[英]Using textures in orthographic projection in OpenGL
我目前正在使用 Python 和 OpenGL 對主要飛行顯示器進行編程。 由於我對 OpenGL 的經驗為零(並且通常很少有編碼經驗),因此我遵循了一個簡單的教程,介紹了用於 2D 應用程序的 OpenGL。 有了這些基本知識,我才開始用多邊形(GL_QUADS)和一些復制的代碼來繪制文本。 這給了我這個:
視覺效果是令人滿意的,但大約 450 次迭代/秒的性能是有問題的,其中一個核心 Ryzen 1700x 100% 和 GTX1080 75%,同時只運行這個小程序(它應該在 RaspberryPI 3 上運行)。
所以我想嘗試為整個人造地平線和無生命的物體使用紋理,比如速度計的比例、分隔線或“十字准線”。 我制作了一個 .png 文件來替換人工地平線(見底部),但我不知道如何渲染它。 我發現的所有教程都是針對 C++ 的,並且給整個程序增加了很多復雜性,所以我想問一下是否有一種“簡單”的方法來為我的應用程序實現可移動的紋理。
這是我目前如何計算地平線位置以及如何繪制它的模型(最后是完整的可運行代碼):
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
from math import tan, radians
window_width = 800
window_height = 480
class Numbers:
mp = 0 #vertical middle point of horizon in pixels
rp = 0 #vertical right point of horizon in pixels
lp = 0 #vertical left point of horizon in pixels
def calc():
# mp- (pitch*(pixels/degree))
Numbers.mp = 240 - (Data.pitch * 8)
#offset is the vertical distance in pixels from mp
#offset =tan(roll) * pixels from horizontal middle point of screen to edge of artifical horizon
offset = tan(radians(Data.roll)) * 300
Numbers.rp = Numbers.mp - offset
Numbers.lp = Numbers.mp + offset
def horizon():
#sky
glBegin(GL_QUADS)
glColor3f(58/255, 109/255, 171/255)
glVertex2f(100, Numbers.lp)
glVertex2f(700, Numbers.rp)
glColor3f(0/255, 83/255, 165/255)
glVertex2f(700, 480)
glVertex2f(100, 480)
glEnd()
#ground
glColor3f(150/255, 70/255, 0/255)
glBegin(GL_QUADS)
glVertex2f(100, 0)
glVertex2f(700, 0)
glColor3f(140/255, 90/255, 0/255)
glVertex2f(700, Numbers.rp)
glVertex2f(100, Numbers.lp)
glEnd()
#devider line
glColor3f(255/255, 255/255, 255/255)
glBegin(GL_QUADS)
glVertex2f(100, Numbers.lp-1)
glVertex2f(700, Numbers.rp-1)
glVertex2f(700, Numbers.rp+1)
glVertex2f(100, Numbers.lp+1)
glEnd()
def iterate():
glViewport(0, 0, window_width, window_height)
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
glOrtho(0.0, window_width, 0.0, window_height, 0.0, 1.0)
glMatrixMode (GL_MODELVIEW)
glLoadIdentity()
def showScreen():
#glutFullScreen()
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glLoadIdentity()
iterate()
calc()
horizon()
glutSwapBuffers()
if __name__ == "__main__":
glutInit()
glutInitDisplayMode(GLUT_RGBA)
glutInitWindowSize(window_width, window_height)
glutInitWindowPosition(10, 10)
wind = glutCreateWindow(b"Pi2Fly")
glutDisplayFunc(showScreen)
glutIdleFunc(showScreen)
glutMainLoop()
真實圖像從 180 到 180 到 但這對 SO 來說太大了
完整代碼:
from OpenGL.GL import glVertex2f, glColor3f, glBegin, glEnd, GL_QUADS, GL_TRIANGLES
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
from time import sleep, perf_counter, time
from math import tan, radians
import pygame
window_width = 800
window_height = 480
pygame.font.init()
font1 = pygame.font.Font (None, 40)
font2 = pygame.font.Font (None, 20)
font3 = pygame.font.Font (None, 25)
font4 = pygame.font.Font (None, 45)
class Numbers:
mp = 0
rp = 0
lp = 0
class Data:
roll = 20
pitch = 0
airspeed = 160
altitude = 4500
altitude_last = 0
altitude_now = 0
altitude_delta = 0
altitude_delta_table = 30 * [0]
time_last = 0
time_now = 0
c1 = True
c2 = True
c3 = 0
class FPS:
