使用结构初始化 OpenGL VBO

如何解决使用结构初始化 OpenGL VBO

我在向 OpenGL VBO 添加 struct 时遇到问题

这是我的struct

struct Vertex {

    //vertices
    std::vector<glm::vec3> vertices;

    //texture coordinates
    std::vector<glm::vec3> texCord;
}

这就是我分配和初始化 VBO 的方式

glGenVertexArrays(1,&buffer.VAO);
glGenBuffers(1,&buffer.VBO);
glGenBuffers(1,&buffer.EBO);

glBindBuffer(GL_ARRAY_BUFFER,buffer.VAO);

//Initialize buffer data 
glBindBuffer(GL_ARRAY_BUFFER,buffer.VBO);
glBufferData(GL_ARRAY_BUFFER,vertex.vertices.size() * sizeof(glm::vec3) +
            vertex.texCord.size() * sizeof(glm::vec3)
            &vertex,GL_STATIC_DRAW);

//indices attribute
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,buffer.EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER,vertex.indices.size() * sizeof(glm::vec2),&vertex.indices[0],GL_STATIC_DRAW);

//vertices coordinates attribute
glEnableVertexAttribArray(0);
glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,sizeof(Vertex),(void*)offsetof(Vertex,vertices));

//texture coordinates attribute
glEnableVertexAttribArray(1);
glVertexAttribPointer(1,2,texCord));

我的绘图命令是这样的

glClearColor(0.2f,0.3f,1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glBindVertexArray(buffer.VAO);
glDrawElements(GL_TRIANGLES,vertex.indices.size(),GL_UNSIGNED_INT,0);
glBindVertexArray(0);

是否可以使用原始 struct 初始化缓冲区数据，如果是，如何初始化？

解决方法

std::vector 存储一个指向动态分配内存的指针。但是，您必须将连续的缓冲区传递给 glBufferData。
使用 glBufferData 创建对象的数据存储，但使用 glBufferSubData 初始化缓冲区：

size_t vertexSize = vertex.vertices.size() * sizeof(glm::vec3);
size_t texCordSize = vertex.texCord.size() * sizeof(glm::vec3);

glBufferData(GL_ARRAY_BUFFER,vertexSize + texCordSize,nullptr,GL_STATIC_DRAW);
glBufferSubData(GL_ARRAY_BUFFER,vertexSize,vertex.vertices.data());
glBufferSubData(GL_ARRAY_BUFFER,texCordSize,vertex.texCord.data());

,

感谢@Rabbid76，我现在解决了我的问题。代码在下面。

注意：我需要在用 glBufferSubData 填充数据之前创建缓冲区

glGenVertexArrays(1,&buffer.VAO);
glGenBuffers(1,&buffer.VBO);
glGenBuffers(1,&buffer.EBO);

glBindBuffer(GL_ARRAY_BUFFER,buffer.VAO);

int vertexSize = sizeof(glm::vec3) * vertex.vertices.size();
int texCordSize = sizeof(glm::vec2) * vertex.texCord.size();
int totalSize = vertexSize + texCordSize;

int indicesSize = sizeof(unsigned int) * vertex.indices.size();

//Create Buffer dynamically
glBufferData(GL_ARRAY_BUFFER,totalSize,NULL,GL_DYNAMIC_DRAW);

//Fill the buffer with data 
glBindBuffer(GL_ARRAY_BUFFER,buffer.VBO);
glBufferSubData(GL_ARRAY_BUFFER,vertex.texCord.data());

//indices attribute
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,buffer.EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER,indicesSize,vertex.indices.data(),GL_STATIC_DRAW);

//position attribute
glEnableVertexAttribArray(0);
glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,sizeof(glm::vec3) + sizeof(glm::vec2),(void*)0);
        
//texture attribute
glEnableVertexAttribArray(1);
glVertexAttribPointer(1,2,(void*)sizeof(glm::vec3));

glBindVertexArray(0);