Fix T52299: X resolution of 4 causes nodes to collapse

Was caused by numeric overflow when calculating preview dimensions.
Now we try to avoid really insance preview resolutions by fitting
aspect into square.

1 files changed, 14 insertions, 2 deletions

diff --git a/source/blender/compositor/intern/COM_compositor.cpp b/source/blender/compositor/intern/COM_compositor.cpp
index e3dfd69d8ec..40db5efda27 100644
--- a/source/blender/compositor/intern/COM_compositor.cpp
+++ b/source/blender/compositor/intern/COM_compositor.cpp
@@ -64,9 +64,21 @@ void COM_execute(RenderData *rd, Scene *scene, bNodeTree *editingtree, int rende
 	/* Make sure node tree has previews.
 	 * Don't create previews in advance, this is done when adding preview operations.
 	 * Reserved preview size is determined by render output for now.
+	 *
+	 * We fit the aspect into COM_PREVIEW_SIZE x COM_PREVIEW_SIZE image to avoid
+	 * insane preview resolution, which might even overflow preview dimensions.
 	 */
-	float aspect = rd->xsch > 0 ? (float)rd->ysch / (float)rd->xsch : 1.0f;
-	BKE_node_preview_init_tree(editingtree, COM_PREVIEW_SIZE, (int)(COM_PREVIEW_SIZE * aspect), false);
+	const float aspect = rd->xsch > 0 ? (float)rd->ysch / (float)rd->xsch : 1.0f;
+	int preview_width, preview_height;
+	if (aspect < 1.0f) {
+		preview_width = COM_PREVIEW_SIZE;
+		preview_height = (int)(COM_PREVIEW_SIZE * aspect);
+	}
+	else {
+		preview_width = (int)(COM_PREVIEW_SIZE / aspect);
+		preview_height = COM_PREVIEW_SIZE;
+	}
+	BKE_node_preview_init_tree(editingtree, preview_width, preview_height, false);
 
 	/* initialize workscheduler, will check if already done. TODO deinitialize somewhere */
 	bool use_opencl = (editingtree->flag & NTREE_COM_OPENCL) != 0;