,7 @@ void TextFieldElement::focusExit() {
 	updateText(Unicode::convertStdToU32(this->text));
 }
 
-void TextFieldElement::draw(UIPoint screenPos, glm::mat4 projection) {
+void TextFieldElement::draw(IntPoint2 screenPos, glm::mat4 projection) {
 	RectangleElement::color = focused ? focusColor : color;
 	RectangleElement::draw(screenPos, projection);
 
@@ -332,7 +333,8 @@ void TextFieldElement::setText(std::string text) {
 }
 
 UIWindowTitleBar::UIWindowTitleBar(UIValue height)
-	: RectangleElement(uiPx(0), uiPx(0), uiPw(1), height) {
+	: RectangleElement(uiPx(0), uiPx(0), uiPw(1), height),
+	  dragDownPos(0, 0) {
 	this->color = Colors::GRAY;
 	this->draggable = true;
 
@@ -354,15 +356,20 @@ UIWindowTitleBar::~UIWindowTitleBar() {
 	delete closeButton;
 }
 
-void UIWindowTitleBar::dragEnter(UIPoint pos, UIPoint screenPos) {
+void UIWindowTitleBar::dragEnter(IntPoint2 pos, IntPoint2 screenPos) {
 	// TODO
+	std::cout << "Drag start" << std::endl;
+	this->dragDownPos = pos;
 }
 
-void UIWindowTitleBar::drag(UIPoint pos, UIPoint screenPos) {
+void UIWindowTitleBar::drag(IntPoint2 pos, IntPoint2 screenPos) {
 	// TODO
+	std::cout << "Drag" << std::endl;
+	this->x = uiPx(screenPos.x + dragDownPos.x);
+	this->y = uiPx(screenPos.y + dragDownPos.y);
 }
 
-void UIWindowTitleBar::dragExit(UIPoint pos, UIPoint screenPos) {
+void UIWindowTitleBar::dragExit(IntPoint2 pos, IntPoint2 screenPos) {
 	// TODO
 }
 
@@ -397,7 +404,7 @@ UIBounds UIWindow::getBounds() {
 	return offsetUIBounds(uiToScreen(w), uiToScreen(h), origin);
 }
 
-void UIWindow::draw(UIPoint screenPos, glm::mat4 projection) {
+void UIWindow::draw(IntPoint2 screenPos, glm::mat4 projection) {
 }
 
 }

src/kekengine/include/constants.h

@@ -28,6 +28,7 @@
 #define KEK_LIGHT_DEFAULT_SPECULAR_STRENGTH 0.1f
 
 #define KEK_INVALID_KEY_BINDING_NAME "INVALID"
+#define KEK_INVALID_KEY_BINDING_ID -1
 #define KEK_INVALID_ID -1u
 
 #define KEK_FONT_RESOLUTION 64
@@ -48,3 +49,6 @@
 #define KEK_PLAYER_HEIGHT 2
 #define KEK_PLAYER_RADIUS 0.5f
 #define KEK_PLAYER_EYE_OFFSET (KEK_PLAYER_HEIGHT / 2 - KEK_PLAYER_RADIUS)
+
+#define KEK_UI_MIN_DRAG_DISTANCE 10
+#define KEK_UI_MIN_DRAG_DISTANCE_SQUARED (KEK_UI_MIN_DRAG_DISTANCE * KEK_UI_MIN_DRAG_DISTANCE)

src/kekengine/include/input.h

@@ -3,6 +3,7 @@
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
 
+#include "constants.h"
 #include "utils.h"
 
 namespace kek {
@@ -45,7 +46,6 @@ typedef GenericCallable<MouseButtonEvent> MouseButtonCallback; // void mouseButt
 
 typedef unsigned int InputListener;
 typedef int GLFWKey;
-typedef int GLFWKeyState;
 typedef unsigned int KeyBinding;
 typedef unsigned int KeyboardCapture;
 
@@ -66,6 +66,17 @@ enum class GLFWMouseButton {
 	MIDDLE = GLFW_MOUSE_BUTTON_MIDDLE
 };
 
+enum class GLFWKeyState {
+	ERROR_INVALID_KEY_BINDING = KEK_INVALID_KEY_BINDING_ID,
+	PRESSED = GLFW_PRESS,
+	RELEASED = GLFW_RELEASE
+};
+
+enum class GLFWMouseButtonState {
+	PRESSED = GLFW_PRESS,
+	RELEASED = GLFW_RELEASE
+};
+
 }
 
 namespace kek::Input {
@@ -93,6 +104,8 @@ void reassignKeyBinding(KeyBinding mapping, GLFWKey key);
 KeyBindingData getKeyBinding(KeyBinding mapping);
 GLFWKeyState getKeyState(KeyBinding mapping);
 
