iphone - How to flex a 3D texture with OpenGL ES? -

i have tried draw 3d squares (with opengl on iphone) , make them rotate around, sphere.

http://i618.photobucket.com/albums/tt265/loyalmoral/post/screenshot2013-05-15at23249pm.png

but square flat (the first 1 on image below), , want flex it:

http://i618.photobucket.com/albums/tt265/loyalmoral/post/untitled-1.jpg

someone told me have use glsl, don't know shading language.

this vertex , fragment (follow ray wenderlich's tutorial):

// vertex.glsl attribute vec4 position;  attribute vec4 sourcecolor;   varying vec4 destinationcolor;   uniform mat4 projection; uniform mat4 modelview;  attribute vec2 texcoordin; varying vec2 texcoordout;  void main(void) {      destinationcolor = sourcecolor;      gl_position = projection * modelview * position;     texcoordout = texcoordin; }   // fragment.glsl      varying lowp vec4 destinationcolor;  varying lowp vec2 texcoordout; uniform sampler2d texture;  void main(void) {      gl_fragcolor = destinationcolor * texture2d(texture, texcoordout); } 

could me? :)

instead of using quad (pair of triangles) square use grid it. able place vertices of grid manually resulting in shape want.