From f2aba94b39abbc6a076d14e644ef23c0464a7279 Mon Sep 17 00:00:00 2001
From: "Tormod G. Hellen" <tormod.hellen@gmail.com>
Date: Mon, 18 Sep 2023 17:01:37 +0200
Subject: [PATCH] Deduplicate camera transform matrix check.

---
 crates/bevy_render/src/camera/camera.rs | 45 +++++++++++++------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/crates/bevy_render/src/camera/camera.rs b/crates/bevy_render/src/camera/camera.rs
index d2570156deaef3..add409a2ef1314 100644
--- a/crates/bevy_render/src/camera/camera.rs
+++ b/crates/bevy_render/src/camera/camera.rs
@@ -244,6 +244,17 @@ impl Camera {
         Ok(projection_matrix)
     }
 
+    #[inline]
+    fn finite_camera_transform_matrix(
+        camera_transform: &GlobalTransform,
+    ) -> Result<Mat4, CameraTransformNotFiniteError> {
+        let camera_transform_matrix = camera_transform.compute_matrix();
+        if !camera_transform_matrix.is_finite() {
+            return Err(CameraTransformNotFiniteError(camera_transform_matrix));
+        }
+        Ok(camera_transform_matrix)
+    }
+
     /// Given a position in world space, use the camera to compute the viewport-space coordinates.
     ///
     /// To get the coordinates in Normalized Device Coordinates, you should use
@@ -298,13 +309,8 @@ impl Camera {
         viewport_position.y = target_size.y - viewport_position.y;
         let ndc = viewport_position * 2. / target_size - Vec2::ONE;
 
-        let camera_transform_matrix = camera_transform.compute_matrix();
-        if !camera_transform_matrix.is_finite() {
-            return Err(ViewportToWorldError::CameraTransformNotFiniteError(
-                camera_transform_matrix,
-            ));
-        }
-        // TODO: Do some code deduplication of the above snippet..
+        let camera_transform_matrix = Self::finite_camera_transform_matrix(camera_transform)
+            .map_err(ViewportToWorldError::CameraTransformNotFiniteError)?;
         let projection_matrix = self
             .finite_projection_matrix()
             .map_err(ViewportToWorldError::ProjectionMatrixNotFiniteError)?;
@@ -370,12 +376,8 @@ impl Camera {
         camera_transform: &GlobalTransform,
         world_position: Vec3,
     ) -> Result<Vec3, WorldToNdcError> {
-        let camera_transform_matrix = camera_transform.compute_matrix();
-        if !camera_transform_matrix.is_finite() {
-            return Err(WorldToNdcError::CameraTransformNotFiniteError(
-                camera_transform_matrix,
-            ));
-        }
+        let camera_transform_matrix = Self::finite_camera_transform_matrix(camera_transform)
+            .map_err(WorldToNdcError::CameraTransformNotFiniteError)?;
 
         let projection_matrix = self
             .finite_projection_matrix()
@@ -408,12 +410,8 @@ impl Camera {
         camera_transform: &GlobalTransform,
         ndc: Vec3,
     ) -> Result<Vec3, NdcToWorldError> {
-        let camera_transform_matrix = camera_transform.compute_matrix();
-        if !camera_transform_matrix.is_finite() {
-            return Err(NdcToWorldError::CameraTransformNotFiniteError(
-                camera_transform_matrix,
-            ));
-        }
+        let camera_transform_matrix = Self::finite_camera_transform_matrix(camera_transform)
+            .map_err(NdcToWorldError::CameraTransformNotFiniteError)?;
 
         let projection_matrix = self
             .finite_projection_matrix()
@@ -436,14 +434,14 @@ impl Camera {
 #[derive(Debug)]
 pub enum NdcToWorldError {
     WorldSpaceCoordsNotFiniteError(Vec3),
-    CameraTransformNotFiniteError(Mat4),
+    CameraTransformNotFiniteError(CameraTransformNotFiniteError),
     ProjectionMatrixNotFiniteError(ProjectionMatrixNotFiniteError),
 }
 
 #[derive(Debug)]
 pub enum WorldToNdcError {
     NdcSpaceCoordsNotFiniteError(Vec3),
-    CameraTransformNotFiniteError(Mat4),
+    CameraTransformNotFiniteError(CameraTransformNotFiniteError),
     ProjectionMatrixNotFiniteError(ProjectionMatrixNotFiniteError),
 }
 
@@ -457,7 +455,7 @@ pub struct LogicalViewportSizeError {
 #[derive(Debug)]
 pub enum ViewportToWorldError {
     LogicalViewportSizeError(LogicalViewportSizeError),
-    CameraTransformNotFiniteError(Mat4),
+    CameraTransformNotFiniteError(CameraTransformNotFiniteError),
     ProjectionMatrixNotFiniteError(ProjectionMatrixNotFiniteError),
     WorldNearPlaneNotFiniteError(Vec3),
     WorldFarPlaneNanError(Vec3), //Presumably this being infinite is sometimes ok?
@@ -479,6 +477,9 @@ pub enum WorldToViewportError {
 #[derive(Debug)]
 pub struct ProjectionMatrixNotFiniteError(Mat4);
 
+#[derive(Debug)]
+pub struct CameraTransformNotFiniteError(Mat4);
+
 /// Control how this camera outputs once rendering is completed.
 #[derive(Debug, Clone, Copy)]
 pub enum CameraOutputMode {