c = 0
fps = 0
def fps():
FPS.c += 1
try: FPS.last_clock = FPS.this_clock
except:FPS.last_clock = perf_counter()
FPS.this_clock = perf_counter()
if round(FPS.this_clock) > round(FPS.last_clock):
FPS.fps = FPS.c
FPS.c = 0
color = (255,198,0, 255)
drawText(5, 9, str(FPS.fps), color, font1)
drawText(55, 10, "FPS", color, font2)
def get_data():
#dummy data for artifical horizon
#pitch
if Data.pitch < 20 and Data.c1: Data.pitch += 0.03
if Data.pitch >= 20 and Data.c1: Data.c1 = False
if Data.pitch < 21 and not Data.c1: Data.pitch = Data.pitch - 0.03
if Data.pitch < -20: Data.c1 = True
#roll
if Data.roll < 20 and Data.c2: Data.roll += 0.02
if Data.roll >= 20 and Data.c2: Data.c2 = False
if Data.roll < 21 and not Data.c2: Data.roll = Data.roll - 0.02
if Data.roll < -20: Data.c2 = True
#airspeed
if Data.pitch > 0: Data.airspeed = Data.airspeed - 0.004 * Data.pitch
elif Data.pitch < 0: Data.airspeed = Data.airspeed + 0.004 * abs(Data.pitch)
#altitude
if Data.pitch > 0: Data.altitude = Data.altitude + 0.01 * Data.pitch
elif Data.pitch < 0: Data.altitude = Data.altitude - 0.01 * abs(Data.pitch)
#altitude_delta
Data.time_now = perf_counter()
if Data.time_now >= Data.time_last + 0.01:
if Data.c3 == 30: Data.c3 = 0
Data.time_last = Data.time_now
Data.altitude_last = Data.altitude_now
Data.altitude_now = Data.altitude
Data.altitude_delta_table[Data.c3] = Data.altitude_now - Data.altitude_last
Data.c3 +=1
Data.altitude_delta = (sum(Data.altitude_delta_table)/len(Data.altitude_delta_table))
def calc():
Numbers.mp = 240 - (Data.pitch * 8)
offset = tan(radians(Data.roll)) * 300
Numbers.rp = Numbers.mp - offset
Numbers.lp = Numbers.mp + offset
def frame():
#frame color = grey
glColor3f(100/255, 100/255, 100/255)
#horizon right line
glBegin(GL_QUADS)
glVertex2f(99, 0)
glVertex2f(100, 0)
glVertex2f(100, window_height)
glVertex2f(99, window_height)
glEnd()
#horizon left line
glBegin(GL_QUADS)
glVertex2f(700, 0)
glVertex2f(701, 0)
glVertex2f(701, window_height)
glVertex2f(700, window_height)
glEnd()
#right upper divider
glBegin(GL_QUADS)
glVertex2f(0, 430)
glVertex2f(100, 430)
glVertex2f(100, 431)
glVertex2f(0, 431)
glEnd()
#left upper divider
glBegin(GL_QUADS)
glVertex2f(700, 430)
glVertex2f(800, 430)
glVertex2f(800, 431)
glVertex2f(700, 431)
glEnd()
#right lower divider
glBegin(GL_QUADS)
glVertex2f(0, 50)
glVertex2f(100, 50)
glVertex2f(100, 51)
glVertex2f(0, 51)
glEnd()
#left lower divider
glBegin(GL_QUADS)
glVertex2f(700, 50)
glVertex2f(800, 50)
glVertex2f(800, 51)
glVertex2f(700, 51)
glEnd()
def horizon():
#sky
glBegin(GL_QUADS)
glColor3f(58/255, 109/255, 171/255)
glVertex2f(100, Numbers.lp)
glVertex2f(700, Numbers.rp)
glColor3f(0/255, 83/255, 165/255)
glVertex2f(700, 480)
glVertex2f(100, 480)
glEnd()
#ground
glColor3f(150/255, 70/255, 0/255)
glBegin(GL_QUADS)
glVertex2f(100, 0)
glVertex2f(700, 0)
glColor3f(140/255, 90/255, 0/255)
glVertex2f(700, Numbers.rp)
glVertex2f(100, Numbers.lp)
glEnd()
#devider line
glColor3f(255/255, 255/255, 255/255)
glBegin(GL_QUADS)
glVertex2f(100, Numbers.lp-1)
glVertex2f(700, Numbers.rp-1)
