如何在面向对象的 PyOpenGL 中进行击退? [英] How to do knock-backs in PyOpenGL with object facing?
本文介绍了如何在面向对象的 PyOpenGL 中进行击退?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
我正在 PyOpenGL 中制作游戏，并且我想在对象足够近时在相机上应用击退.击退只是根据敌人面对的方向将相机向后放.
我在一张纸上模拟了这个并发现
xc = person.pos[0] - camera_pos[0]yc = person.pos[1] - camera_pos[1]zc = person.pos[2] - camera_pos[2]glTranslatef(xc,zc,yc) #由于 gluLookAt()，我的 z 和 y 被翻转但它似乎不起作用，我想处理对象的正面，而不是 x、y 和 z 之间的关系.
另外，我尝试了
I am making a game in PyOpenGL and I want to apply knock-back on camera when an object is close enough. A knock-back is simply putting the camera backward according to the enemy facing direction.
I've modeled this on a piece of paper and found out
xc = person.pos[0] - camera_pos[0]
yc = person.pos[1] - camera_pos[1]
zc = person.pos[2] - camera_pos[2]
glTranslatef(xc,zc,yc) #my z and y are flipped due to gluLookAt()
but it doesn't seem to be working and I want to work with the facing of the object, not relationships between x, y and z.
Also, I've tried the Knocking back the Player in a Unity 2D TopDown Game solution:
xc,yc,zc = normalize([(camera_pos[0] + (camera_pos[0] - person.pos[0])) * 5,(camera_pos[1] + (camera_pos[1] - person.pos[1])) * 5,(camera_pos[2] + (camera_pos[2] - person.pos[2])) * 5])
glTranslatef(xc,zc,yc)
knockback = False
But somehow I can control how am I knocking back if I turn the perspective (e.g. if I face left I will be knocked back to the left).
Full code:
#!/usr/local/bin/python3
import pygame
from pygame.locals import *
from OpenGL.GL import *
from OpenGL.GLU import *
from OpenGL.GLUT import *
import math,sys,numpy,random,ctypes
pygame.init()
display = (1500, 900)
screen = pygame.display.set_mode(display, DOUBLEBUF | OPENGL)
pygame.display.set_caption("Game")
glEnable(GL_DEPTH_TEST)
glEnable(GL_LIGHTING)
glShadeModel(GL_SMOOTH)
glEnable(GL_COLOR_MATERIAL)
glEnable(GL_BLEND)
glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE)
glEnable(GL_LIGHT0)
glLightfv(GL_LIGHT0, GL_AMBIENT, [0.5, 0.5, 0.5, 1])
glLightfv(GL_LIGHT0, GL_DIFFUSE, [1.0, 1.0, 1.0, 1])
glMatrixMode(GL_PROJECTION)
gluPerspective(45, (display[0]/display[1]), 0.1, 50.0)
glMatrixMode(GL_MODELVIEW)
gluLookAt(0, -8, 0, 0, 0, 0, 0, 0, 1)
glTranslatef(0,-8,0)
viewMatrix = glGetFloatv(GL_MODELVIEW_MATRIX)
glLoadIdentity()
# init mouse movement and center mouse on screen
displayCenter = [screen.get_size()[i] // 2 for i in range(2)]
mouseMove = [0, 0]
pygame.mouse.set_pos(displayCenter)
cmddown = False
cam_attack = False
cam_damage = random.randint(20,30)
knockback = False
person_count = 1
up_down_angle = 0.0
camera_pos = (0,0,0)
paused = False
run = True
#xzy = xyz
#Functions & Classes
def InverseMat44(mat):
m = [mat[i][j] for i in range(4) for j in range(4)]
inv = [0]*16
inv[0] = m[5] * m[10] * m[15] - m[5] * m[11] * m[14] - m[9] * m[6] * m[15] + m[9] * m[7] * m[14] + m[13] * m[6] * m[11] - m[13] * m[7] * m[10]
inv[4] = -m[4] * m[10] * m[15] + m[4] * m[11] * m[14] + m[8] * m[6] * m[15] - m[8] * m[7] * m[14] - m[12] * m[6] * m[11] + m[12] * m[7] * m[10]
inv[8] = m[4] * m[9] * m[15] - m[4] * m[11] * m[13] - m[8] * m[5] * m[15] + m[8] * m[7] * m[13] + m[12] * m[5] * m[11] - m[12] * m[7] * m[9]
inv[12] = -m[4] * m[9] * m[14] + m[4] * m[10] * m[13] + m[8] * m[5] * m[14] - m[8] * m[6] * m[13] - m[12] * m[5] * m[10] + m[12] * m[6] * m[9]
inv[1] = -m[1] * m[10] * m[15] + m[1] * m[11] * m[14] + m[9] * m[2] * m[15] - m[9] * m[3] * m[14] - m[13] * m[2] * m[11] + m[13] * m[3] * m[10]
