How can I make an infinite cave using stage3d?

Question

I want to make an infinite cave in my 3d game using flash stage3d. But I got no idea about how to build that cave. Can anyone can give me some solution or hint?
update: I've tried agal fragment shader like squeae tunnel in shadertoy

code:

var fragmentProgramCode:String =
                AGALUtils.build()
                .mov("ft0","v0")
                .div("ft1","ft0.xy","fc3.xy")
                .mul("ft2","fc6.x","ft1")
                .sub("ft3","ft2","fc5.x")//vec2 p = -1.0 + 2.0 * gl_FragCoord.xy / resolution.xy;
                .mul("ft1","ft3.x","ft3.x")
                .mul("ft2","ft3.y","ft3.y")
                .pow("ft4","ft1","fc6.z")//float r = pow( pow(p.x*p.x,16.0) + pow(p.y*p.y,16.0), 1.0/32.0 );
                .pow("ft5","ft2","fc6.z")
                .add("ft1","ft4","ft5")
                .pow("ft4","ft1","fc6.w")
                .mov("ft5","fc5")//uv
                .sub("ft1","fc7.x","ft4")
                .add("ft5.x","fc7.x","ft1")//uv.x = .5*time + 0.5/r;
                .mov("ft6","fc0")//for atan
                .atan2("ft5.y","ft3.y","ft3.x",new <String>["fc7.y","fc5.x","fc7.z","fc7.w","fc8.x","fc8.y","fc8.z","fc8.w","fc9.x","fc9.y"],"ft6")
                .tex("ft0","ft5","fs0","repeat","linear","nomip")//tex
                .mul("ft1","ft4","ft4")
                .mul("ft2","ft1","ft4")//r*r*r
                .mul("ft1","ft0.xyz","ft2")
                .mov("ft0.w","fc5.x")
                .mov("oc","ft1").toString()

it can only apply one material,but my project requires different types of material (like floor,ceilling). so ,I create a 3d model Is there anyway to make that 3d model render like "infinity cave"? use agal to make each side of cave's texture move? thanks for your help

update again:

I tried glsl to make a cube,when using color It looks good,but when I don't know how to apply texture's transform. It's really hard for me to accomplish this,haven't 3d experience before,thanks for your time !     


#ifdef GL_ES
precision highp float;
#endif

uniform vec2 resolution;
uniform float time;
uniform sampler2D tex0;
uniform sampler2D tex1;
uniform sampler2D tex2;
uniform sampler2D tex3;

vec4 p1 = vec4(0.0, 1.0, 0.0, 1.3);//down
vec4 p2 = vec4(0.0, - 1.0, 0.0, 1.3);//up
vec4 p3 = vec4(1.0, 0.0, 0.0, 1.3);//left
vec4 p4 = vec4(-1.0, 0.0, 0.0, 1.3);//right
vec4 p5 = vec4(0.0, 0.0, 1.0, 1.3);//center


void main(){
 vec2 uv = -1.0 + 2.0*gl_FragCoord.xy/resolution.xy;
 uv.x *= resolution.x/resolution.y;
 vec3 o = vec3(0.0, 0.0, 2.3);
 vec3 rd = normalize(vec3(uv, -1.0));
 vec3 lp = vec3(sin(time), sin(time), cos(time));
 float li = 2.0;
 vec3 co;   

 float tm = 10000.0;
 float t=- (dot(p1.xyz, o)+p1.w)/dot(p1.xyz,rd);
 if(t>0.0&&t<tm){
   co =vec3(.2);//down
   tm=t;
 }
 t=- (dot(p2.xyz, o)+p2.w)/dot(p2.xyz,rd);
 if (t>0.0&&t<tm){
   co =vec3(.3);//top
   tm = t;
 }
 t=- (dot(p3.xyz, o)+p3.w)/dot(p3.xyz,rd);
 if (t>0.0&&t<tm){
    co =vec3(.4);//left
    tm = t;
 }
 t=- (dot(p4.xyz, o)+p4.w)/dot(p4.xyz,rd);
 if (t>0.0&&t<tm){
    co =vec3(.5);//right

    tm = t;
 }
 t=- (dot(p5.xyz, o)+p5.w)/dot(p5.xyz,rd);
 if (t>0.0&&t<tm){
     co =vec3(.6); //center
     tm=t;
 }
 gl_FragColor = vec4(co, 1.0);
}

Answer 1

altering the code you've pasted in Shader Toy I've reached something acceptable:

#ifdef GL_ES
precision highp float;
#endif

uniform vec2 resolution;
uniform float time;
uniform sampler2D tex0;
uniform sampler2D tex1;
uniform sampler2D tex2;
uniform sampler2D tex3;

void main(void)
{
    vec2 p = -1.0 + 2.0 * gl_FragCoord.xy / resolution.xy;
    vec2 uv;

    float r = pow( pow(p.x*p.x,32.0) + pow(p.y*p.y,32.0), 1.0/.0 );
    uv.x = .5*time + 0.5/r;
    uv.y = 2.0*atan(p.y,p.x)/3.1416+2.5;    
    vec3 col0 = texture2D(tex0,uv).xyz;
    vec3 col1 = texture2D(tex1,uv).xyz;
    vec3 col2 = texture2D(tex2,uv).xyz;
    vec3 col3 = texture2D(tex3,uv).xyz;
    vec3 col  = vec3(0);
    col += (step (4.0,uv.y) + step(uv.y,1.0)) * col0; 
    col += step (1.0,uv.y) * step(uv.y,2.0) * col1;
    col += step (2.0,uv.y) * step(uv.y,3.0) * col2;
    col += step (3.0,uv.y) * step(uv.y,4.0) * col3;
    gl_FragColor = vec4(col*r*r*r,1.0);
}

this code uses all 4 texture slots so if you want to see the results in shader toy you need to fill all 4 texture units there, here are the textures I used:

unit 0 : http://www.iquilezles.org/apps/shadertoy/presets/tex0.jpg
unit 1 : http://www.iquilezles.org/apps/shadertoy/presets/tex1.jpg
unit 2 : http://www.iquilezles.org/apps/shadertoy/presets/tex2.jpg
unit 3 : http://www.iquilezles.org/apps/shadertoy/presets/tex3.jpg