Route canvas clear state through GL backend

docs/modernization/build-inventory.md

@@ -395,10 +395,13 @@ Known local toolchain state:
   panorama rendering use the same tested active-texture dispatch for
   texture-unit switches, and their live viewport, scissor, and generic
   depth/blend/scissor capability changes now route through the same backend
-  dispatch contracts. `NodeCanvas` saved viewport/clear-color query,
+  dispatch contracts. Retained `Canvas` stroke draw/commit, thumbnail
-  density/offscreen color clear, and clear-color restore paths also use tested
+  generation, object rendering, and `LayerFrame::clear` saved viewport or
-  `pp_renderer_gl` dispatch helpers. Retained desktop HMD eye rendering also
+  clear-color query plus clear-color restore paths also use tested
-  routes viewport execution through tested backend dispatch.
+  `pp_renderer_gl` dispatch helpers. `NodeCanvas` saved viewport/clear-color
+  query, density/offscreen color clear, and clear-color restore paths use the
+  same helpers. Retained desktop HMD eye rendering also routes viewport
+  execution through tested backend dispatch.
   Legacy `Texture2D`, `TextureManager`, `Sampler`, and `RTT` public headers no
   longer expose raw OpenGL enum defaults; default texture formats, sampler
   filters/wraps, and render-target formats resolve through backend-owned
@@ -658,7 +661,8 @@ Known local toolchain state:
   tested viewport/scissor/capability dispatch consumed by retained Canvas,
   NodeCanvas, NodeStrokePreview, and HMD render-state paths,
   tested viewport query, clear-color query, and clear-color restore dispatch
-  consumed by retained `NodeCanvas` and `NodeStrokePreview` draw-state paths,
+  consumed by retained `Canvas`, `CanvasLayer`, `NodeCanvas`, and
+  `NodeStrokePreview` draw-state paths,
   tested color-write-mask dispatch consumed by retained `NodePanelGrid`
   transparent heightmap rendering,
   tested pixel-buffer allocation/readback/map/unmap/delete dispatch

