vec2 vtc = vTexCoord;
vec2 uv = vec2(vtc.x, 1.0-vtc.y);
vec4 img = texture2D(TXP, uv);
float k = MY*0.5;
vec4 imb = texture2D(TXB, uv2dspmd(uv,f2z(img.r)*k,f2z(img.b)*k));
gl_FragColor = imb;
vec2 uv = vec2(vtc.x, 1.0-vtc.y);
vec4 img = texture2D(TXP, uv);
float k = MY*0.5;
vec4 imb = texture2D(TXB, uv2dspmd(uv,f2z(img.r)*k,f2z(img.b)*k));
gl_FragColor = imb;
