本文介绍了如何在3dsMax中实现对鼠标的缩放?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

当您通过移动鼠标滚轮放大/缩小时,我试图模仿3dsmax的行为。在3ds max中,此缩放将朝着鼠标位置移动。到目前为止,我已经提出了这个小mcve:

 从ctypes中导入数学
从import c_void_p

从numpy中以np
的形式从OpenGL.GL import *
从OpenGL.GLU import *
从OpenGL.GLUT import *
从glm import *


class Camera():

def __init __(
self,
eye = None,target = None,up = None,
fov = None,near = 0.1,far = 100000,
** kwargs
):
self.eye = vec3(eye)或vec3(0,0,1)
self.target = vec3(目标)或vec3(0,0,0)
self.up = vec3(up)或vec3(0,1,0)
self.original_up = vec3(self。 up)
self.fov = fov或弧度(45)
self.near =接近
self.far =远

def update(self,Aspect):
self.view = lookAt(self.eye,self.target,self.up)
self.projection =透视图(self.fov,aspect,self.near,self.far)

def zoom(self,* args):
delta = -args [1] * 0.1
距离=长度(self.target-self.eye)
self.eye = self.target +(self.eye-self.target)*(delta + 1)

def zoom_towards_cursor(self,* args):
x = args [2]
y = args [3]
v = glGetIntegerv(GL_VIEWPORT)
视口= vec4(float(v [0]),float(v [1]),float(v [2]),float(v [3]))
高度= viewport.z

p0 = vec3(x,高度-y,0.0)
p1 = vec3(x,高度-y,1.0)
v1 = unProject(p0,self.view,self.projection,视口)
v2 = unProject(p1,self.view,self.projection,视口)

world_from = vec3(
(-v1.z *(v2.x-v1。 x))/(v2.z-v1.z)+ v1.x,
(-v1.z *(v2.y-v1.y))/(v2.z-v1.z)+ v1 .y,
0.0


self.eye.z = self.eye.z *(1.0 + 0.1 * args [1])$ ​​b
$ b视图= lookAt(self.eye,self.target,self.up)
v1 = unProject(p0,视图,self.projection,视口)
v2 = unProject(p1,视图,self.projection,视口)

world_to = vec3(
(v1 .z *(v2.x-v1.x))/(v2.z-v1.z)+ v1.x,
(-v1.z *(v2.y-v1.y))/( v2.z-v1.z)+ v1.y,
0.0


偏移量= world_to-world_from
print(self.eye.z,world_from, world_to,偏移量)

self.eye + =偏移量
self.target + =偏移量


类GlutController():

def __init __(self,camera):
self.camera =相机
self.zoom = self.camera.zoom

def glut_mouse_wheel(self,* args):
self.zoom(* args)


class MyWindow:

def __init __(self,w,h):
self。宽度= w
self.height = h

glutInit()
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)
glutInitWindowSize(w,h)
glutCreateWindow('OpenGL Window')

self.startup()

glutReshapeFunc(self.reshape)
glutDisplayFunc(self.display)
glutMouseWheelFunc(self.controller.glut_mouse_wheel)
glutKeyboardFunc(self.keyboard_func)
glutIdleFunc(self.idle_func)

def keyboard_func(self,* args):
尝试:
键= args [0] .decode( utf8)

如果key == \x1b:
glutLeaveMainLoop()

如果键入['1']:
self.controller.zoom = self.camera.zoom
print(使用普通缩放 )
elif键输入['2']:
self.controller.zoom = self.camera.zoom_towards_cursor
print(使用向鼠标缩放)

例外,例如e:
导入跟踪
traceback.print_ exc()

def startup(self):
glEnable(GL_DEPTH_TEST)

Aspect = self.width / self.height
params = {
eye:vec3(10,10,10),
target:vec3(0,0,0),
up:vec3(0,1,0)
}
self.cameras = [
Camera(** params)
]
self.camera = self.cameras [0]
self.model = mat4(1)
self.controller = GlutController(self.camera)

def run(self):
glutMainLoop()

def idle_func( self):
glutPostRedisplay()

def reshape(self,w,h):
glViewport(0,0,w,h)
self.width = w
self.height = h

def display(self):
self.camera.update(self.width / self.height)

glClearColor(0.2,0.3,0.3,1.0)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