+GLFWMouseButtonState getMouseButtonState(GLFWMouseButton mouseButton);
+
 void setCursorMode(GLFWCursorMode mode);
 GLFWCursorMode getCursorMode();
 

src/kekengine/include/internal/input.h

@@ -3,6 +3,7 @@
 #include <map>
 
 #include "../input.h"
+#include "ui.h"
 
 namespace kek {
 
@@ -23,6 +24,9 @@ struct InputData {
 
 	ActiveKeyboardCapture activeKeyboardCapture;
 	GLFWCursorMode cursorMode;
+
+	bool mouseDown;
+	IntPoint2 mouseDownPosition;
 };
 
 namespace Input {

src/kekengine/include/types.h

@@ -24,4 +24,34 @@ class MemoryBuffer: public std::streambuf {
 	}
 };
 
+struct IntPoint2 {
+	int x, y;
+
+	IntPoint2(int x, int y)
+		: x(x),
+		  y(y) {}
+
+	IntPoint2() = default;
+
+	constexpr IntPoint2 &operator+=(const IntPoint2 &rhs) {
+		this->x += rhs.x;
+		this->y += rhs.y;
+		return *this;
+	}
+
+	constexpr IntPoint2 &operator-=(const IntPoint2 &rhs) {
+		this->x -= rhs.x;
+		this->y -= rhs.y;
+		return *this;
+	}
+
+	constexpr friend IntPoint2 operator+(const IntPoint2 &lhs, const IntPoint2 &rhs) {
+		return IntPoint2(lhs) += rhs;
+	}
+
+	constexpr friend IntPoint2 operator-(const IntPoint2 &lhs, const IntPoint2 &rhs) {
+		return IntPoint2(lhs) -= rhs;
+	}
+};
+
 }

src/kekengine/include/ui.h

@@ -5,6 +5,7 @@
 
 #include "fonts.h"
 #include "input.h"
+#include "types.h"
 
 #define uiPx(val) kek::UIValue(val, kek::UIUnit::PIXELS)
 #define uiPw(val) kek::UIValue(val, kek::UIUnit::PARENT_WIDTH)
@@ -14,14 +15,6 @@
 
 namespace kek {
 
-struct UIPoint {
-	int x, y;
-
-	UIPoint(int x, int y)
-		: x(x),
-		  y(y) {}
-};
-
 struct UIBounds {
 	int x, y, w, h;
 
@@ -32,12 +25,12 @@ struct UIBounds {
 		  h(h) {}
 
 	// Checks if a point is contained in the bounds
-	inline bool contains(UIPoint pos) {
+	inline bool contains(IntPoint2 pos) {
 		return pos.x > x && pos.y > y && pos.x < x + w && pos.y < y + h;
 	}
 
 	// Checks if an already offset point is contained in the bounds
-	inline bool containsOffset(UIPoint pos) {
+	inline bool containsOffset(IntPoint2 pos) {
 		return pos.x > 0 && pos.y > 0 && pos.x < w && pos.y < h;
 	}
 };
@@ -156,16 +149,22 @@ class UIElement {
 	virtual UIElementType getType() = 0;
 
 	// Returns the element's origin position relative to its parent in pixels (not offset by getBounds())
-	UIPoint getOriginPosition();
+	IntPoint2 getOriginPosition();
 
 	// Returns the element's position relative to its parent in pixels (offset by getBounds())
-	UIPoint getPosition();
+	IntPoint2 getPosition();
 
 	// Returns the element's origin position on the screen in pixels (not offset by getBounds())
-	UIPoint getScreenOriginPosition();
+	IntPoint2 getScreenOriginPosition();
 
 	// Returns the element's position on the screen in pixels (offset by getBounds())
-	UIPoint getScreenPosition();
+	IntPoint2 getScreenPosition();
+
+	// Returns the bounds of the element relative to its origin
+	virtual UIBounds getBounds() = 0;
+
+	// Returns the bounds of the element on the screen
+	UIBounds getScreenBounds();
 
 	std::vector<UIElement *> getChildren();
 	void addChild(UIElement *child);
@@ -178,29 +177,26 @@ class UIElement {
 	static UIBounds offsetUIBounds(int w, int h, Origin origin);
 
   public:
-	// Returns the bounds of the element relative to its origin
+	void drawAll(IntPoint2 screenPos, glm::mat4 projection);
-	virtual UIBounds getBounds() = 0;
+	virtual void draw(IntPoint2 screenPos, glm::mat4 projection) = 0;
 
-	void drawAll(UIPoint screenPos, glm::mat4 projection);
+	void hoverAll(IntPoint2 pos, IntPoint2 screenPos);
-	virtual void draw(UIPoint screenPos, glm::mat4 projection) = 0;
-
-	void hoverAll(UIPoint pos, UIPoint screenPos);
 	void hoverExitAll();
-	virtual void hoverEnter(UIPoint pos, UIPoint screenPos){};
+	virtual void hoverEnter(IntPoint2 pos, IntPoint2 screenPos){};
-	virtual void hover(UIPoint pos, UIPoint screenPos){};
+	virtual void hover(IntPoint2 pos, IntPoint2 screenPos){};
 	virtual void hoverExit(){};
 
