我试图从OpenStreetMaps数据中渲染简单的线条。我使用墨卡托投影将我们得到的纬度经度转换为像素坐标，但是Opengl无法渲染这些近点的点。这些是我的一系列观点。我可以使用vispy渲染点，如果它们相距很远但不是这些点。例如，代码中的注释行确实呈现了点。那么有一种方法可以使视图对于数据近似敏感。
[[ 64.59411621 40.28605652 0.1 ]
[ 64.59389496 40.28595352 0.1 ]
[ 64.59381104 40.28591156 0.1 ]
[ 64.59369659 40.28584671 0.1 ]
[ 64.59358978 40.28577423 0.1 ]
[ 64.59277344 40.28533173 0.1 ]
[ 64.59257507 40.2852211 0.1 ]
[ 64.59215546 40.2849884 0.1 ]
[ 64.59153748 40.2846489 0.1 ]
[ 64.59139252 40.28466415 0.1 ]
[ 64.59128571 40.28461456 0.1 ]
[ 64.59088135 40.28437805 0.1 ]
[ 64.59063721 40.28423691 0.1 ]
[ 64.59036255 40.28408813 0.1 ]
[ 64.59024811 40.28401947 0.1 ]
[ 64.59013367 40.28395844 0.1 ]
[ 64.58982086 40.2837944 0.1 ]
[ 64.58907318 40.28339005 0.1 ]
[ 64.58789825 40.28277206 0.1 ]
[ 64.5867157 40.28213882 0.1 ]
[ 64.58557892 40.2815094 0.1 ]
[ 64.58435822 40.28086472 0.1 ]
[ 64.58195496 40.27965927 0.1 ]]
我们使用的代码来自vispy示例，用于渲染用于渲染线条的线条（python）。
# !/usr/bin/env python
# -*- coding: utf-8 -*-
# vispy: gallery 2
""" Show a bunch of lines.
This example demonstrates how multiple line-pieces can be drawn
using one call, by discarting some fragments.
Note that this example uses canvas.context.X() to call gloo functions.
These functions are also available as vispy.gloo.X(), but apply
explicitly to the canvas. We still need to decide which we think is the
preferred API.
"""
import numpy as np
from vispy import gloo
from vispy import app
from vispy.util.transforms import perspective, translate, rotate, ortho
W, H = 400, 400
# Create vertices
n = 100
a_position = np.random.uniform(-1, 1, (n, 3)).astype(np.float32)
VERT_SHADER = """
uniform mat4 u_model;
uniform mat4 u_view;
uniform mat4 u_projection;
attribute vec3 a_position;
// attribute float a_id;
// varying float v_id;
void main (void) {
// v_id = a_id;
gl_Position = u_projection * u_view * u_model * vec4(a_position, 1.0);
}
"""
FRAG_SHADER = """
// varying float v_id;
void main()
{
// float f = fract(v_id);
// The second useless test is needed on OSX 10.8 (fuck)
/*
if( (f > 0.0001) && (f < .9999) )
discard;
else */
gl_FragColor = vec4(1,0,0,1);
}
"""
class Canvas(app.Canvas):
# ---------------------------------
def __init__(self, buffer):
# buffer = np.array([
# [ -4.42757189e-01, -5.16471803e-01, -6.51616335e-01],
# [ 3.70873958e-01, 3.83630782e-01, 1.89464033e-01],
# [ -9.23565388e-01, 8.84109557e-01, 8.74280035e-01],
# [ 7.06181884e-01, 1.11561500e-01, 4.63272840e-01],
# [ -2.33703643e-01, 8.74389410e-01, -7.08803475e-01],
# [ 9.14665759e-01, -4.91853468e-02, 5.51214755e-01],
# [ -3.51651721e-02, 9.53544497e-01, 1.13748061e-02],
# [ -2.00554803e-01, 8.23601604e-01, -2.01624975e-01],
# [ -5.78361809e-01, -7.19190955e-01, -6.34798348e-01],
# [ 2.07641460e-02, -9.39733744e-01, -7.52322018e-01],
# [ -3.88619483e-01, 6.74676895e-02, -9.36758697e-01],
# [ 8.96090984e-01, 9.09111351e-02, -3.39223385e-01],
# [ -9.60957527e-01, 5.22359312e-01, -9.29324806e-01]]).astype(np.float32)
#
# buffer = np.array([
# [ -4.42757189e-01, -5.16471803e-01, 0.0],
# [ 3.70873958e-01, 3.83630782e-01, 0.0],
# [ -9.23565388e-01, 8.84109557e-01, 0.0],
# [ 7.06181884e-01, 1.11561500e-01, 0.0],
# [ 8.96090984e-01, 9.09111351e-02, 0.0],
# [ -9.60957527e-01, 5.22359312e-01, 0.0]]).astype(np.float32)
# buffer = np.array([
# [ -4.42757189e-01, -5.164743803e-01, 0.0],
# [ 3.70873958e-01, 3.83630782e-01, 0.0]]
# ).astype(np.float32)
#
# buffer = np.array([
# [ 6.459411621e-01, 4.028605652e-01, 0.1 ],
# [ 6.453389496e-01, 4.028395352e-01, 0.1 ]]).astype(np.float32)
print(buffer)
