1

我正在用 opengl 简单地展示一个 3d 模型。问题是它显示不正确。我在这段代码上工作了几天，当我开始时，我遇到了完全相同的问题，但我修复了它，后来又把它弄坏了，现在我完全不记得解决方案了，这让我很沮丧。如果我不太注意的话，这可能是一件愚蠢的事情。

我唯一记得它与视口和相机有关，我更改的唯一代码如下。

我真的很感激有人像我一样很久没有看这段代码。也许有人会注意到我做错了什么，谢谢。

生成的图像如下所示：

    #include <windows.h>    // for timeGetTime()
#include <mmsystem.h>   // ditto
#include <iostream>     // I/O
#include <glut.h>   // GLUT
//#include <gl/glu.h>       // for gluPerspective & gluLookAt
#include "model3DS.h" // 3DS model support

model3DS *teddyModel;
model3DS *mush;

void setupScene();
void updateScene();
void renderScene();
void exitScene();
void keypress(unsigned char key, int x, int y);
void setViewport(int width, int height);

int         tetrahedronAngle=0;
bool        wireframe=false;
int         windowId;
int         win_width=1024, win_height = 768;
GLuint      textureId;
DWORD       lastTickCount;
GLfloat white_light[] = {1.0, 1.0, 1.0, 1.0};
GLfloat left_light_position[] = {1500,1500,1500, 1.0}; 
GLfloat right_light_position[] = {-1500,-1500,-1500, 1.0};

void renderScene(){

    // Clear framebuffer & depth buffer
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    //glEnable(GL_LIGHTING);

    // Reset Modelview matrix       
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    // Set view position & direction
    // (Camera at (0,0,5) looking down the negative Z-axis)
    gluLookAt(0,0,5,  0,0,-1,  0,1,0);

    // Draw textured tetrahedron
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D,textureId);

    glPushMatrix();
        glTranslatef(0.0,0.0,-1000.0);
        glRotatef(-1*tetrahedronAngle/2.f,0,1,0);
        teddyModel->draw();
    glPopMatrix();

    glPushMatrix();
        glTranslatef(-300.0,0.0,-1000.0);
        glRotatef(-1*tetrahedronAngle/2.f,0,1,0);
        mush->draw();
    glPopMatrix();

    glDisable(GL_TEXTURE_2D);
    // Swap double buffer for flicker-free animation
    glutSwapBuffers();

}

void updateScene(){

    // Wait until at least 16ms passed since start of last frame
    // Effectively caps framerate at ~60fps
    while(timeGetTime()-lastTickCount<16);
    lastTickCount=timeGetTime();

    // Increment angle for next frame
    tetrahedronAngle+=2;

    // Do any other updates here

    // Draw the next frame
    glutPostRedisplay();

}

void keypress(unsigned char key, int x, int y){

    // Test if user pressed ESCAPE (ascii 27)
    // If so, exit the program
    if(key==27){
        exitScene();
    }

    if(key == 'w' || key == 'W'){
        wireframe=!wireframe;
        if(wireframe){
            glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
        }
        else glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    }
    // Other possible keypresses go here
    //if(key == 'a'){...}
}

void setupScene(){

    std::cout<<"Initializing scene..."<<std::endl;

    //Set up Lighting Stuff
    glLightfv(GL_LIGHT0, GL_POSITION, left_light_position);
    glLightfv(GL_LIGHT0, GL_SPECULAR, white_light);
    glLightfv(GL_LIGHT1, GL_POSITION, right_light_position);
    glLightfv(GL_LIGHT1, GL_SPECULAR, white_light);
    glEnable(GL_LIGHT0);
    glEnable(GL_LIGHT1);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, white_light);
    glLightfv(GL_LIGHT1, GL_DIFFUSE, white_light);
    glShadeModel(GL_SMOOTH);

    glEnable(GL_DEPTH_TEST);

    //Load the teddy model
    teddyModel = new model3DS("teddy\\teddy.3ds", 2);
    mush = new model3DS("mushfat\\mushroom.3ds", 2);

}

void exitScene(){

    std::cout<<"Exiting scene..."<<std::endl;

    // Close window
    glutDestroyWindow(windowId);

    // Free any allocated memory

    // Exit program
    exit(0);
}

void setViewport(int width, int height) {

    // Work out window ratio, avoid divide-by-zero
    if(height==0)height=1;
    float ratio = float(width)/float(height);

    // Reset projection matrix
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    // Fill screen with viewport
    glViewport(0, 0, width, height);

    // Set a 45 degree perspective
    gluPerspective(45, ratio, .1, 2000);

}

int main(int argc, char *argv[]){

    // Initialise OpenGL
    glutInit(&argc, argv); 

    // Set window position, size & create window
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowPosition(50,50);
    glutInitWindowSize(win_width,win_height);
    windowId = glutCreateWindow("Lab 4: Loading a textured model");

    // Set GLUT callback functions
    glutReshapeFunc(setViewport);
    glutDisplayFunc(renderScene);
    glutIdleFunc(updateScene);
    glutKeyboardFunc(keypress);

    // Setup OpenGL state & scene resources (models, textures etc)
    setupScene();

    // Show window & start update loop
    glutMainLoop();    

    return 0;

}
4

0 回答 0