[SDL] Joystick API implementation using HTML5 Gamepad API

Works in browsers that implement the working draft of the standard (current Chrome / Firefox stable):
http://www.w3.org/TR/2012/WD-gamepad-20120529/#gamepad-interface

...and browsers that implement the editor's draft (current Firefox Nightly):
https://dvcs.w3.org/hg/gamepad/raw-file/default/gamepad.html#idl-def-Gamepad

Contains unit tests for both event types.

2 files changed, 199 insertions, 0 deletions

diff --git a/tests/sdl_joystick.c b/tests/sdl_joystick.c
new file mode 100644
index 00000000..7035050f
--- /dev/null
+++ b/tests/sdl_joystick.c
@@ -0,0 +1,123 @@
+#include <stdio.h>
+#include <SDL/SDL.h>
+#include <SDL/SDL_ttf.h>
+#include <assert.h>
+#include <string.h>
+#include <emscripten.h>
+
+int result = 1;
+
+void assertJoystickEvent(int expectedGamepad, int expectedType, int expectedIndex, int expectedValue) {
+  SDL_Event event;
+  while(1) {
+    // Loop ends either when assertion fails (we run out of events), or we find
+    // the event we're looking for.
+    assert(SDL_PollEvent(&event) == 1);
+    if (event.type != expectedType) {
+      continue;
+    }
+    switch(event.type) {
+      case SDL_JOYAXISMOTION: {
+        assert(event.jaxis.which == expectedGamepad);
+        assert(event.jaxis.axis == expectedIndex);
+        assert(event.jaxis.value == expectedValue);
+        break;
+      }
+      case SDL_JOYBUTTONUP: case SDL_JOYBUTTONDOWN: {
+        assert(event.jbutton.which == expectedGamepad);
+        assert(event.jbutton.button == expectedIndex);
+        assert(event.jbutton.state == expectedValue);
+        break;
+      }
+    }
+    // Break out of while loop.
+    break;
+  }
+}
+
+void assertNoJoystickEvent() {
+  SDL_Event event;
+  while(SDL_PollEvent(&event)) {
+    switch(event.type) {
+      case SDL_JOYBUTTONDOWN: case SDL_JOYBUTTONUP: case SDL_JOYAXISMOTION: {
+        // Fail.
+        assert(0);
+      }
+    }
+  }
+}
+
+void main_2(void* arg);
+
+int main() {
+  SDL_Init(SDL_INIT_VIDEO | SDL_INIT_JOYSTICK);
+  SDL_Surface *screen = SDL_SetVideoMode(600, 450, 32, SDL_HWSURFACE);
+  emscripten_async_call(main_2, NULL, 3000); // avoid startup delays and intermittent errors
+  return 0;
+}
+
+void main_2(void* arg) {
+  // TODO: At the moment, we only support joystick support through polling.
+  emscripten_run_script("window.addNewGamepad('Pad Thai', 4, 16)");
+  emscripten_run_script("window.addNewGamepad('Pad Kee Mao', 0, 4)");
+  // Check that the joysticks exist properly.
+  assert(SDL_NumJoysticks() == 2);
+  assert(!SDL_JoystickOpened(0));
+  assert(!SDL_JoystickOpened(1));
+  SDL_Joystick* pad1 = SDL_JoystickOpen(0);
+  assert(SDL_JoystickOpened(0));
+  assert(SDL_JoystickIndex(pad1) == 0);
+  assert(strncmp(SDL_JoystickName(0), "Pad Thai", 9) == 0);
+  assert(strncmp(SDL_JoystickName(1), "Pad Kee Mao", 12) == 0);
+  assert(SDL_JoystickNumAxes(pad1) == 4);
+  assert(SDL_JoystickNumButtons(pad1) == 16);
+
+  // Button events.
+  emscripten_run_script("window.simulateGamepadButtonDown(0, 1)");
+  // We didn't tell SDL to automatically update this joystick's state.
+  assertNoJoystickEvent();
+  SDL_JoystickUpdate();
+  assertJoystickEvent(0, SDL_JOYBUTTONDOWN, 1, SDL_PRESSED);
+  assert(SDL_JoystickGetButton(pad1, 1) == 1);
+  // Enable automatic updates.
+  SDL_JoystickEventState(SDL_ENABLE);
+  assert(SDL_JoystickEventState(SDL_QUERY) == SDL_ENABLE);
+  emscripten_run_script("window.simulateGamepadButtonUp(0, 1)");
+  assertJoystickEvent(0, SDL_JOYBUTTONUP, 1, SDL_RELEASED);
+  assert(SDL_JoystickGetButton(pad1, 1) == 0);
+  // No button change: Should not result in a new event.
+  emscripten_run_script("window.simulateGamepadButtonUp(0, 1)");
+  assertNoJoystickEvent();
+  // Joystick 1 is not opened; should not result in a new event.
+  emscripten_run_script("window.simulateGamepadButtonDown(1, 1)");
+  assertNoJoystickEvent();
+
+  // Joystick wiggling
+  emscripten_run_script("window.simulateAxisMotion(0, 0, 1)");
+  assertJoystickEvent(0, SDL_JOYAXISMOTION, 0, 32767);
+  assert(SDL_JoystickGetAxis(pad1, 0) == 32767);
+  emscripten_run_script("window.simulateAxisMotion(0, 0, 0)");
+  assertJoystickEvent(0, SDL_JOYAXISMOTION, 0, 0);
+  assert(SDL_JoystickGetAxis(pad1, 0) == 0);
+  emscripten_run_script("window.simulateAxisMotion(0, 1, -1)");
+  assertJoystickEvent(0, SDL_JOYAXISMOTION, 1, -32768);
+  assert(SDL_JoystickGetAxis(pad1, 1) == -32768);
+  emscripten_run_script("window.simulateAxisMotion(0, 1, -1)");
+  // No joystick change: Should not result in a new event.
+  assertNoJoystickEvent();
+  // Joystick 1 is not opened; should not result in a new event.
+  emscripten_run_script("window.simulateAxisMotion(1, 1, -1)");
+  assertNoJoystickEvent();
+
+  SDL_JoystickClose(pad1);
+  assert(!SDL_JoystickOpened(0));
+
+  // Joystick 0 is closed; we should not process any new gamepad events from it.
+  emscripten_run_script("window.simulateGamepadButtonDown(0, 1)");
+  assertNoJoystickEvent();
+
+  // End test.
+  result = 2;
+  printf("Test passed!\n");
+}
+
diff --git a/tests/test_browser.py b/tests/test_browser.py
index d52f109f..1900e2cf 100644
--- a/tests/test_browser.py
+++ b/tests/test_browser.py
@@ -874,6 +874,82 @@ keydown(100);keyup(100); // trigger the end
   def test_glut_wheelevents(self):
     self.btest('glut_wheelevents.c', '1')
 
