Support constants of 16-bit integral type in GLSL and MSL.

Constants of 8-bit type aren't supported in GLSL, since there's no
extension letting you use them.

reference/opt/shaders-msl/frag/16bit-constants.frag

@@ -0,0 +1,21 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    half foo [[color(0)]];
+    short bar [[color(1)]];
+    ushort baz [[color(2)]];
+};
+
+fragment main0_out main0()
+{
+    main0_out out = {};
+    out.foo = 1.0h;
+    out.bar = 2;
+    out.baz = 3u;
+    return out;
+}
+

reference/opt/shaders/frag/16bit-constants.frag

@@ -0,0 +1,29 @@
+#version 450
+#if defined(GL_AMD_gpu_shader_half_float)
+#extension GL_AMD_gpu_shader_half_float : require
+#elif defined(GL_NV_gpu_shader5)
+#extension GL_NV_gpu_shader5 : require
+#elif defined(GL_EXT_shader_16bit_storage)
+#extension GL_EXT_shader_16bit_storage : require
+#else
+#error No extension available for FP16.
+#endif
+#if defined(GL_AMD_gpu_shader_int16)
+#extension GL_AMD_gpu_shader_int16 : require
+#elif defined(GL_EXT_shader_16bit_storage)
+#extension GL_EXT_shader_16bit_storage : require
+#else
+#error No extension available for Int16.
+#endif
+
+layout(location = 0) out float16_t foo;
+layout(location = 1) out int16_t bar;
+layout(location = 2) out uint16_t baz;
+
+void main()
+{
+    foo = 1.0hf;
+    bar = 2s;
+    baz = 3us;
+}
+

reference/shaders-msl/frag/16bit-constants.frag

@@ -0,0 +1,21 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    half foo [[color(0)]];
+    short bar [[color(1)]];
+    ushort baz [[color(2)]];
+};
+
+fragment main0_out main0()
+{
+    main0_out out = {};
+    out.foo = 1.0h;
+    out.bar = 2;
+    out.baz = 3u;
+    return out;
+}
+

reference/shaders/frag/16bit-constants.frag

@@ -0,0 +1,29 @@
+#version 450
+#if defined(GL_AMD_gpu_shader_half_float)
+#extension GL_AMD_gpu_shader_half_float : require
+#elif defined(GL_NV_gpu_shader5)
+#extension GL_NV_gpu_shader5 : require
+#elif defined(GL_EXT_shader_16bit_storage)
+#extension GL_EXT_shader_16bit_storage : require
+#else
+#error No extension available for FP16.
+#endif
+#if defined(GL_AMD_gpu_shader_int16)
+#extension GL_AMD_gpu_shader_int16 : require
+#elif defined(GL_EXT_shader_16bit_storage)
+#extension GL_EXT_shader_16bit_storage : require
+#else
+#error No extension available for Int16.
+#endif
+
+layout(location = 0) out float16_t foo;
+layout(location = 1) out int16_t bar;
+layout(location = 2) out uint16_t baz;
+
+void main()
+{
+    foo = 1.0hf;
+    bar = 2s;
+    baz = 3us;
+}
+

shaders-msl/frag/16bit-constants.frag

@@ -0,0 +1,14 @@
+#version 450 core
+
+#extension GL_AMD_gpu_shader_int16 : require
+#extension GL_AMD_gpu_shader_half_float : require
+
+layout(location = 0) out float16_t foo;
+layout(location = 1) out int16_t bar;
+layout(location = 2) out uint16_t baz;
+
+void main() {
+	foo = 1.0hf;
+	bar = 2s;
+	baz = 3us;
+}

shaders/frag/16bit-constants.frag

@@ -0,0 +1,14 @@
+#version 450 core
+
+#extension GL_AMD_gpu_shader_int16 : require
+#extension GL_AMD_gpu_shader_half_float : require
+
+layout(location = 0) out float16_t foo;
+layout(location = 1) out int16_t bar;
+layout(location = 2) out uint16_t baz;
+
+void main() {
+	foo = 1.0hf;
+	bar = 2s;
+	baz = 3us;
+}

spirv_glsl.cpp

@@ -3351,6 +3351,72 @@ string CompilerGLSL::constant_expression_vector(const SPIRConstant &c, uint32_t
 		}
 		break;
 