glVertex2f(700, Numbers.rp+1)
glVertex2f(100, Numbers.lp+1)
glEnd()
#crosshair
#indicator triangle shadow
glColor3f(187/255, 107/255, 1/255)
glBegin(GL_QUADS)
glVertex2f(400, 230)
glVertex2f(365, 215)
glVertex2f(400, 227)
glVertex2f(435, 215)
glEnd()
# indicator triangle
glColor3f(255/255, 198/255, 0/255)
glBegin(GL_QUADS)
glVertex2f(400, 240)
glVertex2f(365, 215)
glVertex2f(400, 230)
glVertex2f(435, 215)
glEnd()
#yellow indicator line
glColor3f(255/255, 198/255, 0/255)
glBegin(GL_QUADS)
glVertex2f(320, 241)
glVertex2f(320, 239)
glVertex2f(350, 239)
glVertex2f(350, 241)
glEnd()
glBegin(GL_QUADS)
glVertex2f(450, 241)
glVertex2f(450, 239)
glVertex2f(480, 239)
glVertex2f(480, 241)
glEnd()
color = (255, 255, 255, 0)
drawText(110, 10, str("roll: "+str(round(Data.roll))), color, font3)
drawText(620, 10, str("pitch: "+str(round(Data.pitch))), color, font3)
def speedometer():
#dial
ssp = 55 #start spacer
sp = 27 #spacer
color = (255,255,255,100)
drawText(14, ssp+sp*0, "0", color, font3)
drawText(10, ssp+sp*1, "20", color, font3)
drawText(10, ssp+sp*2, "40", color, font3)
drawText(10, ssp+sp*3, "60", color, font3)
drawText(10, ssp+sp*4, "80", color, font3)
drawText(5, ssp+sp*5, "100", color, font3)
drawText(5, ssp+sp*6, "120", color, font3)
drawText(5, ssp+sp*7, "140", color, font3)
drawText(5, ssp+sp*8, "160", color, font3)
drawText(5, ssp+sp*9, "180", color, font3)
drawText(5, ssp+sp*10, "200", color, font3)
drawText(5, ssp+sp*11, "220", color, font3)
drawText(5, ssp+sp*12, "240", color, font3)
drawText(5, ssp+sp*13, "260", color, font3)
#green area
glBegin(GL_QUADS)
glColor3f(35/255, 150/255, 29/255)
glVertex2f(40, 142)
glVertex2f(99, 142)
glVertex2f(99, 287)
glVertex2f(40, 287)
glEnd()
#yellow area
glBegin(GL_QUADS)
glColor3f(150/255, 100/255, 27/255)
glVertex2f(40, 287)
glVertex2f(99, 287)
glVertex2f(99, 360)
glVertex2f(40, 360)
glEnd()
#red area
glBegin(GL_QUADS)
glColor3f(151/255, 43/255, 29/255)
glVertex2f(40, 360)
glVertex2f(99, 360)
glVertex2f(99, 374)
glVertex2f(40, 374)
glEnd()
ll=35
l=15
w=1
ssp=64
glColor3f(255/255, 255/255, 255/255)
for x in range(0, 14):
ind_lines(ll, l, w, ssp+sp*x)
#knots
color = (0, 241, 250, 255)
drawText(60, 435, "kn", color, font4)
def speedometer_indicator():
ypos = 63 + round(Data.airspeed) * 1.35
glColor3f(0/255, 241/255, 250/255)
ind_lines(40, 59, 3, ypos)
color = (0, 241, 250, 255)
drawText(5, 435, str(round(Data.airspeed)), color, font4)
def altimeter():
color = (0, 241, 250, 255)
drawText(705, 435, str(round(Data.altitude)), color, font4)
drawText(784, 435, "m", color, font3)
def variometer():
color = (0, 241, 250, 255)
drawText(710, 10, str(round((abs(Data.altitude_delta*10)), 1)), color, font4)
drawText(765, 10, "m/s", color, font3)
if Data.altitude_delta*10 > 0:
glBegin(GL_TRIANGLES)
glVertex2f(767, 30)
glVertex2f(793, 30)
glVertex2f(780, 45)
glEnd()
if Data.altitude_delta*10 < 0:
glBegin(GL_TRIANGLES)
glVertex2f(765, 45)
glVertex2f(795, 45)
glVertex2f(780, 30)
glEnd()
def ind_lines(ll, l, w, sp): #ll=left limit,l=lenght, w=width, sp=spacer
#indicator lines
glBegin(GL_QUADS)
glVertex2f(ll, sp)
