From 3a92cdab3a4b501ae2f58fb6d678cb322b129ade Mon Sep 17 00:00:00 2001
From: Powei Feng <powei@google.com>
Date: Tue, 2 Dec 2025 14:22:38 -0800
Subject: [PATCH] Add flag to guard camera near/far assertion (#9472)

BUGS=465516676
---
 filament/src/Camera.cpp         | 10 ----------
 filament/src/details/Camera.cpp | 18 ++++++++++++++----
 filament/src/details/Engine.h   |  4 ++++
 3 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/filament/src/Camera.cpp b/filament/src/Camera.cpp
index 863bd03af4..17f66529b3 100644
--- a/filament/src/Camera.cpp
+++ b/filament/src/Camera.cpp
@@ -20,8 +20,6 @@
 
 #include <math/mat4.h>
 
-#include <utils/Panic.h>
-
 #include <math/vec2.h>
 #include <math/vec3.h>
 #include <math/vec4.h>
@@ -36,10 +34,6 @@ using namespace math;
 void Camera::setProjection(double const fovInDegrees, double const aspect,
         double const near, double const far, Fov const direction) {
 
-    FILAMENT_CHECK_PRECONDITION(near > 0 && far > near)
-            << "Camera preconditions not met in setProjection(): near <= 0 or far <= near, near="
-            << near << ", far=" << far;
-
     setCustomProjection(
             projection(direction, fovInDegrees, aspect, near),
             projection(direction, fovInDegrees, aspect, near, far),
@@ -49,10 +43,6 @@ void Camera::setProjection(double const fovInDegrees, double const aspect,
 void Camera::setLensProjection(double const focalLengthInMillimeters,
         double const aspect, double const near, double const far) {
 
-    FILAMENT_CHECK_PRECONDITION(near > 0 && far > near)
-        << "Camera preconditions not met in setLensProjection(): near <= 0 or far <= near, near="
-        << near << ", far=" << far;
-
     setCustomProjection(
             projection(focalLengthInMillimeters, aspect, near),
             projection(focalLengthInMillimeters, aspect, near, far),
diff --git a/filament/src/details/Camera.cpp b/filament/src/details/Camera.cpp
index d006e22d4c..1e09c22ff2 100644
--- a/filament/src/details/Camera.cpp
+++ b/filament/src/details/Camera.cpp
@@ -95,8 +95,13 @@ mat4 FCamera::projection(double const focalLengthInMillimeters,
 void UTILS_NOINLINE FCamera::setCustomProjection(mat4 const& projection,
         mat4 const& projectionForCulling, double const near, double const far) noexcept {
 
-    FILAMENT_CHECK_PRECONDITION(near != far)
-            << "Camera preconditions not met in setCustomProjection(): near = far = " << near;
+    FILAMENT_CHECK_PRECONDITION(near > 0)
+            << "Camera preconditions not met in setCustomProjection(): near <= 0, near=" << near;
+    auto const& featureFlags = mEngine.features.engine.debug;
+    FILAMENT_FLAG_GUARDED_CHECK_PRECONDITION(far > near,
+            featureFlags.assert_camera_projection_near_far)
+            << "Camera preconditions not met in setCustomProjection(): far <= near, near="
+            << near << ", far=" << far;
 
     for (auto& eyeProjection: mEyeProjection) {
         eyeProjection = projection;
@@ -110,8 +115,13 @@ void UTILS_NOINLINE FCamera::setCustomEyeProjection(mat4 const* projection, size
         mat4 const& projectionForCulling, double const near, double const far) {
     const Engine::Config& config = mEngine.getConfig();
 
-    FILAMENT_CHECK_PRECONDITION(near != far)
-            << "Camera preconditions not met in setCustomEyeProjection(): near = far = " << near;
+    FILAMENT_CHECK_PRECONDITION(near > 0)
+            << "Camera preconditions not met in setCustomEyeProjection(): near <= 0, near=" << near;
+    auto const& featureFlags = mEngine.features.engine.debug;
+    FILAMENT_FLAG_GUARDED_CHECK_PRECONDITION(far > near,
+            featureFlags.assert_camera_projection_near_far)
+            << "Camera preconditions not met in setCustomEyeProjection(): far <= near, near="
+            << near << ", far=" << far;
 
     FILAMENT_CHECK_PRECONDITION(count >= config.stereoscopicEyeCount)
             << "All eye projections must be supplied together, count must be >= "
diff --git a/filament/src/details/Engine.h b/filament/src/details/Engine.h
index 91c9d35e98..ecf29a4619 100644
--- a/filament/src/details/Engine.h
+++ b/filament/src/details/Engine.h
@@ -778,6 +778,7 @@ public:
                 bool assert_material_instance_texture_descriptor_set_compatible =
                         CORRECTNESS_ASSERTION_DEFAULT;
                 bool assert_texture_can_generate_mipmap = CORRECTNESS_ASSERTION_DEFAULT;
+                bool assert_camera_projection_near_far = CORRECTNESS_ASSERTION_DEFAULT;
             } debug;
             struct {
                 bool disable_gpu_frame_complete_metric = false;
@@ -847,6 +848,9 @@ public:
             { "engine.debug.assert_texture_can_generate_mipmap",
               "Assert if a texture has the correct usage set for generating mipmaps.",
               &features.engine.debug.assert_texture_can_generate_mipmap, false },
+            { "engine.debug.assert_camera_projection_near_far",
+              "Assert that the near plane is smaller than the far plane.",
+              &features.engine.debug.assert_camera_projection_near_far, false },
             { "material.check_crc32_after_loading",
               "Verify the checksum of package data when a material is loaded.",
               &features.material.check_crc32_after_loading, false },