关于OpenGL的一个小问题(2)

沉默的菜鸟

用OpenGL画了一个立方体，实现了鼠标手动旋转以及自动旋转等功能。
但碰到了一个棘手问题，就是当立方体自动旋转时，只有两面有颜色，另外的面为黑色，但我都设置了颜色的呀？？
求大神帮助。。。

代码：

ObjLoader.h

[C++] 纯文本查看 复制代码

#pragma once
#include <GL/glut.h>
#include <vector>
#include <array>
#include <string>
using namespace std;

class ObjLoader
{
public:
        ObjLoader() {};
        ObjLoader( const string& filepath);
        ~ObjLoader();
        void Paint();
private:
        vector<array<GLfloat, 3>> vertexContainer;
        vector<array<GLint, 3>> triangleContainer;
};

ObjLoader.cpp

[C++] 纯文本查看 复制代码

#include "ObjLoader.h"
#include <fstream>
#include <iostream>
#include <sstream>
#include <direct.h>
ObjLoader::ObjLoader(const string& filepath) 
{
        string line;
        ifstream f;
        f.open(filepath, ios::in);
        if (!f.is_open())
        {
                cout << "文件打开失败，请检查文件路径！" << endl;
                return;
        }
        while (!f.eof())
        {
                getline(f, line);
                cout << line << endl;
                istringstream sin(line);
                if (line[0]=='v')
                {
                        char flag;
                        float x, y, z;
                        sin >> flag >> x >> y >> z;
                        this->vertexContainer.push_back(array<GLfloat, 3>{x, y, z});
                }
                else if (line[0]=='f')
                {
                        char flag;
                        int p1, p2, p3;
                        sin >> flag >> p1 >> p2 >> p3;
                        this->triangleContainer.push_back(array<GLint, 3>{p1-1, p2-1, p3-1});
                        //因为顶点索引在obj文件中是从1开始的，而我们存放的顶点array是从0开始的，因此要减1
                }
        }

}

ObjLoader::~ObjLoader()
{
        char buffer[100];
        _getcwd(buffer,100);
        string path = string(buffer);
        string filename = "/data.obj";
        ofstream out;
        out.open(path+filename,ios::out);
        if (!out.is_open())
        {
                cout << "写入路径错误！" << endl;
                return;
        }
        for(auto vertex : this->vertexContainer)
        {
                out << "v " << vertex[0] << " " << vertex[1] << " " << vertex[2] << endl;
        }
        for (auto triangle:this->triangleContainer)
        {
                out << "f " << triangle[0]+1 << " " << triangle[1]+1 << " " << triangle[2]+1 << endl;
        }
        out.close();
        cout << "写入文件成功！" << endl;
}


void ObjLoader::Paint()
{
        glBegin(GL_TRIANGLES);                                                                                                                //开始绘制

        for (size_t i = 0; i < this->triangleContainer.size(); i++)
        {
                array<GLfloat, 3>VN;//三角形的单位法向量
                //三个顶点
                array<GLfloat, 3>Vertex1;
                array<GLfloat, 3>Vertex2;
                array<GLfloat, 3>Vertex3;
                if (this->triangleContainer[i].size() != 3)
                {
                        cout << "数据错误！" << endl;
                }
                else
                {
                        GLint firstVertexIndex = (triangleContainer[i])[0];                                //取出顶点索引
                        GLint secondVertexIndex = (triangleContainer[i])[1];
                        GLint thirdVertexIndex = (triangleContainer[i])[2];

                        for (size_t j = 0; j < 3; j++)
                        {
                                Vertex1[j] = vertexContainer[firstVertexIndex][j];                        //顶点一
                                Vertex2[j] = vertexContainer[secondVertexIndex][j];                //顶点二
                                Vertex3[j] = vertexContainer[thirdVertexIndex][j];                        //顶点三
                        }

                        GLfloat vec1[3], vec2[3], vec3[3];//计算法向量
                        for (size_t z = 0; z < 3; z++)
                        {
                                vec1[z] = Vertex1[z] - Vertex2[z];//v1v2向量
                                vec2[z] = Vertex1[z] - Vertex3[z];//v1v3向量
                        }
                        //由v1v2向量与v1v3向量叉乘即可得平面的法向量
                        vec3[0] = vec1[1] * vec2[2] - vec1[2] * vec2[1];
                        vec3[1] = vec2[0] * vec1[2] - vec2[2] * vec1[0];
                        vec3[2] = vec2[1] * vec1[0] - vec2[0] * vec1[1];

