Initial SDL3 support.

Makefile

@@ -83,6 +83,33 @@ include arch/compat.inc
 
 ifneq (${BUILD_SDL},)
 
+#
+# SDL 3
+#
+ifeq (${BUILD_SDL},3)
+# Check SDL_PKG_CONFIG_PATH and PREFIX/lib/pkgconfig for sdl3.pc.
+# Note --with-path is a pkgconf extension.
+ifneq ($(and ${SDL_PKG_CONFIG_PATH},$(wildcard ${SDL_PKG_CONFIG_PATH}/sdl3.pc)),)
+# nop
+else
+# Check dependencies prefix instead for LIBDIR=. platforms.
+# This is useless for unix/darwin, which should have sdl3.pc in a
+# place pkgconf can find through normal means.
+ifeq (${LIBDIR},.)
+ifneq ($(wildcard ${PREFIX}/lib/pkgconfig/sdl3.pc),)
+SDL_PKG_CONFIG_PATH ?= ${PREFIX}/lib/pkgconfig
+endif
+endif # LIBDIR=.
+endif
+ifneq (${SDL_PKG_CONFIG_PATH},)
+SDL_PKG_CONFIG_FLAGS = --with-path=${SDL_PKG_CONFIG_PATH}
+endif
+
+SDL_PREFIX  := $(shell ${PKGCONF} ${SDL_PKG_CONFIG_FLAGS} sdl3 --variable=prefix)
+SDL_CFLAGS  ?= $(shell ${PKGCONF} ${SDL_PKG_CONFIG_FLAGS} sdl3 --cflags)
+SDL_LDFLAGS ?= $(shell ${PKGCONF} ${SDL_PKG_CONFIG_FLAGS} sdl3 --libs)
+endif # SDL3
+
 #
 # SDL 2
 #

arch/compat.inc

@@ -158,3 +158,12 @@ ifeq (${CLANG_VER_GE_3_3},0)
 HAS_F_STACK_PROTECTOR_STRONG ?= 1
 endif
 endif # clang
+
+#
+# Get pkgconf or pkg-config (prefer pkgconf).
+#
+PKGCONF ?= ${shell \
+ result=false; \
+ command -v pkg-config >/dev/null && result=pkg-config; \
+ command -v pkgconf >/dev/null && result=pkgconf; \
+ echo $$result; }

config.sh

@@ -67,6 +67,7 @@ usage() {
 	echo
 	echo "Platform-dependent options:"
 	echo "  --enable-sdl              Enable SDL backend, typically SDL2 (default)."
+	echo "  --enable-sdl3             Enable SDL3 backend (any version)."
 	echo "  --enable-sdl2             Enable SDL2 backend (any version)."
 	echo "  --enable-sdl1             Enable SDL1 backend (1.2.x)."
 	echo "  --disable-sdl             Disable SDL dependencies and features."
@@ -446,6 +447,7 @@ while [ "$1" != "" ]; do
 	[ "$1" = "--enable-sdl" ]  && SDL="true"
 	[ "$1" = "--enable-sdl1" ] && SDL="1"
 	[ "$1" = "--enable-sdl2" ] && SDL="2"
+	[ "$1" = "--enable-sdl3" ] && SDL="3"
 
 	[ "$1" = "--enable-egl" ]  && EGL="true"
 	[ "$1" = "--disable-egl" ] && EGL="false"
@@ -821,7 +823,7 @@ else
 	#
 	# If no specific version of SDL is selected, select SDL2.
 	#
-	if [ "$SDL" != "1" ] && [ "$SDL" != "2" ]; then
+	if [ "$SDL" != "1" ] && [ "$SDL" != "2" ] && [ "$SDL" != "3" ]; then
 		SDL="2"
 	fi
 	echo "Enabling SDL $SDL.x."
@@ -1139,7 +1141,7 @@ fi
 # Force-disable the softscale renderer for SDL 1.2 (requires SDL_Renderer).
 #
 if [ "$SDL" = "1" ] && [ "$SOFTSCALE" = "true" ]; then
-	echo "Force-disabling softscale renderer (requires SDL 2)."
+	echo "Force-disabling softscale renderer (requires SDL 2+)."
 	SOFTSCALE="false"
 	SDLACCEL="false"
 fi
@@ -1546,7 +1548,7 @@ else
 fi
 
 #
-# Softscale renderer (SDL 2)
+# Softscale renderer (SDL 2+)
 #
 if [ "$SOFTSCALE" = "true" ]; then
 	echo "Softscale renderer enabled."
@@ -1940,7 +1942,7 @@ else
 fi
 
 #
-# SDL_GameControllerDB, if enabled. This depends on SDL 2.
+# SDL_GameControllerDB, if enabled. This depends on SDL 2+.
 #
 if [ "$SDL" != "false" ] && [ "$SDL" -ge "2" ] && \
    [ "$GAMECONTROLLERDB" = "true" ]; then

docs/STYLE.md

@@ -258,6 +258,25 @@ original condition in a block comment after `#endif`.
     // more code
 ```
 
+In complex cases where there is no other option, left-hash indentation is OK:
+
+```
+#ifdef CONFIG_GLES
+# ifdef CONFIG_RENDER_GL_FIXED
+#   if SDL_VERSION_ATLEAST(3,0,0)
+#     include <SDL3/SDL_opengles.h>
+#   else
+#     ...
+#   endif
+# endif
+# ifdef CONFIG_RENDER_GL_PROGRAM
+#   ...
+# endif
+#else
+# ...
+#endif
+```
+
 ### Tabulated definitions
 
 In some places where many values or repetitive structs or enums are defined,

docs/changelog.txt

@@ -7,6 +7,8 @@ FIXES
 
 GIT - MZX 2.93c
 
+Initial support for SDL3 has been added, but as it has not been
+released yet, no MegaZeux release builds use it currently.
 As part of the preparation for SDL3, this release includes many
 long-belated changes to the way MegaZeux resizes windows and
 calculates the scaled display area within the window (including
@@ -56,6 +58,9 @@ USERS
 
 DEVELOPERS
 
++ Added initial support for SDL3. No platforms select SDL3 by
+  default, but it is now possible to build and test MegaZeux for
+  platforms that already support the current prerelease (3.1.6).
 + Split the renderer function "set_video_mode" into two renderer
   functions "create_window" and "resize_window" to more closely
   reflect the reality of SDL2/3. The former is used during

src/Makefile.in

@@ -368,8 +368,12 @@ core_cobjs += ${core_obj}/event_sdl.o ${core_obj}/platform_sdl.o
 core_cobjs += ${core_obj}/render_sdl.o
 
 ifeq (${BUILD_AUDIO},1)
+ifeq (${BUILD_SDL},3)
+core_cobjs += ${audio_obj}/driver_sdl3.o
+else
 core_cobjs += ${audio_obj}/audio_sdl.o
 endif
+endif
 
 core_flags   += $(SDL_CFLAGS)
 core_ldflags += $(SDL_LDFLAGS)