OpenGL:如何将纹理应用于此立方体？

Question

我正在尝试学习OpenGL,并且我已经经历了许多关于加载纹理的教程,但是每一个教程似乎都错过了最重要的一步:我如何实际在某些东西上放置纹理？

我正在使用Python,这是我加载纹理的函数:

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

这是加载我的多维数据集的函数:

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会将我带到loadTexture函数,而不会实际告诉我如何使用它.我在哪里打电话给它？我怎么处理texid？

Answer 1

您的实际代码几乎没有问题:

• 你没有调用加载纹理的方法.
• 您只绘制立方体的线条,您需要用实际纹理填充多边形,这意味着使用具有纹理坐标的三角形或四边形.
• 你没有处理pygame事件

以下是对代码的一些修改:

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()

上面的代码没有使用最佳做法,但它会帮助您解决您的评论问题.

但有一条建议,我建议你在从互联网上随机转储一些代码之前先阅读一些opengl教程,尝试理解图形管道是如何工作的,然后一切都会开始变得有意义.另外,我建议你使用旧的opengl固定管道学习现代的Opengl