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Feb 10, 2012, 6:50:50 AM2/10/12

to glumpy-users, belev...@gmail.com

Hi all,

I am trying to plot large number of lines in 2d (about 40k lines 50

points each). Unfortunately, matplotlib and other libraries are very

slow at plotting large dataset. My initial benchmarks of plotting with

PyOpenGL showed that it can be more than 10 times faster even for

simple 2d graphs.

Then I found glumpy and as far as I understand it tries to solve very

similar problem. It would be great if we could use it for our project.

Is it possible to plot line graphs in glumpy? If not, what would be

necessary to implement such a feature?

Here is my benchmark PyOpenGL code: https://gist.github.com/1716954#file_test_opengl.py

. (if you scroll up/down you will find alternative - slower -

implementations). Please take a look at it, if you want to know

exactly what I have in mind.

Yours,

Bartosz

I am trying to plot large number of lines in 2d (about 40k lines 50

points each). Unfortunately, matplotlib and other libraries are very

slow at plotting large dataset. My initial benchmarks of plotting with

PyOpenGL showed that it can be more than 10 times faster even for

simple 2d graphs.

Then I found glumpy and as far as I understand it tries to solve very

similar problem. It would be great if we could use it for our project.

Is it possible to plot line graphs in glumpy? If not, what would be

necessary to implement such a feature?

Here is my benchmark PyOpenGL code: https://gist.github.com/1716954#file_test_opengl.py

. (if you scroll up/down you will find alternative - slower -

implementations). Please take a look at it, if you want to know

exactly what I have in mind.

Yours,

Bartosz

Feb 10, 2012, 10:33:02 AM2/10/12

to glumpy-users

There is not such 2d graphs even if you can use glumpy window to draw

anything you want. In the previous glumpy version, there was a script

showing how to integrate matplotlib and glumpy and I need to put it

back into the examples. That may be the best solution in your case,

all the fancy stuff is done by matplotlib and the fast stuff is done

using glumpy.

I've looked at your code and I think your OpenGL is quite efficient.

You can speed it up a little bit by discarding depth buffer as shown

below.

Nicolas

import sys

import numpy as np

import OpenGL

OpenGL.ERROR_ON_COPY = True

import OpenGL.GL as gl

import OpenGL.GLUT as glut

frame, timebase = 0, 0

def display():

global frame, timebase

frame = frame+1

time = glut.glutGet( glut.GLUT_ELAPSED_TIME )

if (time - timebase > 1000):

fps = frame*1000.0/(time-timebase)

print fps

timebase,frame = time,0

gl.glClearColor(0,0,0,1)

gl.glEnable(gl.GL_BLEND)

gl.glBlendFunc(gl.GL_SRC_ALPHA, gl.GL_ONE_MINUS_SRC_ALPHA)

gl.glClear(gl.GL_COLOR_BUFFER_BIT)

x,y,width,height = gl.glGetIntegerv(gl.GL_VIEWPORT)

# n = number of lines, p = points per line

n,p = 5000, 50

vertices = np.zeros((n,p,2),dtype=np.float32)

vertices[:,:,0] = np.random.uniform(0,width,n*p).reshape(n,p)

vertices[:,:,1] = np.random.uniform(0,height,n*p).reshape(n,p)

gl.glColor(1, 1, 1, 0.05)

gl.glEnableClientState(gl.GL_VERTEX_ARRAY)

gl.glVertexPointer(2, gl.GL_FLOAT, 0, vertices)

for i in xrange(n):

gl.glDrawArrays(gl.GL_LINE_STRIP, i*p, p)

gl.glDisableClientState(gl.GL_VERTEX_ARRAY);

glut.glutSwapBuffers()

def reshape(width,height):

gl.glViewport(0, 0, width, height)

gl.glMatrixMode(gl.GL_PROJECTION)

gl.glLoadIdentity()

gl.glOrtho(0, width, 0, height, -1, 1)

gl.glMatrixMode(gl.GL_MODELVIEW)

def keyboard( key, x, y ):

if key == '\033': sys.exit( )

if __name__ == '__main__':

glut.glutInit(sys.argv)

glut.glutInitDisplayMode(glut.GLUT_DOUBLE | glut.GLUT_RGBA)

glut.glutCreateWindow('glut-lines')

glut.glutReshapeWindow(800,800)

glut.glutDisplayFunc(display)

glut.glutReshapeFunc(reshape)

glut.glutKeyboardFunc(keyboard )

glut.glutIdleFunc(display)

glut.glutMainLoop()

