FreeGlut

[Charles Pegge]

Code: OxygenBasic

1.  
2.  
3. 'http://www.opengl.org/archives/resources/code/samples/glut_examples/examples/examples.html
4.  
5. include "freeglut.inc"
6. indexbase   0
7.  
8.  
9. 'CUBE
10.  
11. /* Copyright (c) Mark J. Kilgard, 1997. */
12.  
13. /* This program is freely distributable without licensing fees
14.    and is provided without guarantee or warrantee expressed or
15.    implied. This program is -not- in the public domain. */
16.  
17. /* This program was requested by Patrick Earl; hopefully someone else
18.    will write the equivalent Direct3D immediate mode program. */
19.  
20.  
21. GLfloat light_diffuse[4] = {1.0, 0.0, 0.0, 1.0}  'Red diffuse light.
22.  
23. GLfloat light_position[4] = {1.0, 1.0, 1.0, 0.0}  'Infinite light location.
24.  
25. 'arrays- major minor
26.  
27. 'Normals for the 6 faces of a cube.
28. 'float n[6][3]
29. GLfloat n[18]
30. n=>
31. -1.0, 0.0, 0.0, 'left
32. 0.0, 1.0, 0.0, 'top
33. 1.0, 0.0, 0.0, 'right
34. 0.0,-1.0, 0.0, 'bottom
35. 0.0, 0.0, 1.0, 'front
36. 0.0, 0.0,-1.0  'back
37.  
38. 'Vertex indices for the 6 faces of a cube.
39. 'int faces[6][4]
40. GLint faces[24]
41. faces=>
42.  0, 1, 2, 3,
43.  3, 2, 6, 7,
44.  7, 6, 5, 4,
45.  4, 5, 1, 0,
46.  5, 6, 2, 1,
47.  7, 4, 0, 3
48.  
49. 'Will be filled in with X,Y,Z vertexes.
50. 'float v[8][3]
51. GLfloat v[24]
52.  
53.  
54. sub drawBox
55.   sys i
56.   for i=0 to <6
57.     glBegin(GL_QUADS)
58.     glNormal3fv n[i*3]
59.     glVertex3fv v[faces[i*4  ]*3]
60.     glVertex3fv v[faces[i*4+1]*3]
61.     glVertex3fv v[faces[i*4+2]*3]
62.     glVertex3fv v[faces[i*4+3]*3]
63.     glEnd();
64.   next
65. end sub
66.  
67. sub display() callback
68.   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
69.   drawBox()
70.   glutSwapBuffers()
71. end sub
72.  
73.  
74. sub init
75.   '
76.  'Setup cube vertex data.
77.  'x
78.  v[0]=-1 : v[3]=-1 : v[6]=-1 : v[9]=-1
79.   v[12]=1 : v[15]=1 : v[18]=1 : v[21]=1
80.   'y
81.  v[1]=-1 : v[4]=-1 : v[13]=-1 : v[16]=-1
82.   v[7]=1  : v[10]=1 : v[19]=1  : v[22]=1
83.   'z
84.  v[2]=1  : v[11]=1 : v[14]=1  : v[23]=1
85.   v[5]=-1 : v[8]=-1 : v[17]=-1 : v[20]=-1
86.   '
87.  'Enable a single OpenGL light.
88.  '
89.  glLightfv GL_LIGHT0, GL_DIFFUSE, light_diffuse
90.   glLightfv GL_LIGHT0, GL_POSITION, light_position
91.   glEnable GL_LIGHT0
92.   glEnable GL_LIGHTING
93.   '
94.  'Use depth buffering for hidden surface elimination.
95.  '
96.  glEnable GL_DEPTH_TEST
97.  
98.   'Setup the view of the cube.
99.  
100.   glMatrixMode GL_PROJECTION
101.   gluPerspective 40.0, 1.0, 1.0, 10.0
102.   glMatrixMode GL_MODELVIEW
103.   '
104.  '         eye pos,        center pos      up vector
105.  '
106.  gluLookAt 0.0, 0.0, 5.0,  0.0, 0.0, 0.0,  0.0, 1.0, 0.0
107.  
108.   'Adjust cube position to be asthetic angle.
109.  
110.   glTranslatef       0.0,  0.0, -1.0
111.   glRotatef     60,  1.0,  0.0,  0.0
112.   glRotatef    -20,  0.0,  0.0,  1.0
113.   '
114. end sub
115.  
116.  
117.  
118. function main(int argc, char **argv) as sys
119.   glutInit argc, argv
120.   glutInitDisplayMode GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH
121.   glutCreateWindow "red 3D lighted cube"
122.   glutDisplayFunc @display 'set csllback
123.  init
124.   glutMainLoop
125.  return 0             /* ANSI C requires main to return int. */
126. end function
127.  
128. main null,null
129.  

