PR 2: examples rose, dot; make deps; more README; unused version assert

.gitignore

@@ -3,3 +3,4 @@ c_src/env.mk
 ebin
 examples/*/*.beam
 priv
+.DS_Store

Makefile

@@ -13,9 +13,37 @@
 # OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 all:
+	make ebin
+	make bullet
+
+ebin:
 	rm -rf ebin/
 	mkdir -p ebin/
 	erlc -o ebin/ src/*.erl
 	cd c_src && make
+
+bullet: ebin
 	erlc -o examples/bullet_engine examples/bullet_engine/*.erl
 	cd examples/bullet_engine && ./start.sh
+
+hello:  ebin
+	erlc -o examples/hello_sdl examples/hello_sdl/*.erl
+	cd examples/hello_sdl && ./start.sh
+
+dot:    ebin
+	erlc -o examples/dot examples/dot/*.erl
+	cd examples/dot && ./start.sh
+
+rose:   ebin
+	erlc -o examples/rose examples/rose/*.erl
+	cd examples/rose && ./start.sh
+
+clean:
+	@rm -f *.swp
+	@rm -f c_src/env.mk
+	@rm -f priv/esdl2.so
+	@rm -rf ebin/
+	@rm -f examples/*/*.dump
+	@rm -f examples/*/*.beam
+	@rm -f .DS_Store
+	@echo clean

README.md

@@ -1,19 +1,50 @@
 ESDL2
 =====
 
-SDL2 Erlang NIF.
+SDL2 Erlang NIFs
+
+SDL provides cross-platform low level access to graphics, audio, keyboard, mouseand joystick hardware via OpenGL and Direct3D. This is an Erlang binding to SDL2. http://www.libsdl.org/
+
+Note: 'ESDL' used to be Erlang's graphics kit, using SDL 1, before it was replaced by wxWidgets. This is a different implementation, for a new version of SDL.
 
 Status
 ------
 
 Week-end project. Work in progress.
 
-The following limitations apply:
-
+Building
+--------
+
  *  Erlang 17.0+ is required
- *  SDL 2.0.3+ is required
+ *  SDL 2.0.3+ is required (`http://www.libsdl.org/download-2.0.php`)
+ *  SDL\_image is required (`https://www.libsdl.org/projects/SDL_image/`)
  *  No support for UTF-8 strings, only Latin-1
 
+Tip: configure SDL\_image with --disable-webp for not having to install libwebp.
+
+Build using make:
+
+    make
+
+Examples
+--------
+
+Samples in examples/
+
+ * Bullet Engine - rains bullets danmaku style
+ * Hello World - minimal visual: show a graphic
+ * Rose - minimal animation: draw a pixel line
+ * Dot - minimal animation: show a circling dot
+
+Build and run using make from the project root.
+
+    make bullet
+    make hello
+    make rose
+    make dot
+
+Ideas
+-----
 The following ideas need to be investigated:
 
  *  We may benefit from the reference receive optimization when doing calls

c_src/Makefile

@@ -20,7 +20,8 @@ SDL2_LIBS = $(filter-out $(SDL2_LIBS_FILTER_OUT),$(shell sdl2-config --static-li
 
 all: env.mk
 	mkdir -p $(PRIV_DIR)
-	gcc *.c -fPIC -shared -o $(PRIV_DIR)/esdl2.so -I $(ERTS_INCLUDE_DIR) \
+	gcc -undefined dynamic_lookup *.c -fPIC -shared \
+		-o $(PRIV_DIR)/esdl2.so -I $(ERTS_INCLUDE_DIR) \
 		`sdl2-config --cflags` $(SDL2_LIBS) -lSDL2_image
 
 env.mk:

