internal/graphicsdriver/metal: support macOS 10.12 by removing packed types

From the Metal shading language specification [1] Table 2.2.3, attribute
variables in Ebitengine's vertices don't have to be packed. Then, we can
remove `packed` types.

[1] https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf

Closes #2107

internal/graphicsdriver/metal/ca/ca_darwin.go

@@ -30,7 +30,7 @@ import (
 // It is because old Xcode (8 or older?) does not accept @available syntax.
 
 // #cgo CFLAGS: -Wno-unguarded-availability-new
-// #cgo !ios CFLAGS: -mmacosx-version-min=10.14
+// #cgo !ios CFLAGS: -mmacosx-version-min=10.12
 // #cgo LDFLAGS: -framework QuartzCore -framework Foundation -framework CoreGraphics
 //
 // #include "ca_darwin.h"

internal/graphicsdriver/metal/graphics_darwin.go

@@ -29,7 +29,7 @@ import (
 )
 
 // #cgo CFLAGS: -x objective-c
-// #cgo !ios CFLAGS: -mmacosx-version-min=10.14
+// #cgo !ios CFLAGS: -mmacosx-version-min=10.12
 // #cgo LDFLAGS: -framework Foundation
 //
 // #import <Foundation/Foundation.h>
@@ -56,9 +56,9 @@ const source = `#include <metal_stdlib>
 using namespace metal;
 
 struct VertexIn {
-  packed_float2 position;
+  float2 position;
-  packed_float2 tex;
+  float2 tex;
-  packed_float4 color;
+  float4 color;
 };
 
 struct VertexOut {

internal/graphicsdriver/metal/mtl/mtl_darwin.go

@@ -14,7 +14,7 @@
 
 // Package mtl provides access to Apple's Metal API (https://developer.apple.com/documentation/metal).
 //
-// Package mtl requires macOS version 10.14 or newer.
+// Package mtl requires macOS version 10.12 or newer.
 //
 // This package is in very early stages of development.
 // The API will change when opportunities for improvement are discovered; it is not yet frozen.
@@ -28,7 +28,7 @@ import (
 	"unsafe"
 )
 
-// #cgo !ios CFLAGS: -mmacosx-version-min=10.14
+// #cgo !ios CFLAGS: -mmacosx-version-min=10.12
 // #cgo LDFLAGS: -framework Metal -framework CoreGraphics -framework Foundation
 //
 // #include "mtl_darwin.h"

internal/graphicsdriver/metal/mtl/mtl_darwin.m

@@ -48,15 +48,11 @@ void *Device_MakeCommandQueue(void *device) {
 struct Library Device_MakeLibrary(void *device, const char *source,
                                   size_t sourceLength) {
   NSError *error;
-  MTLCompileOptions* options = [[MTLCompileOptions alloc] init];
-  if (@available(macOS 10.14, iOS 12.0, *)) {
-    options.languageVersion = MTLLanguageVersion2_1;
-  }
   id<MTLLibrary> library = [(id<MTLDevice>)device
       newLibraryWithSource:[[NSString alloc] initWithBytes:source
                                                     length:sourceLength
                                                   encoding:NSUTF8StringEncoding]
-                   options:options
+                   options:NULL
                      error:&error];
 
   struct Library l;

internal/graphicsdriver/metal/ns/ns_darwin.go

@@ -25,7 +25,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/ca"
 )
 
-// #cgo !ios CFLAGS: -mmacosx-version-min=10.14
+// #cgo !ios CFLAGS: -mmacosx-version-min=10.12
 //
 // #include "ns_darwin.h"
 import "C"

internal/shader/testdata/vertex.expected.metal

@@ -1,7 +1,7 @@
 struct Attributes {
-	packed_float2 M0;
+	float2 M0;
-	packed_float2 M1;
+	float2 M1;
-	packed_float4 M2;
+	float4 M2;
 };
 
 struct Varyings {

internal/shader/testdata/vertex_fragment.expected.metal

@@ -1,7 +1,7 @@
 struct Attributes {
-	packed_float2 M0;
+	float2 M0;
-	packed_float2 M1;
+	float2 M1;
-	packed_float4 M2;
+	float4 M2;
 };
 