To run, place the glut folder in the projects folder (it needs the GL headers)

Charles

[Peter]

cool Charles!

Try this Triangle!

Code: [Select]

Include "gl3d.inc"

Screen 1024,768,3
SetCaption "PYRAMID"
'Finit

single r, sys kris
Kris = LoadTexture "gfx/kristal256.gfx",256,256

While Key(27)=0
glClearColor  0.0, 0.2, 0.5, 1.0
glClear GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT

glLoadIdentity
glBindTexture GL_TEXTURE_2D, Texture(kris)
glTranslatef -0.0, -0.1, 0.0
glRotatef r, 0.0, 1.0, 0.0 

glBegin GL_TRIANGLES    
  glTexCoord2f 1.0, 0.0: glVertex3f( 0.0, 0.5, 0.0)
  glTexCoord2f 1.0, 1.0: glVertex3f(-0.5,-0.5, 0.5)
  glTexCoord2f 0.0, 1.0: glVertex3f( 0.5,-0.5, 0.5)
  glTexCoord2f 0.0, 0.0: glVertex3f( 0.0, 0.5, 0.0)
 
  glTexCoord2f 1.0, 0.0: glVertex3f( 0.5,-0.5, 0.5)
  glTexCoord2f 1.0, 1.0: glVertex3f( 0.5,-0.5,-0.5)
  glTexCoord2f 0.0, 1.0: glVertex3f( 0.0, 0.5, 0.0)
  glTexCoord2f 0.0, 0.0: glVertex3f( 0.5,-0.5,-0.5)
 
  glTexCoord2f 1.0, 0.0: glVertex3f(-0.5,-0.5,-0.5)
  glTexCoord2f 1.0, 1.0: glVertex3f( 0.0, 0.5, 0.0)
  glTexCoord2f 0.0, 1.0 :glVertex3f(-0.5,-0.5,-0.5)
  glTexCoord2f 0.0, 0.0 :glVertex3f(-0.5,-0.5, 0.5)
glEnd

 r +=1
 
DoEvents
SwapBuffers hdc
SetFps 90
Wend
WinEnd


[Peter]

And this Cube.

Code: [Select]

include "GL3D.inc"

Screen 1024,768,0
Finit

Long a, b, face, holz
face= LoadTexture "gfx/face512.gfx",512,512
holz= LoadTexture "gfx/holz64.gfx",64,64

single r4X,r4Y,r4Z

While WinExit=0
iF Key(vk_escape) Then WinExit=1
glClearColor 0.5, 0.2, 0.8, 1.0
glClear GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT       
glLoadIdentity

glTranslatef 0.0, 0.0, 0.0
glRotatef r4X, 1.0, 0.0, 0.0
glRotatef r4Y, 0.0, 1.0, 0.0
glRotatef r4Z, 0.0, 0.0, 1.0

glBindTexture GL_TEXTURE_2D, Texture(face)
glBegin GL_QUADS
 glTexCoord2f 1.0, 1.0: glVertex3f (  0.1 , 0.1 ,- 0.1 )
 glTexCoord2f 0.0, 1.0: glVertex3f (- 0.1 , 0.1 ,- 0.1 )
 glTexCoord2f 0.0, 0.0: glVertex3f (- 0.1 , 0.1 ,  0.1 )
 glTexCoord2f 1.0, 0.0: glVertex3f (  0.1 , 0.1 ,  0.1 )
 
