From c27904aa92583938ca18d94abd3d403ef27b532a Mon Sep 17 00:00:00 2001
From: "glassmancody.info" <glassmancody.info@gmail.com>
Date: Wed, 14 Jun 2023 11:47:11 -0700
Subject: [PATCH] lua - add world to viewport function to camera

---
 apps/openmw/mwlua/camerabindings.cpp | 17 +++++++++++++++++
 apps/openmw/mwrender/camera.cpp      |  1 +
 apps/openmw/mwrender/camera.hpp      |  2 ++
 files/lua_api/openmw/camera.lua      |  6 ++++++
 4 files changed, 26 insertions(+)

diff --git a/apps/openmw/mwlua/camerabindings.cpp b/apps/openmw/mwlua/camerabindings.cpp
index 4d27ce317c..bd5c43d24c 100644
--- a/apps/openmw/mwlua/camerabindings.cpp
+++ b/apps/openmw/mwlua/camerabindings.cpp
@@ -106,6 +106,23 @@ namespace MWLua
             return invertedViewMatrix.preMult(osg::Vec3f(x, y, -1)) - camera->getPosition();
         };
 
+        api["worldToViewportVector"] = [camera](osg::Vec3f pos) {
+            double width = Settings::Manager::getInt("resolution x", "Video");
+            double height = Settings::Manager::getInt("resolution y", "Video");
+
+            osg::Matrix windowMatrix
+                = osg::Matrix::translate(1.0, 1.0, 1.0) * osg::Matrix::scale(0.5 * width, 0.5 * height, 0.5);
+            osg::Vec3f vpCoords = pos * (camera->getViewMatrix() * camera->getProjectionMatrix() * windowMatrix);
+
+            // Move 0,0 to top left to match viewportToWorldVector
+            vpCoords.y() = height - vpCoords.y();
+
+            // Set the z component to be distance from camera, in world space units
+            vpCoords.z() = (pos - camera->getPosition()).length();
+
+            return vpCoords;
+        };
+
         return LuaUtil::makeReadOnly(api);
     }
 
diff --git a/apps/openmw/mwrender/camera.cpp b/apps/openmw/mwrender/camera.cpp
index cbdf416364..fbe5c6b4c7 100644
--- a/apps/openmw/mwrender/camera.cpp
+++ b/apps/openmw/mwrender/camera.cpp
@@ -127,6 +127,7 @@ namespace MWRender
         }
         cam->setViewMatrixAsLookAt(pos, pos + forward, up);
         mViewMatrix = cam->getViewMatrix();
+        mProjectionMatrix = cam->getProjectionMatrix();
     }
 
     void Camera::update(float duration, bool paused)
diff --git a/apps/openmw/mwrender/camera.hpp b/apps/openmw/mwrender/camera.hpp
index 627697620e..c6500160fd 100644
--- a/apps/openmw/mwrender/camera.hpp
+++ b/apps/openmw/mwrender/camera.hpp
@@ -109,6 +109,7 @@ namespace MWRender
         void setCollisionType(int collisionType) { mCollisionType = collisionType; }
 
         const osg::Matrixf& getViewMatrix() const { return mViewMatrix; }
+        const osg::Matrixf& getProjectionMatrix() const { return mProjectionMatrix; }
 
     private:
         MWWorld::Ptr mTrackingPtr;
@@ -138,6 +139,7 @@ namespace MWRender
         bool mLockPitch = false, mLockYaw = false;
         osg::Vec3d mPosition;
         osg::Matrixf mViewMatrix;
+        osg::Matrixf mProjectionMatrix;
 
         float mCameraDistance, mPreferredCameraDistance;
 
diff --git a/files/lua_api/openmw/camera.lua b/files/lua_api/openmw/camera.lua
index c0307249b9..abe66e2d8c 100644
--- a/files/lua_api/openmw/camera.lua
+++ b/files/lua_api/openmw/camera.lua
@@ -224,5 +224,11 @@
 -- @param openmw.util#Vector2 normalizedScreenPos
 -- @return openmw.util#Vector3
 
+--- Get vector from the world to the viewport for the given point in world space.
+-- (0, 0) is the top left corner of the screen.
+-- The z component of the return value holds the distance from the camera to the position, in world space
+-- @function [parent=#camera] worldToViewportVector
+-- @param openmw.util#Vector3 worldPos
+-- @return openmw.util#Vector3
 
 return nil