+  def test_sdl_joystick_1(self):
+    # Generates events corresponding to the Working Draft of the HTML5 Gamepad API.
+    # http://www.w3.org/TR/2012/WD-gamepad-20120529/#gamepad-interface
+    open(os.path.join(self.get_dir(), 'pre.js'), 'w').write('''
+      var gamepads = [];
+      // Spoof this function.
+      navigator['getGamepads'] = function() {
+        return gamepads;
+      };
+      window['addNewGamepad'] = function(id, numAxes, numButtons) {
+        var index = gamepads.length;
+        gamepads.push({
+          axes: new Array(numAxes),
+          buttons: new Array(numButtons),
+          id: id,
+          index: index
+        });
+        var i;
+        for (i = 0; i < numAxes; i++) gamepads[index].axes[i] = 0;
+        for (i = 0; i < numButtons; i++) gamepads[index].buttons[i] = 0;
+      };
+      window['simulateGamepadButtonDown'] = function (index, button) {
+        gamepads[index].buttons[button] = 1;
+      };
+      window['simulateGamepadButtonUp'] = function (index, button) {
+        gamepads[index].buttons[button] = 0;
+      };
+      window['simulateAxisMotion'] = function (index, axis, value) {
+        gamepads[index].axes[axis] = value;
+      };
+    ''')
+    open(os.path.join(self.get_dir(), 'sdl_joystick.c'), 'w').write(self.with_report_result(open(path_from_root('tests', 'sdl_joystick.c')).read()))
+
+    Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'sdl_joystick.c'), '-O2', '--minify', '0', '-o', 'page.html', '--pre-js', 'pre.js']).communicate()
+    self.run_browser('page.html', '', '/report_result?2')
+
+  def test_sdl_joystick_2(self):
+    # Generates events corresponding to the Editor's Draft of the HTML5 Gamepad API.
+    # https://dvcs.w3.org/hg/gamepad/raw-file/default/gamepad.html#idl-def-Gamepad
+    open(os.path.join(self.get_dir(), 'pre.js'), 'w').write('''
+      var gamepads = [];
+      // Spoof this function.
+      navigator['getGamepads'] = function() {
+        return gamepads;
+      };
+      window['addNewGamepad'] = function(id, numAxes, numButtons) {
+        var index = gamepads.length;
+        gamepads.push({
+          axes: new Array(numAxes),
+          buttons: new Array(numButtons),
+          id: id,
+          index: index
+        });
+        var i;
+        for (i = 0; i < numAxes; i++) gamepads[index].axes[i] = 0;
+        // Buttons are objects
+        for (i = 0; i < numButtons; i++) gamepads[index].buttons[i] = { pressed: false, value: 0 };
+      };
+      // FF mutates the original objects.
+      window['simulateGamepadButtonDown'] = function (index, button) {
+        gamepads[index].buttons[button].pressed = true;
+        gamepads[index].buttons[button].value = 1;
+      };
+      window['simulateGamepadButtonUp'] = function (index, button) {
+        gamepads[index].buttons[button].pressed = false;
+        gamepads[index].buttons[button].value = 0;
+      };
+      window['simulateAxisMotion'] = function (index, axis, value) {
+        gamepads[index].axes[axis] = value;
+      };
+    ''')
+    open(os.path.join(self.get_dir(), 'sdl_joystick.c'), 'w').write(self.with_report_result(open(path_from_root('tests', 'sdl_joystick.c')).read()))
+
+    Popen([PYTHON, EMCC, os.path.join(self.get_dir(), 'sdl_joystick.c'), '-O2', '--minify', '0', '-o', 'page.html', '--pre-js', 'pre.js']).communicate()
+    self.run_browser('page.html', '', '/report_result?2')
+
   def test_webgl_context_attributes(self):
     # Javascript code to check the attributes support we want to test in the WebGL implementation 
     # (request the attribute, create a context and check its value afterwards in the context attributes).