 glTexCoord2f 1.0, 1.0: glVertex3f (  0.1 ,- 0.1 ,  0.1 )
 glTexCoord2f 0.0, 1.0: glVertex3f (- 0.1 ,- 0.1 ,  0.1 )
 glTexCoord2f 0.0, 0.0: glVertex3f (- 0.1 ,- 0.1 ,- 0.1 )
 glTexCoord2f 1.0, 0.0: glVertex3f (  0.1 ,- 0.1 ,- 0.1 )
 
 glTexCoord2f 1.0, 1.0: glVertex3f (  0.1 ,  0.1 ,  0.1 )
 glTexCoord2f 0.0, 1.0: glVertex3f (- 0.1 ,  0.1 ,  0.1 )
 glTexCoord2f 0.0, 0.0: glVertex3f (- 0.1 ,- 0.1 ,  0.1 )
 glTexCoord2f 1.0, 0.0: glVertex3f (  0.1 ,- 0.1 ,  0.1 )
 
 glTexCoord2f 1.0, 1.0: glVertex3f (  0.1 ,- 0.1 ,- 0.1 )
 glTexCoord2f 0.0, 1.0: glVertex3f (- 0.1 ,- 0.1 ,- 0.1 )
 glTexCoord2f 0.0, 0.0: glVertex3f (- 0.1 ,  0.1 ,- 0.1 )
 glTexCoord2f 1.0, 0.0: glVertex3f (  0.1 ,  0.1 ,- 0.1 )
 
 glTexCoord2f 1.0, 1.0: glVertex3f (- 0.1 ,  0.1 ,  0.1 )
 glTexCoord2f 0.0, 1.0: glVertex3f (- 0.1 ,  0.1 ,- 0.1 )
 glTexCoord2f 0.0, 0.0: glVertex3f (- 0.1 ,- 0.1 ,- 0.1 )
 glTexCoord2f 1.0, 0.0: glVertex3f (- 0.1 ,- 0.1 ,  0.1 )
 
 glTexCoord2f 1.0, 1.0: glVertex3f (  0.1 ,  0.1 ,- 0.1 )
 glTexCoord2f 0.0, 1.0: glVertex3f (  0.1 ,  0.1 ,  0.1 )
 glTexCoord2f 0.0, 0.0: glVertex3f (  0.1 ,- 0.1 ,  0.1 )
 glTexCoord2f 1.0, 0.0: glVertex3f (  0.1 ,- 0.1 ,- 0.1 )
glEnd
 
r4X = r4X + 0.8
r4Y = r4Y + 0.6
r4Z = r4Z + 0.4

DoEvents
SwapBuffers hDc
SetFps 70
Wend
WinEnd


[kryton9]

Peter, your posts have nothing to do with freeglut. By the way, I get an error when compiling the triangle demo.

Charles, thanks a lot!!! Can't wait to play with it! Using this as a base, our code will be cross platform ready if ever needed.

http://freeglut.sourceforge.net/docs/api.php

[kryton9]

Charles, very excitedly I pulled out some old code. A couple years back I wrote the same app using Glut, SDL and WinApi to see the differences. I remember Glut was by the far the easiest back then.
So I happily translated the code to oxygen and got all the bugs compiling worked out in the code. Now I am stuck in that it crashes after showing up on the screen. I am at a loss and need the Oxygen Oracle's help when you get a chance. Thanks again for this great cross platform tool!

Everything you need is in the attachment. It will unzip into a folder to put in your projects folder in oxygen.

Commands: the a and z key zoom in and out, all arrow keys rotate the cube appropriately and escape to exit.

Updated: The crash is being caused by the glutTimerFunc, I commented out all of the stuff and one by one uncommented and it only crashes when I get to the glutTimerFunc.
I tried:
glutTimerFunc( 1, @timerLoop, )   shows cube crashes
glutTimerFunc( 1, @timerLoop, 0 )   shows cube crashes
glutTimerFunc( 1, @timerLoop(), 0 ) just crashes
glutTimerFunc( 1, @timerLoop(0), 0 ) just crashes
glutTimerFunc( 1, @timerLoop(),  ) just crashes
glutTimerFunc( 1, int @timerLoop,  )   shows cube crashes
glutTimerFunc( 1, int @timerLoop, 0 )   shows cube crashes
glutTimerFunc( 1, int @timerLoop(), 0 )  just crashes
glutTimerFunc( 1, int @timerLoop(0), 0 ) just crashes
glutTimerFunc( 1, int @timerLoop(),  ) just crashes

I commented out the glutTimerFunc and you see it runs without crashing, but need getTimerFunc to work for input and fps updates.

[kryton9]

I did update the last zip test file. I just added the test code commented out to make it easier to test.

[Charles Pegge]

Hi Kent, nice demo!

I discover that all the callbacks are cdecl

So the solution is to enclose them in an extern block:

extern cdecl
...
end extern

With the extern block, the callback tags are now redundant and may be removed from each function

Charles

[kryton9]

You are the Oracle, not of Delphi but Oxygen that is for sure! I was at a total loss after going through all the different ideas. Thanks so much, now I can work on this full throttle.

[kryton9]

I still have some problems to figure out, the escape, in and out keys are not working and the fps is not showing up. But I should be able to figure those out, I hope. Will upload the latest when figured it out. Thanks again for your help and this new addition!

[Charles Pegge]

The FPS should show up, but I set the decimal places to zero. Check you have the right Oxygen.dll in the Oxygen base directory.

If the lib is specified in the extern block, it covers all the declares within the block.

All the freeglut procs seem to be stdcall (unlike sqlite!) but the callbacks on your side have to be cdecl.

I checked Peter's code, and both examples work. But the aspect ratio and perspective projection are not working correctly. Mysterious, because I use the same algorithm.

Charles

[kryton9]

Charles I will download the latest, I just got it the other day. But just in case. Ok. Downloaded from the http://www.oxygenbasic.org/downloads.htm in progress download.
Still the same problem, no fps and the problem below is still happening.

Anyways, something is wrong, because the print statement is not working as you would think.
So I am bothering you again, because that means something else is lurking that I will never figure out.
Line 187.  

[kryton9]

I solved the a, z and escape key. I changed:

Code: OxygenBasic

1. sub keyboardCB(unsigned char key, int x, int y)
2.         keys[key] = 1
3. end sub
4.  
5. sub keyboardUpCB(unsigned char key, int x, int y)
6.         keys[key] = 0
7. end sub

to:

Code: OxygenBasic

1. sub keyboardCB(int key, int x, int y)
2.     keys[key] = GL_TRUE
3. end sub
4.  
5. sub keyboardUpCB(int key, int x, int y)
6.         keys[key] = GL_FALSE
7. end sub

But FPS is still not printing, so working on that.

[kryton9]

I traced it down to the "static" keyword. When you use it, it puts a strange value the first time. This will show the problem. Solution up to the master to figure out.

Code: OxygenBasic

1. sub displayFPS()
2.         ' this is assigned once because of the word static
3.         static long lastTime = glutGet(GLUT_ELAPSED_TIME)
4.  
5.         ' this keeps track of the loops or frames
6.         static long loops = 0
7.  
8.         ' we will average out the fps to make it less volatile in what it shows
9.         static GLfloat fps = 0
10.  
11.         long newTime = glutGet GLUT_ELAPSED_TIME
12.     long t = newTime - lastTime
13.     glutSetWindowTitle str(lastTime) + "   " + str(newTime)
14.         if t > 100 then
15.                 GLfloat newFPS = loops / ( newTime - lastTime ) * 1000
16.                 fps = ( fps + newFPS ) / 2
17.                 string s = "FPS : " + str(fps,2)
18.         glutSetWindowTitle s
19.                 lastTime = newTime
20.                 loops = 0
21.         end if 
22.         loops ++
23. end sub

[kryton9]

This code below fixes it. It appears that when static is used, it doesn't clear the memory, my guess at least. This is not elegant but it shows that static is where the problem is happening when not initialized to 0 but another value first.

