所以我一直在努力学习3D渲染是如何工作的。我试着写一个脚本,目标是在3D空间中旋转一个平面(2D)正方形。我首先在标准化空间(-1,1)中定义一个正方形。请注意,只有x和y是标准化的
class Vec3:
# 3D VECTOR
def __init__(self, x, y, z):
self.x = x
self.y = y
self.z = z
s = 1
p1 = Vec3(-s, -s, -s)
p2 = Vec3(s, -s, -s)
p3 = Vec3(s, s, -s)
p4 = Vec3(-s, s, -s)
然后将这些点转换到屏幕中:
p1.z += 6
p2.z += 6
p3.z += 6
p4.z += 6
这之后的一切都是在应用程序循环中完成的。我使用以下功能将点缩放到屏幕上,并应用投影:
class Transform:
# IT TRANSFORMS THE X AND Y FROM NORMALISED SPACE TO SCREEN SPACE WITH PROJECTION APPLIED
def worldSpaceTransform(self, vec3, w, h):
if vec3.z == 0:
vec3.z = 0.001
zInverse = 1/ vec3.z
xTransformed = ((vec3.x * zInverse) + 1) * (w/2)
yTransformed = ((-vec3.y * zInverse) + 1) * (h/2)
xTransformed = str(xTransformed)[:6]
yTransformed = str(yTransformed)[:6]
return Vec2(float(xTransformed), float(yTransformed))
像这样:
# TRANSLATING THE SQUARE SHEET INTO THE SCREEN SPACE
point1 = transform.worldSpaceTransform(p1, SCREENWIDTH, SCREENHEIGHT)
point2 = transform.worldSpaceTransform(p2, SCREENWIDTH, SCREENHEIGHT)
point3 = transform.worldSpaceTransform(p3, SCREENWIDTH, SCREENHEIGHT)
point4 = transform.worldSpaceTransform(p4, SCREENWIDTH, SCREENHEIGHT)
并得出以下要点:
# STORING THE POINTS TO A TUPLE SO IT CAN BE DRAWN USING pygame.draw.lines
points = ((point1.x, point1.y), (point2.x, point2.y),
(point2.x, point2.y), (point3.x, point3.y),
(point3.x, point3.y), (point4.x, point4.y),
(point4.x, point4.y), (point1.x, point1.y))
pygame.draw.lines(D, (0, 0, 0), False, points)
到目前为止,一切都是有效的(我认为),因为它画了一个正方形,就像它应该画的那样
现在轮换。我试着旋转所有的轴,但没有一个能工作,但为了具体起见,我将讨论x轴。下面是旋转类。我从维基百科复制了旋转矩阵。我不完全确定它们是如何工作的,所以我也不知道它是否与我上面描述的系统兼容
def multVecMatrix(vec3, mat3):
# MULTIPLIES A Vec3 OBJECT WITH Mat3 OBJECT AND RETURNS A NEW Vec3 ?
x = vec3.x * mat3.matrix[0][0] + vec3.y * mat3.matrix[0][1] + vec3.z * mat3.matrix[0][2]
y = vec3.x * mat3.matrix[1][0] + vec3.y * mat3.matrix[1][1] + vec3.z * mat3.matrix[1][2]
z = vec3.x * mat3.matrix[2][0] + vec3.y * mat3.matrix[2][1] + vec3.z * mat3.matrix[2][2]
return Vec3(x, y, z)
class Rotation:
def rotateX(self, theta):
# ROTATION MATRIX IN X AXIS ??
sinTheta = sin(theta)
cosTheta = cos(theta)
m = Mat3()
m.matrix = [[1, 0, 0],
[0, cosTheta, sinTheta],
[0, -sinTheta, cosTheta]]
return m
def rotate(self, vec3, theta, axis=None):
# ROTATES A Vec3 BY GIVEN THETA AND AXIS ??
if axis == "x":
return multVecMatrix(vec3, self.rotateX(theta))
if axis == "y":
return multVecMatrix(vec3, self.rotateY(theta))
if axis == "z":
return multVecMatrix(vec3, self.rotateZ(theta))
