仅更新所选三角形的颜色，VBO 更新

实际上我对使用glBufferSubData和glMapBuffer有点困惑。在我的程序中，我正在加载三角形网格，因此我创建了一个顶点结构，并使用整个网格的数据初始化了我的顶点缓冲区。我实现了光线投射和光线三角形交集。我想做的是，如果我的光标与网格相交，只要相交，相交的三角形就会改变颜色。它目前可以工作，但是当我尝试加载带有 50.000+ 顶点的更大网格时，它不再工作了。我正在使用glBufferData更新我的整个VBO，因为我不明白如何使用glBufferSubData仅更新三角形的颜色。有人可以解释我如何只更新我的 VBO 的特定部分(例如颜色(吗？

struct Vertex
{
    glm::vec3  Pos;
    glm::vec3  Normal;
    glm::vec3  Color;
};
VertexBuffer(void* vertices, size_t size)
{
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);
    glGenBuffers(1, &buffer);
    glBindBuffer(GL_ARRAY_BUFFER, buffer);
    glBufferData(GL_ARRAY_BUFFER, size, vertices, GL_DYNAMIC_DRAW);
    glBindVertexArray(0);
}
void Render()
{
    glBindVertexArray(vertexBuffer->VAO);
    glUseProgram(Fill->program);
    glUniformMatrix4fv(glGetUniformLocation(Fill->program, "model"), 1, GL_FALSE, glm::value_ptr(model));
    glUniformMatrix4fv(glGetUniformLocation(Fill->program, "view"), 1, GL_FALSE, glm::value_ptr(view));
    glUniformMatrix4fv(glGetUniformLocation(Fill->program, "projection"), 1, GL_FALSE, glm::value_ptr(proj));
    for (int j = 0; j < numVertices; j += 3){
        if (intersectPlane(this->Vertices[j], this->Vertices[j + 1], this->Vertices[j + 2], ray, orig)){
            glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer->buffer);
            this->Vertices[j].Color = glm::vec3(1.0, 0.0, 0.0);
            this->Vertices[j + 1].Color = glm::vec3(1.0, 0.0, 0.0);
            this->Vertices[j + 2].Color = glm::vec3(1.0, 0.0, 0.0);
            glBufferData(GL_ARRAY_BUFFER, numVertices * sizeof(Vertex), Vertices, GL_DYNAMIC_DRAW);
        }
        else{
            glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer->buffer);
            this->Vertices[j].Color = glm::vec3(0.695f, 0.695f, 0.695f);
            this->Vertices[j + 1].Color = glm::vec3(0.695f, 0.695f, 0.695f);
            this->Vertices[j + 2].Color = glm::vec3(0.695f, 0.695f, 0.695f);
            glBufferData(GL_ARRAY_BUFFER, numVertices * sizeof(Vertex), Vertices, GL_DYNAMIC_DRAW);
        }
    }
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer->buffer);
    GLuint posLoc = glGetAttribLocation(Fill->program, "Position");
    GLuint norm = glGetAttribLocation(Fill->program, "Normal");
    GLuint colo = glGetAttribLocation(Fill->program, "Color");
    glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, Pos));
    glVertexAttribPointer(norm, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, Normal));
    glVertexAttribPointer(colo, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, Color));
    glEnableVertexAttribArray(posLoc);
    glEnableVertexAttribArray(norm);
    glEnableVertexAttribArray(colo);
        glDrawArrays(GL_TRIANGLES, 0, numVertices);
    glBindVertexArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glUseProgram(0);
}