glVertex2f(ll+l, sp)
glVertex2f(ll+l, sp+w)
glVertex2f(ll, sp+w)
glEnd()
def drawText(xpos, ypos, textString, color, font):
textSurface = font.render(textString, True, color, (0,0,0,1))
textData = pygame.image.tostring(textSurface, "RGBA", True)
glRasterPos2d(xpos,ypos)
glDrawPixels(textSurface.get_width(), textSurface.get_height(), GL_RGBA, GL_UNSIGNED_BYTE, textData)
def draw_once():
speedometer()
frame()
def draw():
horizon()
speedometer_indicator()
altimeter()
variometer()
def iterate():
glViewport(0, 0, window_width, window_height)
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
glOrtho(0.0, window_width, 0.0, window_height, 0.0, 1.0)
glMatrixMode (GL_MODELVIEW)
glLoadIdentity()
def showScreen():
#glutFullScreen()
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glLoadIdentity()
iterate()
try:get_data()
except Exception as e:print("get_data:\t", e)
try:calc()
except Exception as e:print("calc:\t", e)
try:draw_once()
except Exception as e:print("draw_once:\t", e)
try:draw()
except Exception as e:print("draw:\t", e)
try:fps()
except Exception as e:print("fps:\t", e)
glutSwapBuffers()
if __name__ == "__main__":
glutInit()
glutInitDisplayMode(GLUT_RGBA)
glutInitWindowSize(window_width, window_height)
glutInitWindowPosition(10, 10)
wind = glutCreateWindow(b"Pi2Fly")
glutDisplayFunc(showScreen)
glutIdleFunc(showScreen)
glutMainLoop()
您可以使用 pygame 加載紋理圖像:
def LoadTexture(filename):
image = pygame.image.load(filename)
datas = pygame.image.tostring(image, 'RGBA')
texID = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, texID)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.get_width(), image.get_height(),
0, GL_RGBA, GL_UNSIGNED_BYTE, datas)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE)
glGenerateMipmap(GL_TEXTURE_2D)
glBindTexture(GL_TEXTURE_2D, 0)
return texID
from PIL import Image
import numpy
image = Image.open(filename)
imageData = numpy.array(list(image.getdata()), numpy.uint8)
texID = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, texID)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.size[0], image.size[1],
0, GL_RGBA, GL_UNSIGNED_BYTE, imageData)
# [...]
當您想在Legacy OpenGL 中使用紋理時,您必須:
glVertex
之前通過glTexCoord2f
設置紋理坐標glBindTexture
綁定紋理glEnable(GL_TEXTURE_2D)
啟用二維紋理下面的示例在整個視口上繪制一個四邊形並在其上包裹一個紋理。 例如:
def DrawTexture(texID, x, y, w, h):
glBindTexture(GL_TEXTURE_2D, texID)
glEnable(GL_TEXTURE_2D)
glColor4f(1, 1, 1, 1)
glBegin(GL_QUADS)
glTexCoord2f(0, 1); glVertex2f(x, y)
glTexCoord2f(0, 0); glVertex2f(x, y+h)
glTexCoord2f(1, 0); glVertex2f(x+w, y+h)
glTexCoord2f(1, 1); glVertex2f(x+w, y)
glEnd()
glDisable(GL_TEXTURE_2D)
請注意,如果啟用了紋理,則默認情況下,紋理像素的顏色將乘以當前顏色,因為默認情況下紋理環境模式( GL_TEXTURE_ENV_MODE
)為GL_MODULATE
。 請參閱glTexEnv
。
這會導致紋理的紋素顏色與您通過glColor4f
設置的最后一種顏色“混合”。
在渲染紋理之前設置“白色”顏色,以解決您的問題:
glColor4f(1, 1, 1, 1)
同樣,您可以將環境模式更改為GL_REPLACE
,而不是:
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
此外,如果紋理部分透明,則必須在繪制紋理之前啟用混合:
glEnable(GL_BLEND)
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
DrawTexture(....)
glDisable(GL_BLEND)
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