Route paint UI clear state through GL backend

docs/modernization/roadmap.md

@@ -1110,17 +1110,20 @@ Legacy `util.cpp` OpenGL error naming and `gl_state` save/restore now delegate
 error codes, state queries, framebuffer targets, texture binding targets, and
 active texture units to `pp_renderer_gl`.
 `NodeStrokePreview` brush preview rendering now delegates depth/scissor/blend
-state, viewport/clear-color queries, active texture unit execution, fallback
-2D texture unbinds, 2D texture targets, copy targets, sampler filters/wraps,
-and destination-feedback copy/fetch decisions to `pp_renderer_gl` and
-`pp_paint_renderer`. Its live stroke-mixer and brush-preview viewport,
-scissor, and depth/blend state changes now also execute through tested
-`pp_renderer_gl` dispatch with only local OpenGL adapter endpoints retained.
+state, tested viewport/clear-color query dispatch, clear-color restore, active
+texture unit execution, fallback 2D texture unbinds, 2D texture targets, copy
+targets, sampler filters/wraps, and destination-feedback copy/fetch decisions
+to `pp_renderer_gl` and `pp_paint_renderer`. Its live stroke-mixer and
+brush-preview viewport, scissor, and depth/blend state changes now also
+execute through tested `pp_renderer_gl` dispatch with only local OpenGL adapter
+endpoints retained.
 Retained `Canvas` stroke/thumbnail/object/export paths and `NodeCanvas`
 panorama rendering use the same tested active-texture dispatch for their
 texture-unit switches, and their live viewport, scissor, and generic
 depth/blend/scissor capability changes now route through the same backend
-dispatch contracts.
+dispatch contracts. `NodeCanvas` saved viewport/clear-color query, density
+target color clear, and clear-color restore paths also use tested
+`pp_renderer_gl` dispatch helpers.
 Desktop HMD eye rendering now routes eye framebuffer viewport changes through
 the tested `pp_renderer_gl` viewport dispatch while platform VR SDK bridges
 remain isolated for later platform-shell extraction.
@@ -2027,11 +2030,13 @@ Results:
   renderer GL backend mapping. The retained canvas-tip pick readback remains
   direct legacy OpenGL until the readback boundary is finished under DEBT-0036.
 - `NodeCanvas` panorama UI rendering now routes sampler defaults, saved
-  viewport/clear/blend/depth/scissor state, color clears, active texture units,
+  viewport/clear/blend/depth/scissor state, tested viewport and clear-color
+  query dispatch, color clears, clear-color restore, active texture units,
   fallback 2D texture unbinds, 2D framebuffer-to-texture copy dispatch, and
   RGBA8 render-target formats through the renderer GL backend mapping.
-  Its live viewport and generic blend/depth/scissor capability changes now
-  execute through tested `pp_renderer_gl` dispatch adapters.
+  Its live viewport, generic blend/depth/scissor capability changes, and
+  density/offscreen color-buffer clears now execute through tested
+  `pp_renderer_gl` dispatch adapters.
 - Canvas resource setup now routes stroke-buffer RGBA8/RGBA16F/RGBA32F
   formats, flood-fill texture upload format/type, brush/stencil/mix sampler
   filters and wraps, and cube-strip import channel formats through the renderer
@@ -2066,6 +2071,10 @@ Results:
   `NodeBorder`, `NodeImage`, `NodeImageTexture`, `NodeColorWheel`,
   `NodeAnimationTimeline`, `NodeScroll`, `NodeText`, `NodeTextInput`, and
   `NodeViewport` without changing their legacy draw ordering.
+- Retained paint UI surface paths now use tested `pp_renderer_gl` viewport
+  query, clear-color query, clear-color restore, and color-buffer clear helpers
+  in `NodeCanvas` and `NodeStrokePreview`, removing direct query/clear calls
+  from those draw bodies while keeping their legacy compositing order.
 - Canvas draw-merge shader-blend selection now consumes the extracted
   `pp_paint_renderer` stroke composite planner for current layer and primary
   brush blend modes, while preserving legacy OpenGL compositing execution under