Replace float type for arguments to create heightfield with int

To reduce amount of computations on the caller side and restrict possible
values.

* verts can't be non-int because it's a number of things.
* worldsize is initially defined as int by ESM::Land::REAL_SIZE.
* Put function to calculate heightfied shift into components to be able to
  reuse by other binaries.

apps/openmw/mwphysics/heightfield.cpp

@@ -1,6 +1,8 @@
 #include "heightfield.hpp"
 #include "mtphysics.hpp"
 
+#include <components/bullethelpers/heightfield.hpp>
+
 #include <osg/Object>
 
 #include <BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h>
@@ -19,17 +21,17 @@
 namespace
 {
     template <class T>
-    auto makeHeights(const T* heights, float sqrtVerts)
+    auto makeHeights(const T* heights, int verts)
         -> std::enable_if_t<std::is_same<btScalar, T>::value, std::vector<btScalar>>
     {
         return {};
     }
 
     template <class T>
-    auto makeHeights(const T* heights, float sqrtVerts)
+    auto makeHeights(const T* heights, int verts)
         -> std::enable_if_t<!std::is_same<btScalar, T>::value, std::vector<btScalar>>
     {
-        return std::vector<btScalar>(heights, heights + static_cast<std::ptrdiff_t>(sqrtVerts * sqrtVerts));
+        return std::vector<btScalar>(heights, heights + static_cast<std::ptrdiff_t>(verts * verts));
     }
 
     template <class T>
@@ -50,16 +52,17 @@ namespace
 
 namespace MWPhysics
 {
-    HeightField::HeightField(const float* heights, int x, int y, float triSize, float sqrtVerts, float minH, float maxH, const osg::Object* holdObject, PhysicsTaskScheduler* scheduler)
+    HeightField::HeightField(const float* heights, int x, int y, int size, int verts, float minH, float maxH,
+                             const osg::Object* holdObject, PhysicsTaskScheduler* scheduler)
         : mHoldObject(holdObject)
 #if BT_BULLET_VERSION < 310
-        , mHeights(makeHeights(heights, sqrtVerts))
+        , mHeights(makeHeights(heights, verts))
 #endif
         , mTaskScheduler(scheduler)
     {
 #if BT_BULLET_VERSION < 310
         mShape = std::make_unique<btHeightfieldTerrainShape>(
-            sqrtVerts, sqrtVerts,
+            verts, verts,
             getHeights(heights, mHeights),
             1,
             minH, maxH, 2,
@@ -67,10 +70,12 @@ namespace MWPhysics
         );
 #else
         mShape = std::make_unique<btHeightfieldTerrainShape>(
-            sqrtVerts, sqrtVerts, heights, minH, maxH, 2, false);
+            verts, verts, heights, minH, maxH, 2, false);
 #endif
         mShape->setUseDiamondSubdivision(true);
-        mShape->setLocalScaling(btVector3(triSize, triSize, 1));
+
+        const float scaling = static_cast<float>(size) / static_cast<float>(verts - 1);
+        mShape->setLocalScaling(btVector3(scaling, scaling, 1));
 
 #if BT_BULLET_VERSION >= 289
         // Accelerates some collision tests.
@@ -81,10 +86,8 @@ namespace MWPhysics
         mShape->buildAccelerator();
 #endif
 
-        btTransform transform(btQuaternion::getIdentity(),
+        const btTransform transform(btQuaternion::getIdentity(),
-                                btVector3((x+0.5f) * triSize * (sqrtVerts-1),
+                                    BulletHelpers::getHeightfieldShift(x, y, size, minH, maxH));
-                                          (y+0.5f) * triSize * (sqrtVerts-1),
-                                          (maxH+minH)*0.5f));
 
         mCollisionObject = std::make_unique<btCollisionObject>();
         mCollisionObject->setCollisionShape(mShape.get());

apps/openmw/mwphysics/heightfield.hpp

@@ -23,7 +23,8 @@ namespace MWPhysics
     class HeightField
     {
     public:
-        HeightField(const float* heights, int x, int y, float triSize, float sqrtVerts, float minH, float maxH, const osg::Object* holdObject, PhysicsTaskScheduler* scheduler);
+        HeightField(const float* heights, int x, int y, int size, int verts, float minH, float maxH,
+                    const osg::Object* holdObject, PhysicsTaskScheduler* scheduler);
         ~HeightField();
 
         btCollisionObject* getCollisionObject();

apps/openmw/mwphysics/physicssystem.cpp

@@ -472,9 +472,9 @@ namespace MWPhysics
         return MovementSolver::traceDown(ptr, position, found->second.get(), mCollisionWorld.get(), maxHeight);
     }
 
