我不知道如何从屏幕坐标到世界坐标。我正在使用 VisPy，我想在 3D 中实现光线追踪和拾取能力。
我准备了一些基于多维数据集示例的代码。下面的代码通过改变 z 值通过屏幕发送粗射线并打印 3D 坐标（在 ''on_mouse_press'' 方法中）。然而结果并不正确。如果我单击沿射线某处的立方体的右上角应该打印（3,3,3），但事实并非如此。有人可以帮我吗？
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# vispy: gallery 50
"""
This example shows how to display 3D objects.
You should see a colored outlined spinning cube.
"""
import numpy as np
from vispy import app, gloo
from vispy.util.transforms import perspective, translate, rotate
vert = """
// Uniforms
// ------------------------------------
uniform mat4 u_model;
uniform mat4 u_view;
uniform mat4 u_projection;
uniform vec4 u_color;
// Attributes
// ------------------------------------
attribute vec3 a_position;
attribute vec4 a_color;
attribute vec3 a_normal;
// Varying
// ------------------------------------
varying vec4 v_color;
void main()
{
v_color = a_color * u_color;
gl_Position = u_projection * u_view * u_model * vec4(a_position,1.0);
}
"""
frag = """
uniform mat4 u_model;
uniform mat4 u_view;
uniform mat4 u_normal;
uniform vec3 u_light_intensity;
uniform vec3 u_light_position;
varying vec3 v_position;
varying vec3 v_normal;
varying vec4 v_color;
void main()
{
gl_FragColor = v_color;
}
"""
# -----------------------------------------------------------------------------
def cube(num_of_cubes):
"""
Build vertices for a colored cube.
V is the vertices
I1 is the indices for a filled cube (use with GL_TRIANGLES)
I2 is the indices for an outline cube (use with GL_LINES)
"""
for i in range(0,num_of_cubes):
# Vertices positions
v = np.array([[1, 1, 1], [-1, 1, 1], [-1, -1, 1], [1, -1, 1],
[1, -1, -1], [1, 1, -1], [-1, 1, -1], [-1, -1, -1]],dtype=np.float32)
v[:,0]=v[:,0]+2.
v[:,1]=v[:,1]+2.
v[:,2]=v[:,2]+2.
# Face Normals
n =np.array([[0, 0, 1], [1, 0, 0], [0, 1, 0],
[-1, 0, 1], [0, -1, 0], [0, 0, -1]],dtype=np.float32)
# Vertice colors
c = np.array([[0, 0, 1, 1], [0, 0, 1, 1], [0, 0, 1, 1], [0, 0, 1, 1],
[0, 0, 1, 1], [0, 0, 1, 1], [0, 0, 1, 1], [0, 0, 1, 1]],dtype=np.float32)
V_aux = np.array([(v[0], n[0], c[0]), (v[1], n[0], c[1]),
(v[2], n[0], c[2]), (v[3], n[0], c[3]),
(v[0], n[1], c[0]), (v[3], n[1], c[3]),
(v[4], n[1], c[4]), (v[5], n[1], c[5]),
(v[0], n[2], c[0]), (v[5], n[2], c[5]),
(v[6], n[2], c[6]), (v[1], n[2], c[1]),
(v[1], n[3], c[1]), (v[6], n[3], c[6]),
(v[7], n[3], c[7]), (v[2], n[3], c[2]),
(v[7], n[4], c[7]), (v[4], n[4], c[4]),
(v[3], n[4], c[3]), (v[2], n[4], c[2]),
(v[4], n[5], c[4]), (v[7], n[5], c[7]),
(v[6], n[5], c[6]), (v[5], n[5], c[5])]
)
I1_aux = np.resize(np.array([0, 1, 2, 0, 2, 3], dtype=np.uint32), 6 * (2 * 3))
I1_aux += np.repeat(4 * np.arange(2 * 3, dtype=np.uint32), 6)
I2_aux = np.resize(
np.array([0, 1, 1, 2, 2, 3, 3, 0], dtype=np.uint32), 6 * (2 * 4))
I2_aux += np.repeat(4 * np.arange(6, dtype=np.uint32), 8)
if i==0:
V=V_aux
I1=I1_aux
I2=I2_aux
else:
V=np.vstack((V,V_aux))
I1=np.vstack((I1,I1_aux+i*24))
I2=np.vstack((I2,I2_aux+i*24))
return V, I1, I2
