Fix crash when using the Image graph node with an empty image

doc/source/changelog.md

@@ -29,6 +29,7 @@ Primarily developped with Godot 4.3.
         - Fixed wrong values when using `OutputWeight` with optimized execution map enabled, when weights are determined to be locally constant
         - Fixed occasional holes in terrain when using `FastNoise3D` nodes with the `OpenSimplex2S` noise type
         - Fixed shader generation error when using the `Distance3D` node (vec2 instead of vec3, thanks to scwich)
+        - Fixed crash when assigning an empty image to the `Image` node
     - `VoxelMesherTransvoxel`: revert texturing logic that attempted to prevent air voxels from contributing, but was lowering quality. It is now optional as an experimental property.
     - `VoxelStreamSQLite`: Fixed "empty size" errors when loading areas with edited `VoxelInstancer` data
     - `.vox` scene importer: disabled threaded import to workaround the editor freezing when saving meshes

generators/graph/image_range_grid.cpp

@@ -23,6 +23,10 @@ void ImageRangeGrid::generate(const Image &im) {
 
 	clear();
 
+	if (im.is_empty()) {
+		return;
+	}
+
 	const int lod_base = 4; // Start at 16
 
 	// Compute first lod

generators/graph/nodes/image.h

@@ -148,6 +148,10 @@ void register_image_nodes(Span<NodeType> types) {
 									   .format(varray(Image::get_class_static())));
 				return;
 			}
+			if (image->is_empty()) {
+				ctx.make_error(String(ZN_TTR("{0} is empty").format(varray(Image::get_class_static()))));
+				return;
+			}
 			ImageRangeGrid *im_range = ZN_NEW(ImageRangeGrid);
 			im_range->generate(**image);
 			Params p;
@@ -167,6 +171,12 @@ void register_image_nodes(Span<NodeType> types) {
 			// Cache image size to reduce API calls in GDExtension
 			const int w = im.get_width();
 			const int h = im.get_height();
+#ifdef DEBUG_ENABLED
+			if (w == 0 || h == 0) {
+				ZN_PRINT_ERROR_ONCE("Image is empty");
+				return;
+			}
+#endif
 			// TODO Optimized path for most used formats, `get_pixel` is kinda slow
 			if (p.filter == FILTER_NEAREST) {
 				for (uint32_t i = 0; i < out.size; ++i) {

generators/graph/voxel_generator_graph.cpp

@@ -1665,7 +1665,7 @@ VoxelSingleValue VoxelGeneratorGraph::generate_single(Vector3i position, unsigne
 			RWLockRead rlock(_runtime_lock);
 			runtime_ptr = _runtime;
 		}
-		ERR_FAIL_COND_V(runtime_ptr == nullptr, v);
+		ERR_FAIL_COND_V_MSG(runtime_ptr == nullptr, v, "no compiled graph available");
 		if (runtime_ptr->sdf_output_buffer_index == -1) {
 			return v;
 		}
@@ -1688,7 +1688,7 @@ VoxelSingleValue VoxelGeneratorGraph::generate_single(Vector3i position, unsigne
 			RWLockRead rlock(_runtime_lock);
 			runtime_ptr = _runtime;
 		}
-		ERR_FAIL_COND_V(runtime_ptr == nullptr, v);
+		ERR_FAIL_COND_V_MSG(runtime_ptr == nullptr, v, "no compiled graph available");
 		if (runtime_ptr->single_texture_output_buffer_index == -1) {
 			return v;
 		}

tests/tests.cpp

@@ -90,6 +90,7 @@ void run_voxel_tests() {
 	VOXEL_TEST(test_voxel_graph_many_weight_outputs);
 	VOXEL_TEST(test_voxel_graph_many_subdivisions);
 	VOXEL_TEST(test_voxel_graph_non_square_image);
+	VOXEL_TEST(test_voxel_graph_empty_image);
 	VOXEL_TEST(test_voxel_graph_4_default_weights);
 	VOXEL_TEST(test_island_finder);
 	VOXEL_TEST(test_unordered_remove_if);

tests/voxel/test_voxel_graph.cpp

@@ -2329,4 +2329,33 @@ void test_voxel_graph_4_default_weights() { // Related to issue #686
 	L::test(0.5, 0.2, 0.4, 0.8);
 }
 
+void test_voxel_graph_empty_image() {
+	// This used to crash
+
+	Ref<VoxelGeneratorGraph> generator;
+	generator.instantiate();
+
+	VoxelGraphFunction &g = **generator->get_main_function();
+
+	const uint32_t n_x = g.create_node(VoxelGraphFunction::NODE_INPUT_X);
+	const uint32_t n_z = g.create_node(VoxelGraphFunction::NODE_INPUT_Z);
+	const uint32_t n_image = g.create_node(VoxelGraphFunction::NODE_IMAGE_2D);
+	const uint32_t n_out_sdf = g.create_node(VoxelGraphFunction::NODE_OUTPUT_SDF);
+
+	Ref<Image> image;
+	image.instantiate();
+	g.set_node_param(n_image, 0, image);
+
+	g.add_connection(n_x, 0, n_image, 0);
+	g.add_connection(n_z, 0, n_image, 1);
+	g.add_connection(n_image, 0, n_out_sdf, 0);
+
+	CompilationResult result = generator->compile(false);
+
+	// Try to generate before asserting compilation result. It should fail without crashing.
+	generator->generate_single(Vector3i(405, 2, 305), VoxelBuffer::CHANNEL_SDF);
+
+	ZN_TEST_ASSERT(result.success == false);
+}
+
 } // namespace zylann::voxel::tests

tests/voxel/test_voxel_graph.h

@@ -36,6 +36,7 @@ void test_image_range_grid();
 void test_voxel_graph_many_subdivisions();
 void test_voxel_graph_non_square_image();
 void test_voxel_graph_4_default_weights();
+void test_voxel_graph_empty_image();
 
 } // namespace zylann::voxel::tests
 

util/io/log.h

@@ -13,6 +13,15 @@
 #define ZN_PRINT_WARNING(msg) zylann::print_warning(msg, __FUNCTION__, __FILE__, __LINE__)
 #define ZN_PRINT_ERROR(msg) zylann::print_error(msg, __FUNCTION__, __FILE__, __LINE__)
 
+#define ZN_PRINT_ERROR_ONCE(msg)                                                                                       \
+	{                                                                                                                  \
+		static bool s_first_print = true;                                                                              \
+		if (s_first_print) {                                                                                           \
+			s_first_print = false;                                                                                     \
+			zylann::print_error(msg, __FUNCTION__, __FILE__, __LINE__);                                                \
+		}                                                                                                              \
+	}
+
 namespace zylann {
 
 bool is_verbose_output_enabled();