glDrawTransformFeedback not write to buffer - opengl

Question

I try to use transform features to create a particle system, so there are 2 tranform buffer and 2 array buffer, use ping-pong to switch.
And my shader is simple, just keep add source position.
gs_Position = vs_Position[0] + vec3(1, 0, 1);
If use glDrawTransformFeedback(), 2 buffer will keep original data, not change.But if I switch to glDrawArrays(), then ping-pong works, position value keep increase.
Initial code
shader.setupShaderFromFile(GL_VERTEX_SHADER, "feedback.vert");
shader.setupShaderFromFile(GL_GEOMETRY_SHADER, "feedback.geom");
const GLchar* feedbackVaryings[] = { "gs_Position", "gs_Velocity" };
glTransformFeedbackVaryings(shader.getProgram(), 2, feedbackVaryings, GL_INTERLEAVED_ATTRIBS);
shader.linkProgram();
glGenTransformFeedbacks(2, tfo);
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
Particle* p = new Particle[2];
p[0].position = glm::vec3(1, 2, 3);
p[1].position = glm::vec3(2, 3, 4);
glGenBuffers(2, bfo);
glBindBuffer(GL_ARRAY_BUFFER, bfo[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(Particle)*2, p, GL_STATIC_DRAW);
glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, tfo[0]);
glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, bfo[0]);
glBindBuffer(GL_ARRAY_BUFFER, bfo[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(Particle)*2, nullptr, GL_STATIC_READ);
glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, tfo[1]);
glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, bfo[1]);
perform transform
int from = pid;
int to = (pid + 1) % 2;
glEnable(GL_RASTERIZER_DISCARD);
glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, tfo[to]);
glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, bfo[to]);
shader.begin();
glBindBuffer(GL_ARRAY_BUFFER, bfo[from]);
{
GLint inputAttrib = shader.getAttributeLocation("a_Position");
glEnableVertexAttribArray(inputAttrib);
glVertexAttribPointer(inputAttrib, 3, GL_FLOAT, GL_FALSE, sizeof(Particle), (void*)offsetof(Particle, position));
}
{
GLint inputAttrib = shader.getAttributeLocation("a_Velocity");
glEnableVertexAttribArray(inputAttrib);
glVertexAttribPointer(inputAttrib, 3, GL_FLOAT, GL_FALSE, sizeof(Particle), (void*)offsetof(Particle, velocity));
}
glBeginTransformFeedback(GL_POINTS);
//glDrawArrays(GL_POINTS, 0, 2);
glDrawTransformFeedback(GL_POINTS, tfo[from]);
glEndTransformFeedback();
shader.end();
glDisable(GL_RASTERIZER_DISCARD);
glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, 0);