 struct Varyings {

internal/shaderir/msl/msl.go

@@ -72,7 +72,7 @@ func Compile(p *shaderir.Program, vertex, fragment string) (shader string) {
 		lines = append(lines, "")
 		lines = append(lines, "struct Attributes {")
 		for i, a := range p.Attributes {
-			lines = append(lines, fmt.Sprintf("\t%s;", c.varDecl(p, &a, fmt.Sprintf("M%d", i), true, false)))
+			lines = append(lines, fmt.Sprintf("\t%s;", c.varDecl(p, &a, fmt.Sprintf("M%d", i), false)))
 		}
 		lines = append(lines, "};")
 	}
@@ -82,7 +82,7 @@ func Compile(p *shaderir.Program, vertex, fragment string) (shader string) {
 		lines = append(lines, "struct Varyings {")
 		lines = append(lines, "\tfloat4 Position [[position]];")
 		for i, v := range p.Varyings {
-			lines = append(lines, fmt.Sprintf("\t%s;", c.varDecl(p, &v, fmt.Sprintf("M%d", i), false, false)))
+			lines = append(lines, fmt.Sprintf("\t%s;", c.varDecl(p, &v, fmt.Sprintf("M%d", i), false)))
 		}
 		lines = append(lines, "};")
 	}
@@ -108,7 +108,7 @@ func Compile(p *shaderir.Program, vertex, fragment string) (shader string) {
 			"\tconst device Attributes* attributes [[buffer(0)]]")
 		for i, u := range p.Uniforms {
 			lines[len(lines)-1] += ","
-			lines = append(lines, fmt.Sprintf("\tconstant %s [[buffer(%d)]]", c.varDecl(p, &u, fmt.Sprintf("U%d", i), false, true), i+1))
+			lines = append(lines, fmt.Sprintf("\tconstant %s [[buffer(%d)]]", c.varDecl(p, &u, fmt.Sprintf("U%d", i), true), i+1))
 		}
 		for i := 0; i < p.TextureNum; i++ {
 			lines[len(lines)-1] += ","
@@ -130,7 +130,7 @@ func Compile(p *shaderir.Program, vertex, fragment string) (shader string) {
 			"\tVaryings varyings [[stage_in]]")
 		for i, u := range p.Uniforms {
 			lines[len(lines)-1] += ","
-			lines = append(lines, fmt.Sprintf("\tconstant %s [[buffer(%d)]]", c.varDecl(p, &u, fmt.Sprintf("U%d", i), false, true), i+1))
+			lines = append(lines, fmt.Sprintf("\tconstant %s [[buffer(%d)]]", c.varDecl(p, &u, fmt.Sprintf("U%d", i), true), i+1))
 		}
 		for i := 0; i < p.TextureNum; i++ {
 			lines[len(lines)-1] += ","
@@ -153,7 +153,7 @@ func Compile(p *shaderir.Program, vertex, fragment string) (shader string) {
 		for i, t := range c.structTypes {
 			stlines = append(stlines, fmt.Sprintf("struct S%d {", i))
 			for j, st := range t.Sub {
-				stlines = append(stlines, fmt.Sprintf("\t%s;", c.varDecl(p, &st, fmt.Sprintf("M%d", j), false, false)))
+				stlines = append(stlines, fmt.Sprintf("\t%s;", c.varDecl(p, &st, fmt.Sprintf("M%d", j), false)))
 			}
 			stlines = append(stlines, "};")
 		}
@@ -169,18 +169,18 @@ func Compile(p *shaderir.Program, vertex, fragment string) (shader string) {
 	return ls
 }
 
-func (c *compileContext) typ(p *shaderir.Program, t *shaderir.Type, packed bool, ref bool) string {
+func (c *compileContext) typ(p *shaderir.Program, t *shaderir.Type) string {
 	switch t.Main {
 	case shaderir.None:
 		return "void"
 	case shaderir.Struct:
 		return c.structName(p, t)
 	default:
-		return typeString(t, packed, ref)
+		return typeString(t, false)
 	}
 }
 
-func (c *compileContext) varDecl(p *shaderir.Program, t *shaderir.Type, varname string, packed bool, ref bool) string {
+func (c *compileContext) varDecl(p *shaderir.Program, t *shaderir.Type, varname string, ref bool) string {
 	switch t.Main {
 	case shaderir.None:
 		return "?(none)"
@@ -191,7 +191,7 @@ func (c *compileContext) varDecl(p *shaderir.Program, t *shaderir.Type, varname
 		}
 		return fmt.Sprintf("%s %s", s, varname)
 	default:
-		t := typeString(t, packed, ref)
+		t := typeString(t, ref)
 		return fmt.Sprintf("%s %s", t, varname)
 	}
 }
@@ -209,9 +209,9 @@ func (c *compileContext) varInit(p *shaderir.Program, t *shaderir.Type) string {
 	case shaderir.Int:
 		return "0"
 	case shaderir.Float, shaderir.Vec2, shaderir.Vec3, shaderir.Vec4, shaderir.Mat2, shaderir.Mat3, shaderir.Mat4:
-		return fmt.Sprintf("%s(0)", basicTypeString(t.Main, false))
+		return fmt.Sprintf("%s(0)", basicTypeString(t.Main))
 	default:
-		t := c.typ(p, t, false, false)
+		t := c.typ(p, t)
 		panic(fmt.Sprintf("?(unexpected type: %s)", t))
 	}
 }
@@ -221,7 +221,7 @@ func (c *compileContext) function(p *shaderir.Program, f *shaderir.Func, prototy
 
