Fixed bug 5213 - Add support to metal in iOS/tvOS simulator

Vincent Hamm

Xcode11 and ios13 added support for metal simulator.
Here is a quick and dirty patch to enable it. Pretty early and only tested on a few samples for now. Required mostly to enable metal support on correct version of ios, generate simulator compatible shaders and enforce buffer alignments on simulator (same as osx).

include/SDL_config_iphoneos.h

@@ -171,8 +171,10 @@
 #define SDL_VIDEO_RENDER_OGL_ES 1
 #define SDL_VIDEO_RENDER_OGL_ES2    1
 
-/* Metal supported on 64-bit devices running iOS 8.0 and tvOS 9.0 and newer */
-#if !TARGET_OS_SIMULATOR && !TARGET_CPU_ARM && ((__IPHONE_OS_VERSION_MIN_REQUIRED >= 80000) || (__TV_OS_VERSION_MIN_REQUIRED >= 90000))
+/* Metal supported on 64-bit devices running iOS 8.0 and tvOS 9.0 and newer
+   Also supported in simulator from iOS 13.0 and tvOS 13.0
+ */
+#if (TARGET_OS_SIMULATOR && ((__IPHONE_OS_VERSION_MIN_REQUIRED >= 130000) || (__TV_OS_VERSION_MIN_REQUIRED >= 130000))) || (!TARGET_CPU_ARM && ((__IPHONE_OS_VERSION_MIN_REQUIRED >= 80000) || (__TV_OS_VERSION_MIN_REQUIRED >= 90000)))
 #define SDL_PLATFORM_SUPPORTS_METAL	1
 #else
 #define SDL_PLATFORM_SUPPORTS_METAL	0

src/render/metal/SDL_render_metal.m

@@ -39,10 +39,18 @@
 #ifdef __MACOSX__
 #include "SDL_shaders_metal_osx.h"
 #elif defined(__TVOS__)
+#if TARGET_OS_SIMULATOR
+#include "SDL_shaders_metal_tvsimulator.h"
+#else
 #include "SDL_shaders_metal_tvos.h"
+#endif
+#else
+#if TARGET_OS_SIMULATOR
+#include "SDL_shaders_metal_iphonesimulator.h"
 #else
 #include "SDL_shaders_metal_ios.h"
 #endif
+#endif
 
 /* Apple Metal renderer implementation */
 
@@ -51,7 +59,7 @@ extern int SDL_RecreateWindow(SDL_Window * window, Uint32 flags);
 
 /* macOS requires constants in a buffer to have a 256 byte alignment. */
 /* Use native type alignments from https://developer.apple.com/metal/Metal-Shading-Language-Specification.pdf */
-#ifdef __MACOSX__
+#if defined(__MACOSX__) || TARGET_OS_SIMULATOR
 #define CONSTANT_ALIGN(x) (256)
 #else
 #define CONSTANT_ALIGN(x) (x < 4 ? 4 : x)

src/render/metal/build-metal-shaders.sh

@@ -6,7 +6,7 @@ cd `dirname "$0"`
 
 generate_shaders()
 {
-	fileplatform=$1
+    fileplatform=$1
     compileplatform=$2
     sdkplatform=$3
     minversion=$4
@@ -19,4 +19,6 @@ generate_shaders()
 
 generate_shaders osx osx macosx 10.11
 generate_shaders ios ios iphoneos 8.0
+generate_shaders iphonesimulator ios iphonesimulator 8.0
 generate_shaders tvos ios appletvos 9.0
+generate_shaders tvsimulator ios appletvsimulator 9.0