[英]Initializing a OpenGL VBO with a struct
Im having problems to add a struct
to a OpenGL VBO我在向 OpenGL VBO 添加
struct
时遇到问题
This is my struct
这是我的
struct
struct Vertex {
//vertices
std::vector<glm::vec3> vertices;
//texture coordinates
std::vector<glm::vec3> texCord;
}
This is how im assigning and initializing the VBO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, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, texCord));
And my draw command looks like this我的绘图命令看起来像这样
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glBindVertexArray(buffer.VAO);
glDrawElements(GL_TRIANGLES, vertex.indices.size(), GL_UNSIGNED_INT, 0);
glBindVertexArray(0);
Is it possible to initialize buffer data with a raw struct
and if yes how?是否可以使用原始
struct
初始化缓冲区数据,如果可以,如何?
std::vector
stores a pointer to dynamically allocated memory. std::vector
存储指向动态分配的 memory 的指针。 However, you must pass a consecutive buffer to glBufferData
.但是,您必须将连续缓冲区传递给
glBufferData
。
Create the object's data store with glBufferData
, but use glBufferSubData
to initialize the buffer:使用
glBufferSubData
glBufferData
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, 0, vertexSize, vertex.vertices.data());
glBufferSubData(GL_ARRAY_BUFFER, vertexSize, texCordSize, vertex.texCord.data());
Thanks to @Rabbid76 I now solved my problem.感谢@Rabbid76,我现在解决了我的问题。 Code is down below.
代码在下面。
Note: I need to create the buffer before filling data with glBufferSubData
注意:我需要在使用
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, 0, vertexSize, vertex.vertices.data());
glBufferSubData(GL_ARRAY_BUFFER, vertexSize, texCordSize, 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, GL_FLOAT, GL_FALSE, sizeof(glm::vec3) + sizeof(glm::vec2), (void*)sizeof(glm::vec3));
glBindVertexArray(0);
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