From 4caa65a4374a0e510e5dd7426d4346ec44d35763 Mon Sep 17 00:00:00 2001
From: maelstrom <maelstrom@maelstrom.dev>
Date: Sat, 1 Feb 2025 21:15:53 +0100
Subject: [PATCH] intersting

---
 editor/mainglwidget.cpp    | 69 +++++++++++++++++++++++++++++++++++---
 src/physics/simulation.cpp | 11 +++++-
 src/physics/simulation.h   |  5 ++-
 3 files changed, 79 insertions(+), 6 deletions(-)

diff --git a/editor/mainglwidget.cpp b/editor/mainglwidget.cpp
index 0e8e09f..6b82f16 100644
--- a/editor/mainglwidget.cpp
+++ b/editor/mainglwidget.cpp
@@ -2,11 +2,17 @@
 #include <chrono>
 
 #include <QMouseEvent>
+#include <glm/ext/matrix_projection.hpp>
+#include <glm/ext/vector_float3.hpp>
+#include <glm/geometric.hpp>
+#include <glm/matrix.hpp>
+#include <reactphysics3d/collision/RaycastInfo.h>
 
 #include "GLFW/glfw3.h"
 #include "qcursor.h"
 #include "qevent.h"
 #include "qnamespace.h"
+#include "qwindowdefs.h"
 #include "rendering/renderer.h"
 #include "physics/simulation.h"
 #include "camera.h"
@@ -50,11 +56,66 @@ void MainGLWidget::mouseMoveEvent(QMouseEvent* evt) {
     // QCursor::setPos(lastMousePos);
 }
 
-void MainGLWidget::mousePressEvent(QMouseEvent* evt) {
-    if (evt->button() != Qt::RightButton) return;
+class FirstRayHit : public rp::RaycastCallback {
+    rp::Body** target;
 
-    lastMousePos = evt->pos();
-    isMouseDragging = true;
+    virtual rp::decimal notifyRaycastHit(const rp::RaycastInfo& raycastInfo) override {
+        if (reinterpret_cast<Part*>(raycastInfo.body->getUserData())->name == "Baseplate") return 1;
+
+        *target = raycastInfo.body;
+        return 0;
+    }
+
+public:
+    FirstRayHit(rp::Body** target) : target(target) {}
+};
+
+void MainGLWidget::mousePressEvent(QMouseEvent* evt) {
+    switch(evt->button()) {
+    // Camera drag
+    case Qt::RightButton: {
+        lastMousePos = evt->pos();
+        isMouseDragging = true;
+        return;
+    // Clicking on objects
+    } case Qt::LeftButton: {
+        QPoint position = evt->pos();
+        rp::Body* rayHitTarget = NULL;
+
+        // VVV Thank goodness for this person's answer
+        // https://stackoverflow.com/a/30005258/16255372
+
+        // glm::vec3 worldPos = camera.cameraPos + glm::vec3(glm::vec4(float(position.x()) / width() - 0.5f, float(position.y()) / height() - 0.5f, 0, 0) * camera.getLookAt());
+        glm::mat4 projection = glm::perspective(glm::radians(45.f), (float)width() / (float)height(), 0.1f, 100.0f);
+        glm::mat4 view = glm::lookAt(glm::vec3(0), camera.cameraFront, camera.cameraUp);
+        glm::mat4 inverseViewport = glm::inverse(projection * view);
+
+        glm::vec2 ndc = glm::vec2(float(position.x()) / width() * 2.f - 1.f, -float(position.y()) / height() * 2.f + 1.f);
+        glm::vec4 world = glm::normalize(inverseViewport * glm::vec4(ndc, 1, 1));
+        glm::vec3 flat = glm::vec3(world) / world.w; // https://stackoverflow.com/a/68870587/16255372
+        
+        printf("At: %f; %f; %f\n", world.x, world.y, world.z);
+
+        workspace->AddChild(lastPart = Part::New({
+            .position = camera.cameraPos + glm::vec3(world) * 10.f,
+            .rotation = glm::vec3(0),
+            .scale = glm::vec3(1, 1, 1),
+            .material = Material {
+                .diffuse = glm::vec3(1.0f, 0.5f, 0.31f),
+                .specular = glm::vec3(0.5f, 0.5f, 0.5f),
+                .shininess = 32.0f,
+            },
+            .anchored = true,
+        }));
+        syncPartPhysics(lastPart);
+
+        castRay(camera.cameraPos, world, 500, new FirstRayHit(&rayHitTarget));
+        if (!rayHitTarget) return;
+        printf("Hit: %s\n", reinterpret_cast<Part*>(rayHitTarget->getUserData())->name.c_str());
+        return;
+    } default:
+        return;
+    }
 }
 