Feb 10, 2012, 10:46:40 AM2/10/12

to glumpy...@googlegroups.com, Дмитро Бєлєвцов

Thanks for reply and tips.

Do you think that 2d graphs could be included in glumpy? We do not actually need much fancy matplotlib stuff, such as ticks, axes and so on; just plotting the lines + zoom in/out.

Bartek

Feb 13, 2012, 1:39:02 AM2/13/12

to glumpy-users

I've started this some time ago and I will reconsider including it in

glumpy. It won't in the next fex days since I'm a bit busy until end

of February. I intend to update glumpy after that.

On Feb 10, 4:46 pm, Bartosz Telenczuk <bartosz.telenc...@gmail.com>

wrote:

Feb 13, 2012, 6:53:46 AM2/13/12

to glumpy...@googlegroups.com

Cool. Please keep me informed. I will be definitely interested to test it.

Bartosz

May 3, 2012, 3:43:18 PM5/3/12

to glumpy...@googlegroups.com

Hi,

Понеділок, 13 лютого 2012 р. 13:53:46 UTC+2 користувач Bartosz написав:

I'm currently trying to port the Bartosz's example to glumpy. It runs, but I can't get the alpha blending to work. What could be the problem?

import numpy as np

import OpenGL.GL as gl

import glumpy

fig = glumpy.figure(size=(400,400))

n_pts = 34

n_lines = 50

t = np.linspace(-1, 1, n_pts)

y = np.sin(t*np.pi)

vertices = np.empty((n_lines, n_pts, 2), dtype=np.float)

vertices[:,:,0] = t[:, None].T

for i in xrange(n_lines):

vertices[i,:,1] = y + (np.random.uniform(size=n_pts)-0.5)*0.5

vertices = vertices.flatten()

@fig.event

def on_draw():

fig.clear()

gl.glEnable(gl.GL_BLEND)

gl.glBlendFunc(gl.GL_SRC_ALPHA, gl.GL_ONE_MINUS_SRC_ALPHA)

gl.glMatrixMode(gl.GL_PROJECTION)

gl.glLoadIdentity()

gl.glEnableClientState(gl.GL_VERTEX_ARRAY)

gl.glVertexPointer(2, gl.GL_FLOAT, 0, vertices)

gl.glColor4f(1.0,0.0,0.0,0.1)

for i in xrange(n_lines):

gl.glDrawArrays(gl.GL_LINE_STRIP, i*n_pts, n_pts)

gl.glDisableClientState(gl.GL_VERTEX_ARRAY)

fig.show()

Cheers,

Dmytro

Cool. Please keep me informed. I will be definitely interested to test it.

BartoszWhat

May 8, 2012, 4:53:57 AM5/8/12

to glumpy...@googlegroups.com

Ok, figured it out, the problem was that I didn't disable the depth buffer:

gl.glDisable(gl.GL_DEPTH_TEST)

Now it works just fine.

Четвер, 3 травня 2012 р. 22:43:18 UTC+3 користувач Дмитро Бєлєвцов написав:

Четвер, 3 травня 2012 р. 22:43:18 UTC+3 користувач Дмитро Бєлєвцов написав:

Aug 17, 2012, 4:20:43 AM8/17/12

to glumpy...@googlegroups.com

I've added a link int the news to some experiment I'm currently doing for rendering lines and shapes. You can find it here:

and you might be interested in the very last screenshots that show pan/zoom with a bunch of lines.

Code is available from:

I intend to integrate it into glumpy at some point in the future but may the demo-lines is what you want.

Nicolas

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