glMatrixMode(GL_PROJECTION)
glLoadIdentity()
gluPerspective(degrees(self.camera.fov),self.width / self.height,self.camera.near, self.camera.far)
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
e = self.camera.eye
t = self.camera.target
u = self.camera。向上
gluLookAt(ex,ey,ez,tx,ty,tz,ux,uy,uz)
glColor3f(1,1,1)
glBegin(GL_LINES)
为i在范围(-5,6)中:
如果i == 0:
继续
glVertex3f(-5,0,i)
glVertex3f(5,0,i)
glVertex3f(i,0,-5)
glVertex3f(i,0,5)
glEnd()

glBegin(GL_LINES)
glColor3f( 1,1,1)
glVertex3f(-5,0,0)
glVertex3f(0,0,0)
glVertex3f(0,0,-5)
glVertex3f( 0,0,0)

glColor3f(1、0、0)
glVertex3f(0、0、0)
glVertex3f(5、0、0)
glColor3f(0、1、0)
glVertex3f( 0,0,0)
glVertex3f(0,5,0)
glColor3f(0,0,1)
glVertex3f(0,0,0)
glVertex3f(0, 0,5)
glEnd()

glutSwapBuffers()


如果__name__ =='__main__':
window = MyWindow( 800,600)
window.run()

在此代码段中,您可以在2个之间切换按下 1或 2键可进入缩放模式。



按'1'时,我正在执行标准缩放,到目前为止效果很好。



问题是当按下'2'时,在这种情况下,我尝试从


I'm trying to mimick the 3dsmax behaviour when you zoom in/out by moving the mouse wheel. In 3ds max this zooming will be towards the mouse position. So far I've come up with this little mcve:

import math
from ctypes import c_void_p

import numpy as np
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *
from glm import *


class Camera():

    def __init__(
        self,
        eye=None, target=None, up=None,
        fov=None, near=0.1, far=100000,
        **kwargs
    ):
        self.eye = vec3(eye) or vec3(0, 0, 1)
        self.target = vec3(target) or vec3(0, 0, 0)
        self.up = vec3(up) or vec3(0, 1, 0)
        self.original_up = vec3(self.up)
        self.fov = fov or radians(45)
        self.near = near
        self.far = far

    def update(self, aspect):
        self.view = lookAt(self.eye, self.target, self.up)
        self.projection = perspective(self.fov, aspect, self.near, self.far)

    def zoom(self, *args):
        delta = -args[1] * 0.1
        distance = length(self.target - self.eye)
        self.eye = self.target + (self.eye - self.target) * (delta + 1)

    def zoom_towards_cursor(self, *args):
        x = args[2]
        y = args[3]
        v = glGetIntegerv(GL_VIEWPORT)
        viewport = vec4(float(v[0]), float(v[1]), float(v[2]), float(v[3]))
        height = viewport.z

        p0 = vec3(x, height - y, 0.0)
        p1 = vec3(x, height - y, 1.0)
        v1 = unProject(p0, self.view, self.projection, viewport)
        v2 = unProject(p1, self.view, self.projection, viewport)

        world_from = vec3(
            (-v1.z * (v2.x - v1.x)) / (v2.z - v1.z) + v1.x,
            (-v1.z * (v2.y - v1.y)) / (v2.z - v1.z) + v1.y,
            0.0
        )

        self.eye.z = self.eye.z * (1.0 + 0.1 * args[1])

        view = lookAt(self.eye, self.target, self.up)
        v1 = unProject(p0, view, self.projection, viewport)
        v2 = unProject(p1, view, self.projection, viewport)

        world_to = vec3(
            (v1.z * (v2.x - v1.x)) / (v2.z - v1.z) + v1.x,
            (-v1.z * (v2.y - v1.y)) / (v2.z - v1.z) + v1.y,
            0.0
        )

        offset = world_to - world_from
        print(self.eye.z, world_from, world_to, offset)

        self.eye += offset
        self.target += offset


class GlutController():

    def __init__(self, camera):
        self.camera = camera
        self.zoom = self.camera.zoom

    def glut_mouse_wheel(self, *args):
        self.zoom(*args)


class MyWindow:

    def __init__(self, w, h):
        self.width = w
        self.height = h

        glutInit()
        glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)
        glutInitWindowSize(w, h)
        glutCreateWindow('OpenGL Window')

        self.startup()

        glutReshapeFunc(self.reshape)
        glutDisplayFunc(self.display)
        glutMouseWheelFunc(self.controller.glut_mouse_wheel)
        glutKeyboardFunc(self.keyboard_func)
        glutIdleFunc(self.idle_func)

    def keyboard_func(self, *args):
        try:
            key = args[0].decode("utf8")

            if key == "\x1b":
                glutLeaveMainLoop()

