From a07b462e36141a84f32c8b027bee92f2c36eb044 Mon Sep 17 00:00:00 2001
From: Hans-Kristian Arntzen <post@arntzen-software.no>
Date: Thu, 23 Jan 2025 11:36:46 +0100
Subject: [PATCH] GLSL: Deal with gl_Layer in vert/tese.

---
 reference/shaders-no-opt/vert/vertex-layer.vert | 17 +++++++++++++++++
 shaders-no-opt/vert/vertex-layer.vert           |  7 +++++++
 spirv_glsl.cpp                                  | 10 ++++++++++
 3 files changed, 34 insertions(+)
 create mode 100644 reference/shaders-no-opt/vert/vertex-layer.vert
 create mode 100644 shaders-no-opt/vert/vertex-layer.vert

diff --git a/reference/shaders-no-opt/vert/vertex-layer.vert b/reference/shaders-no-opt/vert/vertex-layer.vert
new file mode 100644
index 000000000..ae2388bdf
--- /dev/null
+++ b/reference/shaders-no-opt/vert/vertex-layer.vert
@@ -0,0 +1,17 @@
+#version 450
+#ifdef GL_ARB_shader_draw_parameters
+#extension GL_ARB_shader_draw_parameters : enable
+#endif
+#extension GL_ARB_shader_viewport_layer_array : require
+
+#ifdef GL_ARB_shader_draw_parameters
+#define SPIRV_Cross_BaseInstance gl_BaseInstanceARB
+#else
+uniform int SPIRV_Cross_BaseInstance;
+#endif
+
+void main()
+{
+    gl_Layer = (gl_InstanceID + SPIRV_Cross_BaseInstance);
+}
+
diff --git a/shaders-no-opt/vert/vertex-layer.vert b/shaders-no-opt/vert/vertex-layer.vert
new file mode 100644
index 000000000..a6f4ec87f
--- /dev/null
+++ b/shaders-no-opt/vert/vertex-layer.vert
@@ -0,0 +1,7 @@
+#version 450
+#extension GL_ARB_shader_viewport_layer_array : require
+
+void main()
+{
+	gl_Layer = gl_InstanceIndex;
+}
diff --git a/spirv_glsl.cpp b/spirv_glsl.cpp
index be65c042c..5f087a847 100644
--- a/spirv_glsl.cpp
+++ b/spirv_glsl.cpp
@@ -9824,7 +9824,17 @@ string CompilerGLSL::builtin_to_glsl(BuiltIn builtin, StorageClass storage)
 	case BuiltInInvocationId:
 		return "gl_InvocationID";
 	case BuiltInLayer:
+	{
+		auto model = get_execution_model();
+		if (model == ExecutionModelVertex || model == ExecutionModelTessellationEvaluation)
+		{
+			if (options.es)
+				require_extension_internal("GL_NV_viewport_array2");
+			else
+				require_extension_internal("GL_ARB_shader_viewport_layer_array");
+		}
 		return "gl_Layer";
+	}
 	case BuiltInViewportIndex:
 		return "gl_ViewportIndex";
 	case BuiltInTessLevelOuter: