Simple OpenGL Program

Totally Frustrated, using Win 10 and Fortran to Opengl calls, output 'crazy': PROGRAM BASIC INCLUDE <clearwin.ins>,nolist INCLUDE <opengl.ins>,nolist DIMENSION X(N),Y(N),Z(N) INTEGER ctrl X=0. Y=0. Z=0. i=winio@('%es%ca[Simple Opengl Sample]&') i=winio@('%sp%ww[no border]%og[static]%1w', * 0, 0, 1000, 1000, ctrl) CALL glBegin(GL_LINES) CALL glRotatef(22.0,1.0,0.0,0.0) CALL glRotatef(22.0,0.0,1.0,0.0) CALL glRotatef(22.0,0.0,0.0,1.0) INDX=0 DO 10 I=1,7 INDX=INDX+1 IF (INDX .EQ. N) GOTO 20 CALL glVertex3f(X(INDX),Y(INDX),Z(INDX)) CALL glVertex3f(X(INDX+1),Y(INDX+1),Z(INDX+1)) 10 CONTINUE 20 CALL glEnd END

Note: N in above was 8, tried to submit and it entered a emoticon? No matter what I change the glRotate commands to, get the same thing, a vertical and a horizontal line on the output, no Z axis and had addition curve date yet did not plot the curve. Have this identical program in C++ works great??? How Simple can one get??? Anyone have ideas? Sid Kraft

I have not tested your program but a quick glance shows %1w instead of %lw.

John Silver: I left out 3 statements by mistake where I set the input values to 1.: after the below which set the values all to zero for the complete arrays: x=0. y=0. z=0. should have been additional codes:

x(2)=1. y(4)=1. z(6)=1. this should have drawn the x,y,z axes but after changing the 1 to l, still did not work! Sid

So Frustrated with this system, cannot post a screen shot so have to type in every line of code and other statements whenever I want to ask question ! BOO bad system!

I finally got the above program to work but there appears to be a memory management problem with the Fortran to OpenGL callable system, the minute that I add more code to above, I get 'crazy' output data from OpenGL, zig zag lines all over the place. I would suggest exploring this problem as is not good for the system to act this way, Sid kraft

stfark1, did you look at the opengl examples in ftn95 documentation? (use ftn95 /help)

      PROGRAM Simple
      INCLUDE <clearwin.ins>,nolist
      INCLUDE <opengl.ins>,nolist
      REAL t1,t2
      INTEGER i, ctrl
      i=winio@('%es%ca[Simple OpengGL Sample]&')
      i=winio@('%sp%ww[no_border]%og[static]%lw',
     *         0, 0, 500, 500, ctrl)
      CALL glClearColor (0.0, 0.0, 0.0, 0.0)
      CALL glClear(GL_COLOR_BUFFER_BIT)
      CALL glColor3f(1.0, 1.0, 1.0)
      CALL glMatrixMode(GL_PROJECTION)
      CALL glLoadIdentity()
      CALL glOrtho(-1d0, 1d0, -1d0, 1d0, -1d0, 1d0)
      CALL glBegin(GL_POLYGON)     
C
      CALL glColor3f(1.0,0.0,0.0)
      CALL glVertex2f(-0.5, -0.5)
C      
      CALL glColor3f(0.0,1.0,0.0)
      CALL glVertex2f(-0.5, 0.5)
C
      CALL glColor3f(0.0,0.0,1.0)      
      CALL glVertex2f( 0.5, 0.5)
C
      CALL glColor3f(1.0,0.0,0.0)      
      CALL glVertex2f( 0.5, -0.5)
      CALL glEnd()
      CALL glFlush()
      END

There is also another opengl example which shows you some rotations. In general, I prefer to use SCC, because in the internet more useful examples are written in C++.

First you should read some simple opengl manuals and understand how opengl works in the basic structure. Your main code has some basic fortran errors... Dimension N unknown, X,Y,Z initialized incorrectly... and some basic opengl calls are missing...