From bdcaefc871fe8efcfa3920109e8a52d6a194955d Mon Sep 17 00:00:00 2001
From: Jonathan Bradley <jcb@pikum.xyz>
Date: Tue, 7 Nov 2023 16:32:51 -0500
Subject: display debug box for hovered entity

---
 src/game.cpp | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

(limited to 'src/game.cpp')

diff --git a/src/game.cpp b/src/game.cpp
index cd27812..bd13a22 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -15,9 +15,9 @@
 #include "window.hpp"
 
 #include <BulletCollision/CollisionShapes/btConvexHullShape.h>
+#include <BulletCollision/NarrowPhaseCollision/btRaycastCallback.h>
 #include <GLFW/glfw3.h>
 #include <cstring>
-#include <glm/gtc/quaternion.hpp>
 #include <iomanip>
 #include <ostream>
 
@@ -491,6 +491,22 @@ void teardownEditor() {
 	PkeInput_DeactivateSet(debugControlsHandle);
 }
 
+glm::vec3 unproject(glm::vec3 windowCoords) {
+		double xDevNorm = (2.0f * windowCoords.x) / Extent.width - 1.0f;
+		double yDevNorm = 1.0f - (2.0f * windowCoords.y) / Extent.height;
+		yDevNorm *= -1;
+		glm::vec4 clipCoords(xDevNorm, yDevNorm, windowCoords.z, 1.f);
+
+		glm::vec4 rayEye = glm::inverse(UBO.proj) * clipCoords;
+
+		glm::vec4 worldCoords = glm::inverse(UBO.model) * glm::inverse(UBO.view) * rayEye;
+		if (std::abs(0.0f - worldCoords.w) > 0.00001f) {
+			worldCoords *= 1.0f / worldCoords.w;
+		}
+
+		return glm::vec3(worldCoords);
+}
+
 void Game_Tick(double delta) {
 	/*
 	 * ECS_Tick() gets called first because it updates the public
@@ -512,6 +528,39 @@ void Game_Tick(double delta) {
 		ActiveCamera = &cameraDbg;
 	}
 	ECS_Tick_Early(delta);
+
+	// raycast for hovering
+	do // while(0)
+	{
+		double xMousePos, yMousePos;
+		glfwGetCursorPos(window, &xMousePos, &yMousePos);
+
+		glm::vec3 fromCoords{unproject(glm::vec3(xMousePos, yMousePos, -1.f))};
+		glm::vec3 toCoords{unproject(glm::vec3(xMousePos, yMousePos, 1.f))};
+
+		btVector3 rayOrigin{};
+		btVector3 rayDestination{};
+		GlmToBullet(fromCoords, rayOrigin);
+		GlmToBullet(toCoords, rayDestination);
+
+		btCollisionWorld::ClosestRayResultCallback rayResult{rayOrigin, rayDestination};
+		rayResult.m_flags |= btTriangleRaycastCallback::kF_FilterBackfaces;
+
+		BtDynamicsWorld->rayTest(rayOrigin, rayDestination, rayResult);
+		if (rayResult.hasHit()) {
+			EntityHandle_T hoveredEntity_T{reinterpret_cast<EntityHandle_T>(rayResult.m_collisionObject->getUserPointer())};
+			EntityHandle hoveredEntity{hoveredEntity_T};
+			const auto *inst = ECS_GetInstance(hoveredEntity);
+			const auto *grBinds = ECS_GetGrBinds(inst->grBindsHandle);
+			pkeDebugHitbox.instanceBuffer = grBinds->instanceBuffer;
+			pkeDebugHitbox.instanceStartingIndex = inst->index;
+		} else {
+			pkeDebugHitbox.instanceBuffer = VK_NULL_HANDLE;
+			pkeDebugHitbox.instanceStartingIndex = 0;
+		}
+	}
+	while (0);
+
 	if (shouldCreateEntityType) {
 		assert(entityTypeToCreate != nullptr);
 		assert(entityTypeToCreate != CAFE_BABE(EntityType));
-- 
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