inv[5] = m[0] * m[10] * m[15] - m[0] * m[11] * m[14] - m[8] * m[2] * m[15] + m[8] * m[3] * m[14] + m[12] * m[2] * m[11] - m[12] * m[3] * m[10]
inv[9] = -m[0] * m[9] * m[15] + m[0] * m[11] * m[13] + m[8] * m[1] * m[15] - m[8] * m[3] * m[13] - m[12] * m[1] * m[11] + m[12] * m[3] * m[9]
inv[13] = m[0] * m[9] * m[14] - m[0] * m[10] * m[13] - m[8] * m[1] * m[14] + m[8] * m[2] * m[13] + m[12] * m[1] * m[10] - m[12] * m[2] * m[9]
inv[2] = m[1] * m[6] * m[15] - m[1] * m[7] * m[14] - m[5] * m[2] * m[15] + m[5] * m[3] * m[14] + m[13] * m[2] * m[7] - m[13] * m[3] * m[6]
inv[6] = -m[0] * m[6] * m[15] + m[0] * m[7] * m[14] + m[4] * m[2] * m[15] - m[4] * m[3] * m[14] - m[12] * m[2] * m[7] + m[12] * m[3] * m[6]
inv[10] = m[0] * m[5] * m[15] - m[0] * m[7] * m[13] - m[4] * m[1] * m[15] + m[4] * m[3] * m[13] + m[12] * m[1] * m[7] - m[12] * m[3] * m[5]
inv[14] = -m[0] * m[5] * m[14] + m[0] * m[6] * m[13] + m[4] * m[1] * m[14] - m[4] * m[2] * m[13] - m[12] * m[1] * m[6] + m[12] * m[2] * m[5]
inv[3] = -m[1] * m[6] * m[11] + m[1] * m[7] * m[10] + m[5] * m[2] * m[11] - m[5] * m[3] * m[10] - m[9] * m[2] * m[7] + m[9] * m[3] * m[6]
inv[7] = m[0] * m[6] * m[11] - m[0] * m[7] * m[10] - m[4] * m[2] * m[11] + m[4] * m[3] * m[10] + m[8] * m[2] * m[7] - m[8] * m[3] * m[6]
inv[11] = -m[0] * m[5] * m[11] + m[0] * m[7] * m[9] + m[4] * m[1] * m[11] - m[4] * m[3] * m[9] - m[8] * m[1] * m[7] + m[8] * m[3] * m[5]
inv[15] = m[0] * m[5] * m[10] - m[0] * m[6] * m[9] - m[4] * m[1] * m[10] + m[4] * m[2] * m[9] + m[8] * m[1] * m[6] - m[8] * m[2] * m[5]
det = m[0] * inv[0] + m[1] * inv[4] + m[2] * inv[8] + m[3] * inv[12]
for i in range(16):
inv[i] /= det
return inv
def touched(tar_x,tar_y,tar_z,tar_x1,tar_y1,tar_z1):
centerPt = pygame.math.Vector3(tar_x,tar_y,tar_z)
point2 = pygame.math.Vector3(tar_x1, tar_y1, tar_z1)
distance = centerPt.distance_to(point2)
return distance
def follower(x,y,z,x1,y1,z1,speed):
dir_x, dir_y = (x1-x, y1-y)
distance = math.hypot(dir_x, dir_y)
dir_x, dir_y = (dir_x/distance, dir_y/distance)
angle = math.degrees(math.atan2(dir_y, dir_x)) + 90
return (dir_x*speed, dir_y*speed, 0, angle)
def random_pos(max_distance):
x_value_change = random.randrange(-max_distance + 2,max_distance + 2)
y_value_change = random.randrange(-max_distance + 2,max_distance + 2)
z_value_change = 0
return (x_value_change, y_value_change, z_value_change)
def blit_text(x,y,font,text,r,g,b):
blending = False
if glIsEnabled(GL_BLEND):
blending = True
glColor3f(r,g,b)
glWindowPos2f(x,y)
for ch in text:
glutBitmapCharacter(font,ctypes.c_int(ord(ch)))
if not blending:
glDisable(GL_BLEND)
def subtract(v0, v1):
return [v0[0]-v1[0], v0[1]-v1[1], v0[2]-v1[2]]
def dot(v0, v1):
return v0[0]*v1[0]+v0[1]*v1[1]+v0[2]*v1[2]
def length(v):
return math.sqrt(v[0]*v[0]+v[1]*v[1]+v[2]*v[2])
def normalize(v):
l = length(v)
return [v[0]/l, v[1]/l, v[2]/l]
# Ray - Sphere intersection
#
# Sphere: dot(p-C, p-C) = R*R `C`: center, `p`: point on the sphere, `R`, radius
# Ray: p(t) = A + B * t `A`: origin, `B`: direction
# Intersection: dot(A+B*t-C, A+B*t-C) = R*R
# t*t*dot(B,B) + 2*t*dot(B,A-C) + dot(A-C,A-C) - R*R = 0
def isectObj(p0, p1, C, R):
A = p0 #Origin
B = normalize(subtract(p1, p0)) #Direction
oc = subtract(A, C)
a = dot(B, B)
b = 2 * dot(oc, B)
c = dot(oc, oc) - R*R
discriminant = b*b - 4*a*c
if discriminant > 0:
t1 = (-b - math.sqrt(discriminant)) / (2*a)
t2 = (-b + math.sqrt(discriminant)) / (2*a)
t = min(t1, t2)
return t if t >= 0.0 else None