# buffer = a_position
a_id = np.random.randint(0, high=len(buffer) - 1, size=(len(buffer), 1))
a_id = np.sort(a_id, axis=0).astype(np.float32)
app.Canvas.__init__(self, keys='interactive', size=(W, H))
self.program = gloo.Program(VERT_SHADER, FRAG_SHADER)
# Set uniform and attribute
# self.program['a_id'] = gloo.VertexBuffer(a_id)
self.program['a_position'] = gloo.VertexBuffer(buffer[0:3])
self.translate = 5
self.view = translate((0, 0, -self.translate), dtype=np.float32)
self.model = np.eye(4, dtype=np.float32)
gloo.set_viewport(0, 0, self.physical_size[0], self.physical_size[1])
self.projection = perspective(45.0, self.size[0] /
float(self.size[1]), -100.0, 1000.0)
self.projection = ortho(-200, 200, -200, 200, -100, 100)
self.program['u_projection'] = self.projection
self.program['u_model'] = self.model
self.program['u_view'] = self.view
self.theta = 0
self.phi = 0
self.context.set_clear_color('white')
self.context.set_state('translucent')
self.timer = app.Timer('auto', connect=self.on_timer)
self.show()
# ---------------------------------
def on_key_press(self, event):
if event.text == ' ':
if self.timer.running:
self.timer.stop()
else:
self.timer.start()
# ---------------------------------
def on_timer(self, event):
self.theta += .5
self.phi += .5
self.model = np.dot(rotate(self.theta, (0, 0, 1)),
rotate(self.phi, (0, 1, 0)))
self.program['u_model'] = self.model
self.update()
# ---------------------------------
def on_resize(self, event):
gloo.set_viewport(0, 0, event.physical_size[0], event.physical_size[1])
self.projection = perspective(45.0, event.size[0] /
float(event.size[1]), 1.0, 1000.0)
self.projection = ortho(-200, 200, -200, 200, -100, 100)
self.program['u_projection'] = self.projection
# ---------------------------------
def on_mouse_wheel(self, event):
self.translate += event.delta[1]
self.translate = max(2, self.translate)
self.view = translate((0, 0, -self.translate))
self.program['u_view'] = self.view
self.update()
# ---------------------------------
def on_draw(self, event):
self.context.clear()
self.program.draw('points')
if __name__ == '__main__':
buffer = np.array([[ 64.59411621, 40.28605652, 0.1 ],
[ 64.59389496, 40.28595352, 0.1 ],
[ 64.59381104, 40.28591156, 0.1 ],
[ 64.59369659, 40.28584671, 0.1 ],
[ 64.59358978, 40.28577423, 0.1 ],
[ 64.59277344, 40.28533173, 0.1 ],
[ 64.59257507, 40.2852211 , 0.1 ],
[ 64.59215546, 40.2849884 , 0.1 ],
[ 64.59153748, 40.2846489 , 0.1 ],
[ 64.59139252, 40.28466415, 0.1 ],
[ 64.59128571, 40.28461456, 0.1 ],
[ 64.59088135, 40.28437805, 0.1 ],
[ 64.59063721, 40.28423691, 0.1 ],
[ 64.59036255, 40.28408813, 0.1 ],
[ 64.59024811, 40.28401947, 0.1 ],
[ 64.59013367, 40.28395844, 0.1 ],
[ 64.58982086, 40.2837944 , 0.1 ],
[ 64.58907318, 40.28339005, 0.1 ],
[ 64.58789825, 40.28277206, 0.1 ],
[ 64.5867157 , 40.28213882, 0.1 ],
[ 64.58557892, 40.2815094 , 0.1 ],
[ 64.58435822, 40.28086472, 0.1 ],
[ 64.58195496, 40.27965927, 0.1 ]]).astype(np.float32)
c = Canvas(buffer)
app.run()