feat: add moving platform support + fix jolt

lightkeeper/src/components/FirstPersonController.cpp

@@ -27,6 +27,16 @@ namespace {
         }
         return current + delta / distance * maxDelta;
     }
+
+    glm::vec3 ProjectOntoSlope(const glm::vec3& vector, const glm::vec3& slopeNormal)
+    {
+        const glm::vec3 projected = vector - slopeNormal * glm::dot(vector, slopeNormal);
+        const float projectedLength = glm::length(projected);
+        if (projectedLength < 1e-6f) {
+            return glm::vec3{0.0f};
+        }
+        return projected * (glm::length(vector) / projectedLength);
+    }
 }
 
 FirstPersonController::FirstPersonController(GameObject& parent)
@@ -130,22 +140,38 @@ void FirstPersonController::FixedUpdate(float fixedDt)
     m_PreviousPosition = GetTransform().GetWorldPosition();
     m_HasPreviousPosition = true;
 
-    glm::vec3 velocity = m_Rigidbody->GetLinearVelocity();
+    const std::optional<GroundContact> ground = FindGround();
+    const glm::vec3 groundVelocity = ground ? ground->velocity : glm::vec3{0.0f};
 
-    m_Grounded = velocity.y <= 0.1f && CheckGrounded();
+    // Movement happens relative to whatever is underneath, so moving platforms carry the player
+    glm::vec3 velocity = m_Rigidbody->GetLinearVelocity() - groundVelocity;
+
+    m_Grounded = ground.has_value() && glm::dot(velocity, ground->normal) <= 0.1f;
+    m_GroundNormal = m_Grounded ? ground->normal : glm::vec3{0.0f, 1.0f, 0.0f};
     m_CoyoteTimer = m_Grounded ? m_CoyoteTime : std::max(m_CoyoteTimer - fixedDt, 0.0f);
 
     const auto& input = InputManager::GetInstance();
     const bool sprinting = m_Possessed && input.IsKeyDown(SDL_SCANCODE_LSHIFT);
     const glm::vec3 wishVelocity = GetWishDirection() * (sprinting ? m_SprintSpeed : m_WalkSpeed);
 
-    const float acceleration = m_Grounded ? m_GroundAcceleration : m_AirAcceleration;
-    const glm::vec3 horizontal = MoveTowards(
-        glm::vec3{velocity.x, 0.0f, velocity.z},
-        wishVelocity,
-        acceleration * fixedDt);
-    velocity.x = horizontal.x;
-    velocity.z = horizontal.z;
+    if (m_Grounded)
+    {
+        const glm::vec3 velocityAlongSlope = velocity - m_GroundNormal * glm::dot(velocity, m_GroundNormal);
+        velocity = MoveTowards(
+            velocityAlongSlope,
+            ProjectOntoSlope(wishVelocity, m_GroundNormal),
+            m_GroundAcceleration * fixedDt);
+        velocity -= m_GroundNormal * m_GroundStickSpeed;
+    }
+    else
+    {
+        const glm::vec3 horizontal = MoveTowards(
+            glm::vec3{velocity.x, 0.0f, velocity.z},
+            wishVelocity,
+            m_AirAcceleration * fixedDt);
+        velocity.x = horizontal.x;
+        velocity.z = horizontal.z;
+    }
 
     if (m_JumpBufferTimer > 0.0f && m_CoyoteTimer > 0.0f)
     {
@@ -155,22 +181,25 @@ void FirstPersonController::FixedUpdate(float fixedDt)
         m_Grounded = false;
     }
 
-    // Falling faster than rising, and letting go of jump early cuts the jump short
-    float gravity = m_Gravity;
-    if (velocity.y < 0.0f || !m_JumpHeld)
+    if (!m_Grounded)
     {
-        gravity *= m_FallGravityMultiplier;
+        // Falling faster than rising, and letting go of jump early cuts the jump short
+        float gravity = m_Gravity;
+        if (velocity.y < 0.0f || !m_JumpHeld)
+        {
+            gravity *= m_FallGravityMultiplier;
+        }
+        velocity.y -= gravity * fixedDt;
     }
-    velocity.y -= gravity * fixedDt;
 
