MSL: Support ClipDistance as an input stage variable.

MSL does not support this, so we have to emulate it by passing it around
as a varying between stages. We use a special "user(clipN)" attribute
for this rather than locN which is used for user varyings.

1 files changed, 29 insertions, 0 deletions

diff --git a/reference/opt/shaders-msl/asm/vert/clip-distance-plain-variable.asm.vert b/reference/opt/shaders-msl/asm/vert/clip-distance-plain-variable.asm.vert
new file mode 100644
index 00000000..1528c835
--- /dev/null
+++ b/reference/opt/shaders-msl/asm/vert/clip-distance-plain-variable.asm.vert
@@ -0,0 +1,29 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float4 gl_Position [[position]];
+    float gl_ClipDistance [[clip_distance]] [2];
+    float gl_ClipDistance_0 [[user(clip0)]];
+    float gl_ClipDistance_1 [[user(clip1)]];
+};
+
+struct main0_in
+{
+    float4 pos [[attribute(0)]];
+};
+
+vertex main0_out main0(main0_in in [[stage_in]])
+{
+    main0_out out = {};
+    out.gl_Position = in.pos;
+    out.gl_ClipDistance[0] = in.pos.x;
+    out.gl_ClipDistance[1] = in.pos.y;
+    out.gl_ClipDistance_0 = out.gl_ClipDistance[0];
+    out.gl_ClipDistance_1 = out.gl_ClipDistance[1];
+    return out;
+}
+