OpengGL开发例子，一个图片可以旋转的例子

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;Copyright 2016-2080 evilbinary.
;作者:evilbinary on 01/08/17.
;邮箱:rootdebug@163.com
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(import  (scheme) (glut glut) (gles gles1) (gui imgui) )
;;资源文件目录设置
(define res-dir 
         (case (machine-type)
           ((arm32le) "/data/data/org.evilbinary.chez/files/")
           (else "./")
            ))
            
(define (draw-image)
      (glut-init (lambda ()
          (let ( 
            ; (texture-id  0)
          (texture-id (imgui-load-texture  (string-append res-dir "/test2.jpg")))
          (rotation 2.0)
          (square-vertices (glut-vector 'float 
            (vector 
              -0.2 -0.2
                      0.2 -0.2                               
                      -0.2 0.2
                      0.2 0.2
                    )))
          (texture-array (glut-vector 'float 
            (vector 
            0.0 1.0 
            1.0 1.0  
            0.0 0.0 
            1.0 0.0) ))
          )
          (glut-display (lambda()
                   (glClearColor 0.5  0.5  0.5  1.0 );
                   (glClear GL_COLOR_BUFFER_BIT);
                   (glRotatef rotation 0.0 0.0 0.1)
                   ;;绘制矩形
                   (glEnable GL_TEXTURE_2D);                       // 启用纹理映射 
                 (glBindTexture GL_TEXTURE_2D texture-id);
                   (glEnableClientState GL_TEXTURE_COORD_ARRAY); 

                   (glEnableClientState GL_VERTEX_ARRAY);
                   (glVertexPointer 2  GL_FLOAT  0  square-vertices);
                   (glTexCoordPointer 2 GL_FLOAT 0 texture-array);
                   (glDrawArrays GL_TRIANGLE_STRIP  0 4);
                   (glDisableClientState GL_VERTEX_ARRAY)
                   (glDisable GL_TEXTURE_2D)
                   (glDisable GL_TEXTURE_COORD_ARRAY)

                   )
                 )

         )
        ))

      (glut-touch-event (lambda (type x y)
          (glut-log (format "type ~a ~a ~a" type x y ))
          ))
      (glut-key-event (lambda (event)
          (glut-log (format "event ~a" event))
            (if (= 4 (glut-event-get event 'keycode ))
                          (begin (imgui-exit)
                                 (glut-exit)))

          ))
      (glut-reshape (lambda(w h)
	                   (glut-log (format "reshape"))
	                ;    (glClearDepthf 1.0)
		               ; (glClearColor 0.0 0.0 0.0 0.0 )
		               ; (glViewport 0 0 w h)
		               ; (glMatrixMode GL_PROJECTION)
		               ; (glLoadIdentity)

                   ))
      (glut-main-loop)
      (glut-exit)
      )

(draw-image)