simple verts lister for Blender

Warning:
This code must be executed under Edit mode.

import bpy
import bmesh

def up(v):
    for e in v.link_edges:
        ov = e.other_vert(v)
        if ov not in verts:
            verts.append(ov)
            up(ov)
    print(v.co.x, ",", v.co.y, ",", v.co.z, "," )
    
def down(v):
    print(v.co.x, ",", v.co.y, ",", v.co.z, "," )
    for e in v.link_edges:
        ov = e.other_vert(v)
        if ov not in verts:
            verts.append(ov)
            down(ov)
    
obj = bpy.context.active_object
bm = bmesh.from_edit_mesh(obj.data)

verts = []

def main():
    v0 = bm.verts[0]
    verts.append(v0)
    e0 = v0.link_edges
    u = e0[0].other_vert(v0)
    verts.append(u)
    up(u)
    print(v0.co.x, ",", v0.co.y, ",", v0.co.z, "," )
    if len(e0)>1:
        d = e0[1].other_vert(v0)
        verts.append(d)
        down(d)

render to texture in OpenGL ES

The key is glFramebufferTexture2D in creating FBO. The image is rendered to the bound image buffer through the attachment point.

/*
texId[0] = texture from resource file
texId[3] = texture on the fly in Frame Buffer 1
*/

/////////////////////////
void initRenderTexFbo(){
    // FBO
    glGenFramebuffers(1, fboId);
    glBindFramebuffer(GL_FRAMEBUFFER, fboId);

    // texture
    glGenTextures(1, &texId[3]);
    glBindTexture(GL_TEXTURE_2D, texId[3]);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, fboWidth, fboHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);

    // Framebuffer Texture
    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texId[3], 0);
    GLenum DrawBuffers[1] = {GL_COLOR_ATTACHMENT0};
    glDrawBuffers(1, DrawBuffers);

    // RBO
    glGenRenderbuffers(1, &rboId);
    glBindRenderbuffer(GL_RENDERBUFFER, rboId);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, fboWidth, fboHeight);

    // back to default
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

/////////////////////////
void render_to_FrameBuffer1(){

	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, pFooGlInfo->fboId);

	glActiveTexture(GL_TEXTURE0 + texUnit);
	glBindTexture(GL_TEXTURE_2D, pFooGlInfo->texId[0]);

	glBindVertexArray(id_vao);
	glUseProgram(shaderProgramId);

	glClearColor(1.0, 0.0, 0.0, 1.0);
	glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

//      ...

	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, idbIdx);
	glDrawElements(type, idx_n, GL_UNSIGNED_SHORT, NULL);

	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);

	glBindVertexArray(0);
}

/////////////////////////
void render_from_FrameBuffer1(){

	glBindVertexArray(id_vao);
	glUseProgram(shaderProgramId);

	glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);

	glActiveTexture(GL_TEXTURE0 + texUnit);
	glBindTexture(GL_TEXTURE_2D, texId[3]);

//	...

	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, idbIdx);
	glDrawElements(type, idx_n, GL_UNSIGNED_SHORT, NULL);

	glBindVertexArray(0);
}

simple verts detection on a line 

import bpy
import bmesh

obj = bpy.context.scene.objects.active
m = obj.data
bm = bmesh.new()
bm.from_mesh(m)
bm.verts.index_update()

verts = []

# [6] [12] are examples
firstV = bm.verts[6]
secondV = bm.verts[12]

verts.append(firstV)
verts.append(secondV)

for v in bm.verts:
    for e in v.link_edges:
        vv = e.other_vert(v)
        print(v.index, obj.matrix_world *v.co, vv.index)
        
def findGrandChild(v, vv):
    for e in vv.link_edges:
        vvv = e.other_vert(vv)
        if vvv.index != v.index:
            if vvv.index == firstV.index:
                break
            verts.append(vvv)
            findGrandChild(vv, vvv)
           
findGrandChild(firstV, secondV)
for x in verts:
    x.index

# show results
# do not forget matrix_world
for x in verts:
    print(x.index, obj.matrix_world * x.co)

for x in verts:
    print(x.index, obj.matrix_world * x.normal)