Hello,
OpenGL allows you to get the current modelview matrix via the function
'glGetDoublev'.
Here's that procedure from 'gl.ss' that comes with Ikarus:
;; void glGetDoublev( GLenum pname, GLdouble *params )
(define-function void glGetDoublev (int byte*))
So, you pass in a bytevector.
Included below is a test program for getting and printing the modelview
matrix. This is the portion of the code that gets and prints the matrix:
(let ((bv (make-bytevector (* 16 8) 0)))
(glGetDoublev GL_MODELVIEW_MATRIX bv)
(display bv)
(newline))
It should be the identity matrix.
This is the output I get from Ypsilon:
Ypsilon 0.9.6-trunk/r413 Copyright (c) 2009 Y.Fujita, LittleWing Company
Limited.
>
#vu8(0 0 0 0 0 0 240 63 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 240 63 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 240 63 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 240 63)
And from Ikarus:
Ikarus Scheme version 0.0.4-rc1+ (revision 1747, build 2009-04-02)
Copyright (c) 2006-2008 Abdulaziz Ghuloum
> #vu8(0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0)
Ed
(import (gl) (glut))
(glutInit (vector 0) (vector ""))
(define display-func
(lambda ()
(glMatrixMode GL_MODELVIEW)
(glLoadIdentity)
(glClearColor 0.0 0.0 0.0 1.0)
(glClear GL_COLOR_BUFFER_BIT)
(glColor4d 1.0 1.0 1.0 1.0)
(glBegin GL_LINES)
(glVertex2d 10.0 10.0)
(glVertex2d 90.0 90.0)
(glEnd)
(let ((bv (make-bytevector (* 16 8) 0)))
(glGetDoublev GL_MODELVIEW_MATRIX bv)
(display bv)
(newline))
(glFlush)))
(define reshape-func
(lambda (w h)
(glViewport 0 0 w h)
(glMatrixMode GL_PROJECTION)
(glLoadIdentity)
(glOrtho 0.0 (+ w 0.0) 0.0 (+ h 0.0) -10.0 10.0)))
(glutInitWindowPosition 100 100)
(glutInitWindowSize 500 500)
(glutCreateWindow "Hello GLUT")
(glutDisplayFunc display-func)
(glutReshapeFunc reshape-func)
(glutMainLoop)