在填充屏幕白色之后,在将点从标准化空间缩放到屏幕空间之前,它被称为这样
# screen is filled with white color
# ROTATING THE POINTS AROUND X AXIS ?????
p1.x = rotation.rotate(p1, thetax, axis='x').x
p1.y = rotation.rotate(p1, thetay, axis='x').y
p1.z = rotation.rotate(p1, thetax, axis='x').z
p2.x = rotation.rotate(p2, thetax, axis='x').x
p2.y = rotation.rotate(p2, thetay, axis='x').y
p2.z = rotation.rotate(p2, thetax, axis='x').z
p3.x = rotation.rotate(p3, thetax, axis='x').x
p3.y = rotation.rotate(p3, thetay, axis='x').y
p3.z = rotation.rotate(p3, thetax, axis='x').z
p4.x = rotation.rotate(p4, thetax, axis='x').x
p4.y = rotation.rotate(p4, thetay, axis='x').y
p4.z = rotation.rotate(p4, thetax, axis='x').z
# then the points are translated into world space
应用旋转后,看起来它正在移动并绕x轴旋转,但没有旋转。我希望它在原地旋转。我做错了什么
完整的复制和粘贴代码以供参考:
import pygame
from math import sin, cos, radians
pygame.init()
### PYGAME STUFF ######################################
SCREENWIDTH = 600
SCREENHEIGHT = 600
D = pygame.display.set_mode((SCREENWIDTH, SCREENHEIGHT))
pygame.display.set_caption("PRESS SPACE TO ROTATE AROUND X")
######### MATH FUNCTIONS AND CLASSES ####################
class Mat3:
# 3X3 MATRIX INITIALIZED WITH ALL 0's
def __init__(self):
self.matrix = [[0 for i in range(3)],
[0 for i in range(3)],
[0 for i in range(3)]]
class Vec2:
# 2D VECTOR
def __init__(self, x, y):
self.x = x
self.y = y
class Vec3:
# 3D VECTOR
def __init__(self, x, y, z):
self.x = x
self.y = y
self.z = z
def multVecMatrix(vec3, mat3):
# MULTIPLIES A Vec3 OBJECT WITH Mat3 OBJECT AND RETURNS A NEW Vec3
x = vec3.x * mat3.matrix[0][0] + vec3.y * mat3.matrix[0][1] + vec3.z * mat3.matrix[0][2]
y = vec3.x * mat3.matrix[1][0] + vec3.y * mat3.matrix[1][1] + vec3.z * mat3.matrix[1][2]
z = vec3.x * mat3.matrix[2][0] + vec3.y * mat3.matrix[2][1] + vec3.z * mat3.matrix[1][2]
return Vec3(x, y, z)
class Transform:
# IT TRANSFORMS THE X AND Y FROM NORMALIZED SPACE TO SCREEN SPACE WITH PROJECTION APPLIED
def worldSpaceTransform(self, vec3, w, h):
if vec3.z == 0:
vec3.z = 0.001
zInverse = 1/ vec3.z
xTransformed = ((vec3.x * zInverse) + 1) * (w/2)
yTransformed = ((-vec3.y * zInverse) + 1) * (h/2)
xTransformed = str(xTransformed)[:6]
yTransformed = str(yTransformed)[:6]
return Vec2(float(xTransformed), float(yTransformed))
class Rotation:
def rotateX(self, theta):
# ROTATION MATRIX IN X AXIS
sinTheta = sin(theta)
cosTheta = cos(theta)
m = Mat3()
m.matrix = [[1, 0, 0],
[0, cosTheta, sinTheta],
[0, -sinTheta, cosTheta]]
return m
def rotate(self, vec3, theta, axis=None):
# ROTATES A Vec3 BY GIVEN THETA AND AXIS
if axis == "x":
return multVecMatrix(vec3, self.rotateX(theta))
if axis == "y":
return multVecMatrix(vec3, self.rotateY(theta))
if axis == "z":
return multVecMatrix(vec3, self.rotateZ(theta))
transform = Transform()
rotation = Rotation()
# ASSIGNING 4 Vec3's FOR 4 SIDES OF SQUARE IN NORMALIZED SPACE
s = 1
p1 = Vec3(-s, -s, -s)
p2 = Vec3(s, -s, -s)
p3 = Vec3(s, s, -s)
p4 = Vec3(-s, s, -s)
# TRANSLATING THE POINTS OF THE CUBE A LITTLE BIT INTO THE SCREEN
p1.z += 6
p2.z += 6
p3.z += 6
p4.z += 6
# ASSIGNING THE ROTATION ANGLES
thetax = 0
# APPLICATION LOOP
while True:
pygame.event.get()
D.fill((255, 255, 255))
# ROTATING THE POINTS AROUND X AXIS
p1.x = rotation.rotate(p1, thetax, axis='x').x
p1.y = rotation.rotate(p1, thetax, axis='x').y
p1.z = rotation.rotate(p1, thetax, axis='x').z
p2.x = rotation.rotate(p2, thetax, axis='x').x
p2.y = rotation.rotate(p2, thetax, axis='x').y
p2.z = rotation.rotate(p2, thetax, axis='x').z
p3.x = rotation.rotate(p3, thetax, axis='x').x
p3.y = rotation.rotate(p3, thetax, axis='x').y
p3.z = rotation.rotate(p3, thetax, axis='x').z
p4.x = rotation.rotate(p4, thetax, axis='x').x
p4.y = rotation.rotate(p4, thetax, axis='x').y
p4.z = rotation.rotate(p4, thetax, axis='x').z
# TRANSLATING THE SQUARE SHEET INTO THE SCREEN SPACE
point1 = transform.worldSpaceTransform(p1, SCREENWIDTH, SCREENHEIGHT)
point2 = transform.worldSpaceTransform(p2, SCREENWIDTH, SCREENHEIGHT)
point3 = transform.worldSpaceTransform(p3, SCREENWIDTH, SCREENHEIGHT)
point4 = transform.worldSpaceTransform(p4, SCREENWIDTH, SCREENHEIGHT)
# STORING THE POINTS TO A TUPLE SO IT CAN BE DRAWN USING pygame.draw.lines
points = ((point1.x, point1.y), (point2.x, point2.y),
(point2.x, point2.y), (point3.x, point3.y),
(point3.x, point3.y), (point4.x, point4.y),
(point4.x, point4.y), (point1.x, point1.y))
keys = pygame.key.get_pressed()
# ROTATE X ?
if keys[pygame.K_SPACE]:
thetax -= 0.005
pygame.draw.lines(D, (0, 0, 0), False, points)
pygame.display.flip()
不必单独旋转向量的每个分量。如果你这样做
然后
p1
的x
组件发生了变化,传递给下一条指令的p1
不同只需旋转整个顶点一次即可:
将向量与旋转矩阵相乘时,向量将旋转一圈(0,0,0)。您必须在旋转后进行平移。
将
+
-运算符添加到Vec3
类:切勿更改原始顶点坐标
p1
、p2
、p3
和p4
。计算旋转,然后计算平移:我建议在列表中组织顶点坐标:
请参见完整示例:
相关问题 更多 >
编程相关推荐