OpenGL读取OBJ文件
时间: 2023-10-23 10:14:02 浏览: 72
要读取OBJ文件并在OpenGL中渲染它,可以使用以下步骤:
1. 打开OBJ文件并读取其内容。
2. 解析文件内容以获取顶点、法线和纹理坐标数据。
3. 将这些数据存储在OpenGL缓冲区中。
4. 使用OpenGL绘制命令绘制模型。
以下是一个简单的示例代码,演示如何读取OBJ文件并在OpenGL中渲染它:
```c++
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include <GL/glut.h>
using namespace std;
struct Vertex {
float x, y, z;
};
struct Normal {
float x, y, z;
};
struct TexCoord {
float u, v;
};
struct Face {
int v1, v2, v3;
int n1, n2, n3;
int t1, t2, t3;
};
vector<Vertex> vertices;
vector<Normal> normals;
vector<TexCoord> texCoords;
vector<Face> faces;
void loadObjFile(const char* filename) {
ifstream file(filename);
if (!file) {
cerr << "Error: Cannot open file " << filename << endl;
exit(1);
}
string line;
while (getline(file, line)) {
istringstream iss(line);
string type;
iss >> type;
if (type == "v") {
Vertex v;
iss >> v.x >> v.y >> v.z;
vertices.push_back(v);
} else if (type == "vn") {
Normal n;
iss >> n.x >> n.y >> n.z;
normals.push_back(n);
} else if (type == "vt") {
TexCoord t;
iss >> t.u >> t.v;
texCoords.push_back(t);
} else if (type == "f") {
Face f;
char slash;
iss >> f.v1 >> slash >> f.t1 >> slash >> f.n1
>> f.v2 >> slash >> f.t2 >> slash >> f.n2
>> f.v3 >> slash >> f.t3 >> slash >> f.n3;
faces.push_back(f);
}
}
}
void display() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0, 0, 5, 0, 0, 0, 0, 1, 0);
glBegin(GL_TRIANGLES);
for (const auto& face : faces) {
const auto& v1 = vertices[face.v1 - 1];
const auto& v2 = vertices[face.v2 - 1];
const auto& v3 = vertices[face.v3 - 1];
const auto& n1 = normals[face.n1 - 1];
const auto& n2 = normals[face.n2 - 1];
const auto& n3 = normals[face.n3 - 1];
const auto& t1 = texCoords[face.t1 - 1];
const auto& t2 = texCoords[face.t2 - 1];
const auto& t3 = texCoords[face.t3 - 1];
glNormal3f(n1.x, n1.y, n1.z);
glTexCoord2f(t1.u, t1.v);
glVertex3f(v1.x, v1.y, v1.z);
glNormal3f(n2.x, n2.y, n2.z);
glTexCoord2f(t2.u, t2.v);
glVertex3f(v2.x, v2.y, v2.z);
glNormal3f(n3.x, n3.y, n3.z);
glTexCoord2f(t3.u, t3.v);
glVertex3f(v3.x, v3.y, v3.z);
}
glEnd();
glutSwapBuffers();
}
int main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(800, 600);
glutCreateWindow("OBJ Viewer");
glEnable(GL_DEPTH_TEST);
glEnable(GL_TEXTURE_2D);
loadObjFile("model.obj");
glutDisplayFunc(display);
glutMainLoop();
return 0;
}
```