Code: OxygenBasic

1. include "freeglut.inc"
2. indexbase 0
3.  
4. 'function Main at the end of the file
5.  
6. ' GLOBAL VARIABLES
7. 'escape to exit
8. % GLUT_KEY_ESCAPE 27
9. 'Arrow keys to rotate cube
10. 'A zoom in
11. % GLUT_KEY_IN 97
12. 'Z zoom out
13. % GLUT_KEY_OUT 122
14.  
15. sys flagOnceForLastTime = 0
16.  
17. const GLsizei windowWidth  = 1024
18. const GLsizei windowHeight = 768
19.  
20. const GLfloat speed     = 1
21. const GLfloat zoomSpeed = 0.05
22.  
23. GLfloat cubeRotateX = 45
24. GLfloat cubeRotateY = 45
25. GLfloat camMovZ     = -5
26.  
27. bool keys[255]
28.  
29. ' NON CALLBACK FUNCTIONS AND SUBS
30. sub establishProjectionMatrix( GLsizei width, GLsizei height )
31.         glViewport 0, 0, width, height
32.         glMatrixMode GL_PROJECTION
33.         glLoadIdentity
34.         gluPerspective 45, ( width / height ), 0.1, 200
35. end sub
36.  
37.  
38. sub initGL( GLsizei width, GLsizei height )
39.         establishProjectionMatrix width, height
40.         glShadeModel GL_SMOOTH
41.         glClearColor 0, 0, 0, 1
42.         glEnable GL_DEPTH_TEST
43.         glDepthFunc GL_LEQUAL
44.         glHint GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST
45.         glEnable GL_PERSPECTIVE_CORRECTION_HINT
46. end sub
47.  
48. sub displayFPS()
49.         static sys lastTime = 0
50.     if flagOnceForLastTime = 0 then
51.         lastTime = glutGet(GLUT_ELAPSED_TIME)
52.         flagOnceForLastTime = 1
53.     end if
54.  
55.         ' this keeps track of the loops or frames
56.         static sys loops = 0
57.  
58.         ' we will average out the fps to make it less volatile in what it shows
59.         static GLfloat fps = 0
60.  
61.         sys newTime = glutGet GLUT_ELAPSED_TIME
62.     sys t = newTime - lastTime
63.     'glutSetWindowTitle str(lastTime) + "   " + str(newTime) + "    t: " + str(t)
64.         if t > 100 then
65.                 GLfloat newFPS = loops / ( newTime - lastTime ) * 1000
66.                 fps = ( fps + newFPS ) / 2
67.                 string s = "FPS : " + str(fps,2)
68.         glutSetWindowTitle s
69.                 lastTime = newTime
70.                 loops = 0
71.         end if 
72.         loops ++
73. end sub
74.  
75. function checkKeys() as GLboolean
76.         if keys[GLUT_KEY_ESCAPE] = GL_TRUE then
77.                 return GL_TRUE
78.     end if
79.  
80.         if keys[GLUT_KEY_LEFT] = GL_TRUE then
81.                 cubeRotateY -= speed
82.     end if
83.        
84.         if keys[GLUT_KEY_RIGHT] = GL_TRUE then
85.                 cubeRotateY += speed
86.     end if
87.        
88.         if keys[GLUT_KEY_UP] = GL_TRUE then
89.                 cubeRotateX -= speed
90.     end if
91.  
92.         if keys[GLUT_KEY_DOWN] = GL_TRUE then
93.                 cubeRotateX += speed
94.     end if
95.  
96.         if keys[GLUT_KEY_IN] = GL_TRUE then
97.                 camMovZ += zoomSpeed
98.     end if
99.  
100.         if keys[GLUT_KEY_OUT] = GL_TRUE then
101.                 camMovZ -= zoomSpeed
102.     end if     
103.  
104.         return GL_FALSE
105. end function
106.  
107. '===========
108. extern cdecl ' because of this syntax, no need to add callback to each sub or function below
109. '===========
110.  
111. 'CALLBACK FUNCTIONS AND SUBS
112.  
113. ' by declaring and defining here, we don't need to do it twice
114. sub drawSceneCB()
115.  
116.         ' for 3D we clear both bits, if 2D only the one on the left
117.         glClear GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT
118.  
119.         glMatrixMode GL_MODELVIEW
120.         glLoadIdentity()
121.  
122.         ' moves the camera back
123.         glTranslatef 0, 0, camMovZ
124.         glRotatef cubeRotateX, 1, 0, 0
125.         glRotatef cubeRotateY, 0, 1, 0
126.  
127.         ' Draw cube
128.         glBegin GL_QUADS
129.                 ' top face
130.                  glColor3f  1, 0.5,  0
