OpenGL:如何将纹理应用到这个立方体? [英] OpenGL: How do I apply a texture to this cube?
问题描述
我正在尝试学习 OpenGL，并且我已经阅读了很多关于加载纹理的教程，但每一个教程似乎都错过了最重要的一步:我如何在某物上实际放置纹理?
I'm trying to learn OpenGL, and I've been going through a lot of tutorials on loading a texture, but every single one seems to miss the most important step: how do I actually put a texture on something?
我为此使用 Python，这是我加载纹理的函数:
I'm using Python for this, and here is my function that loads the texture:
def loadTexture():
textureSurface = pygame.image.load('test_image.png')
textureData = pygame.image.tostring(textureSurface,"RGBA",1)
width = textureSurface.get_width()
height = textureSurface.get_height()
glEnable(GL_TEXTURE_2D)
texid = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, texid)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
return texid
这是加载我的 Cube 的函数:
And here is the function that loads my Cube:
vertices = (
# x y z
( 1,-1,-1),
( 1, 1,-1),
(-1, 1,-1),
(-1,-1,-1),
( 1,-1, 1),
( 1, 1, 1),
(-1,-1, 1),
(-1, 1, 1)
)
edges = (
(0,1),
(0,3),
(0,4),
(2,1),
(2,3),
(2,7),
(6,3),
(6,4),
(6,7),
(5,1),
(5,4),
(5,7)
)
def Cube():
glBegin(GL_LINES)
for edge in edges:
glColor3fv((1,1,1))
for vertex in edge:
glVertex3fv(vertices[vertex])
glEnd()
这是主循环:
pygame.init()
display = (800,600)
screen = pygame.display.set_mode(display, DOUBLEBUF | OPENGL | OPENGLBLIT)
gluPerspective(45, display[0]/display[1],0.1,50.0)
glTranslatef(0.0,0.0,-5)
while True:
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
Cube()
pygame.display.flip()
pygame.time.wait(10)
但是立方体没有纹理.我不知道如何在立方体上实际使用加载的纹理，我找到的每个纹理教程都将我带到了 loadTexture 函数，而没有告诉我如何使用它.我在哪里称呼它?我用 texid 做什么?
But the cube is untextured. I don't know how to actually use the loaded texture on the cube, and every texture tutorial I find takes me as far as the loadTexture function without actually telling me how to use it. Where do I call it? What do I do with texid?
推荐答案
您的实际代码几乎没有问题:
There are few issues with your actual code:
- 您没有调用加载纹理的方法.
- 您只绘制立方体的线条，需要用实际纹理填充多边形，这意味着使用带有纹理坐标的三角形或四边形.
- 您没有处理 pygame 事件
以下是对您的代码的一些修改:
Here's some modifications of your code:
import pygame
import sys
from OpenGL.GL import *
from OpenGL.GLU import *
vertices = (
# x y z
(1, -1, -1),
(1, 1, -1),
(-1, 1, -1),
(-1, -1, -1),
(1, -1, 1),
(1, 1, 1),
(-1, -1, 1),
(-1, 1, 1)
)
edges = (
(0, 1),
(0, 3),
(0, 4),
(2, 1),
(2, 3),
(2, 7),
(6, 3),
(6, 4),
(6, 7),
(5, 1),
(5, 4),
(5, 7)
)
def loadTexture():
textureSurface = pygame.image.load('test_image.png')
textureData = pygame.image.tostring(textureSurface, "RGBA", 1)
width = textureSurface.get_width()
height = textureSurface.get_height()
glEnable(GL_TEXTURE_2D)
texid = glGenTextures(1)
glBindTexture(GL_TEXTURE_2D, texid)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height,
0, GL_RGBA, GL_UNSIGNED_BYTE, textureData)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
return texid
def draw_cube(lines=False):
if lines:
glBegin(GL_LINES)
for edge in edges:
glColor3fv((1, 1, 1))
for vertex in edge:
glVertex3fv(vertices[vertex])
glEnd()
else:
glBegin(GL_QUADS)
glTexCoord2f(0.0, 0.0)
glVertex3f(-1.0, -1.0, 1.0)
glTexCoord2f(1.0, 0.0)
glVertex3f(1.0, -1.0, 1.0)
glTexCoord2f(1.0, 1.0)
glVertex3f(1.0, 1.0, 1.0)
glTexCoord2f(0.0, 1.0)
glVertex3f(-1.0, 1.0, 1.0)
glTexCoord2f(1.0, 0.0)
glVertex3f(-1.0, -1.0, -1.0)
glTexCoord2f(1.0, 1.0)
glVertex3f(-1.0, 1.0, -1.0)
glTexCoord2f(0.0, 1.0)
glVertex3f(1.0, 1.0, -1.0)
glTexCoord2f(0.0, 0.0)
glVertex3f(1.0, -1.0, -1.0)
glTexCoord2f(0.0, 1.0)
glVertex3f(-1.0, 1.0, -1.0)
glTexCoord2f(0.0, 0.0)
glVertex3f(-1.0, 1.0, 1.0)
glTexCoord2f(1.0, 0.0)
glVertex3f(1.0, 1.0, 1.0)
glTexCoord2f(1.0, 1.0)
glVertex3f(1.0, 1.0, -1.0)
glTexCoord2f(1.0, 1.0)
glVertex3f(-1.0, -1.0, -1.0)
glTexCoord2f(0.0, 1.0)
glVertex3f(1.0, -1.0, -1.0)
glTexCoord2f(0.0, 0.0)
glVertex3f(1.0, -1.0, 1.0)
glTexCoord2f(1.0, 0.0)
glVertex3f(-1.0, -1.0, 1.0)
glTexCoord2f(1.0, 0.0)
glVertex3f(1.0, -1.0, -1.0)
glTexCoord2f(1.0, 1.0)
glVertex3f(1.0, 1.0, -1.0)
glTexCoord2f(0.0, 1.0)
glVertex3f(1.0, 1.0, 1.0)
glTexCoord2f(0.0, 0.0)
glVertex3f(1.0, -1.0, 1.0)
glTexCoord2f(0.0, 0.0)
glVertex3f(-1.0, -1.0, -1.0)
glTexCoord2f(1.0, 0.0)
glVertex3f(-1.0, -1.0, 1.0)
glTexCoord2f(1.0, 1.0)
glVertex3f(-1.0, 1.0, 1.0)
glTexCoord2f(0.0, 1.0)
glVertex3f(-1.0, 1.0, -1.0)
glEnd()
pygame.init()
display = (800, 600)
screen = pygame.display.set_mode(
display, pygame.DOUBLEBUF | pygame.OPENGL | pygame.OPENGLBLIT)
loadTexture()
gluPerspective(45, display[0] / display[1], 0.1, 50.0)
glTranslatef(0.0, 0.0, -5)
while True:
for event in pygame.event.get():
if event.type == pygame.QUIT:
pygame.quit()
sys.exit()
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
draw_cube(lines=False)
pygame.display.flip()
以上代码未使用最佳实践，但可以帮助您解决您所评论的问题.
The above code is not using the best practices but it'll help you with your commented issues.
尽管有一个建议，我建议您先阅读一些 opengl 教程，然后再从互联网上随机转储一些代码，尝试了解图形管道的工作原理，然后一切都会变得有意义.另外，我建议您了解 现代 Opengl 而不是使用旧的 opengl 固定管道
One advice though, I'd recommend you go through some opengl tutorial before dumping some code randomly from the internet, try to understand how the graphics pipeline works and then everything will start making sense. Also, I'd recommend you learn about modern Opengl instead using the old opengl fixed pipeline
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