-    void PhysicsSystem::addHeightField (const float* heights, int x, int y, float triSize, float sqrtVerts, float minH, float maxH, const osg::Object* holdObject)
+    void PhysicsSystem::addHeightField(const float* heights, int x, int y, int size, int verts, float minH, float maxH, const osg::Object* holdObject)
     {
-        mHeightFields[std::make_pair(x,y)] = std::make_unique<HeightField>(heights, x, y, triSize, sqrtVerts, minH, maxH, holdObject, mTaskScheduler.get());
+        mHeightFields[std::make_pair(x,y)] = std::make_unique<HeightField>(heights, x, y, size, verts, minH, maxH, holdObject, mTaskScheduler.get());
     }
 
     void PhysicsSystem::removeHeightField (int x, int y)

apps/openmw/mwphysics/physicssystem.hpp

@@ -150,7 +150,7 @@ namespace MWPhysics
             void updateRotation (const MWWorld::Ptr& ptr, osg::Quat rotate);
             void updatePosition (const MWWorld::Ptr& ptr);
 
-            void addHeightField (const float* heights, int x, int y, float triSize, float sqrtVerts, float minH, float maxH, const osg::Object* holdObject);
+            void addHeightField(const float* heights, int x, int y, int size, int verts, float minH, float maxH, const osg::Object* holdObject);
 
             void removeHeightField (int x, int y);
 

apps/openmw/mwworld/scene.cpp

@@ -383,17 +383,17 @@ namespace MWWorld
         {
             osg::ref_ptr<const ESMTerrain::LandObject> land = mRendering.getLandManager()->getLand(cellX, cellY);
             const ESM::Land::LandData* data = land ? land->getData(ESM::Land::DATA_VHGT) : nullptr;
-            const float verts = ESM::Land::LAND_SIZE;
+            const int verts = ESM::Land::LAND_SIZE;
-            const float worldsize = ESM::Land::REAL_SIZE;
+            const int worldsize = ESM::Land::REAL_SIZE;
             if (data)
             {
-                mPhysics->addHeightField (data->mHeights, cellX, cellY, worldsize / (verts-1), verts, data->mMinHeight, data->mMaxHeight, land.get());
+                mPhysics->addHeightField(data->mHeights, cellX, cellY, worldsize, verts, data->mMinHeight, data->mMaxHeight, land.get());
             }
             else
             {
                 static std::vector<float> defaultHeight;
                 defaultHeight.resize(verts*verts, ESM::Land::DEFAULT_HEIGHT);
-                mPhysics->addHeightField (&defaultHeight[0], cellX, cellY, worldsize / (verts-1), verts, ESM::Land::DEFAULT_HEIGHT, ESM::Land::DEFAULT_HEIGHT, land.get());
+                mPhysics->addHeightField(defaultHeight.data(), cellX, cellY, worldsize, verts, ESM::Land::DEFAULT_HEIGHT, ESM::Land::DEFAULT_HEIGHT, land.get());
             }
             if (const auto heightField = mPhysics->getHeightField(cellX, cellY))
             {

components/bullethelpers/heightfield.hpp

@@ -0,0 +1,14 @@
+#ifndef OPENMW_COMPONENTS_BULLETHELPERS_HEIGHTFIELD_H
+#define OPENMW_COMPONENTS_BULLETHELPERS_HEIGHTFIELD_H
+
+#include <LinearMath/btVector3.h>
+
+namespace BulletHelpers
+{
+    inline btVector3 getHeightfieldShift(int x, int y, int size, float minHeight, float maxHeight)
+    {
+        return btVector3((x + 0.5f) * size, (y + 0.5f) * size, (maxHeight + minHeight) * 0.5f);
+    }
+}
+
+#endif