-    m_Rigidbody->SetLinearVelocity(velocity);
+    m_Rigidbody->SetLinearVelocity(velocity + groundVelocity);
 }
 
-bool FirstPersonController::CheckGrounded() const
+std::optional<FirstPersonController::GroundContact> FirstPersonController::FindGround() const
 {
     const auto* world = m_Rigidbody->GetPhysicsWorld();
     if (world == nullptr || m_Capsule == nullptr)
-        return false;
+        return std::nullopt;
 
     const glm::vec3 center = GetTransform().GetWorldPosition() + m_Capsule->GetCenterOffset();
     const float radius = m_Capsule->GetRadius();
@@ -187,6 +216,7 @@ bool FirstPersonController::CheckGrounded() const
 
     constexpr float startHeight = 0.2f;
     constexpr float probeDistance = 0.1f;
+    const float minWalkableNormalY = std::cos(m_MaxSlopeAngle);
     for (const glm::vec2& offset : offsets)
     {
         const glm::vec3 origin{center.x + offset.x, bottom + startHeight, center.z + offset.y};
@@ -194,12 +224,15 @@ bool FirstPersonController::CheckGrounded() const
         PhysicsRaycastHit hit{};
         if (world->Raycast(origin, glm::vec3{0.0f, -1.0f, 0.0f}, startHeight + probeDistance, hit,
                            m_Rigidbody->GetBody()) &&
-            hit.normal.y > 0.6f)
+            hit.normal.y >= minWalkableNormalY)
         {
-            return true;
+            return GroundContact{
+                .normal = glm::normalize(hit.normal),
+                .velocity = hit.body.IsValid() ? world->GetLinearVelocity(hit.body) : glm::vec3{0.0f},
+            };
         }
     }
-    return false;
+    return std::nullopt;
 }
 
 glm::vec3 FirstPersonController::GetWishDirection() const
@@ -243,9 +276,12 @@ void FirstPersonController::ImGuiInspector()
     ImGui::DragFloat("Coyote Time", &m_CoyoteTime, 0.005f, 0.0f, 1.0f);
     ImGui::DragFloat("Jump Buffer Time", &m_JumpBufferTime, 0.005f, 0.0f, 1.0f);
     ImGui::DragFloat("Interact Distance", &m_InteractDistance, 0.05f, 0.0f, 20.0f);
+    ImGui::SliderAngle("Max Slope Angle", &m_MaxSlopeAngle, 0.0f, 89.0f);
+    ImGui::DragFloat("Ground Stick Speed", &m_GroundStickSpeed, 0.05f, 0.0f, 20.0f);
     ImGui::DragFloat("Mouse Sensitivity", &m_MouseSensitivity, 0.0001f, 0.0f, 0.1f);
     ImGui::DragFloat("Eye Height", &m_EyeHeight, 0.01f, -2.0f, 2.0f);
     ImGui::Text("Grounded: %s", m_Grounded ? "yes" : "no");
+    ImGui::Text("Ground slope: %.1f deg", glm::degrees(std::acos(glm::clamp(m_GroundNormal.y, -1.0f, 1.0f))));
     ImGui::Text("Yaw: %.1f deg", glm::degrees(m_Yaw));
     ImGui::Text("Pitch: %.1f deg", glm::degrees(m_Pitch));
     if (bool possessed = m_Possessed; ImGui::Checkbox("Possessed", &possessed)) {
@@ -266,6 +302,8 @@ nlohmann::json FirstPersonController::Serialize() const
         {"coyoteTime", m_CoyoteTime},
         {"jumpBufferTime", m_JumpBufferTime},
         {"interactDistance", m_InteractDistance},
+        {"maxSlopeAngle", m_MaxSlopeAngle},
+        {"groundStickSpeed", m_GroundStickSpeed},
         {"mouseSensitivity", m_MouseSensitivity},
         {"eyeHeight", m_EyeHeight},
         {"yaw", m_Yaw},
@@ -285,6 +323,8 @@ void FirstPersonController::Deserialize(const nlohmann::json& data)
     m_CoyoteTime = data.value("coyoteTime", m_CoyoteTime);
     m_JumpBufferTime = data.value("jumpBufferTime", m_JumpBufferTime);
     m_InteractDistance = data.value("interactDistance", m_InteractDistance);
+    m_MaxSlopeAngle = data.value("maxSlopeAngle", m_MaxSlopeAngle);
+    m_GroundStickSpeed = data.value("groundStickSpeed", m_GroundStickSpeed);
     m_MouseSensitivity = data.value("mouseSensitivity", m_MouseSensitivity);
     m_EyeHeight = data.value("eyeHeight", m_EyeHeight);
     m_Yaw = data.value("yaw", m_Yaw);

