Add live pass sampler dispatch regression

docs/modernization/debt.md

@@ -533,6 +533,10 @@ agent or engineer to remove them without reconstructing context from chat.
   texture dispatch now has regression coverage through
   `make_legacy_canvas_stroke_main_pass_texture_dispatch(...)`; the live path
   still owns the concrete texture objects and sampler state.
+- 2026-06-13: DEBT-0036 was narrowed again. `Canvas::stroke_draw()` live-pass
+  sampler dispatch now has regression coverage through
+  `make_legacy_canvas_stroke_live_pass_sampler_dispatch(...)`; the live path
+  still owns the concrete sampler objects and binding state.
 - 2026-06-13: DEBT-0036 was narrowed again. `Canvas::draw_merge` checkerboard
   background shader setup and final merged-texture redraw setup now route
   through `legacy_canvas_draw_merge_services.h`. The retained Canvas path still

docs/modernization/tasks.md

@@ -609,7 +609,7 @@ ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_composito
 
 ### STR-021 - Extract Stroke Draw Live Pass Sampler Dispatch
 
-Status: Ready
+Status: Done
 Score: +1 renderer boundary and OpenGL parity
 Debt: `DEBT-0036`
 Scope: `src/canvas.cpp`, `src/legacy_canvas_stroke_execution_services.h`, `tests/paint_renderer/compositor_tests.cpp`
@@ -634,6 +634,12 @@ Validation:
 ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_compositor|pp_paint_renderer_stroke_execution" --output-on-failure
 ```
 
+### Completed Task Log
+
+| Date | Task | Score | Validation | Commit |
+| --- | --- | --- | --- | --- |
+| 2026-06-13 | STR-021 | +1 renderer boundary and OpenGL parity | `ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_compositor|pp_paint_renderer_stroke_execution" --output-on-failure` | `pending` |
+
 Progress Notes:
 
 - 2026-06-13: `NodeStrokePreview::draw_stroke_immediate()` now routes final

tests/paint_renderer/compositor_tests.cpp

@@ -1797,6 +1797,101 @@ void legacy_canvas_stroke_main_pass_texture_dispatch_preserves_order(pp::tests::
     PP_EXPECT(h, steps == expected);
 }
 
+void legacy_canvas_stroke_live_pass_sampler_dispatch_preserves_order(pp::tests::Harness& h)
+{
+    std::vector<std::string> steps;
+    const auto dispatch = pp::panopainter::make_legacy_canvas_stroke_live_pass_sampler_dispatch(
+        [&](int slot) {
+            steps.emplace_back("activate:" + std::to_string(slot));
+        },
+        [&] {
+            steps.emplace_back("bind-brush");
+        },
+        [&] {
+            steps.emplace_back("unbind-brush");
+        },
+        [&] {
+            steps.emplace_back("bind-pattern");
+        },
+        [&] {
+            steps.emplace_back("unbind-pattern");
+        },
+        [&] {
+            steps.emplace_back("bind-mixer");
+        },
+        [&] {
+            steps.emplace_back("unbind-mixer");
+        },
+        [&] {
+            steps.emplace_back("bind-stencil");
+        },
+        [&] {
+            steps.emplace_back("unbind-stencil");
+        });
+
+    pp::panopainter::bind_legacy_canvas_stroke_sampler_inputs(
+        std::array {
+            pp::panopainter::LegacyCanvasStrokeTextureBinding {
+                .input = pp::panopainter::LegacyCanvasStrokeTextureInput::brush_tip,
+                .slot = 0,
+            },
+            pp::panopainter::LegacyCanvasStrokeTextureBinding {
+                .input = pp::panopainter::LegacyCanvasStrokeTextureInput::stroke_destination,
+                .slot = 1,
+            },
+            pp::panopainter::LegacyCanvasStrokeTextureBinding {
+                .input = pp::panopainter::LegacyCanvasStrokeTextureInput::pattern,
+                .slot = 2,
+            },
+            pp::panopainter::LegacyCanvasStrokeTextureBinding {
+                .input = pp::panopainter::LegacyCanvasStrokeTextureInput::mixer,
+                .slot = 3,
+            },
+        },
+        dispatch);
+
+    pp::panopainter::unbind_legacy_canvas_stroke_sampler_inputs(
+        std::array {
+            pp::panopainter::LegacyCanvasStrokeTextureBinding {
+                .input = pp::panopainter::LegacyCanvasStrokeTextureInput::mixer,
+                .slot = 3,
+            },
+            pp::panopainter::LegacyCanvasStrokeTextureBinding {
+                .input = pp::panopainter::LegacyCanvasStrokeTextureInput::pattern,
+                .slot = 2,
+            },
+            pp::panopainter::LegacyCanvasStrokeTextureBinding {
+                .input = pp::panopainter::LegacyCanvasStrokeTextureInput::stroke_destination,
+                .slot = 1,
+            },
+            pp::panopainter::LegacyCanvasStrokeTextureBinding {
+                .input = pp::panopainter::LegacyCanvasStrokeTextureInput::brush_tip,
+                .slot = 0,
+            },
+        },
+        dispatch);
+
+    const std::vector<std::string> expected {
+        "activate:0",
+        "bind-brush",
+        "activate:1",
+        "bind-stencil",
+        "activate:2",
+        "bind-pattern",
+        "activate:3",
+        "bind-mixer",
+        "activate:3",
+        "unbind-mixer",
+        "activate:2",
+        "unbind-pattern",
+        "activate:1",
+        "unbind-stencil",
+        "activate:0",
+        "unbind-brush",
+    };
+    PP_EXPECT(h, steps == expected);
+}
+
 void plans_canvas_stroke_commit_erase_sequence(pp::tests::Harness& h)
 {
     const auto plan = plan_canvas_stroke_commit_sequence(
@@ -3669,6 +3764,9 @@ int main()
     harness.run(
         "legacy_canvas_stroke_main_pass_texture_dispatch_preserves_order",
         legacy_canvas_stroke_main_pass_texture_dispatch_preserves_order);
+    harness.run(
+        "legacy_canvas_stroke_live_pass_sampler_dispatch_preserves_order",
+        legacy_canvas_stroke_live_pass_sampler_dispatch_preserves_order);
     harness.run("plans_canvas_stroke_commit_erase_sequence", plans_canvas_stroke_commit_erase_sequence);
     harness.run("plans_canvas_stroke_commit_composite_sequence", plans_canvas_stroke_commit_composite_sequence);
     harness.run(