Route framebuffer texture copies through GL backend

docs/modernization/build-inventory.md

@@ -292,7 +292,11 @@ Known local toolchain state:
   clear-mask and clear-value mapping, and color-write-mask query tokens. `RTT` no longer
   spells GL enum names directly. `RTT` also exposes a retained RGBA8
   region-readback helper that uses the tested framebuffer readback dispatch for
-  canvas pick/history/snapshot and transform history paths. It also
+  canvas pick/history/snapshot and transform history paths. 2D
+  framebuffer-to-texture copies used by retained canvas, transform,
+  layer-conversion, panorama UI, and brush-preview paths now execute through a
+  tested `pp_renderer_gl` dispatch via `copy_framebuffer_to_texture_2d`; the
+  retained cube-map framebuffer copy remains tracked by `DEBT-0036`. It also
   validates renderer API primitive-topology to OpenGL draw-mode mapping, Shape
   index-type, fill/stroke primitive-mode, buffer target, static upload usage,
   and vertex attribute component/normalization mapping used by
@@ -414,12 +418,12 @@ Known local toolchain state:
   Early canvas draw helpers also consume backend-owned pick readback
   format/type and RTT-backed region-readback execution, stroke mixer
   depth/scissor/blend state, saved viewport and clear-state queries, active
-  texture units, fallback 2D texture unbind targets, and stroke background copy
-  targets.
+  texture units, fallback 2D texture unbind targets, and stroke background
+  framebuffer-copy dispatch.
   Canvas stroke commit also consumes backend-owned saved viewport/clear/blend
   state, history readback format/type and RTT-backed region-readback execution,
   active texture units, fallback 2D texture unbind targets, and layer
-  compositing copy targets.
+  compositing framebuffer-copy dispatch.
   Canvas layer merge rendering and explicit layer-merge compositing also consume
   backend-owned depth/blend state, active texture units, fallback 2D texture
   unbind targets, and merge framebuffer copy targets.
@@ -615,7 +619,8 @@ Known local toolchain state:
   consumed by the retained `gl_state` utility, tested texture lifecycle/readback dispatch consumed by
   the retained `Texture2D` utility, tested framebuffer blit/readback dispatch
   consumed by retained `RTT` resize/copy/readback and RGBA8 region-readback
-  paths, tested framebuffer
+  paths, tested framebuffer-to-texture 2D copy dispatch consumed by retained
+  canvas/UI paint paths, tested framebuffer
   bind/restore dispatch consumed by retained `RTT` render-target pass entry
   and exit paths, tested depth renderbuffer allocation/delete and framebuffer
   depth attach/detach dispatch consumed by canvas object-drawing helpers,

docs/modernization/debt.md

@@ -53,7 +53,7 @@ agent or engineer to remove them without reconstructing context from chat.
 | DEBT-0033 | Open | Modernization | Tools menu planning and direct command execution dispatch now consume pure `pp_app_core` through `App::init_menu_tools`, `pano_cli plan-tools-menu`, `pano_cli plan-tools-panel`, and the `ToolsMenuServices` boundary, and direct command execution is centralized in `src/legacy_app_shell_services.*`; SonarPen availability/startup now routes through `PlatformServices`, but live adapters still construct legacy `NodePanelFloating` panels, mutate legacy panel nodes, clear `CanvasModeGrid`, reset `NodeCanvas` camera state, open legacy shortcuts UI, and rely on the legacy platform adapter for the retained iOS SonarPen bridge | Preserve current Tools menu behavior while UI shell actions move toward app/UI/platform services | `pp_app_core_tools_menu_tests`; `pp_platform_api_tests`; `pano_cli plan-tools-menu --command shortcuts`; `pano_cli plan-tools-panel --panel layers`; `pano_cli plan-tools-panel --panel animation --already-visible`; `ctest --preset desktop-fast --build-config Debug` | Tools panel creation, submenu routing, grid clear, camera reset, shortcuts dialog, and SonarPen dispatch are owned by injected app/UI/platform services with `App::init_menu_tools` acting only as a UI adapter and no legacy Tools adapter |
 | DEBT-0034 | Open | Modernization | About menu command planning and execution dispatch now consume pure `pp_app_core` through `App::init_menu_about`, `pano_cli plan-about-menu`, and the `AboutMenuServices` boundary, and live execution is centralized in `src/legacy_app_shell_services.*`, but the bridge still opens legacy About/manual/what's-new dialogs, invokes the injected crash hook, and runs the legacy Canvas stroke performance test directly | Preserve About menu behavior while dialogs and diagnostics move toward app/UI/platform services | `pp_app_core_about_menu_tests`; `pano_cli plan-about-menu --command news --version-major 2 --version-minor 5 --version-fix 7`; `pano_cli plan-about-menu --command performance --no-canvas`; `ctest --preset desktop-fast --build-config Debug` | About/manual/what's-new dialog dispatch, crash-test dispatch, and performance-test execution are owned by injected app/UI/platform services with `App::init_menu_about` acting only as a UI adapter and no legacy About adapter |
