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| try: | |
| from ctypes import c_float | |
| except ImportError: | |
| pass | |
| import pyglet.gl as pgl | |
| from math import sqrt as _sqrt, acos as _acos | |
| def cross(a, b): | |
| return (a[1] * b[2] - a[2] * b[1], | |
| a[2] * b[0] - a[0] * b[2], | |
| a[0] * b[1] - a[1] * b[0]) | |
| def dot(a, b): | |
| return a[0] * b[0] + a[1] * b[1] + a[2] * b[2] | |
| def mag(a): | |
| return _sqrt(a[0]**2 + a[1]**2 + a[2]**2) | |
| def norm(a): | |
| m = mag(a) | |
| return (a[0] / m, a[1] / m, a[2] / m) | |
| def get_sphere_mapping(x, y, width, height): | |
| x = min([max([x, 0]), width]) | |
| y = min([max([y, 0]), height]) | |
| sr = _sqrt((width/2)**2 + (height/2)**2) | |
| sx = ((x - width / 2) / sr) | |
| sy = ((y - height / 2) / sr) | |
| sz = 1.0 - sx**2 - sy**2 | |
| if sz > 0.0: | |
| sz = _sqrt(sz) | |
| return (sx, sy, sz) | |
| else: | |
| sz = 0 | |
| return norm((sx, sy, sz)) | |
| rad2deg = 180.0 / 3.141592 | |
| def get_spherical_rotatation(p1, p2, width, height, theta_multiplier): | |
| v1 = get_sphere_mapping(p1[0], p1[1], width, height) | |
| v2 = get_sphere_mapping(p2[0], p2[1], width, height) | |
| d = min(max([dot(v1, v2), -1]), 1) | |
| if abs(d - 1.0) < 0.000001: | |
| return None | |
| raxis = norm( cross(v1, v2) ) | |
| rtheta = theta_multiplier * rad2deg * _acos(d) | |
| pgl.glPushMatrix() | |
| pgl.glLoadIdentity() | |
| pgl.glRotatef(rtheta, *raxis) | |
| mat = (c_float*16)() | |
| pgl.glGetFloatv(pgl.GL_MODELVIEW_MATRIX, mat) | |
| pgl.glPopMatrix() | |
| return mat | |