- DagStep: preview_open flag (default false).
- dag_compile: emit `uniform int u_preview_target` and a series of
early-return branches at the start of fragColor selection. -1 (default)
falls through to the real Output-driven fragColor.
- dag_node_previews (new fn): per-node FBO keyed by editor_uid, lazy
created. Renders each node with preview_open=true to its FBO by
setting u_preview_target = step index. Texture exposed via
dag_preview_texture(uid) for ImGui::Image.
- dag_node_editor: small toggle button "[+] preview"/"[-] preview" in
each non-Output node; when open, ImGui::Image(96x64, V-flipped).
- dag_node_editor: double right-click on hovered node deletes it
(Output is protected).
- main.cpp: dag_previews_render after Canvas DAG; dag_previews_destroy
on shutdown.
Single GL program drives both the canvas and all thumbnails — moving
sliders never recompiles, only the topology change does.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
egutierrez
ac65791663