Loops 在OpenGL中使用多个纹理仅显示一个

我修改了原始代码（）以使用两种纹理。这是：

#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "support.h"

using namespace std;

GLuint *images;
GLubyte *image;
GLuint texture1=0;
GLuint texture2=0;
GLuint LoadTexture(int width, int height, char *fName);

int n=200;
int m=200;

void showPictureW();
void showPictureR();

float rX=0;
float rY=0;
float rZ=0;
float tX=0;
float tY=0;
float tZ=-3.5;
float nr = -5.0;
float fr = -4.0;
float tpx = 1.0;
float tpy = 1.0;
float btx = -1.0;
float bty = -1.0;
float dZ =-2.0;

void showPictureW()
{
    /*  clear all pixels  */
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glColor3d(1,1,1);

    //face 1
    glBegin( GL_POLYGON );
        glTexCoord2d(1.0,1.0); glVertex3d(-1.0,1.0,-2.0);
        glTexCoord2d(1.0,0.0); glVertex3d(-1,-1.0,-2.0);
        glTexCoord2d(0.0,0.0); glVertex3d(1.0,-1.0,-2.0);
    glEnd();

    //face 2
    glBegin( GL_POLYGON );
        glTexCoord2d(0.0,0.0); glVertex3d(1.0,-1.0,-2.0);
        glTexCoord2d(0.0,1.0); glVertex3d(1.0,1.0,-2.0);
        glTexCoord2d(1.0,1.0); glVertex3d(-1.0,1.0,-2.0);
    glEnd();
}

void showPictureR()
{
    //clear all pixels
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glColor3d(1,1,1);

    //face 1
    glBegin( GL_POLYGON );
        glTexCoord2d(1.0,1.0); glVertex3d(-1.2,1.0,-2.0);
        glTexCoord2d(1.0,0.0); glVertex3d(0.0,1.0,-2.0);
        glTexCoord2d(0.0,0.0); glVertex3d(0.0,2.0,-2.0);
    glEnd();

    //face 2
    glBegin( GL_POLYGON );
        glTexCoord2d(0.0,0.0); glVertex3d(0.0,2.0,-2.0);
        glTexCoord2d(0.0,1.0); glVertex3d(0.0,1.0,-2.0);
        glTexCoord2d(1.0,1.0); glVertex3d(1.2,1.0,-2.0);
    glEnd();
}

static void resize(int width, int height)
{
    const float ar = (float) width / (float) height;

    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glFrustum(-ar, ar, -1.0, 1.0, 1.0, 100.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity() ;
}

static void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glColor3d(1,0,0);

    glEnable( GL_TEXTURE_2D );
    glBindTexture( GL_TEXTURE_2D, texture1 );
    glPushMatrix();
        glTranslated(0,0,0);
        glRotated(rX,0,0,1);
        glRotated(rY,0,1,0);
        glRotated(rZ,1,0,0);
        showPictureW();
    glPopMatrix();

    glBindTexture( GL_TEXTURE_2D, texture2 );
    glPushMatrix();
        glTranslated(0,0,0);
        glRotated(rX,0,0,1);
        glRotated(rY,0,1,0);
        glRotated(rZ,1,0,0);
        showPictureR();
    glPopMatrix();

    glutSwapBuffers();
}

static void key(unsigned char key, int x, int y)
{
    switch (key) 
    {
        case 27 : 
        case 'q':
            exit(0);
            break;
        case '+':
            break;
        ...
    }
    glutPostRedisplay();
}

static void idle(void)
{
    glutPostRedisplay();
}

const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f };

const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };
const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };
const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat high_shininess[] = { 100.0f };

/* Program entry point */

int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitWindowSize(640,480);
    glutInitWindowPosition(10,10);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);

    glutCreateWindow("FreeGLUT Shapes");
    glutReshapeFunc(resize);
    glutDisplayFunc(display);
    glutKeyboardFunc(key);
    glutIdleFunc(idle);

    glClearColor(1,1,1,1);
    glEnable(GL_CULL_FACE);
    glCullFace(GL_BACK);

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glEnable(GL_COLOR_MATERIAL);
    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);
    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);
    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);
    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    texture1 = LoadTexture( 200, 200, "wall.ppm" );
    texture2 = LoadTexture( 200, 200, "roof.ppm" );

    glutMainLoop();

    return EXIT_SUCCESS;
}

GLuint LoadTexture(int width, int height, char *fName)
{
    FILE *fd;
    int k, nm;

    int i;
    char bc[71];
    float s;
    unsigned int red, green, blue;
    char c;

    fd = fopen(fName,"r");
    fscanf(fd,"%[^\n]",bc); // reads data from stream
    printf("Nilai %s \n\n",bc);
    if(bc[0]!='P'|| bc[1]!='3')
    {
        printf("%s Not a PPM file\n",bc);
        exit(0);
    }
    printf("%s is a PPM file\n",bc);

    fscanf(fd,"%s",bc);
    printf("line 1 %s \n",bc);

    fscanf(fd,"%s",bc);
    printf("line 2 %s \n",bc);

    fscanf(fd,"%s",bc);
    printf("line 3 %s \n",bc);

    fscanf(fd,"%s",bc);
    printf("line 4 %s \n",bc);

    fscanf(fd,"%c",&c);
    ungetc(c,fd);
    fscanf(fd,"%d %d %d", &n,&m,&k);

    nm = n*m;
    images = new GLuint[3*sizeof(GLuint)*nm];

    for (i=0;i<nm;i++)
    {
        fscanf(fd,"%u %u %u", &red, &green, &blue);
        images[3*nm-3*i-3] = red;
        images[3*nm-3*i-2] = green;
        images[3*nm-3*i-1] = blue;    
    }
    int totSize = 3*nm;
    int tot=0;
    for(i=0;i<nm;i++)
    {
        tot++;
    }

    image = new BYTE[width*height*3*sizeof(BYTE)];
    int nmOne = width*height;
    for(int i=0;i<nmOne*3;i++)//copy each value 3 times
    {
        image[i] = (GLubyte)images[i];
        image[i] = (GLubyte)images[i];
        image[i] = (GLubyte)images[i];
    }  

    bool wrap = true;
    GLuint texture = 0;
    glGenTextures( 1, &texture );
    // select our current texture
    glBindTexture( GL_TEXTURE_2D, texture );
    // select modulate to mix texture with color for shading
    glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
    // when texture area is small, bilinear filter the closest mipmap
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST );
    // when texture area is large, bilinear filter the first mipmap
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
    // if wrap is true, the texture wraps over at the edges (repeat)
    //       ... false, the texture ends at the edges (clamp)
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrap ? GL_REPEAT : GL_CLAMP );
    glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,wrap ? GL_REPEAT : GL_CLAMP );
    // build our texture mipmaps
    gluBuild2DMipmaps( GL_TEXTURE_2D, 3, width, height,
    GL_RGB, GL_UNSIGNED_BYTE, image );

    return texture;
}

你打过电话吗

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

在您的

showPictureW

和

showPictureR

函数中，最后只能看到这些调用中最后一个调用的效果，这应该不会让您感到惊讶。

您确实调用了

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

在

showPictureW

和

showPictureR

函数中，最后只能看到这些调用的最后一个效果，这应该不会让您感到惊讶。

我省略了

glClear（GL\u COLOR\u BUFFER\u BIT | GL\u DEPTH\u BUFFER\u BIT）和添加的
glDepthMask（true）。现在可以了。谢谢你的帮助：）我省略了
glClear（GL_颜色_缓冲区_位| GL_深度_缓冲区_位）和添加的
glDepthMask（true）。现在可以了。谢谢你的帮助：）