I want to create a PyOpenGL/QtOpenGL widget that will allow me to visualize an arbitrary NumPy 3D matrix, not unlike the following Hinton diagram envisioned as a "cube of cubes" instead of a "square of squares":
I'm having a bit of a rough time with OpenGL though. Here is my code thus far:
from OpenGL.GL import *
from OpenGL.GLUT import *
from PyQt4 import QtGui, QtOpenGL
import numpy as np
action_keymap = {
# 'a': lambda: glTranslate(-1, 0, 0),
# 'd': lambda: glTranslate( 1, 0, 0),
# 'w': lambda: glTranslate( 0, 1, 0),
# 's': lambda: glTranslate( 0,-1, 0),
'a': lambda: glRotate(-5, 0, 1, 0),
'd': lambda: glRotate( 5, 0, 1, 0),
# 'W': lambda: glRotate(-5, 1, 0, 0),
# 'S': lambda: glRotate( 5, 1, 0, 0),
}
ARRAY = np.ones([3,3,3])
class GLWidget(QtOpenGL.QGLWidget):
def paintGL(self):
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
for idx, value in np.ndenumerate(ARRAY):
rel_pos = np.array(idx)/np.max(ARRAY.shape)
glTranslate(* rel_pos)
glutSolidCube(0.9/np.max(ARRAY.shape))
glTranslate(*-rel_pos)
def resizeGL(self, w, h):
glLoadIdentity()
glRotate(35,1,0,0)
glRotate(45,0,1,0)
def initializeGL(self):
glClearColor(0.1, 0.1, 0.3, 1.0)
def keyPressEvent(self, event):
action = action_keymap.get(str(event.text()))
if action:
action()
self.updateGL()
def mousePressEvent(self, event):
super().mousePressEvent(event)
self.press_point = event.pos()
def mouseMoveEvent(self, event):
super().mouseMoveEvent(event)
motion = event.pos()-self.press_point
self.press_point = event.pos()
glRotate(motion.x(),0,1,0)
glRotate(motion.y(),1,0,0)
self.updateGL()
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
w = GLWidget()
w.show()
sys.exit(app.exec_())
My problems are as follows:
1) Lighting. I've been reading up on lighting and materials, but I cannot seem to get a simple light somewhere giving the shape some clarity. I'd like the simplest, most basic possible light to be able to distinguish the squares instead of them being all rendered as pure white on all sides. I know how to change the color, but it doesn't alleviate the problem. What is the simplest light I can shine on this lattice to get some clarity on the subcomponents?
2) It is slow. I'll work out the math to achieve proper positioning and resizing of squares down the line, but I was wondering if there was a way to vectorize the process (after all, it's only turning the index into a translation and the value into a cube size for every element in the array). Should I write an extension in cpp, wrap my code with ctypes, or is there a way to outsource the work to OpenGL explicitly? What is the standard way to send a repetitive task to OpenGL from Python?
glutSolidCubewithglutWireCube? – lmjohns3 Aug 6 '13 at 16:49Joaqimapp I found on Google. I didn't do a very good job, though, since the top of all cubes was white and the bottom of all cubes was black, but it allowed some idea of what was what. – RodericDay Aug 6 '13 at 16:52