 	// Uniform variables and texture variables. In Metal, non-const global variables are not available.
 	for i, u := range p.Uniforms {
-		args = append(args, "constant "+c.varDecl(p, &u, fmt.Sprintf("U%d", i), false, true))
+		args = append(args, "constant "+c.varDecl(p, &u, fmt.Sprintf("U%d", i), true))
 	}
 	for i := 0; i < p.TextureNum; i++ {
 		args = append(args, fmt.Sprintf("texture2d<float> T%d", i))
@@ -229,11 +229,11 @@ func (c *compileContext) function(p *shaderir.Program, f *shaderir.Func, prototy
 
 	var idx int
 	for _, t := range f.InParams {
-		args = append(args, c.varDecl(p, &t, fmt.Sprintf("l%d", idx), false, false))
+		args = append(args, c.varDecl(p, &t, fmt.Sprintf("l%d", idx), false))
 		idx++
 	}
 	for _, t := range f.OutParams {
-		args = append(args, "thread "+c.varDecl(p, &t, fmt.Sprintf("l%d", idx), false, true))
+		args = append(args, "thread "+c.varDecl(p, &t, fmt.Sprintf("l%d", idx), true))
 		idx++
 	}
 	argsstr := "void"
@@ -241,7 +241,7 @@ func (c *compileContext) function(p *shaderir.Program, f *shaderir.Func, prototy
 		argsstr = strings.Join(args, ", ")
 	}
 
-	t := c.typ(p, &f.Return, false, false)
+	t := c.typ(p, &f.Return)
 	sig := fmt.Sprintf("%s F%d(%s)", t, f.Index, argsstr)
 
 	var lines []string
@@ -323,7 +323,7 @@ func (c *compileContext) initVariable(p *shaderir.Program, topBlock, block *shad
 
 	var lines []string
 	if decl {
-		lines = append(lines, fmt.Sprintf("%s%s = %s;", idt, c.varDecl(p, &t, name, false, false), c.varInit(p, &t)))
+		lines = append(lines, fmt.Sprintf("%s%s = %s;", idt, c.varDecl(p, &t, name, false), c.varInit(p, &t)))
 	} else {
 		lines = append(lines, fmt.Sprintf("%s%s = %s;", idt, name, c.varInit(p, &t)))
 	}
@@ -477,7 +477,7 @@ func (c *compileContext) block(p *shaderir.Program, topBlock, block *shaderir.Bl
 			t := s.ForVarType
 			init := constantToNumberLiteral(ct, s.ForInit)
 			end := constantToNumberLiteral(ct, s.ForEnd)
-			ts := typeString(&t, false, false)
+			ts := typeString(&t, false)
 			lines = append(lines, fmt.Sprintf("%sfor (%s %s = %s; %s %s %s; %s) {", idt, ts, v, init, v, op, end, delta))
 			lines = append(lines, c.block(p, topBlock, s.Blocks[0], level+1)...)
 			lines = append(lines, fmt.Sprintf("%s}", idt))

internal/shaderir/msl/type.go

@@ -64,10 +64,10 @@ func opString(op shaderir.Op) string {
 	return fmt.Sprintf("?(unexpected operator: %d)", op)
 }
 
-func typeString(t *shaderir.Type, packed bool, ref bool) string {
+func typeString(t *shaderir.Type, ref bool) string {
 	switch t.Main {
 	case shaderir.Array:
-		st := typeString(&t.Sub[0], packed, false)
+		st := typeString(&t.Sub[0], false)
 		t := fmt.Sprintf("array<%s, %d>", st, t.Length)
 		if ref {
 			t += "&"
@@ -76,7 +76,7 @@ func typeString(t *shaderir.Type, packed bool, ref bool) string {
 	case shaderir.Struct:
 		panic("msl: a struct is not implemented")
 	default:
-		t := basicTypeString(t.Main, packed)
+		t := basicTypeString(t.Main)
 		if ref {
 			t += "&"
 		}
@@ -84,7 +84,7 @@ func typeString(t *shaderir.Type, packed bool, ref bool) string {
 	}
 }
 
-func basicTypeString(t shaderir.BasicType, packed bool) string {
+func basicTypeString(t shaderir.BasicType) string {
 	switch t {
 	case shaderir.None:
 		return "?(none)"
@@ -95,19 +95,10 @@ func basicTypeString(t shaderir.BasicType, packed bool) string {
 	case shaderir.Float:
 		return "float"
 	case shaderir.Vec2:
-		if packed {
-			return "packed_float2"
-		}
 		return "float2"
 	case shaderir.Vec3:
-		if packed {
-			return "packed_float3"
-		}
 		return "float3"
 	case shaderir.Vec4:
-		if packed {
-			return "packed_float4"
-		}
 		return "float4"
 	case shaderir.Mat2:
 		return "float2x2"