def _approx_derivative(easing_name, t, easing_args, offsets):
delta = 1e-10
t0 = max(0, t - delta)
t1 = min(1, t + delta)
y0 = ngl.easing_evaluate(easing_name, t0, easing_args, offsets)
y1 = ngl.easing_evaluate(easing_name, t1, easing_args, offsets)
return (y1 - y0) / (t1 - t0)
def anim_forward_api(nb_points=7):
scale = 1.0 / float(nb_points)
ret = []
times = [i * scale for i in range(nb_points + 1)]
for easing in _easing_list:
easing_name, easing_args = _easing_split(easing)
for offsets in _offsets:
values = [ngl.easing_evaluate(easing_name, t, easing_args, offsets) for t in times]
ret.append((easing_name, values))
return ret
def _get_easing_node(cfg, easing, curve_zoom, color_program, nb_points=128):
text_vratio = 1 / 8.
graph_hpad_ratio = 1 / 16.
area_size = 2.0
width, height = area_size, area_size
text_height = text_vratio * height
pad_height = graph_hpad_ratio * height
# Colors
hue = random.uniform(0, 0.6)
color = list(colorsys.hls_to_rgb(hue, 0.6, 1.0)) + [1]
ucolor = ngl.UniformVec4(value=color)
graph_bg_ucolor = ngl.UniformVec4(value=(.15, .15, .15, 1))
normed_graph_bg_ucolor = ngl.UniformVec4(value=(0, 0, 0, 1))
line_ucolor = ngl.UniformVec4(value=(1, 1, 1, .4))
# Text legend
text = ngl.Text(text=easing,
fg_color=color,
padding=3,
bg_color=(0, 0, 0, 1),
box_corner=(-width / 2., height / 2. - text_height, 0),
box_width=(width, 0, 0),
box_height=(0, text_height, 0),
label='%s legend' % easing)
# Graph drawing area (where the curve may overflow)
graph_size = area_size - text_height - pad_height * 2
graph_block = _block(graph_size,
graph_size,
color_program,
corner=(-graph_size / 2,
-(graph_size + text_height) / 2, 0),
color=graph_bg_ucolor)
# Normed area of the graph
normed_graph_size = graph_size * curve_zoom
normed_graph_block = _block(normed_graph_size,
normed_graph_size,
color_program,
corner=(-normed_graph_size / 2,
-(normed_graph_size + text_height) / 2,
0),
color=normed_graph_bg_ucolor)
# Curve
easing_name, easing_args = _easing_split(easing)
curve_scale_factor = graph_size / area_size * curve_zoom
vertices_data = array.array('f')
for i in range(nb_points + 1):
t = i / float(nb_points)
v = ngl.easing_evaluate(easing_name, t, easing_args)
x = curve_scale_factor * (t * width - width / 2.)
y = curve_scale_factor * (v * height - height / 2.)
y -= text_height / 2.
vertices_data.extend([x, y, 0])
vertices = ngl.BufferVec3(data=vertices_data)
geometry = ngl.Geometry(vertices, topology='line_strip')
curve = ngl.Render(geometry, color_program, label='%s curve' % easing)
curve.update_uniforms(color=ucolor)
# Value cursor
y = 2 / 3. * pad_height
x = y * math.sqrt(3)
cursor_geometry = ngl.Triangle((-x, y, 0), (0, 0, 0), (-x, -y, 0))
cursor = ngl.Render(cursor_geometry,
color_program,
label='%s cursor' % easing)
cursor.update_uniforms(color=ucolor)
# Horizontal value line
hline_data = array.array('f', (0, 0, 0, graph_size, 0, 0))
hline_vertices = ngl.BufferVec3(data=hline_data)
hline_geometry = ngl.Geometry(hline_vertices, topology='line_strip')
hline = ngl.Render(hline_geometry,
color_program,
label='%s value line' % easing)
hline.update_uniforms(color=line_ucolor)
# Value animation (cursor + h-line)
value_x = -graph_size / 2.
value_y = (-text_height - normed_graph_size) / 2.
value_animkf = (
ngl.AnimKeyFrameVec3(0, (value_x, value_y, 0)),
ngl.AnimKeyFrameVec3(cfg.duration,
(value_x, value_y + normed_graph_size, 0),
easing_name, easing_args),
)
value_anim = ngl.Group(children=(hline, cursor))
value_anim = ngl.Translate(value_anim,
anim=ngl.AnimatedVec3(value_animkf),
label='%s value anim' % easing)
# Vertical time line
vline_data = array.array('f', (0, 0, 0, 0, graph_size, 0))
vline_vertices = ngl.BufferVec3(data=vline_data)
vline_geometry = ngl.Geometry(vline_vertices, topology='line_strip')
vline = ngl.Render(vline_geometry,
color_program,
label='%s time line' % easing)
vline.update_uniforms(color=line_ucolor)
# Time animation (v-line only)
time_x = -normed_graph_size / 2.
time_y = (-text_height - graph_size) / 2.
time_animkf = (ngl.AnimKeyFrameVec3(0, (time_x, time_y, 0)),
ngl.AnimKeyFrameVec3(
cfg.duration, (time_x + normed_graph_size, time_y, 0)))
time_anim = ngl.Translate(vline,
anim=ngl.AnimatedVec3(time_animkf),
label='%s time anim' % easing)
group = ngl.Group(label='%s block' % easing)
group.add_children(text, graph_block, normed_graph_block, curve,
value_anim, time_anim)
return group