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. The retained `copy_framebuffer_to_texture_2d` utility bridge now routes 2D framebuffer-to-texture copies through tested `pp_renderer_gl` dispatch, retained `RTT::create`/`RTT::destroy` render-target texture parameter setup, optional depth renderbuffer allocation, framebuffer allocation/attachment/status checks, binding restore, and resource deletion now route through tested `pp_renderer_gl` dispatch, retained RTT clear, masked clear with color-write-mask restore, and texture bind/unbind now route through tested `pp_renderer_gl` dispatch, retained Canvas, NodeCanvas, and NodeStrokePreview texture-unit switches now route through tested active-texture dispatch, retained Canvas, NodeCanvas, NodeStrokePreview, and desktop HMD viewport/scissor/capability execution now route through tested `pp_renderer_gl` dispatch adapters, CanvasLayer cube/equirect generation plus frame clears now route blend state, active texture units, viewport execution, color clears, and cube-face framebuffer-to-texture copies through tested `pp_renderer_gl` dispatch adapters, `NodePanelGrid` live heightmap draw and bake setup now route depth/blend state, depth clears, color-write-mask toggles, active texture selection, and bake viewport execution through tested `pp_renderer_gl` dispatch adapters, retained CanvasMode overlay/mask/transform paths now route active texture, depth/blend state, and transform/cut viewport execution through tested `pp_renderer_gl` dispatch adapters while the retained canvas-tip pick readback remains direct legacy OpenGL, retained simple UI draw paths now share `legacy_ui_gl_dispatch` for blend-state execution, fallback 2D texture unbinds, `NodeViewport` viewport query/restore, color-buffer clears, and clear-color restore, and retained `NodeCanvas` plus `NodeStrokePreview` draw-state paths now route viewport query, clear-color query, color-buffer clear, and clear-color restore through tested `pp_renderer_gl` dispatch helpers, but 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, retained `RTT::create`/`RTT::destroy` render-target texture parameter setup, optional depth renderbuffer allocation, framebuffer allocation/attachment/status checks, binding restore, and resource deletion now route through tested `pp_renderer_gl` dispatch, retained RTT clear, masked clear with color-write-mask restore, and texture bind/unbind now route through tested `pp_renderer_gl` dispatch, retained Canvas, NodeCanvas, and NodeStrokePreview texture-unit switches now route through tested active-texture dispatch, retained Canvas, NodeCanvas, NodeStrokePreview, and desktop HMD viewport/scissor/capability execution now route through tested `pp_renderer_gl` dispatch adapters, CanvasLayer cube/equirect generation plus frame clears now route blend state, active texture units, viewport execution, color clears, and cube-face framebuffer-to-texture copies through tested `pp_renderer_gl` dispatch adapters, `NodePanelGrid` live heightmap draw and bake setup now route depth/blend state, depth clears, color-write-mask toggles, active texture selection, and bake viewport execution through tested `pp_renderer_gl` dispatch adapters, retained CanvasMode overlay/mask/transform paths now route active texture, depth/blend state, and transform/cut viewport execution through tested `pp_renderer_gl` dispatch adapters while the retained canvas-tip pick readback remains direct legacy OpenGL, retained simple UI draw paths now share `legacy_ui_gl_dispatch` for blend-state execution, fallback 2D texture unbinds, `NodeViewport` viewport query/restore, color-buffer clears, and clear-color restore, retained `NodeCanvas` plus `NodeStrokePreview` draw-state paths now route viewport query, clear-color query, color-buffer clear, and clear-color restore through tested `pp_renderer_gl` dispatch helpers, and retained `Canvas` plus `CanvasLayer` stroke/object/thumbnail/frame-clear draw-state paths now route saved viewport or clear-color query and restore through the same tested helpers, but 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-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.*`, and retained `PBO` allocation/readback/map/unmap/delete operations now route through tested `pp_renderer_gl` dispatch, but the bridge still owns legacy recording thread startup/shutdown, platform recorded-file cleanup, progress UI, retained `App::rec_loop` readback call sites, 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`; `pp_renderer_gl_capabilities_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 scheduling, 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

@@ -1121,9 +1121,11 @@ 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. `NodeCanvas` saved viewport/clear-color query, density
+dispatch contracts. Retained `Canvas` stroke draw/commit, thumbnail
-target color clear, and clear-color restore paths also use tested
+generation, object drawing, and `LayerFrame::clear` saved viewport/clear-color
-`pp_renderer_gl` dispatch helpers.
+query plus clear-color restore paths also use tested `pp_renderer_gl` dispatch
+helpers. `NodeCanvas` saved viewport/clear-color query, density target color
+clear, and clear-color restore paths use the same 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.
@@ -2075,6 +2077,10 @@ Results:
   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.
+- Retained Canvas stroke draw/commit, thumbnail, object-render, and
+  `LayerFrame::clear` paths now use the same tested backend viewport query,
+  clear-color query, and clear-color restore helpers, removing direct
+  viewport/clear-state queries from `src/canvas.cpp` and the frame clear path.
 - 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

src/canvas.cpp

@@ -7,6 +7,7 @@
 #include "paint_renderer/compositor.h"
 #include "renderer_gl/opengl_capabilities.h"
 #include "util.h"
+#include <array>
 #include <thread>
 #include <algorithm>
 #include <cstdint>
@@ -111,16 +112,6 @@ GLenum unsigned_byte_component_type()
     return static_cast<GLenum>(pp::renderer::gl::unsigned_byte_component_type());
 }
 
