class AndroidCameraPreview(Image):
"""
Android camera preview widget. Extends Image with a custom shader that
displays textures of target GL_TEXTURE_EXTERNAL_OES. Note, this requires
Android API 11 because of it's use of SurfaceTexture.
"""
play = BooleanProperty(False)
resolution = ListProperty([720, 720])
camera_id = NumericProperty(-1)
_camera = None
_previewCallback = None
_previewTexture = None
_previewSurface = None
_secondary_texture = None
def __init__(self, **kwargs):
self.canvas = RenderContext()
super(AndroidCameraPreview, self).__init__(**kwargs)
self.bind(resolution=self._resolution_changed)
self.bind(camera_id=self._camera_id_changed)
self.bind(play=self._play_changed)
# This is needed for the default vertex shader.
self.canvas['projection_mat'] = Window.render_context['projection_mat']
with self.canvas:
Callback(self._draw_callback)
BindTexture(texture=self._secondary_texture, index=1)
self.canvas['secondary_texture'] = 1
self._init_texture(self.resolution)
def start(self, play=True):
self._init_camera(self.camera_id)
self.play = play
def stop(self):
self._release_camera()
def _init_texture(self, resolution):
width, height = resolution
# Image looks at self.texture to determine layout, so we create
# texture but don't actually display it.
self.texture = Texture.create(size=(height, width))
self.texture_size = self.texture.size
if IsAndroid:
self._secondary_texture = Texture(width=height, height=width, target=GL_TEXTURE_EXTERNAL_OES, colorfmt='rgba')
self._secondary_texture.bind()
self._previewTexture = SurfaceTexture(int(self._secondary_texture.id))
def _init_camera(self, camera_id):
Logger.info('Init camera %d' % camera_id)
if self._camera and self.camera_id == camera_id:
return
self._release_camera()
if IsAndroid:
self._camera = Camera.open(camera_id)
parameters = self._camera.getParameters()
#print parameters.flatten()
if parameters is None:
Logger.warning('Can''t read parameters')
return
supportedSizes = parameters.getSupportedVideoSizes()
if supportedSizes is None:
supportedSizes = parameters.getSupportedPreviewSizes()
sizes = []
if supportedSizes is not None:
iterator = supportedSizes.iterator()
while iterator.hasNext():
cameraSize = iterator.next()
sizes.append((cameraSize.width, cameraSize.height))
pickedSize = self._pick_optimal_size(sizes)
# Update texture according to picked size
self.resolution = list(pickedSize)
parameters.setPreviewSize(*pickedSize)
self._camera.setParameters(parameters)
self._camera.setPreviewTexture(self._previewTexture)
def get_camera(self):
return self._camera
def _resolution_changed(self, instance, value):
Logger.info('Resolution changed to ' + str(value))
self._init_texture(value)
def _camera_id_changed(self, instance, value):
Logger.info('Changed camera %d' % value)
if not IsAndroid:
return
# Transform orientation based on selected camera
if self.camera_id == 0:
sampleVec = ('1.0-tex_coord0.y','1.0-tex_coord0.x')
elif self.camera_id == 1:
sampleVec = ('tex_coord0.y','1.0-tex_coord0.x')
else:
raise Exception('Invalid camera id')
self.canvas.shader.fs = '''
#extension GL_OES_EGL_image_external : require
#ifdef GL_ES
precision highp float;
#endif
/* Outputs from the vertex shader */
varying vec4 frag_color;
varying vec2 tex_coord0;
/* uniform texture samplers */
uniform sampler2D texture0;
uniform samplerExternalOES texture1;
void main()
{
// Flip & Mirror coordinates to rotate source texture by 90 degress
gl_FragColor = texture2D(texture1, vec2(%s,%s));
}
''' % (sampleVec[0], sampleVec[1])
def _play_changed(self, instance, value):
Logger.info('camera %d _play_changed %d' % (self.camera_id, value))
if not IsAndroid:
return
if value:
if not self._camera:
self._init_camera(self.camera_id)
self._camera.startPreview()
Clock.schedule_interval(self._update_canvas, 1.0/30)
else:
if self._camera:
Clock.unschedule(self._update_canvas)
self._camera.stopPreview()
def _release_camera(self):
self.play = False
if self._camera:
self._camera.release()
self._camera = None
def _pick_optimal_size(self, sizes):
# Now just returns the one guaranteed support size
return sizes[0]
def _draw_callback(self, instr):
if self._previewTexture:
self._previewTexture.updateTexImage()
def _update_canvas(self, dt):
self.canvas.ask_update()
