Make meshoptim optional

src/ifcviewer/CMakeLists.txt

@@ -26,7 +26,6 @@ set(QT_VERSION 6 CACHE STRING "Qt version")
 find_package(Qt${QT_VERSION} COMPONENTS Core Gui Widgets OpenGL REQUIRED PATHS ${QT_DIR})
 
 find_package(OpenGL REQUIRED)
-find_package(meshoptimizer REQUIRED)
 
 file(GLOB IFCVIEWER_CPP_FILES ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp)
 file(GLOB IFCVIEWER_H_FILES ${CMAKE_CURRENT_SOURCE_DIR}/*.h)
@@ -40,6 +39,12 @@ set_target_properties(IfcViewer PROPERTIES
     SOVERSION "${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}"
 )
 
+if (WITH_MESH_OPTIMIZER)
+find_package(meshoptimizer REQUIRED)
+set(MESH_OPTIMIZER_LIB meshoptimizer::meshoptimizer)
+target_compile_definitions(IfcViewer PUBLIC -DWITH_MESH_OPTIMIZER)
+endif()
+
 # Consumers include headers as `#include "ViewportWindow.h"`, so expose this
 # directory on the public interface.
 target_include_directories(IfcViewer PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
@@ -57,7 +62,7 @@ target_link_libraries(IfcViewer PUBLIC
     Qt${QT_VERSION}::Widgets
     Qt${QT_VERSION}::OpenGL
     OpenGL::GL
-    meshoptimizer::meshoptimizer
+    ${MESH_OPTIMIZER_LIB}
 )
 
 if(UNIX AND NOT APPLE)

src/ifcviewer/LodBuilder.cpp

@@ -19,7 +19,9 @@
 
 #include "LodBuilder.h"
 
+#ifdef WITH_MESH_OPTIMIZER
 #include <meshoptimizer.h>
+#endif
 
 #include <algorithm>
 #include <cstdio>
@@ -31,6 +33,13 @@ void buildLods(SidecarData& sd,
                int min_triangles,
                float target_ratio,
                float target_error) {
+#ifndef WITH_MESH_OPTIMIZER
+    (void)sd;
+    (void)min_triangles;
+    (void)target_ratio;
+    (void)target_error;
+    return;
+#else
     if (sd.meshes.empty() || sd.vertices.empty() || sd.indices.empty()) return;
 
     const size_t vtx_stride_bytes   = INSTANCED_VERTEX_STRIDE_BYTES;
@@ -165,6 +174,7 @@ void buildLods(SidecarData& sd,
             dbg_accepted, dbg_rejected_noreduce, dbg_rejected_savings,
             target_error, target_ratio, min_savings);
     }
+#endif
 }
 
 LodStats summariseLods(const SidecarData& sd) {