return None
class Ground:
def __init__(self,mul=1):
self.vertices = [
[-20,20,-1],
[20,20,-1],
[-20,-300,-1],
[20,-300,-1]
]
def draw(self):
glBegin(GL_QUADS) #Begin fill
for vertex in self.vertices:
glColor3f(0,0.5,0.5)
glVertex3fv(vertex)
glEnd()
class Person:
def __init__(self):
self.vertices = [
[-1,0,1],
[-1,0,-1],
[1,0,-1],
[1,0,1],
[-1,1,1],
[-1,1,-1],
[1,1,-1],
[1,1,1]
]
self.vertices = list(numpy.multiply(numpy.array(self.vertices),1))
self.edges = (
(0,1),
(0,3),
(0,4),
(1,2),
(1,5),
(2,3),
(2,6),
(3,7),
(4,5),
(4,7),
(5,6),
(6,7)
)
self.surfaces = (
(0,1,2,3),
(0,1,5,4),
(4,5,6,7),
(1,2,6,5),
(0,3,7,4),
(2,3,7,6)
)
self.x = self.vertices[1][0]
self.y = self.vertices[1][2]
self.z = self.vertices[1][1]
self.pos = (self.x,self.y,self.z)
self.rot = 0
self.health = 100
self.damage = random.randint(20,40)
self.level = 1
def draw(self):
glTranslated(self.pos[0], self.pos[1], self.pos[2])
glRotated(self.rot,0,0,1)
glBegin(GL_QUADS) #Begin fill
for surface in self.surfaces:
for vertex in surface:
glColor3f(0,1,0)
glVertex3fv(self.vertices[vertex])
glEnd()
glLineWidth(5) #Set width of the line
glBegin(GL_LINES) #Begin outline
for edge in self.edges:
for vertex in edge:
glColor3f(1,1,0)
glVertex3fv(self.vertices[vertex])
glEnd()
def move(self,x,y,z):
self.pos = (self.pos[0]+x,self.pos[1]+y,self.pos[2]+z)
glutInit()
persons = [Person() for person in range(person_count)]
ground = Ground()
for person in persons:
person.pos = random_pos(12)
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_ESCAPE:
run = False
if event.key == pygame.K_p:
paused = not paused
if not paused:
if event.type == pygame.MOUSEMOTION:
mouseMove = [event.pos[i] - displayCenter[i] for i in range(2)]
pygame.mouse.set_pos(displayCenter)
if event.type == pygame.MOUSEBUTTONDOWN:
if event.button == 1:
cam_attack = True
pygame.mouse.set_visible(False)
if not paused:
#Get keys
keypress = pygame.key.get_pressed()
#Init model view matrix
glLoadIdentity()
#------------------------View------------------------
#Apply the look up and down (with 90° angle limit)
if up_down_angle < -90:
if mouseMove[1] > 0:
up_down_angle += mouseMove[1]*0.1
elif up_down_angle > 90:
if mouseMove[1] < 0:
up_down_angle += mouseMove[1]*0.1
else:
up_down_angle += mouseMove[1]*0.1
glRotatef(up_down_angle, 1.0, 0.0, 0.0)
#Init the view matrix
glPushMatrix()
glLoadIdentity()
#Apply the movement
if keypress[pygame.K_w]:
glTranslatef(0,0,0.1)
if keypress[pygame.K_s]:
glTranslatef(0,0,-0.1)
if keypress[pygame.K_d]:
glTranslatef(-0.1,0,0)
if keypress[pygame.K_a]:
glTranslatef(0.1,0,0)
if knockback:
#Knockback
xc,yc,zc = normalize([(camera_pos[0] + (camera_pos[0] - person.pos[0])) * 5,(camera_pos[1] + (camera_pos[1] - person.pos[1])) * 5,(camera_pos[2] + (camera_pos[2] - person.pos[2])) * 5])
glTranslatef(xc,zc,yc)
knockback = False
#Apply the look left and right
glRotatef(mouseMove[0]*0.1, 0.0, 1.0, 0.0)
#------------------------View------------------------
#Multiply the current matrix by the new view matrix and store the final view matrix
glMultMatrixf(viewMatrix)
viewMatrix = glGetFloatv(GL_MODELVIEW_MATRIX)
invVM = InverseMat44(viewMatrix)
camera_pos = (invVM[12],invVM[13],invVM[14])
#Apply view matrix
glPopMatrix()
glMultMatrixf(viewMatrix)
#Get current view matrix, projection matrix and viewport rectangle
mv_matrix = glGetDoublev(GL_MODELVIEW_MATRIX)
proj_matrix = glGetDoublev(GL_PROJECTION_MATRIX)
vp_rect = glGetIntegerv(GL_VIEWPORT)
