Route VR texture state through GL dispatch

docs/modernization/build-inventory.md

@@ -437,8 +437,8 @@ Known local toolchain state:
   counts so automation can assert backend interpretation without an OpenGL
   context.
   Desktop VR drawing also consumes backend-owned scissor/depth/blend state,
-  blend/depth state query-restore, depth clear masks, active texture units,
-  and fallback 2D texture unbind targets; VR SDK start/stop now dispatches
+  blend/depth state query-restore, depth clear masks, active texture unit
+  dispatch, and fallback 2D texture unbind dispatch; VR SDK start/stop now dispatches
   through `PlatformServices` while retaining the existing Windows OpenVR bridge
   shape.
   Canvas mode overlay, mask, and transform paths also consume backend-owned

docs/modernization/debt.md

@@ -23,7 +23,9 @@ agent or engineer to remove them without reconstructing context from chat.
   tested `pp_renderer_gl` capability-state dispatch; CanvasLayer equirect
   export now binds cube textures through tested `pp_renderer_gl` dispatch; and
   `Font` text drawing now activates texture units through tested
-  `pp_renderer_gl` dispatch. The debt remains open for live stroke
+  `pp_renderer_gl` dispatch. Desktop VR drawing also now routes active texture
+  unit switches and fallback 2D texture unbinds through tested `pp_renderer_gl`
+  dispatch. The debt remains open for live stroke
   rasterization, dual-brush compositing, pattern feedback math, thumbnail layer
   compositing, brush-preview compositing, and retained `ShaderManager::ext_*`
   compatibility fields.

docs/modernization/roadmap.md

@@ -798,9 +798,10 @@ VR UI framebuffer viewport and scissor-test setup now also consumes those
 `pp_renderer_gl` contracts, keeping desktop and VR UI rendering aligned while
 the retained OpenVR app path is split incrementally.
 VR draw blend/depth state snapshots, transitions, restore, and depth-buffer
-clears now use generic tested `pp_renderer_gl` capability query/apply and clear
-dispatch contracts, reducing direct OpenGL execution in the retained VR app
-path without changing state restore behavior.
+clears, active texture unit switches, and fallback 2D texture unbinds now use
+generic tested `pp_renderer_gl` capability query/apply, clear, active-texture,
+and texture-bind dispatch contracts, reducing direct OpenGL execution in the
+retained VR app path without changing state restore behavior.
 The retained `gl_state` save/restore utility now snapshots and restores through
 tested `pp_renderer_gl` saved-state dispatch contracts, covering capability
 state, viewport, clear color, framebuffer/program bindings, active texture,
@@ -2034,7 +2035,7 @@ Results:
   wrapper and compiled headless foundation/tool/test targets.
 - Desktop VR drawing now routes generic OpenGL scissor/depth/blend state,
   blend/depth state snapshots and restores, depth clears, active texture units,
-  and fallback 2D texture unbinds through the renderer GL backend mapping;
+  and fallback 2D texture unbinds through tested renderer GL backend dispatch;
   platform VR SDK bridges remain isolated for later platform-shell extraction.
   Eye framebuffer viewport execution in the retained HMD path also routes
   through tested `pp_renderer_gl` viewport dispatch.

src/app_vr.cpp

@@ -11,12 +11,30 @@ namespace {
 
 void set_active_texture_unit(std::uint32_t unit_index)
 {
-    glActiveTexture(pp::renderer::gl::active_texture_unit(unit_index));
+    const auto status = pp::renderer::gl::activate_opengl_texture_unit(
+        unit_index,
+        pp::renderer::gl::OpenGlActiveTextureDispatch {
+            .active_texture = [](std::uint32_t texture_unit) noexcept
+            {
+                glActiveTexture(static_cast<GLenum>(texture_unit));
+            },
+        });
+    if (!status.ok())
+        LOG("OpenGL VR active texture dispatch failed: %s", status.message);
 }
 
 void unbind_texture_2d()
 {
-    glBindTexture(pp::renderer::gl::texture_2d_target(), 0);
+    const auto status = pp::renderer::gl::bind_opengl_texture_2d(
+        0U,
+        pp::renderer::gl::OpenGlTexture2DBindDispatch {
+            .bind_texture = [](std::uint32_t target, std::uint32_t texture) noexcept
+            {
+                glBindTexture(static_cast<GLenum>(target), static_cast<GLuint>(texture));
+            },
+        });
+    if (!status.ok())
+        LOG("OpenGL VR texture unbind dispatch failed: %s", status.message);
 }
 
 void enable_opengl_state(std::uint32_t state) noexcept