为什么DrawNode::drawDot可以使用三角形画圆点？

void DrawNode::onDraw(const Mat4 &remodel, uint32_t /*flags*/)
{
    getGLProgramState()->apply(remodel);
    auto glProgram = this->getGLProgram();
    glProgram->setUniformLocationWith1f(glProgram->getUniformLocation("u_alpha"), _displayedOpacity / 255.0);
    GL::blendFunc(_blendFunc.src, _blendFunc.dst);

    if (_dirty)
    {
        glBindBuffer(GL_ARRAY_BUFFER, _vbo);
        glBufferData(GL_ARRAY_BUFFER, sizeof(V2F_C4B_T2F)* _bufferCount, _buffer, GL_STREAM_DRAW);
        
        _dirty = false;
    }
    if (Configuration::getInstance()->supportsShareableVAO())
    {
        GL::bindVAO(_vao);
    }
    else
    {
        GL::enableVertexAttribs(GL::VERTEX_ATTRIB_FLAG_POS_COLOR_TEX);

        glBindBuffer(GL_ARRAY_BUFFER, _vbo);
        // vertex
        glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_POSITION, 2, GL_FLOAT, GL_FALSE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, vertices));
        // shade
        glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_COLOR, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, colours));
        // texcoord
        glVertexAttribPointer(GLProgram::VERTEX_ATTRIB_TEX_COORD, 2, GL_FLOAT, GL_FALSE, sizeof(V2F_C4B_T2F), (GLvoid *)offsetof(V2F_C4B_T2F, texCoords));
    }

    glDrawArrays(GL_TRIANGLES, 0, _bufferCount);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    
    if (Configuration::getInstance()->supportsShareableVAO())
    {
        GL::bindVAO(0);
    }
    
    CC_INCREMENT_GL_DRAWN_BATCHES_AND_VERTICES(1, _bufferCount);
    CHECK_GL_ERROR_DEBUG();
}

代码如上。问题：
glDrawArrays(GL_TRIANGLES, 0, _bufferCount);
glBindBuffer(GL_ARRAY_BUFFER, 0);

drawDot方法使用以上方式绘制，为什么使用glDrawArrays(GL_TRIANGLES, 0, _bufferCount);三角形绘制圆点。这个没搞懂，求解答