"""
This example demonstrates the use of GLSurfacePlotItem.
"""

import numpy as np

import pyqtgraph as pg
import pyqtgraph.opengl as gl
from pyqtgraph.Qt import QtCore

## Create a GL View widget to display data
app = pg.mkQApp("GLSurfacePlot Example")
w = gl.GLViewWidget()
w.show()
w.setWindowTitle('pyqtgraph example: GLSurfacePlot')
w.setCameraPosition(distance=50)

## Add a grid to the view
g = gl.GLGridItem()
g.scale(2,2,1)
g.setDepthValue(10)  # draw grid after surfaces since they may be translucent
w.addItem(g)


## Simple surface plot example
## x, y values are not specified, so assumed to be 0:50
z = pg.gaussianFilter(np.random.normal(size=(50,50)), (1,1))
p1 = gl.GLSurfacePlotItem(z=z, shader='shaded', color=(0.5, 0.5, 1, 1))
p1.scale(16./49., 16./49., 1.0)
p1.translate(-18, 2, 0)
w.addItem(p1)


## Saddle example with x and y specified
x = np.linspace(-8, 8, 50)
y = np.linspace(-8, 8, 50)
z = 0.1 * ((x.reshape(50,1) ** 2) - (y.reshape(1,50) ** 2))
p2 = gl.GLSurfacePlotItem(x=x, y=y, z=z, shader='normalColor')
p2.translate(-10,-10,0)
w.addItem(p2)


## Manually specified colors
z = pg.gaussianFilter(np.random.normal(size=(50,50)), (1,1))
x = np.linspace(-12, 12, 50)
y = np.linspace(-12, 12, 50)
colors = np.ones((50,50,4), dtype=np.float32)
colors[...,0] = np.clip(np.cos(((x.reshape(50,1) ** 2) + (y.reshape(1,50) ** 2)) ** 0.5), 0, 1)
colors[...,1] = colors[...,0]

p3 = gl.GLSurfacePlotItem(z=z, colors=colors.reshape(50*50,4), shader='shaded', smooth=False)
p3.scale(16./49., 16./49., 1.0)
p3.translate(2, -18, 0)
w.addItem(p3)




## Animated example
## compute surface vertex data
cols = 90
rows = 100
x = np.linspace(-8, 8, cols+1).reshape(cols+1,1)
y = np.linspace(-8, 8, rows+1).reshape(1,rows+1)
d = (x**2 + y**2) * 0.1
d2 = d ** 0.5 + 0.1

## precompute height values for all frames
phi = np.arange(0, np.pi*2, np.pi/20.)
z = np.sin(d[np.newaxis,...] + phi.reshape(phi.shape[0], 1, 1)) / d2[np.newaxis,...]


## create a surface plot, tell it to use the 'heightColor' shader
## since this does not require normal vectors to render (thus we 
## can set computeNormals=False to save time when the mesh updates)
p4 = gl.GLSurfacePlotItem(x=x[:,0], y = y[0,:], shader='heightColor', computeNormals=False, smooth=False)
p4.shader()['colorMap'] = np.array([0.2, 2, 0.5, 0.2, 1, 1, 0.2, 0, 2])
p4.translate(10, 10, 0)
w.addItem(p4)

index = 0
def update():
    global p4, z, index
    index -= 1
    p4.setData(z=z[index%z.shape[0]])
    
timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(30)

if __name__ == '__main__':
    pg.exec()