            if key in ['1']:
                self.controller.zoom = self.camera.zoom
                print("Using normal zoom")
            elif key in ['2']:
                self.controller.zoom = self.camera.zoom_towards_cursor
                print("Using zoom towards mouse")

        except Exception as e:
            import traceback
            traceback.print_exc()

    def startup(self):
        glEnable(GL_DEPTH_TEST)

        aspect = self.width / self.height
        params = {
            "eye": vec3(10, 10, 10),
            "target": vec3(0, 0, 0),
            "up": vec3(0, 1, 0)
        }
        self.cameras = [
            Camera(**params)
        ]
        self.camera = self.cameras[0]
        self.model = mat4(1)
        self.controller = GlutController(self.camera)

    def run(self):
        glutMainLoop()

    def idle_func(self):
        glutPostRedisplay()

    def reshape(self, w, h):
        glViewport(0, 0, w, h)
        self.width = w
        self.height = h

    def display(self):
        self.camera.update(self.width / self.height)

        glClearColor(0.2, 0.3, 0.3, 1.0)
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()
        gluPerspective(degrees(self.camera.fov), self.width / self.height, self.camera.near, self.camera.far)
        glMatrixMode(GL_MODELVIEW)
        glLoadIdentity()
        e = self.camera.eye
        t = self.camera.target
        u = self.camera.up
        gluLookAt(e.x, e.y, e.z, t.x, t.y, t.z, u.x, u.y, u.z)
        glColor3f(1, 1, 1)
        glBegin(GL_LINES)
        for i in range(-5, 6):
            if i == 0:
                continue
            glVertex3f(-5, 0, i)
            glVertex3f(5, 0, i)
            glVertex3f(i, 0, -5)
            glVertex3f(i, 0, 5)
        glEnd()

        glBegin(GL_LINES)
        glColor3f(1, 1, 1)
        glVertex3f(-5, 0, 0)
        glVertex3f(0, 0, 0)
        glVertex3f(0, 0, -5)
        glVertex3f(0, 0, 0)

        glColor3f(1, 0, 0)
        glVertex3f(0, 0, 0)
        glVertex3f(5, 0, 0)
        glColor3f(0, 1, 0)
        glVertex3f(0, 0, 0)
        glVertex3f(0, 5, 0)
        glColor3f(0, 0, 1)
        glVertex3f(0, 0, 0)
        glVertex3f(0, 0, 5)
        glEnd()

        glutSwapBuffers()


if __name__ == '__main__':
    window = MyWindow(800, 600)
    window.run()

In this snippet you can switch between 2 zooming modes by pressing keys '1' or '2' keys.

When pressing '1' I'm doing an standard zooming, so far so good.

Problem is when pressing '2', in this case I've tried to adapt code from this thread to python/pyopengl/pygml but because I didn't understand very well the underlying maths of that answer I don't know very well how to fix the bad behaviour.

How would you fix the posted code so it will zoom in/out towards the mouse properly like 3dsmax?

解决方案

A possible solution is to move the camera along a ray, from the camera position through the cursor (mouse) position and to move the target position in parallel.

self.eye    = self.eye    + ray_cursor * delta
self.target = self.target + ray_cursor * delta

For this the window position of the cursor has to be "un-projected" (unProject).

Calculate the cursor position in world space (e.g. on the far plane):

pt_wnd   = vec3(x, height - y, 1.0)
pt_world = unProject(pt_wnd, self.view, self.projection, viewport)

The ray from the eye position through the cursor is given by the the normalized vector from the eye position to the world space cursor position:

ray_cursor = normalize(pt_world - self.eye)

There is an issue in your code when you get the window height from the viewport rectangle, because the height is the .w component rather than the .z component:

v = glGetIntegerv(GL_VIEWPORT)
viewport = vec4(float(v[0]), float(v[1]), float(v[2]), float(v[3]))
width  = viewport.z
height = viewport.w

Full code listing of the function zoom_towards_cursor:

def zoom_towards_cursor(self, *args):
    x = args[2]
    y = args[3]
    v = glGetIntegerv(GL_VIEWPORT)
    viewport = vec4(float(v[0]), float(v[1]), float(v[2]), float(v[3]))
    width  = viewport.z
    height = viewport.w

    pt_wnd     = vec3(x, height - y, 1.0)
    pt_world   = unProject(pt_wnd, self.view, self.projection, viewport)
    ray_cursor = normalize(pt_world - self.eye)

    delta = -args[1]
    self.eye    = self.eye    + ray_cursor * delta
    self.target = self.target + ray_cursor * delta

Preview:

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09-02 12:59