-GLenum viewport_query()
-{
-    return static_cast<GLenum>(pp::renderer::gl::viewport_query());
-}
-
-GLenum color_clear_value_query()
-{
-    return static_cast<GLenum>(pp::renderer::gl::color_clear_value_query());
-}
-
 GLenum depth_test_state()
 {
     return static_cast<GLenum>(pp::renderer::gl::depth_test_state());
@@ -213,6 +204,26 @@ void set_opengl_viewport(std::int32_t x, std::int32_t y, std::int32_t width, std
     glViewport(static_cast<GLint>(x), static_cast<GLint>(y), static_cast<GLsizei>(width), static_cast<GLsizei>(height));
 }
 
+void set_opengl_clear_color(float r, float g, float b, float a) noexcept
+{
+    glClearColor(r, g, b, a);
+}
+
+void get_opengl_integer(std::uint32_t name, std::int32_t* values) noexcept
+{
+    GLint raw_values[4] {};
+    glGetIntegerv(static_cast<GLenum>(name), raw_values);
+    values[0] = static_cast<std::int32_t>(raw_values[0]);
+    values[1] = static_cast<std::int32_t>(raw_values[1]);
+    values[2] = static_cast<std::int32_t>(raw_values[2]);
+    values[3] = static_cast<std::int32_t>(raw_values[3]);
+}
+
+void get_opengl_float(std::uint32_t name, float* values) noexcept
+{
+    glGetFloatv(static_cast<GLenum>(name), values);
+}
+
 void set_opengl_scissor(std::int32_t x, std::int32_t y, std::int32_t width, std::int32_t height) noexcept
 {
     glScissor(static_cast<GLint>(x), static_cast<GLint>(y), static_cast<GLsizei>(width), static_cast<GLsizei>(height));
@@ -234,6 +245,41 @@ void apply_canvas_viewport(std::int32_t x, std::int32_t y, std::int32_t width, s
         LOG("Canvas viewport dispatch failed because: %s", status.message);
 }
 
+pp::renderer::gl::OpenGlViewportRect query_canvas_viewport()
+{
+    const auto result = pp::renderer::gl::query_opengl_viewport(
+        pp::renderer::gl::OpenGlViewportQueryDispatch {
+            .get_integer = get_opengl_integer,
+        });
+    if (!result.ok()) {
+        LOG("Canvas viewport query dispatch failed because: %s", result.status().message);
+    }
+    return result.value();
+}
+
+std::array<float, 4> query_canvas_clear_color()
+{
+    const auto result = pp::renderer::gl::query_opengl_clear_color(
+        pp::renderer::gl::OpenGlClearColorQueryDispatch {
+            .get_float = get_opengl_float,
+        });
+    if (!result.ok()) {
+        LOG("Canvas clear-color query dispatch failed because: %s", result.status().message);
+    }
+    return result.value();
+}
+
+void apply_canvas_clear_color(std::array<float, 4> color)
+{
+    const auto status = pp::renderer::gl::apply_opengl_clear_color(
+        color,
+        pp::renderer::gl::OpenGlClearColorDispatch {
+            .clear_color = set_opengl_clear_color,
+        });
+    if (!status.ok())
+        LOG("Canvas clear-color dispatch failed because: %s", status.message);
+}
+
 void apply_canvas_scissor(std::int32_t x, std::int32_t y, std::int32_t width, std::int32_t height)
 {
     const auto status = pp::renderer::gl::apply_opengl_scissor_rect(
@@ -500,7 +546,11 @@ void Canvas::stroke_draw_mix(const glm::vec2& bb_min, const glm::vec2& bb_sz)
     apply_canvas_capability(scissor_test_state(), true);
     apply_canvas_capability(blend_state(), false);
 
-    apply_canvas_scissor(bb_min.x, bb_min.y, bb_sz.x, bb_sz.y);
+    apply_canvas_scissor(
+        static_cast<std::int32_t>(bb_min.x),
+        static_cast<std::int32_t>(bb_min.y),
+        static_cast<std::int32_t>(bb_sz.x),
+        static_cast<std::int32_t>(bb_sz.y));
 
     auto layer_index = m_current_layer_idx;
     for (int plane_index = 0; plane_index < 6; plane_index++)
@@ -777,10 +827,8 @@ void Canvas::stroke_draw()
     m_dirty = true;
     std::array<bool, 6> merge_faces;
 
