android: initial support for C output using sokol_main (#6164)

examples/sokol/particles/main.v

@@ -46,12 +46,12 @@ fn (mut a App) cleanup() {
 	a.ps.free()
 }
 
-fn (a App) run() {
+fn (mut a App) run() {
 	title := 'V Particle Example'
 	desc := C.sapp_desc{
 		width: a.width
 		height: a.height
-		user_data: &a
+		user_data: a
 		init_userdata_cb: init
 		frame_userdata_cb: frame
 		event_userdata_cb: event
@@ -59,6 +59,7 @@ fn (a App) run() {
 		html5_canvas_name: title.str
 		cleanup_userdata_cb: cleanup
 	}
+
 	sapp.run(&desc)
 }
 
@@ -126,6 +127,15 @@ fn event(ev &C.sapp_event, user_data voidptr) {
 			}
 		}
 	}
+
+	if ev.@type == .touches_began || ev.@type == .touches_moved {
+		if ev.num_touches > 0 {
+
+			touch_point := ev.touches[0]
+			app.ps.explode(touch_point.pos_x, touch_point.pos_y)
+
+		}
+	}
 }
 
 fn draw(a &App) {

vlib/sokol/c/declaration.c.v

@@ -27,7 +27,16 @@ pub const (
 // for simplicity, all header includes are here because import order matters and we dont have any way
 // to ensure import order with V yet
 #define SOKOL_IMPL
-#define SOKOL_NO_ENTRY
+
+// TODO should not be defined for android graphic (apk/aab using sokol) builds, but we have no ways to undefine
+//#define SOKOL_NO_ENTRY
+#flag linux   -DSOKOL_NO_ENTRY
+#flag darwin  -DSOKOL_NO_ENTRY
+#flag windows -DSOKOL_NO_ENTRY
+#flag freebsd -DSOKOL_NO_ENTRY
+#flag solaris -DSOKOL_NO_ENTRY
+// TODO end
+
 #include "sokol_app.h"
 
 #define SOKOL_IMPL

vlib/v/gen/cmain.v

@@ -11,11 +11,15 @@ pub fn (mut g Gen) gen_c_main() {
 	}
 	g.out.writeln('')
 	main_fn_start_pos := g.out.len
-	g.gen_c_main_header()
-	g.writeln('\tmain__main();')
-	g.gen_c_main_footer()
-	if g.pref.printfn_list.len > 0 && 'main' in g.pref.printfn_list {
-		println(g.out.after(main_fn_start_pos))
+	if g.pref.os == .android && g.pref.is_apk {
+		g.gen_c_android_sokol_main()
+	} else {
+		g.gen_c_main_header()
+		g.writeln('\tmain__main();')
+		g.gen_c_main_footer()
+		if g.pref.printfn_list.len > 0 && 'main' in g.pref.printfn_list {
+			println(g.out.after(main_fn_start_pos))
+		}
 	}
 }
 
@@ -84,6 +88,24 @@ pub fn (mut g Gen) gen_c_main_footer() {
 	g.writeln('}')
 }
 
+pub fn (mut g Gen) gen_c_android_sokol_main() {
+	// TODO get autofree weaved into android lifecycle somehow
+	/*
+	if g.autofree {
+		g.writeln('\t_vcleanup();')
+	}
+	*/
+	// TODO do proper check for the global g_desc field we need
+	g.writeln('sapp_desc sokol_main(int argc, char* argv[]) {')
+	g.writeln('\t(void)argc; (void)argv;')
+	g.writeln('')
+	g.writeln('\t_vinit();')
+	g.writeln('\tmain__main();')
+	g.writeln('')
+	g.writeln('\treturn g_desc;')
+	g.writeln('}')
+}
+
 pub fn (mut g Gen) write_tests_main() {
 	g.includes.writeln('#include <setjmp.h> // write_tests_main')
 	g.definitions.writeln('int g_test_oks = 0;')

vlib/v/pref/pref.v

@@ -123,6 +123,7 @@ pub mut:
 	experimental        bool // enable experimental features
 	show_timings        bool // show how much time each compiler stage took
 	is_ios_simulator    bool
+	is_apk              bool // build as Android .apk format
 }
 
 pub fn parse_args(args []string) (&Preferences, string) {
@@ -134,6 +135,9 @@ pub fn parse_args(args []string) (&Preferences, string) {
 		arg := args[i]
 		current_args := args[i..]
 		match arg {
+			'-apk' {
+				res.is_apk = true
+			}
 			'-show-timings' {
 				res.show_timings = true
 			}