diff --git a/runtime/native/vk_mac.ll b/runtime/native/vk_mac.ll
index 70e3b19d..52c27be3 100644
--- a/runtime/native/vk_mac.ll
+++ b/runtime/native/vk_mac.ll
@@ -182,3 +182,11 @@ entry:
   %r = call i32 %fn(i32 %a0, ptr %a1)
   ret i32 %r
 }
+
+; a command-buffer command with three counts, through a pointer (vkCmdDrawMeshTasksEXT: the Streamline
+; interposer exports no such command, so it is looked up per device with vkGetDeviceProcAddr)
+define void @lsl_call_piii(ptr %fn, ptr %a0, i32 %a1, i32 %a2, i32 %a3) {
+entry:
+  call void %fn(ptr %a0, i32 %a1, i32 %a2, i32 %a3)
+  ret void
+}
diff --git a/runtime/native/vk_win.ll b/runtime/native/vk_win.ll
index 0fa872af..1d816b94 100644
--- a/runtime/native/vk_win.ll
+++ b/runtime/native/vk_win.ll
@@ -323,3 +323,11 @@ entry:
   %r = call i32 %fn(i32 %a0, ptr %a1)
   ret i32 %r
 }
+
+; a command-buffer command with three counts, through a pointer (vkCmdDrawMeshTasksEXT: the Streamline
+; interposer exports no such command, so it is looked up per device with vkGetDeviceProcAddr)
+define void @lsl_call_piii(ptr %fn, ptr %a0, i32 %a1, i32 %a2, i32 %a3) {
+entry:
+  call void %fn(ptr %a0, i32 %a1, i32 %a2, i32 %a3)
+  ret void
+}
diff --git a/tools/ludic-cli/shaders.ludic b/tools/ludic-cli/shaders.ludic
index 615e80e9..ede3319c 100644
--- a/tools/ludic-cli/shaders.ludic
+++ b/tools/ludic-cli/shaders.ludic
@@ -232,7 +232,12 @@ function cmd_shaders() -> int {
     let depth_remap = "\n#undef main\nvoid main() {\n  ludic_gl_main();\n  gl_Position.z = (gl_Position.z + gl_Position.w) * 0.5;\n}\n"
     # invariant: the foliage's depth prepass and its lit pass (depth EQUAL) are different variants,
     # and without it the compiler may compute their positions a hair apart and fail the test
-    let vsrc = "#version 460\n" + defines + "invariant gl_Position;\n#define main ludic_gl_main\n" + shd_file(parts[0]) + depth_remap
+    var vsrc = "#version 460\n" + defines + "invariant gl_Position;\n#define main ludic_gl_main\n" + shd_file(parts[0]) + depth_remap
+    # A mesh shader stands in for the vertex stage (a variant whose first file is *.mesh): it writes an
+    # array of positions, so it cannot be wrapped for the depth remap or take invariant gl_Position -
+    # it remaps depth itself. Its SPIR-V keeps the .vert name, so the manifest and loader are unchanged.
+    let is_mesh = Text.ends_with(parts[0], ".mesh")
+    if is_mesh { vsrc = "#version 460\n#extension GL_EXT_mesh_shader : require\n" + defines + shd_file(parts[0]) }
     let fsrc = "#version 460\n" + defines + shd_noise + shd_lighting + shd_file(parts[1])
     # one binding table for both stages, and one location table for the varyings between them
     shd_names = new []pointer
@@ -264,8 +269,10 @@ function cmd_shaders() -> int {
       let spv = `{outdir}/{id}.{stage}.spv`
       var extra = ""
       if stage == "frag" { extra = " --shift-UBO-binding frag 1" }
+      var sflag = stage
+      if stage == "vert" and is_mesh { sflag = "mesh";  extra = extra + " --target-env vulkan1.3" }
       let logf = `{tmp}/{id}.{stage}.log`
-      if not shq(`{shd_q(shd_bin + "/glslangValidator")} -V -R --auto-map-bindings --auto-map-locations{extra} -S {stage} {shd_q(glsl)} -o {shd_q(spv)} > {shd_q(logf)} 2>&1`) {
+      if not shq(`{shd_q(shd_bin + "/glslangValidator")} -V -R --auto-map-bindings --auto-map-locations{extra} -S {sflag} {shd_q(glsl)} -o {shd_q(spv)} > {shd_q(logf)} 2>&1`) {
         err(`shaders: {parts[0]} + {parts[1]} [{defs}] ({stage}) did not compile:\n{capture("grep ERROR " + shd_q(logf) + " | head -5")}\n`)
         return 1
       }