+	case SPIRType::UShort:
+		if (splat)
+		{
+			res += convert_to_string(c.scalar(vector, 0));
+			if (is_legacy())
+			{
+				// Fake unsigned constant literals with signed ones if possible.
+				// Things like array sizes, etc, tend to be unsigned even though they could just as easily be signed.
+				if (c.scalar_i16(vector, 0) < 0)
+					SPIRV_CROSS_THROW("Tried to convert uint literal into int, but this made the literal negative.");
+			}
+			else if (backend.uint16_t_literal_suffix)
+				res += backend.uint16_t_literal_suffix;
+		}
+		else
+		{
+			for (uint32_t i = 0; i < c.vector_size(); i++)
+			{
+				if (c.vector_size() > 1 && c.specialization_constant_id(vector, i) != 0)
+					res += to_name(c.specialization_constant_id(vector, i));
+				else
+				{
+					res += convert_to_string(c.scalar(vector, i));
+					if (is_legacy())
+					{
+						// Fake unsigned constant literals with signed ones if possible.
+						// Things like array sizes, etc, tend to be unsigned even though they could just as easily be signed.
+						if (c.scalar_i16(vector, i) < 0)
+							SPIRV_CROSS_THROW(
+							    "Tried to convert uint literal into int, but this made the literal negative.");
+					}
+					else if (backend.uint16_t_literal_suffix)
+						res += backend.uint16_t_literal_suffix;
+				}
+
+				if (i + 1 < c.vector_size())
+					res += ", ";
+			}
+		}
+		break;
+
+	case SPIRType::Short:
+		if (splat)
+		{
+			res += convert_to_string(c.scalar_i16(vector, 0));
+			if (backend.int16_t_literal_suffix)
+				res += backend.int16_t_literal_suffix;
+		}
+		else
+		{
+			for (uint32_t i = 0; i < c.vector_size(); i++)
+			{
+				if (c.vector_size() > 1 && c.specialization_constant_id(vector, i) != 0)
+					res += to_name(c.specialization_constant_id(vector, i));
+				else
+				{
+					res += convert_to_string(c.scalar_i16(vector, i));
+					if (backend.int16_t_literal_suffix)
+						res += backend.int16_t_literal_suffix;
+				}
+				if (i + 1 < c.vector_size())
+					res += ", ";
+			}
+		}
+		break;
+
 	case SPIRType::Boolean:
 		if (splat)
 			res += c.scalar(vector, 0) ? "true" : "false";

spirv_glsl.hpp

@@ -366,6 +366,8 @@ protected:
 		const char *basic_int16_type = "int16_t";
 		const char *basic_uint16_type = "uint16_t";
 		const char *half_literal_suffix = "hf";
+		const char *int16_t_literal_suffix = "s";
+		const char *uint16_t_literal_suffix = "us";
 		bool swizzle_is_function = false;
 		bool shared_is_implied = false;
 		bool flexible_member_array_supported = true;

spirv_hlsl.cpp

@@ -4616,6 +4616,8 @@ string CompilerHLSL::compile()
 	backend.half_literal_suffix = nullptr;
 	backend.long_long_literal_suffix = true;
 	backend.uint32_t_literal_suffix = true;
+	backend.int16_t_literal_suffix = nullptr;
+	backend.uint16_t_literal_suffix = "u";
 	backend.basic_int_type = "int";
 	backend.basic_uint_type = "uint";
 	backend.swizzle_is_function = false;

spirv_msl.cpp

@@ -390,6 +390,8 @@ string CompilerMSL::compile()
 	backend.float_literal_suffix = false;
 	backend.half_literal_suffix = "h";
 	backend.uint32_t_literal_suffix = true;
+	backend.int16_t_literal_suffix = nullptr;
+	backend.uint16_t_literal_suffix = "u";
 	backend.basic_int_type = "int";
 	backend.basic_uint_type = "uint";
 	backend.basic_int8_type = "char";