在某些情况下，多个 OpenGL 纹理不起作用?

我正在尝试加载OBJ文件以在OpenGL中使用它们。OBJ 文件中的每个对象都有自己的纹理。在我的代码中，我将文件的每个对象拆分为一个结构，该结构的防御方式如下：

struct ObjModelComponent {
std::vector<glm::vec3> vertices;
std::vector<glm::vec2> uvs;
std::vector<glm::vec3> normals;
Texture tex;
ArrayBuffer vertex, uv, normal;
GLuint VAO;
};

Texture类是一个简单的类，用于更轻松地加载和处理纹理。

在模型的课堂上，我对我的ObjModelComponent有std::vector.

我像这样渲染对象：

void ObjModel::render() {
for(int i = 0; i < components.size(); i++) {
components[i].vertex.activate();
components[i].uv.activate();
components[i].normal.activate();
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, components[i].tex.getTextureID());
shader->sendInt(0, components[i].tex.getTextureName());
glBindVertexArray(components[i].VAO);
shader->sendMat4(*data->projection, "projection");
shader->sendMat4(data->viewMat, "view");
shader->sendMat4(model, "model");
glDrawArrays(GL_TRIANGLES, 0, int(components[i].vertices.size()));
glBindVertexArray(0);
}
}

纹理类如下所示：

Texture::Texture(std::string fileName, TextureType type):
textureName("tex"), fileName(fileName), type(type) {
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
unsigned char *image = SOIL_load_image(fileName.c_str(), &texWidth, &texHeight, 0, SOIL_LOAD_RGBA);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
switch (type) {
case TEXTURE_GENERATE_MIPMAP:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glGenerateMipmap(GL_TEXTURE_2D);
break;
case TEXTURE_NO_MIP_MAP:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
default:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
break;
}
glBindTexture(GL_TEXTURE_2D, 0);
SOIL_free_image_data(image);
}
Texture::Texture() {
}
Texture& Texture::operator=(const Texture &other) {
this->fileName = other.fileName;
this->textureName = other.textureName;
this->type = other.type;
//    glDeleteTextures(1, &tex);
glGenTextures(1, &tex);
glBindTexture(GL_TEXTURE_2D, tex);
unsigned char *image = SOIL_load_image(fileName.c_str(), &texWidth, &texHeight, 0, SOIL_LOAD_RGBA);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
switch (type) {
case TEXTURE_GENERATE_MIPMAP:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_NEAREST);
glGenerateMipmap(GL_TEXTURE_2D);
break;
case TEXTURE_NO_MIP_MAP:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
default:
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
break;
}
glBindTexture(GL_TEXTURE_2D, 0);
SOIL_free_image_data(image);
return *this;
}
Texture::~Texture() {
glDeleteTextures(1, &tex);
}
GLuint Texture::getTextureID() {
return tex;
}
void Texture::setTextureName(std::string name) {
textureName = name;
}
std::string Texture::getTextureName() {
return textureName;
}
glm::vec2 Texture::getTextureSize() {
return glm::vec2(texWidth, texHeight);
}

组件的生成方式如下：

for(int i = 0; i < fileLines.size(); i++) {
if(fileLines[i].substr(0, 2) == "o ") {
if(!first) {
tmpComp.tex = tmpTex;
components.emplace_back(tmpComp);
componentIndex++;
}
first = false;
tmpTex = Texture(hg::substr(path, 0, int(path.find_last_of("/"))) + "/" + hg::substr(fileLines[i], 2, int(fileLines[i].length())) + ".png");
}
}

以下是生成 VAO 和数组缓冲区的方式：

for(int i = 0; i < components.size(); i++) {
glGenVertexArrays(1, &components[i].VAO);
glBindVertexArray(components[i].VAO);
components[i].vertex.setData(components[i].vertices.data(), sizeof(glm::vec3) * components[i].vertices.size(), 0);
components[i].uv.setData(components[i].uvs.data(), sizeof(glm::vec2) * components[i].uvs.size(), 1);
components[i].normal.setData(components[i].normals.data(), sizeof(glm::vec3) * components[i].normals.size(), 2);
components[i].vertex.activate();
components[i].uv.activate();
components[i].normal.activate();
glBindVertexArray(0);
}

你可以在GitHub上找到我的完整代码：https://github.com/Kuechenzwiebel/SDL-OpenGL-Tests

问题是，我的对象上显示的纹理是最后一个渲染的对象使用的纹理。

更新：删除纹理析构函数中的glDeleteTextures，结果是所有组件上显示的纹理是用于最后一个组件的纹理。

我真的不明白为什么这不起作用，我从其他只使用一种纹理的原语中复制了它。那里一切正常。