-    GLint vp[4];
+    const auto vp = query_canvas_viewport();
-    GLfloat cc[4];
+    const auto cc = query_canvas_clear_color();
-    glGetIntegerv(viewport_query(), vp);
-    glGetFloatv(color_clear_value_query(), cc);
     
     const auto& brush = m_current_stroke->m_brush;
     const auto& dual_brush = m_dual_stroke->m_brush;
@@ -975,8 +1023,8 @@ void Canvas::stroke_draw()
     m_sampler_nearest.unbind();
     m_sampler_stencil.unbind();
     
-    apply_canvas_viewport(vp[0], vp[1], vp[2], vp[3]);
+    apply_canvas_viewport(vp.x, vp.y, vp.width, vp.height);
-    glClearColor(cc[0], cc[1], cc[2], cc[3]);
+    apply_canvas_clear_color(cc);
 
     if (m_commit_delayed)
     {
@@ -1086,10 +1134,8 @@ void Canvas::stroke_commit()
     App::I->redraw = true;
     
     // save viewport and clear color states
-    GLint vp[4];
+    const auto vp = query_canvas_viewport();
-    GLfloat cc[4];
+    const auto cc = query_canvas_clear_color();
-    glGetIntegerv(viewport_query(), vp);
-    glGetFloatv(color_clear_value_query(), cc);
     auto blend = glIsEnabled(blend_state());
     
     // allocate action to add to history
@@ -1259,8 +1305,8 @@ void Canvas::stroke_commit()
     
     // restore viewport and clear color states
     blend ? apply_canvas_capability(blend_state(), true) : apply_canvas_capability(blend_state(), false);
-    apply_canvas_viewport(vp[0], vp[1], vp[2], vp[3]);
+    apply_canvas_viewport(vp.x, vp.y, vp.width, vp.height);
-    glClearColor(cc[0], cc[1], cc[2], cc[3]);
+    apply_canvas_clear_color(cc);
     set_active_texture_unit(0);
     
     // save history
@@ -2962,10 +3008,8 @@ Image Canvas::thumbnail_generate(int w, int h)
     App::I->render_task([this, w, h, &image]
     {
         // save viewport and clear color states
-        GLint vp[4];
+        const auto vp = query_canvas_viewport();
-        GLfloat cc[4];
+        const auto cc = query_canvas_clear_color();
-        glGetIntegerv(viewport_query(), vp);
-        glGetFloatv(color_clear_value_query(), cc);
         auto blend = glIsEnabled(blend_state());
 
         // prepare common states
@@ -3057,8 +3101,8 @@ Image Canvas::thumbnail_generate(int w, int h)
 
         // restore viewport and clear color states
         blend ? apply_canvas_capability(blend_state(), true) : apply_canvas_capability(blend_state(), false);
-        apply_canvas_viewport(vp[0], vp[1], vp[2], vp[3]);
+        apply_canvas_viewport(vp.x, vp.y, vp.width, vp.height);
-        glClearColor(cc[0], cc[1], cc[2], cc[3]);
+        apply_canvas_clear_color(cc);
         set_active_texture_unit(0);
     });
 
@@ -3097,10 +3141,8 @@ void Canvas::draw_objects_direct(std::function<void(const glm::mat4& camera, con
     App::I->render_task([&]
     {
         // save viewport and clear color states
-        GLint vp[4];
+        const auto vp = query_canvas_viewport();
-        GLfloat cc[4];
+        const auto cc = query_canvas_clear_color();
-        glGetIntegerv(viewport_query(), vp);
-        glGetFloatv(color_clear_value_query(), cc);
         auto blend = glIsEnabled(blend_state());
 