-	bool clickAll(UIPoint pos, UIPoint screenPos, GLFWMouseButton button);
+	bool clickAll(IntPoint2 pos, IntPoint2 screenPos, GLFWMouseButton button);
-	virtual void click(UIPoint pos, UIPoint screenPos, GLFWMouseButton button){};
+	virtual void click(IntPoint2 pos, IntPoint2 screenPos, GLFWMouseButton button){};
 
-	bool focusEnterAll(UIPoint pos, UIPoint screenPos);
+	bool focusEnterAll(IntPoint2 pos, IntPoint2 screenPos);
 	virtual void focusEnter(){};
 	virtual void focusExit(){};
 
-	UIElement *dragEnterAll(UIPoint pos, UIPoint screenPos);
+	UIElement *dragEnterAll(IntPoint2 pos, IntPoint2 screenPos);
-	virtual void dragEnter(UIPoint pos, UIPoint screenPos){};
+	virtual void dragEnter(IntPoint2 pos, IntPoint2 screenPos){};
-	virtual void drag(UIPoint pos, UIPoint screenPos){};
+	virtual void drag(IntPoint2 pos, IntPoint2 screenPos){};
-	virtual void dragExit(UIPoint pos, UIPoint screenPos){};
+	virtual void dragExit(IntPoint2 pos, IntPoint2 screenPos){};
 };
 
 namespace UI {
@@ -215,6 +211,9 @@ void removeElement(UIElement *element);
 void focusElement(UIElement *element);
 void unfocusElement(UIElement *element);
 
+// Finds the first (topmost) element at the given screen position
+UIElement *findElementAt(IntPoint2 screenPos);
+
 };
 
 }

src/kekengine/include/uielements.h

@@ -42,7 +42,7 @@ class TextElement: public UIElement {
 
 	std::string getText();
 
-	virtual void draw(UIPoint screenPos, glm::mat4 projection);
+	virtual void draw(IntPoint2 screenPos, glm::mat4 projection);
 };
 
 class RectangleElement: public UIElement {
@@ -64,7 +64,7 @@ class RectangleElement: public UIElement {
 
 	virtual UIBounds getBounds();
 
-	virtual void draw(UIPoint screenPos, glm::mat4 projection);
+	virtual void draw(IntPoint2 screenPos, glm::mat4 projection);
 };
 
 class ButtonElement: public RectangleElement {
@@ -81,9 +81,9 @@ class ButtonElement: public RectangleElement {
 
 	virtual UIElementType getType();
 
-	virtual void click(UIPoint pos, UIPoint screenPos, GLFWMouseButton button);
+	virtual void click(IntPoint2 pos, IntPoint2 screenPos, GLFWMouseButton button);
 
-	virtual void draw(UIPoint screenPos, glm::mat4 projection);
+	virtual void draw(IntPoint2 screenPos, glm::mat4 projection);
 };
 
 typedef GenericCallable<std::string> SubmitCallback;
@@ -119,13 +119,16 @@ class TextFieldElement: public RectangleElement {
 	virtual void focusEnter();
 	virtual void focusExit();
 
-	virtual void draw(UIPoint screenPos, glm::mat4 projection);
+	virtual void draw(IntPoint2 screenPos, glm::mat4 projection);
 
 	void setText(std::string text);
 };
 
 class UIWindowTitleBar: public RectangleElement {
 
+  protected:
+	IntPoint2 dragDownPos;
+
   public:
 	TextElement *text;
 	ButtonElement *closeButton;
@@ -134,9 +137,9 @@ class UIWindowTitleBar: public RectangleElement {
 
 	virtual ~UIWindowTitleBar();
 
-	virtual void dragEnter(UIPoint pos, UIPoint screenPos);
+	virtual void dragEnter(IntPoint2 pos, IntPoint2 screenPos);
-	virtual void drag(UIPoint pos, UIPoint screenPos);
+	virtual void drag(IntPoint2 pos, IntPoint2 screenPos);
-	virtual void dragExit(UIPoint pos, UIPoint screenPos);
+	virtual void dragExit(IntPoint2 pos, IntPoint2 screenPos);
 };
 
 class UIWindow: public UIElement {
@@ -155,7 +158,7 @@ class UIWindow: public UIElement {
 
 	virtual UIBounds getBounds();
 
-	virtual void draw(UIPoint screenPos, glm::mat4 projection);
+	virtual void draw(IntPoint2 screenPos, glm::mat4 projection);
 };
 
 }