#Calculate "near" and "far" point
pt_near = gluUnProject(displayCenter[0], displayCenter[1], 0, mv_matrix, proj_matrix, vp_rect)
pt_far = gluUnProject(displayCenter[0], displayCenter[1], 1, mv_matrix, proj_matrix, vp_rect)
glLightfv(GL_LIGHT0, GL_POSITION, [1, -1, 1, 0])
#Follow, attack
crosshair_color = (1,1,1)
attacklist = []
for person in persons:
freturn = follower(person.pos[0],person.pos[1],person.pos[2],camera_pos[0],camera_pos[1],camera_pos[2],0.02)
xchange,ychange,zchange = freturn[0],freturn[1],freturn[2]
person.rot = freturn[3]
if (touched(person.pos[0],person.pos[1],person.pos[2],camera_pos[0],camera_pos[1],camera_pos[2])) < 2.5:
xchange,ychange,zchange = 0,0,0
knockback = True
person.move(xchange,ychange,zchange)
if (touched(person.pos[0],person.pos[1],person.pos[2],camera_pos[0],camera_pos[1],camera_pos[2])) < 5 and isectObj(pt_near, pt_far, person.pos, 1) != None:
crosshair_color = (1,0,0)
if len(attacklist) >= 2:
bigger = attacklist[1] > touched(person.pos[0],person.pos[1],person.pos[2],camera_pos[0],camera_pos[1],camera_pos[2])
if bigger == True:
attacklist = [person,touched(person.pos[0],person.pos[1],person.pos[2],camera_pos[0],camera_pos[1],camera_pos[2])]
else:
attacklist = [person,touched(person.pos[0],person.pos[1],person.pos[2],camera_pos[0],camera_pos[1],camera_pos[2])]
if attacklist:
if cam_attack == True:
attacklist[0].health -= cam_damage
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
#Draw crosshair, health
blit_text(displayCenter[0] - 5,displayCenter[1] - 5,GLUT_BITMAP_TIMES_ROMAN_24,"+",crosshair_color[0],crosshair_color[1],crosshair_color[2])
for person in persons:
if person.health > 0:
#print(person.health)
pass
glPushMatrix()
glColor4f(0.2, 0.2, 0.5, 1)
for person in persons:
glPushMatrix()
person.draw()
glPopMatrix()
ground.draw()
glPopMatrix()
for person in persons:
if person.health <= 0:
persons.remove(person)
cam_attack = False
pygame.display.flip()
pygame.time.wait(10)
pygame.quit()
sys.exit()
I expected to be knocked back no matter how I rotate the view, but I can change where I am knocking back if I rotate the view.
解决方案
The "knock back direction is the direction from the current position (camera_pos) to the object (person.pos). Calculate the Unit vector of this direction (the length of the unit vector is 1):
knockback_dir = normalize(subtract(person.pos, camera_pos))
Do not calculate a new position by adding a vector to the camera position (camera_pos), because glTranslatef does that for you. It creates a new matrix and multiplies the current matrix by the new matrix, so the translation is relative to the current translation.
Scale the direction by a certain distance (knockback_dist). The vector has to be applied to the camera in world space, this means after the view matrix was set:
viewMatrix = viewMatrix * knockBackTranslation
The distance of the object to the camera has to be increased, so the vector has to be added to the object. Note, the view space position of the eye (camera) is always (0, 0, 0). What has to be changed is the the scene (all the objects) in relation to the camera.
#Multiply the current matrix by the new view matrix and store the final view matrix
glMultMatrixf(viewMatrix)
if knockback:
knockback_dist = 10
knockback_dir = normalize(subtract(person.pos, camera_pos))
glTranslatef(knockback_dir[0]*knockback_dist, knockback_dir[1]*knockback_dist, 0)
knockback = False
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