Method bind_instance_buffer

native/shared/src/renderer/material_system.rs:1635–1654

EN-001 — resolve an instanced draw command's vertex slot 1 binding and return the instance range. For non-instanced draws (`info` is None) this is a no-op and returns `0..1`. For instanced draws with a missing/destroyed buffer slot we return an empty range so the caller skips the draw rather than crashing on a stale handle.

(
        &'pass self,
        pass: &mut wgpu::RenderPass<'pass>,
        info: &Option<InstanceDrawInfo>,
    )

    /// so the caller skips the draw rather than crashing on a stale
    /// handle.
    fn bind_instance_buffer<'pass>(
        &'pass self,
        pass: &mut wgpu::RenderPass<'pass>,
        info: &Option<InstanceDrawInfo>,
    ) -> std::ops::Range<u32> {
        match info {
            None => 0..1,
            Some(inst) => {
                if inst.buffer_handle == 0 { return 0..1; }
                let slot_idx = inst.buffer_handle as usize - 1;
                match self.instance_buffers.get(slot_idx).and_then(|s| s.as_ref()) {
                    Some(ib_slot) => {
                        pass.set_vertex_buffer(1, ib_slot.buffer.slice(..));
                        0..inst.count
                    }
                    None => 0..0,
                }
            }
        }
    }

    /// Phase 4b — rebuild the SceneInputs (group 4) bind group with
    /// the current frame's snapshot textures. Called by the Renderer