         // prepare common states
@@ -3129,8 +3171,8 @@ void Canvas::draw_objects_direct(std::function<void(const glm::mat4& camera, con
 
         // restore viewport and clear color states
         blend ? apply_canvas_capability(blend_state(), true) : apply_canvas_capability(blend_state(), false);
-        apply_canvas_viewport(vp[0], vp[1], vp[2], vp[3]);
+        apply_canvas_viewport(vp.x, vp.y, vp.width, vp.height);
-        glClearColor(cc[0], cc[1], cc[2], cc[3]);
+        apply_canvas_clear_color(cc);
         set_active_texture_unit(0);
     });
 }
@@ -3140,10 +3182,8 @@ void Canvas::draw_objects(std::function<void(const glm::mat4& camera, const glm:
     App::I->render_task([&]
     {
         // save viewport and clear color states
-        GLint vp[4];
+        const auto vp = query_canvas_viewport();
-        GLfloat cc[4];
+        const auto cc = query_canvas_clear_color();
-        glGetIntegerv(viewport_query(), vp);
-        glGetFloatv(color_clear_value_query(), cc);
         auto blend = glIsEnabled(blend_state());
 
         // prepare common states
@@ -3235,8 +3275,8 @@ void Canvas::draw_objects(std::function<void(const glm::mat4& camera, const glm:
 
         // restore viewport and clear color states
         blend ? apply_canvas_capability(blend_state(), true) : apply_canvas_capability(blend_state(), false);
-        apply_canvas_viewport(vp[0], vp[1], vp[2], vp[3]);
+        apply_canvas_viewport(vp.x, vp.y, vp.width, vp.height);
-        glClearColor(cc[0], cc[1], cc[2], cc[3]);
+        apply_canvas_clear_color(cc);
         set_active_texture_unit(0);
     });
 }

src/canvas_layer.cpp

@@ -6,6 +6,8 @@
 #include "rtt.h"
 #include "util.h"
 
+#include <array>
+
 uint32_t Layer::s_count = 0;
 
 namespace {
@@ -40,6 +42,11 @@ void clear_opengl_buffer(std::uint32_t mask) noexcept
     glClear(static_cast<GLbitfield>(mask));
 }
 
+void get_opengl_float(std::uint32_t name, float* values) noexcept
+{
+    glGetFloatv(static_cast<GLenum>(name), values);
+}
+
 void copy_opengl_tex_sub_image_2d(
     std::uint32_t target,
     std::int32_t level,
@@ -142,9 +149,27 @@ void clear_layer_color_buffer(const glm::vec4& color)
         LOG("Layer clear dispatch failed because: %s", status.message);
 }
 
-void restore_layer_clear_color(const GLfloat* color)
+std::array<float, 4> query_layer_clear_color()
 {
-    set_opengl_clear_color(color[0], color[1], color[2], color[3]);
+    const auto result = pp::renderer::gl::query_opengl_clear_color(
+        pp::renderer::gl::OpenGlClearColorQueryDispatch {
+            .get_float = get_opengl_float,
+        });
+    if (!result.ok()) {
+        LOG("Layer clear-color query dispatch failed because: %s", result.status().message);
+    }
+    return result.value();
+}
+
+void restore_layer_clear_color(std::array<float, 4> color)
+{
+    const auto status = pp::renderer::gl::apply_opengl_clear_color(
+        color,
+        pp::renderer::gl::OpenGlClearColorDispatch {
+            .clear_color = set_opengl_clear_color,
+        });
+    if (!status.ok())
+        LOG("Layer clear-color dispatch failed because: %s", status.message);
 }
 
 }
@@ -601,8 +626,7 @@ void LayerFrame::clear(const glm::vec4& c)
     App::I->render_task([&]
     {
         // push clear color state
-        GLfloat cc[4];
+        const auto cc = query_layer_clear_color();
-        glGetFloatv(pp::renderer::gl::color_clear_value_query(), cc);
 
         bool erase = (c.a == 0.f);