 | DEBT-0035 | Open | Modernization | Main toolbar/status command planning and execution dispatch now consume pure `pp_app_core` through `App::init_toolbar_main`, `pano_cli plan-main-toolbar`, and the `MainToolbarServices` boundary, history/canvas commands now hand off through `HistoryUiServices` and `DocumentCanvasClearServices`, and live execution is centralized in `src/legacy_app_shell_services.*`, but the bridge still opens legacy open/save/settings/message-box dialogs and delegates to legacy history/canvas adapters | Preserve reachable toolbar/status behavior while app shell commands move toward app/document/UI services | `pp_app_core_main_toolbar_tests`; `pano_cli plan-main-toolbar --command undo --undo-count 2`; `pano_cli plan-main-toolbar --command clear-canvas --no-canvas`; `ctest --preset desktop-fast --build-config Debug` | Open/save/settings/message-box routing, undo/redo/clear-history execution, and canvas-clear execution are owned by injected app/document/UI services with `App::init_toolbar_main` acting only as a UI adapter and no legacy toolbar adapter |
-| DEBT-0036 | Open | Modernization | `pp_renderer_api`, `pp_paint_renderer`, `pano_cli plan-paint-feedback`, and `pano_cli plan-stroke-composite` can choose backend-neutral complex paint feedback strategies for fixed-function blending, framebuffer-fetch-capable renderers, or ping-pong render targets. OpenGL extension detection now stores `pp::renderer::RenderDeviceFeatures` through `ShaderManager`, using `pp_renderer_gl::query_opengl_capability_detection`, `detect_opengl_feature_state`, and `render_device_features` as the backend conversion point; that feature snapshot now includes float32-linear filtering, so canvas stroke texture format selection, renderer diagnostics, grid lightmap render planning, and grid bake target selection no longer read `ShaderManager::ext_*` flags directly. `pp_paint_renderer::plan_canvas_blend_gate` owns the compatibility mapping from persisted layer/brush blend indices to the extracted stroke-composite planner, and live `Canvas::draw_merge` plus `NodeCanvas` panorama rendering both call it with the stored renderer-neutral feature set for their existing shader-blend gates and destination-copy versus framebuffer-fetch decisions. `pp_paint_renderer::plan_canvas_stroke_feedback` also owns the current destination-feedback decision, and live `Canvas::stroke_draw`, thumbnail layer blending, and `NodeStrokePreview` brush-preview rendering use it for framebuffer-fetch versus destination-copy decisions. Actual live stroke rasterization, dual-brush compositing, pattern feedback math, thumbnail layer compositing, brush-preview compositing, and the retained `ShaderManager::ext_*` compatibility fields still use legacy OpenGL canvas/UI execution | Preserve current painting behavior while the renderer boundary matures for OpenGL parity and later Vulkan/Metal experiments | `pp_renderer_api_tests`; `pp_renderer_gl_capabilities_tests`; `pp_paint_renderer_compositor_tests`; `pano_cli plan-paint-feedback --framebuffer-fetch --explicit-transitions --render-only`; `pano_cli plan-paint-feedback --texture-copy`; `pano_cli plan-stroke-composite --stroke-blend 10 --framebuffer-fetch --explicit-transitions --render-only`; `pano_cli plan-stroke-composite --layer-blend 4 --dual-blend --texture-copy`; `ctest --preset desktop-fast --build-config Debug`; `cmake --build --preset windows-msvc-default --config Debug --target PanoPainter` | Live stroke/layer compositing chooses its feedback path through `pp_paint_renderer` and renderer services, with OpenGL golden parity and Vulkan/Metal lab tests covering framebuffer-fetch and ping-pong behavior |