                        //单位法向量
                        GLfloat D = sqrtf(pow(vec3[0], 2) + pow(vec3[1], 2) + pow(vec3[2], 2));
                        for (size_t n = 0; n < 3; n++)
                        {
                                VN[n] = vec3[n] / D;
                        }

                        int p = 7;//扩大倍数

                        glColor3ub(163, 85, 104);
                        glNormal3f(VN[0], VN[1], VN[2]);//绘制单位法向量
                        glColor3ub(163, 85, 104);
                        glVertex3f(Vertex1[0] *p, Vertex1[1] * p, Vertex1[2] * p);
                        glColor3ub(73,90,128);
                        glVertex3f(Vertex2[0] * p, Vertex2[1] * p, Vertex2[2] * p);
                        glColor3ub(221,240, 237);
                        glVertex3f(Vertex3[0] * p, Vertex3[1] * p, Vertex3[2] * p);
                }
        }
        glEnd();
}

main.cpp

[C++] 纯文本查看 复制代码

#include "ObjLoader.h"
#include <iostream>
using namespace std;

ObjLoader objModel;

int angles = 0;        //转动角度
int xyz[3] = { 0,1,0 };

//实现移动鼠标观察模型所需变量
static float c = 3.1415926f / 180.0f;
static float r = 1.0f;
static int degree = 90;
static int oldPosY = -1;
static int oldPosX = -1;

//安置光源
void setLightRes() {
        GLfloat lightPosition[] = { 0.0f, 0.0f, 1.0f, 0.0f };
        glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
        glEnable(GL_LIGHTING); //启用光源
        glEnable(GL_LIGHT0);   //使用指定灯光
}

//初始化
void init() {
        cout << "please input the path of the obj file：";
        string path;
        cin >> path;
        cout << endl;
        objModel = ObjLoader(path);
        glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
        glutInitWindowSize(500, 500);
        glutCreateWindow("ObjBuilder");
        glEnable(GL_DEPTH_TEST);
        glShadeModel(GL_SMOOTH);
        setLightRes();
        glEnable(GL_DEPTH_TEST);
        glColorMaterial(GL_FRONT, GL_DIFFUSE);
        glEnable(GL_COLOR_MATERIAL);

        glEnable(GL_LIGHTING);
        glEnable(GL_LIGHT0);
        glEnable(GL_AUTO_NORMAL);
        glEnable(GL_NORMALIZE);
}

void timerPoc(int id) 
{
        angles += 20;
        angles %= 360;
        glutPostRedisplay();
        glutTimerFunc(200, timerPoc, 1);
}

void display()
{
        glColor3f(1.0, 1.0, 1.0);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        glTranslatef(0.0f, 0.0f, -20.0f);
        glRotatef(angles, xyz[0], xyz[1], xyz[2]);
        setLightRes();
        glPushMatrix();

        gluLookAt(r * cos(c * degree), 0, r * sin(c * degree), 0.0f, 0.0f, 0.0f, 0.0f,1.0f, 0.0f);

        objModel.Paint();//绘制obj模型
        glPopMatrix();
        glutSwapBuffers();
}

void keyboard(unsigned char key, int x, int y) 
{
        if (key == 114) {
                glutTimerFunc(200, timerPoc, 1);
                cout << "Unhandled key press r" << endl;
        }
}

void reshape(int width, int height)
{
        glViewport(0, 0, width, height);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluPerspective(60.0f, (GLdouble)width / (GLdouble)height, 1.0f, 200.0f);
        glMatrixMode(GL_MODELVIEW);
}

//移动鼠标360观察模型
void moseMove(int button, int state, int x, int y)
{
        if (state == GLUT_DOWN) {
                oldPosX = x; oldPosY = y;
        }
}
void changeViewPoint(int x, int y)
{
        int temp = x - oldPosX;
        degree += temp;
        oldPosX = x;
        oldPosY = y;
}

void myIdle()
{
        glutPostRedisplay();
}

int main(int argc, char* argv[])
{
        glutInit(&argc, argv);
        init();
        glutDisplayFunc(display);
        glutKeyboardFunc(keyboard);
        glutReshapeFunc(reshape);
        glutMouseFunc(moseMove);
        glutMotionFunc(changeViewPoint);
        glutIdleFunc(myIdle);
        glutMainLoop();
        return 0;
}

效果：




我觉得可能是光源的问题，但不知道怎么解决。。。

沉默的菜鸟

okxiaobo 发表于 2019-9-7 21:47
牛逼，高手啊

汗颜了，我才敢刚学

沉默的菜鸟

okxiaobo 发表于 2019-9-7 21:48
这是光照问题

应该怎么改呢？？？