131.                 glVertex3f  1,   1, -1
132.                 glVertex3f -1,   1, -1
133.                 glVertex3f -1,   1,  1
134.                 glVertex3f  1,   1,  1
135.                 ' bottom face
136.                  glColor3f  0,  1,  0
137.                 glVertex3f  1, -1, -1
138.                 glVertex3f -1, -1, -1
139.                 glVertex3f -1, -1,  1
140.                 glVertex3f  1, -1,  1
141.                 ' front face
142.                  glColor3f  1,  0, 0
143.                 glVertex3f  1,  1, 1
144.                 glVertex3f -1,  1, 1
145.                 glVertex3f -1, -1, 1
146.                 glVertex3f  1, -1, 1
147.                 ' back face
148.                  glColor3f  1,  1,  0
149.                 glVertex3f  1,  1, -1
150.                 glVertex3f -1,  1, -1
151.                 glVertex3f -1, -1, -1
152.                 glVertex3f  1, -1, -1
153.                 ' left face
154.                  glColor3f  0,  0,  1
155.                 glVertex3f -1,  1,  1
156.                 glVertex3f -1,  1, -1
157.                 glVertex3f -1, -1, -1
158.                 glVertex3f -1, -1,  1
159.                 ' right face
160.         glColor3f 1,  0,  1
161.                 glVertex3f 1,  1,  1
162.                 glVertex3f 1,  1, -1
163.                 glVertex3f 1, -1, -1
164.                 glVertex3f 1, -1,  1
165.         glEnd
166.         glFlush
167.  
168.         ' this line will change depending on which window interface
169.         ' is being used. Like SDL and GLUT
170.         glutSwapBuffers
171.     displayFPS
172. end sub
173.  
174. 'timerLoop must match glutTimerFunc's requirements
175. sub timerLoopCB (int value)
176.  
177.         if checkKeys() = GL_TRUE then
178.                 glutExit
179.     end if
180.  
181.         ' glut will call the drawscene function when it ready
182.         ' very important for this to be allowed
183.         glutPostRedisplay
184.  
185.         ' by putting this here, we created a loop.
186.         ' SDL doesn't need something like this
187.         glutTimerFunc 1, @timerLoopCB, 0
188. end sub
189.  
190. sub keyboardCB(int key, int x, int y)
191.     keys[key] = GL_TRUE
192. end sub
193.  
194. sub keyboardUpCB(int key, int x, int y)
195.         keys[key] = GL_FALSE
196. end sub
197.  
198. sub keyboardSpecialCB(int key, int x, int y)
199.         keys[key] = GL_TRUE
200. end sub
201.  
202. sub keyboardSpecialUpCB(int key, int x, int y)
203.         keys[key] = GL_FALSE
204. end sub
205.  
206. '=========
207. end extern
208. '=========
209.  
210. function main(int argc, char **argv) as sys
211.  
212.         ' initialize glut, passing the above parameters to gluInit
213.         glutInit argc, argv
214.         ' enable double frame buffering, so we don't get flicker
215.        glutInitDisplayMode GLUT_DOUBLE
216.  
217.         sys windowID = glutCreateWindow "OpenGL FreeGlut Cube Demo"
218.         ' by default, glut knows the last window used,
219.        'so we can resize it after we create it
220.        glutReshapeWindow windowWidth, windowHeight
221.        
222.         ' our procedure
223.        initGL windowWidth, windowHeight
224.  
225.         glutDisplayFunc    @drawSceneCB
226.         glutKeyboardFunc   @keyboardCB
227.         glutKeyboardUpFunc @keyboardUpCB
228.         glutSpecialFunc    @keyboardSpecialCB
229.         glutSpecialUpFunc  @keyboardSpecialUpCB
230.         glutTimerFunc 1,   @timerLoopCB, 0
231.        
232.         ' this goes to the main loop and stays there till the end
233.        glutMainLoop
234.         'should never get here, but just in case
235.         return 0
236. end function
237.  
238. ' THIS IS THE PROGRAM
239. main null,null
240. '====================

[Aurel]

i don't know much about game engines but as i said ,i tried HGE and seems to me that
work fine and compile fine under EB.So what about HGE ?