lightkeeper/src/components/MovingPlatform.cpp

@@ -0,0 +1,79 @@
+#include <components/MovingPlatform.h>
+
+#include <algorithm>
+#include <cmath>
+
+#include <destrum/ObjectModel/GameObject.h>
+
+#include <imgui.h>
+
+MovingPlatform::MovingPlatform(GameObject& parent)
+    : Component(parent, "MovingPlatform")
+{
+}
+
+void MovingPlatform::Start()
+{
+    const glm::vec3 currentPosition = GetTransform().GetLocalPosition();
+    m_StartPosition = currentPosition - GetOffsetAt(GetTravelProgress());
+    m_Started = true;
+}
+
+void MovingPlatform::Update(float dt)
+{
+    if (!m_Started) {
+        return;
+    }
+
+    m_ElapsedTime += dt;
+    GetTransform().SetLocalPosition(m_StartPosition + GetOffsetAt(GetTravelProgress()));
+}
+
+float MovingPlatform::GetTravelProgress() const
+{
+    const float travelDuration = std::max(m_TravelDuration, 0.01f);
+    const float pauseDuration = std::max(m_PauseDuration, 0.0f);
+    const float legDuration = travelDuration + pauseDuration;
+
+    const float timeInCycle = std::fmod(m_ElapsedTime, legDuration * 2.0f);
+    const bool returning = timeInCycle >= legDuration;
+    const float timeInLeg = returning ? timeInCycle - legDuration : timeInCycle;
+
+    const float legProgress = std::clamp((timeInLeg - pauseDuration) / travelDuration, 0.0f, 1.0f);
+    return returning ? 1.0f - legProgress : legProgress;
+}
+
+glm::vec3 MovingPlatform::GetOffsetAt(float progress) const
+{
+    const float eased = progress * progress * (3.0f - 2.0f * progress);
+    return m_TravelOffset * eased;
+}
+
+nlohmann::json MovingPlatform::Serialize() const
+{
+    return {
+        {"travelOffset", {m_TravelOffset.x, m_TravelOffset.y, m_TravelOffset.z}},
+        {"travelDuration", m_TravelDuration},
+        {"pauseDuration", m_PauseDuration},
+        {"elapsedTime", m_ElapsedTime},
+    };
+}
+
+void MovingPlatform::Deserialize(const nlohmann::json& data)
+{
+    if (data.contains("travelOffset")) {
+        const auto& offset = data.at("travelOffset");
+        m_TravelOffset = {offset.at(0).get<float>(), offset.at(1).get<float>(), offset.at(2).get<float>()};
+    }
+    m_TravelDuration = std::max(data.value("travelDuration", m_TravelDuration), 0.01f);
+    m_PauseDuration = std::max(data.value("pauseDuration", m_PauseDuration), 0.0f);
+    m_ElapsedTime = std::max(data.value("elapsedTime", m_ElapsedTime), 0.0f);
+}
+
+void MovingPlatform::ImGuiInspector()
+{
+    ImGui::Text("Progress: %.0f%%", GetTravelProgress() * 100.0f);
+    ImGui::DragFloat3("Travel Offset", &m_TravelOffset.x, 0.05f);
+    ImGui::DragFloat("Travel Duration", &m_TravelDuration, 0.05f, 0.01f, 60.0f, "%.2f s");
+    ImGui::DragFloat("Pause Duration", &m_PauseDuration, 0.05f, 0.0f, 60.0f, "%.2f s");
+}

lightkeeper/src/scenes/MainScene.cpp

@@ -19,6 +19,7 @@
 #include <components/Door.h>
 #include <components/InteractableButton.h>
 #include <components/LightToggle.h>
+#include <components/MovingPlatform.h>
 #include <components/TriggerLoggerComponent.h>
 
