From 73a596cb2f06c41f2ea49b4ea3ea1abe0621c977 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Wed, 21 Aug 2024 21:54:22 +0200
Subject: [PATCH] Add `OrthographicSize` to Camera for fixed ortho projection
 size

#1970
---
 Source/Engine/Level/Actors/Camera.cpp | 25 ++++++++++++++++++++++---
 Source/Engine/Level/Actors/Camera.h   | 14 +++++++++++++-
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/Source/Engine/Level/Actors/Camera.cpp b/Source/Engine/Level/Actors/Camera.cpp
index 008f00520..a2822b09e 100644
--- a/Source/Engine/Level/Actors/Camera.cpp
+++ b/Source/Engine/Level/Actors/Camera.cpp
@@ -39,6 +39,7 @@ Camera::Camera(const SpawnParams& params)
     , _customAspectRatio(0.0f)
     , _near(10.0f)
     , _far(40000.0f)
+    , _orthoSize(0.0f)
     , _orthoScale(1.0f)
 {
 #if USE_EDITOR
@@ -120,6 +121,21 @@ void Camera::SetFarPlane(float value)
     }
 }
 
+float Camera::GetOrthographicSize() const
+{
+    return _orthoSize;
+}
+
+void Camera::SetOrthographicSize(float value)
+{
+    value = Math::Clamp(value, 0.0f, 1000000.0f);
+    if (Math::NotNearEqual(_orthoSize, value))
+    {
+        _orthoSize = value;
+        UpdateCache();
+    }
+}
+
 float Camera::GetOrthographicScale() const
 {
     return _orthoScale;
@@ -201,7 +217,9 @@ Ray Camera::ConvertMouseToRay(const Float2& mousePosition, const Viewport& viewp
         Float2 screenPosition(mousePosition.X / viewport.Width - 0.5f, -mousePosition.Y / viewport.Height + 0.5f);
         Quaternion orientation = GetOrientation();
         Float3 direction = orientation * Float3::Forward;
-        Vector3 rayOrigin(screenPosition.X * viewport.Width * _orthoScale, screenPosition.Y * viewport.Height * _orthoScale, 0);
+        const float orthoSize = (_orthoSize > 0.0f ? _orthoSize : viewport.Height) * _orthoScale;
+        const float aspect = _customAspectRatio <= 0.0f ? viewport.GetAspectRatio() : _customAspectRatio;
+        Vector3 rayOrigin(screenPosition.X * orthoSize * aspect, screenPosition.Y * orthoSize, 0);
         rayOrigin = position + Vector3::Transform(rayOrigin, orientation);
         rayOrigin += direction * _near;
         return Ray(rayOrigin, direction);
@@ -260,14 +278,15 @@ void Camera::GetMatrices(Matrix& view, Matrix& projection, const Viewport& viewp
 void Camera::GetMatrices(Matrix& view, Matrix& projection, const Viewport& viewport, const Vector3& origin) const
 {
     // Create projection matrix
+    const float aspect = _customAspectRatio <= 0.0f ? viewport.GetAspectRatio() : _customAspectRatio;
     if (_usePerspective)
     {
-        const float aspect = _customAspectRatio <= 0.0f ? viewport.GetAspectRatio() : _customAspectRatio;
         Matrix::PerspectiveFov(_fov * DegreesToRadians, aspect, _near, _far, projection);
     }
     else
     {
-        Matrix::Ortho(viewport.Width * _orthoScale, viewport.Height * _orthoScale, _near, _far, projection);
+        const float orthoSize = (_orthoSize > 0.0f ? _orthoSize : viewport.Height) * _orthoScale;
+        Matrix::Ortho(orthoSize * aspect, orthoSize, _near, _far, projection);
     }
 
     // Create view matrix
diff --git a/Source/Engine/Level/Actors/Camera.h b/Source/Engine/Level/Actors/Camera.h
index 190126e54..7da37c4b6 100644
--- a/Source/Engine/Level/Actors/Camera.h
+++ b/Source/Engine/Level/Actors/Camera.h
@@ -44,6 +44,7 @@ private:
     float _customAspectRatio;
     float _near;
     float _far;
+    float _orthoSize;
     float _orthoScale;
 
 #if USE_EDITOR
@@ -88,7 +89,7 @@ public:
     /// <summary>
     /// Gets the custom aspect ratio. 0 if not use custom value.
     /// </summary>
-    API_PROPERTY(Attributes="EditorOrder(50), DefaultValue(0.0f), Limit(0, 10, 0.01f), EditorDisplay(\"Camera\"), VisibleIf(nameof(UsePerspective))")
+    API_PROPERTY(Attributes="EditorOrder(50), DefaultValue(0.0f), Limit(0, 10, 0.01f), EditorDisplay(\"Camera\")")
     float GetCustomAspectRatio() const;
 
     /// <summary>
@@ -118,6 +119,17 @@ public:
     /// </summary>
     API_PROPERTY() void SetFarPlane(float value);
 
+    /// <summary>
+    /// Gets the orthographic projection view height (width is based on the aspect ratio). Use `0` for size to be based on the viewport size.
+    /// </summary>
+    API_PROPERTY(Attributes="EditorOrder(59), DefaultValue(0.0f), Limit(0.0f), EditorDisplay(\"Camera\"), VisibleIf(nameof(UsePerspective), true)")
+    float GetOrthographicSize() const;
+
+    /// <summary>
+    /// Sets the orthographic projection view height (width is based on the aspect ratio). Use `0` for size to be based on the viewport size.
+    /// </summary>
+    API_PROPERTY() void SetOrthographicSize(float value);
+
     /// <summary>
     /// Gets the orthographic projection scale.
     /// </summary>