+| DEBT-0036 | Open | Modernization | `pp_renderer_api`, `pp_paint_renderer`, `pano_cli plan-paint-feedback`, and `pano_cli plan-stroke-composite` can choose backend-neutral complex paint feedback strategies for fixed-function blending, framebuffer-fetch-capable renderers, or ping-pong render targets. OpenGL extension detection now stores `pp::renderer::RenderDeviceFeatures` through `ShaderManager`, using `pp_renderer_gl::query_opengl_capability_detection`, `detect_opengl_feature_state`, and `render_device_features` as the backend conversion point; that feature snapshot now includes float32-linear filtering, so canvas stroke texture format selection, renderer diagnostics, grid lightmap render planning, and grid bake target selection no longer read `ShaderManager::ext_*` flags directly. `pp_paint_renderer::plan_canvas_blend_gate` owns the compatibility mapping from persisted layer/brush blend indices to the extracted stroke-composite planner, and live `Canvas::draw_merge` plus `NodeCanvas` panorama rendering both call it with the stored renderer-neutral feature set for their existing shader-blend gates and destination-copy versus framebuffer-fetch decisions. `pp_paint_renderer::plan_canvas_stroke_feedback` also owns the current destination-feedback decision, and live `Canvas::stroke_draw`, thumbnail layer blending, and `NodeStrokePreview` brush-preview rendering use it for framebuffer-fetch versus destination-copy decisions. The retained `copy_framebuffer_to_texture_2d` utility bridge now routes 2D framebuffer-to-texture copies through tested `pp_renderer_gl` dispatch, but actual live stroke rasterization, dual-brush compositing, pattern feedback math, thumbnail layer compositing, brush-preview compositing, the retained cube-map framebuffer copy, and the retained `ShaderManager::ext_*` compatibility fields still use legacy OpenGL canvas/UI execution | Preserve current painting behavior while the renderer boundary matures for OpenGL parity and later Vulkan/Metal experiments | `pp_renderer_api_tests`; `pp_renderer_gl_capabilities_tests`; `pp_paint_renderer_compositor_tests`; `pano_cli plan-paint-feedback --framebuffer-fetch --explicit-transitions --render-only`; `pano_cli plan-paint-feedback --texture-copy`; `pano_cli plan-stroke-composite --stroke-blend 10 --framebuffer-fetch --explicit-transitions --render-only`; `pano_cli plan-stroke-composite --layer-blend 4 --dual-blend --texture-copy`; `ctest --preset desktop-fast --build-config Debug`; `cmake --build --preset windows-msvc-default --config Debug --target PanoPainter` | Live stroke/layer compositing chooses its feedback path through `pp_paint_renderer` and renderer services, with OpenGL golden parity and Vulkan/Metal lab tests covering framebuffer-fetch and ping-pong behavior |
 | DEBT-0037 | Open | Modernization | Recording lifecycle/export planning and execution dispatch now consume pure `pp_app_core` through `App::rec_start`, `App::rec_stop`, `App::rec_clear`, `App::rec_export`, `pano_cli plan-recording-session`, and the `RecordingServices` boundary; live execution is centralized in `src/legacy_recording_services.*`, but the bridge still owns legacy recording thread startup/shutdown, platform recorded-file cleanup, progress UI, PBO readback through `App::rec_loop`, and `MP4Encoder::write_mp4` execution | Preserve current timelapse/MP4 behavior while recording moves toward app/document/renderer/video services | `pp_app_core_document_recording_tests`; `pano_cli plan-recording-session --running --frame-count 12`; `pano_cli plan-recording-session --platform-clears-files`; `ctest --preset desktop-fast --build-config Debug` | Recording thread lifecycle, frame readback, platform cleanup, progress reporting, and MP4 writing are owned by injected app/renderer/video services with `App` methods acting only as adapters |
 | DEBT-0038 | Open | Modernization | Cloud upload/browse/bulk planning and execution dispatch now consume pure `pp_app_core` through `App::cloud_upload`, `App::cloud_upload_all`, `App::cloud_browse`, `pano_cli plan-cloud-upload`, `pano_cli plan-cloud-upload-all`, `pano_cli plan-cloud-browse`, and the `CloudServices` boundary; live execution is centralized in `src/legacy_cloud_services.*`, the app-owned `upload`/`download`/license curl helpers now ask `PlatformServices` for the Android TLS-verification bypass policy, and retained `Asset::open_url`, `LogRemote::net_init`, and `NodeDialogCloud::load_thumbs_thread` curl sites consume the `pp_platform_api` default TLS policy helper instead of spelling Android branches locally, but the bridge still uses legacy save-before-upload, app-owned curl helpers instead of an injected network service, progress/message UI, OpenGL context guarding, `NodeDialogCloud`, `Canvas` project open, layer refresh, and `ActionManager` reset | Preserve current cloud behavior while cloud/network/document import flows move toward app/document/platform services | `pp_app_core_document_cloud_tests`; `pp_platform_api_tests`; `pano_cli plan-cloud-upload --new-document --unsaved`; `pano_cli plan-cloud-browse --selected-file demo.ppi`; `pano_cli plan-cloud-upload-all --file-count 3`; `ctest --preset desktop-fast --build-config Debug` | Cloud upload/download, TLS policy, save-before-upload, progress reporting, cloud browse dialog, downloaded project opening, layer refresh, OpenGL context ownership, and action-history reset are owned by injected app/document/network/platform/renderer services with `App` methods acting only as adapters |