 #include <glm/gtc/constants.hpp>
@@ -26,6 +27,7 @@
 
 #include <spdlog/spdlog.h>
 
+#include <cmath>
 #include <memory>
 #include <optional>
 #include <string>
@@ -124,10 +126,12 @@ namespace {
 
     GameObject* CreateBox(Scene& scene, GfxDevice& gfxDevice, RenderResources& resources,
                           const std::string& name, const glm::vec3& position, const glm::vec3& size,
-                          MaterialID materialID, RigidbodyType type)
+                          MaterialID materialID, RigidbodyType type,
+                          const glm::quat& rotation = glm::quat{1.0f, 0.0f, 0.0f, 0.0f})
     {
         GameObject* box = scene.CreateGameObject(name);
         box->GetTransform().SetWorldPosition(position);
+        box->GetTransform().SetWorldRotation(rotation);
 
         auto* boxMeshComp = box->AddComponent<MeshRendererComponent>();
         boxMeshComp->SetMeshID(resources.meshes().addMesh(gfxDevice, PrimitiveMeshes::MakeBox(size)));
@@ -221,6 +225,42 @@ namespace {
         button->AddComponent<InteractableButton>()->AddTarget(target);
     }
 
+    void CreateMovingPlatform(Scene& scene, GfxDevice& gfxDevice, RenderResources& resources)
+    {
+        const MaterialID rampMaterial = AddPrototypeMaterial(gfxDevice, resources, "Green", 0.6f);
+        const MaterialID platformMaterial = AddPrototypeMaterial(gfxDevice, resources, "Purple", 0.5f);
+
+        constexpr float laneZ = 2.0f;
+        constexpr float platformHeight = 1.0f;
+        constexpr float rampStartX = 9.0f;
+        constexpr float rampLength = 3.0f;
+        constexpr float rampThickness = 0.3f;
+        constexpr float travelDistance = 8.0f;
+        const glm::vec3 platformSize{3.0f, 0.3f, 3.0f};
+
+        const float platformTop = GroundHeight + platformHeight;
+        const glm::quat rampRotation =
+            glm::angleAxis(std::atan2(platformHeight, rampLength), glm::vec3{0.0f, 0.0f, 1.0f});
+        const glm::vec3 rampTopCenter{rampStartX + rampLength * 0.5f, GroundHeight + platformHeight * 0.5f, laneZ};
+        const glm::vec3 rampCenter = rampTopCenter - rampRotation * glm::vec3{0.0f, rampThickness * 0.5f, 0.0f};
+        const float rampSlopeLength = glm::length(glm::vec2{rampLength, platformHeight});
+
+        CreateBox(scene, gfxDevice, resources, "PlatformRamp", rampCenter,
+                  {rampSlopeLength, rampThickness, platformSize.z}, rampMaterial, RigidbodyType::Static,
+                  rampRotation);
+
+        const float platformStartX = rampStartX + rampLength + platformSize.x * 0.5f;
+        GameObject* platform = CreateBox(scene, gfxDevice, resources, "MovingPlatform",
+                                         {platformStartX, platformTop - platformSize.y * 0.5f, laneZ},
+                                         platformSize, platformMaterial, RigidbodyType::Kinematic);
+        platform->AddComponent<MovingPlatform>()->SetTravelOffset({travelDistance, 0.0f, 0.0f});
+
+        const float landingStartX = platformStartX + travelDistance + platformSize.x * 0.5f;
+        CreateBox(scene, gfxDevice, resources, "PlatformLanding",
+                  {landingStartX + 1.0f, GroundHeight + platformHeight * 0.5f, laneZ},
+                  {2.0f, platformHeight, platformSize.z}, rampMaterial, RigidbodyType::Static);
+    }
+
     struct WallOpening {
         float offset;
         float width;
@@ -467,6 +507,7 @@ MainSceneObjects BuildMainScene(Scene& scene, GfxDevice& gfxDevice, RenderResour
     const GameObject* door = CreateDoorway(scene, gfxDevice, resources);
     CreateButton(scene, gfxDevice, resources, *door);
     CreateHouse(scene, gfxDevice, resources);
+    CreateMovingPlatform(scene, gfxDevice, resources);
     CreatePlayer(scene, objects);
     LoadSpawnBallResources(gfxDevice, resources, objects);