# -----------------------------------------------------------------------------
class Canvas(app.Canvas):
def __init__(self):
app.Canvas.__init__(self, keys='interactive', size=(800, 600))
num_of_cubes=1 #number of cubes to draw
self.V, self.filled, self.outline = cube(num_of_cubes)
self.store_pos=np.array((0,0)) #for mouse interaction
self.vert_data=np.vstack(self.V[:,0])
self.V_buf=np.vstack(self.V[:,0])
self.V_buf.dtype=[('a_position',np.float32,3)]
self.vert_buf=gloo.VertexBuffer(self.V_buf)
self.N_buf=np.vstack(self.V[:,1])
self.N_buf.dtype=[('a_normal',np.float32,3)]
self.norm_buf=gloo.VertexBuffer(self.N_buf)
self.C_buf=np.vstack(self.V[:,2])
self.C_buf.dtype=[('a_color',np.float32,4)]
self.colo_buf=gloo.VertexBuffer(self.C_buf)
self.filled_buf=gloo.IndexBuffer(self.filled.flatten())
self.outline_buf=gloo.IndexBuffer(self.outline.flatten())
self.program = gloo.Program(vert, frag)
self.translate = 1
#self.vert_buf=gloo.VertexBuffer(self.vertices.flatten())
self.program.bind(self.vert_buf)
self.program.bind(self.norm_buf)
self.program.bind(self.colo_buf)
self.view = translate((0, 0, -10))
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]), 2.0, 10.0)
self.program['u_projection'] = self.projection
self.program['u_model'] = self.model
self.program['u_view'] = self.view
self.theta = 0
self.phi = 0
gloo.set_clear_color('white')
gloo.set_state('opaque')
gloo.set_polygon_offset(1, 1)
self._timer = app.Timer('auto', connect=self.on_timer, start=True)
self.show()
self.t=0
# ---------------------------------
def on_timer(self, event):
self.update()
# ---------------------------------
def print_mouse_event(self, event, what):
modifiers = ', '.join([key.name for key in event.modifiers])
print('%s - pos: %r, button: %s, modifiers: %s, delta: %r' %
(what, event.pos, event.button, modifiers, event.delta))
def on_mouse_press(self, event):
self.print_mouse_event(event, 'Mouse press')
#convert to NDC
left=event.pos[0]*2/self.size[0]-1
bottom=(self.size[1]-event.pos[1])*2/self.size[1]-1
z_clip=np.linspace(-1.,1.,100)
for val in z_clip:
aux=np.dot(np.dot(np.linalg.inv(self.view),np.linalg.inv(self.projection)),np.array((left,bottom,val,1.)))
pos3d=aux/aux[3]
print(pos3d)
def on_mouse_wheel(self, event):
self.translate -= event.delta[1]
self.translate = max(-1, self.translate)
self.view[3,2]=-self.translate
self.program['u_view'] = self.view
self.update()
def on_draw(self, event):
gloo.clear()
# Filled cube
gloo.set_state(blend=False, depth_test=True, polygon_offset_fill=True)
self.program['u_color'] = 1, 0, 1, 1
self.program.draw('triangles', self.filled_buf)
# Outline
gloo.set_state(polygon_offset_fill=False, blend=True, depth_mask=False)
gloo.set_depth_mask(False)
self.program['u_color'] = 0, 0, 0, 1
self.program.draw('lines', self.outline_buf)
gloo.set_depth_mask(True)
# -----------------------------------------------------------------------------
if __name__ == '__main__':
c = Canvas()
app.run()
