From ca7ea820ba6c916fd8ab8980fc160266eca717fe Mon Sep 17 00:00:00 2001
From: omigamedev <omarator@gmail.com>
Date: Sat, 13 Jun 2026 19:25:45 +0200
Subject: [PATCH] Extract stroke mix shell wrapper

---
 docs/modernization/debt.md  |  4 ++++
 docs/modernization/tasks.md |  4 ++++
 src/canvas.cpp              | 43 +++++++++++++++++++++----------------
 3 files changed, 32 insertions(+), 19 deletions(-)

diff --git a/docs/modernization/debt.md b/docs/modernization/debt.md
index 49c8661..4ec32be 100644
--- a/docs/modernization/debt.md
+++ b/docs/modernization/debt.md
@@ -441,6 +441,10 @@ agent or engineer to remove them without reconstructing context from chat.
   preserving caller-specific texture slot uniforms. Mixer framebuffer,
   viewport/scissor/capability state, sampler binding, texture binding, and draw
   execution remain retained Canvas code.
+- 2026-06-13: DEBT-0036 was narrowed again. `Canvas::stroke_draw_mix()` now
+  routes retained mix-shell execution through a local wrapper around
+  `execute_legacy_canvas_stroke_mix_pass_shell(...)`; the live path still owns
+  the concrete mixer framebuffer setup and GL capability toggles.
 - 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
diff --git a/docs/modernization/tasks.md b/docs/modernization/tasks.md
index 10b693e..cf59eae 100644
--- a/docs/modernization/tasks.md
+++ b/docs/modernization/tasks.md
@@ -619,6 +619,10 @@ Progress Notes:
   closeout.
 - 2026-06-13: `STR-004` closed the last inline stroke dispatch glue. `LATER-003`
   remains at the binding-only tail.
+- 2026-06-13: `Canvas::stroke_draw_mix()` now routes the retained shell
+  execution through a local wrapper around
+  `execute_legacy_canvas_stroke_mix_pass_shell(...)`; the live path still owns
+  the concrete mixer framebuffer setup and GL capability toggles.
 - 2026-06-13: `Canvas::stroke_draw_samples()` now reuses a retained destination
   texture dispatch helper for the live sample path; `Canvas` still owns the
   concrete face textures and callback execution.
diff --git a/src/canvas.cpp b/src/canvas.cpp
index e0c8ab4..160905e 100644
--- a/src/canvas.cpp
+++ b/src/canvas.cpp
@@ -405,26 +405,22 @@ void Canvas::stroke_draw_mix(const glm::vec2& bb_min, const glm::vec2& bb_sz)
     const auto& b = m_current_stroke->m_brush;
     const auto mix_shell = pp::panopainter::make_legacy_canvas_stroke_mix_pass_shell(
         [&] {
-                m_mixer.bindFramebuffer();
-                apply_canvas_viewport(0, 0, m_mixer.getWidth(), m_mixer.getHeight());
-                apply_canvas_capability(depth_test_state(), false);
-                apply_canvas_capability(scissor_test_state(), true);
-                apply_canvas_capability(blend_state(), false);
-                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));
-            },
+            m_mixer.bindFramebuffer();
+            apply_canvas_viewport(0, 0, m_mixer.getWidth(), m_mixer.getHeight());
+            apply_canvas_capability(depth_test_state(), false);
+            apply_canvas_capability(scissor_test_state(), true);
+            apply_canvas_capability(blend_state(), false);
+            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));
+        },
         [&] {
-                m_mixer.unbindFramebuffer();
-            });
-    [[maybe_unused]] const auto mix_result =
-        pp::panopainter::execute_legacy_canvas_stroke_mix_pass_shell(
-            mix_shell.setup.begin,
-            mix_shell.setup.end,
-            mix_shell.request);
-    
+            m_mixer.unbindFramebuffer();
+        });
+    [[maybe_unused]] const auto mix_result = execute_canvas_stroke_mix_pass_shell(mix_shell);
+
     gl.restore();
 }
 
@@ -537,6 +533,15 @@ static void execute_canvas_draw_merge_final_plane_composite(
     pp::panopainter::execute_legacy_canvas_draw_merge_final_plane_composite(uniforms, execution);
 }
 
+static void execute_canvas_stroke_mix_pass_shell(
+    const pp::panopainter::LegacyCanvasStrokeMixPassShell& shell)
+{
+    pp::panopainter::execute_legacy_canvas_stroke_mix_pass_shell(
+        shell.setup.begin,
+        shell.setup.end,
+        shell.request);
+}
+
 glm::vec4 Canvas::stroke_draw_samples(
     int i,
     std::vector<vertex_t>& P,