examples/dot/dot.erl

@@ -0,0 +1,50 @@
+%% Minimal animation example: a single dot looping in circles.
+%% Build and run from project root: make dot
+%% Feel free to copy and reuse as you wish.
+
+-module(dot).
+-export([run/0]).
+
+run() ->
+	spawn_opt(fun init/0, [{scheduler, 0}]).
+
+init() ->
+	%% setup sdl, window and renderer
+	ok = sdl:start([video]),
+	ok = sdl:stop_on_exit(),
+	{ok, Window} = sdl_window:create("Dot", 10, 10, 500, 500, []),
+	{ok, Renderer} = sdl_renderer:create(Window, -1, [accelerated, present_vsync]),
+	%% start animaton
+	loop(#{window=>Window, renderer=>Renderer, t=>0}).
+
+%% animation loop
+loop(State) ->
+	events_loop(),
+	loop(render(State)).
+
+%% check for termination
+events_loop() ->
+	case sdl_events:poll() of
+		false -> ok;
+		#{type:=quit} -> terminate();
+		_ -> events_loop()
+	end.
+
+%% render one frame
+render(#{renderer:=Renderer, t:=T}=State) ->
+	%% clear screen
+	ok = sdl_renderer:set_draw_color(Renderer, 0,0,0,0),
+	ok = sdl_renderer:clear(Renderer),
+	%% draw dot
+	X = erlang:round(250 + 100 * math:sin(T/250) * (math:cos(T/100) + math:cos(T/10))), 
+	Y = erlang:round(250 + 100 * math:sin(T/250) * (math:sin(T/100) + math:sin(T/10))),
+	ok = sdl_renderer:set_draw_color(Renderer, 255, 255, 255, 255),
+	ok = sdl_renderer:draw_point(Renderer, #{x=>X, y=>Y}),
+	%% render
+	ok = sdl_renderer:present(Renderer),
+	%% progress timeline
+	State#{t=>T + 1}.
+
+terminate() ->
+	init:stop(),
+	exit(normal).

examples/dot/start.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+erl +stbt db -pa ../../ebin -eval "dot:run()."

examples/planets/planets.erl

@@ -0,0 +1,79 @@
+%% Minimal animation example: rose line art.
+%% Build and run from project root: make rose
+%% Feel free to copy and reuse as you wish.
+
+-module(planets).
+-export([run/0]).
+
+run() ->
+	spawn_opt(fun init/0, [{scheduler, 0}]).
+
+init() ->
+	%% setup sdl, window and renderer
+	ok = sdl:start([video]),
+	ok = sdl:stop_on_exit(),
+	{ok, Window} = sdl_window:create("Planets", 10, 10, 500, 500, []),
+	{ok, Renderer} = sdl_renderer:create(Window, -1, [accelerated, present_vsync]),
+	%% clear screen (once ever in this example)
+	ok = sdl_renderer:set_draw_color(Renderer, 0,0,0,0),
+	ok = sdl_renderer:clear(Renderer),
+	%% start animaton
+	loop(#{window=>Window, renderer=>Renderer, t=>os:timestamp()}).
+
+%% animation loop
+loop(State) ->
+	events_loop(),
+	render(State),
+	loop(State).
+
+%% check for termination
+events_loop() ->
+	case sdl_events:poll() of
+		false -> ok;
+		#{type:=quit} -> terminate();
+		_ -> events_loop()
+	end.
+
+%% render one frame
+render(#{renderer:=Renderer, t:=TT}=State) ->
+	T = timer:now_diff(os:timestamp(), TT) / 20000,
+	ok = sdl_renderer:set_draw_color(Renderer, 0,0,0,0),
+	ok = sdl_renderer:clear(Renderer),
+	%% draw one dot (it is not cleared next frame)
+	draw_star(Renderer, T), 
+	draw_planet(Renderer,  7, 200, 450, 600, 100, T), 
+	draw_planet(Renderer,  3, 100, 280, 300, 30, T), 
+	draw_planet(Renderer,  3, 100, 900, 300, 30, T+70), 
+	draw_planet(Renderer,  5, 200, 290, 200, 30, T+100), 
+	draw_planet(Renderer, 12, 300, 650, 700, 300, T), 
+	%% render
+	ok = sdl_renderer:present(Renderer).
+
+draw_star(Renderer, T) ->
+	ok = sdl_renderer:set_draw_color(Renderer, 255, 255, 255, 255),
+	ok = sdl_renderer:draw_points(Renderer, circle(100, 250, 50, 120, T, 1)), 
+	ok = sdl_renderer:draw_points(Renderer, circle(100, 250, 53, 30, -T, 1)), 
+	ok = sdl_renderer:draw_points(Renderer, circle(100, 250, 45, 300, T/100, 1)).
+
+
+draw_planet(Renderer, W, N, R, D, V, T) ->
+	X = 100 + erlang:round(R * math:cos(T/D)), 
+	Y = 250 + erlang:round(R * math:sin(T/D) / 5), 
+	ok = sdl_renderer:set_draw_color(Renderer, 100, 100, 100, 255),
+        ok = sdl_renderer:draw_points(Renderer, circle(X, Y, W, N, T/V, 1.25)),
+	ok = sdl_renderer:set_draw_color(Renderer, 255, 255, 255, 255),
+        ok = sdl_renderer:draw_points(Renderer, circle(X, Y, W, N, T/V, 1)).
+
+%% T effects a slow ant crawl of the dashed circle line when N is small enough
+%% in relation to R. 
+%% S gives a breathing effect of the size, scaling the entire radius.
+circle(X, Y, R0, N, T, S) ->
+	R = S * (R0 + math:cos(T/20)), %% radius
+	D = math:pi() * 2 / N,
+	[ #{x => X + erlang:round(R * math:cos((TT+T/30)/D)), 
+            y => Y + erlang:round(R * math:sin((TT+T/30)/D))}
+	||  TT <- lists:seq(1, N)]. 
+
+terminate() ->
+	init:stop(),
+	exit(normal).