 | DEBT-0039 | Open | Modernization | Document-open planning and execution dispatch now consume pure `pp_app_core` through `App::open_document`, `pano_cli plan-open-route`, `DocumentOpenServices`, and `src/legacy_document_open_services.*`, but the bridge still opens ABR/PPBR import prompts before delegating import execution to `src/legacy_brush_package_import_services.*`, applies unsaved-project discard prompts, calls legacy project-open execution, refreshes layer UI, updates the app title, and clears legacy history directly | Preserve current file-open/import behavior while document loading and brush import move toward app/document/asset/UI services | `pp_app_core_document_route_tests`; `pp_app_core_document_session_tests`; `pano_cli plan-open-route --path D:/Paint/Scenes/demo.ppi --unsaved`; `pano_cli plan-open-route --path D:/Paint/Brushes/clouds.ABR --unsaved`; `ctest --preset desktop-fast --build-config Debug` | Brush import prompting, project-open execution, unsaved-project discard prompting, layer refresh, title updates, and history clearing are owned by injected app/document/asset/UI services with `App::open_document` acting only as an adapter |

docs/modernization/roadmap.md

@@ -1005,7 +1005,11 @@ framebuffer targets, binding queries, attachment points, and completion status
 used by `RTT::create` and framebuffer bind/restore paths, also live in
 `pp_renderer_gl`. Depth renderbuffer allocation/storage/delete and framebuffer
 depth attach/detach sequences used by canvas object-drawing helpers now execute
-through tested `pp_renderer_gl` dispatch contracts. RTT clear color/depth masks, renderer API render-pass
+through tested `pp_renderer_gl` dispatch contracts. 2D framebuffer-to-texture
+copies used by canvas, transform, layer-conversion, panorama UI, and brush
+preview paths now route through a tested `pp_renderer_gl` copy dispatch via the
+retained `copy_framebuffer_to_texture_2d` utility bridge; the remaining cube-map
+copy is tracked under `DEBT-0036`. RTT clear color/depth masks, renderer API render-pass
 color/depth/stencil clear-mask and clear-value mapping, and color-write-mask query tokens also
 live in `pp_renderer_gl`. `RTT` no longer spells GL enum names directly.
 Renderer API primitive-topology to OpenGL draw-mode mapping, mesh index-type
@@ -1979,13 +1983,13 @@ Results:
   and fallback 2D texture unbinds through the renderer GL backend mapping;
   platform VR SDK bridges remain isolated for later platform-shell extraction.
 - Canvas mode overlay, mask, and transform paths now route generic OpenGL
-  blend/depth state, active texture units, 2D copy targets, RGBA8 readback
-  formats, and RTT-backed transform history region readbacks through the
-  renderer GL backend mapping.
+  blend/depth state, active texture units, 2D framebuffer-to-texture copy
+  dispatch, RGBA8 readback formats, and RTT-backed transform history region
+  readbacks through the renderer GL backend mapping.
 - `NodeCanvas` panorama UI rendering now routes sampler defaults, saved
   viewport/clear/blend/depth/scissor state, color clears, active texture units,
-  fallback 2D texture unbinds, copy targets, and RGBA8 render-target formats
-  through the renderer GL backend mapping.
+  fallback 2D texture unbinds, 2D framebuffer-to-texture copy dispatch, and
+  RGBA8 render-target formats through the renderer GL backend mapping.
 - 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
@@ -1999,7 +2003,9 @@ Results:
   readbacks, active texture units, fallback 2D texture unbinds, and layer
   compositing copy targets through the renderer GL backend mapping; the
   RTT-backed dirty-region readbacks now execute through the retained `RTT`
-  region-readback helper rather than direct `glReadPixels`.
+  region-readback helper rather than direct `glReadPixels`, and 2D framebuffer
+  copies now execute through the retained utility bridge instead of direct
+  `glCopyTexSubImage2D`.
 - Canvas layer merge rendering and explicit layer-merge compositing now route
   depth/blend state, active texture units, fallback 2D texture unbinds, and
   merge framebuffer copy targets through the renderer GL backend mapping.