 void MainGLWidget::mouseReleaseEvent(QMouseEvent* evt) {
diff --git a/src/physics/simulation.cpp b/src/physics/simulation.cpp
index 6dba846..d86e4c4 100644
--- a/src/physics/simulation.cpp
+++ b/src/physics/simulation.cpp
@@ -2,12 +2,14 @@
 #include <glm/ext/matrix_float3x3.hpp>
 #include <glm/gtc/quaternion.hpp>
 #include <memory>
+#include <reactphysics3d/collision/RaycastInfo.h>
 #include <reactphysics3d/collision/shapes/BoxShape.h>
 #include <reactphysics3d/collision/shapes/CollisionShape.h>
 #include <reactphysics3d/components/RigidBodyComponents.h>
 #include <reactphysics3d/engine/EventListener.h>
 #include <reactphysics3d/engine/PhysicsCommon.h>
 #include <reactphysics3d/mathematics/Quaternion.h>
+#include <reactphysics3d/mathematics/Ray.h>
 #include <reactphysics3d/mathematics/Transform.h>
 #include <reactphysics3d/mathematics/Vector3.h>
 #include <reactphysics3d/memory/DefaultAllocator.h>
@@ -36,6 +38,8 @@ void simulationInit() {
     world = physicsCommon->createPhysicsWorld();
 
     world->setGravity(rp::Vector3(0, -196.2, 0));
+
+    world->setEventListener(&eventListener);
 }
 
 void syncPartPhysics(std::shared_ptr<Part> part) {
@@ -58,7 +62,7 @@ void syncPartPhysics(std::shared_ptr<Part> part) {
         part->rigidBody->addCollider(shape, rp::Transform());
     part->rigidBody->setType(part->anchored ? rp::BodyType::STATIC : rp::BodyType::DYNAMIC);
 
-    world->setEventListener(&eventListener);
+    part->rigidBody->setUserData(&*part);
 }
 
 void physicsStep(float deltaTime) {
@@ -75,4 +79,9 @@ void physicsStep(float deltaTime) {
         // part.rotation = glm::eulerAngles(rpToGlm(transform.getOrientation()));
         part->rotation = rpToGlm(transform.getOrientation());
     }
+}
+
+void castRay(glm::vec3 point, glm::vec3 rotation, float maxLength, rp::RaycastCallback* callback) {
+    rp::Ray ray(glmToRp(point), glmToRp(glm::normalize(rotation)) * maxLength);
+    world->raycast(ray, callback);
 }
\ No newline at end of file
diff --git a/src/physics/simulation.h b/src/physics/simulation.h
index f9d4f0a..203671d 100644
--- a/src/physics/simulation.h
+++ b/src/physics/simulation.h
@@ -1,8 +1,11 @@
 #pragma once
 
 #include "../objects/part.h"
+#include <glm/ext/vector_float3.hpp>
 #include <memory>
+#include <reactphysics3d/collision/RaycastInfo.h>
 
 void simulationInit();
 void syncPartPhysics(std::shared_ptr<Part> part);
-void physicsStep(float deltaTime);
\ No newline at end of file
+void physicsStep(float deltaTime);
+void castRay(glm::vec3 point, glm::vec3 rotation, float maxLength, rp::RaycastCallback* callback);
\ No newline at end of file