examples/planets/start.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+erl +stbt db -pa ../../ebin -eval "planets:run()."

examples/rose/rose.erl

@@ -0,0 +1,50 @@
+%% Minimal animation example: rose line art.
+%% Build and run from project root: make rose
+%% Feel free to copy and reuse as you wish.
+
+-module(rose).
+-export([run/0]).
+
+run() ->
+	spawn_opt(fun init/0, [{scheduler, 0}]).
+
+init() ->
+	%% setup sdl, window and renderer
+	ok = sdl:start([video]),
+	ok = sdl:stop_on_exit(),
+	{ok, Window} = sdl_window:create("Dot", 10, 10, 500, 500, []),
+	{ok, Renderer} = sdl_renderer:create(Window, -1, [accelerated, present_vsync]),
+	%% clear screen (once ever in this example)
+	ok = sdl_renderer:set_draw_color(Renderer, 0,0,0,0),
+	ok = sdl_renderer:clear(Renderer),
+	%% start animaton
+	loop(#{window=>Window, renderer=>Renderer, t=>0}).
+
+%% animation loop
+loop(State) ->
+	events_loop(),
+	loop(render(State)).
+
+%% check for termination
+events_loop() ->
+	case sdl_events:poll() of
+		false -> ok;
+		#{type:=quit} -> terminate();
+		_ -> events_loop()
+	end.
+
+%% render one frame
+render(#{renderer:=Renderer, t:=T}=State) ->
+	%% draw one dot (it is not cleared next frame)
+	X = erlang:round(250 + 100 * math:sin(T/250) * math:cos(T/100)), 
+	Y = erlang:round(250 + 100 * math:sin(T/250) * math:sin(T/100)),
+	ok = sdl_renderer:set_draw_color(Renderer, 255, 0, 0, 255),
+	ok = sdl_renderer:draw_point(Renderer, #{x=>X, y=>Y}),
+	%% render
+	ok = sdl_renderer:present(Renderer),
+	%% progress frame number
+	State#{t=>T + 1}.
+
+terminate() ->
+	init:stop(),
+	exit(normal).

examples/rose/start.sh

@@ -0,0 +1,2 @@
+#!/bin/sh
+erl +stbt db -pa ../../ebin -eval "rose:run()."

src/sdl_version.erl

@@ -16,6 +16,7 @@
 
 -export([get_version/0]).
 -export([get_revision/0]).
+-export([assert_erlang_version/0]).
 
 -spec get_version() -> {byte(), byte(), byte()}.
 get_version() ->
@@ -24,3 +25,8 @@ get_version() ->
 -spec get_revision() -> string().
 get_revision() ->
 	esdl2:get_revision().
+
+-spec assert_erlang_version() -> true.
+assert_erlang_version() ->
+	V = list_to_integer(string:substr(erlang:system_info(otp_release),2,2)),
+	true = V >= 17.