fix(3d): restore correct orientation in test_3d_render (direct-to-surface)

Add Renderer3D::set_direct_render(bool) flag (must be set before init()).
When true, uses standard CCW winding and un-negates perspective Y, restoring
the pre-ba7ea27 orientation for direct-to-surface rendering where the
post-process Y-flip is absent.

handoff(Gemini): set_direct_render() is the escape hatch for any future
renderer usage that bypasses the post-process chain.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/3d/renderer_pipelines.cc b/src/3d/renderer_pipelines.cc
index 3abc3bd..195baad 100644
--- a/src/3d/renderer_pipelines.cc
+++ b/src/3d/renderer_pipelines.cc
@@ -253,7 +253,10 @@ void Renderer3D::create_mesh_pipeline() {
   pipeline_desc.vertex.buffers = &vert_buffer_layout;
   pipeline_desc.primitive.topology = WGPUPrimitiveTopology_TriangleList;
   pipeline_desc.primitive.cullMode = WGPUCullMode_Back;
-  pipeline_desc.primitive.frontFace = WGPUFrontFace_CW;  // Y-flipped perspective
+  // CW winding compensates for Y-negation in perspective() (post-process chain).
+  // Direct-to-surface rendering uses standard CCW winding.
+  pipeline_desc.primitive.frontFace =
+      direct_render_ ? WGPUFrontFace_CCW : WGPUFrontFace_CW;
   pipeline_desc.multisample.count = 1;
   pipeline_desc.fragment = &fragment_state;
   pipeline_desc.depthStencil = &depth_stencil;