OpenGL
In this task, the goal is to display a smooth shaded triangle with OpenGL.
You are encouraged to solve this task according to the task description, using any language you may know.
Ada
opengl.adb: <lang Ada>with Lumen.Window; with Lumen.Events; with Lumen.Events.Animate; with GL; with GLU;
procedure OpenGL is
The_Window : Lumen.Window.Handle;
Program_Exit : Exception;
-- simply exit this program
procedure Quit_Handler (Event : in Lumen.Events.Event_Data) is
begin
raise Program_Exit;
end;
-- Resize the scene
procedure Resize_Scene (Width, Height : in Natural) is
use GL;
use GLU;
begin
-- reset current viewport
glViewport (0, 0, GLsizei (Width), GLsizei (Height));
-- select projection matrix and reset it
glMatrixMode (GL_PROJECTION);
glLoadIdentity;
-- calculate aspect ratio
gluPerspective (45.0, GLdouble (Width) / GLdouble (Height), 0.1, 100.0);
-- select modelview matrix and reset it
glMatrixMode (GL_MODELVIEW);
glLoadIdentity;
end Resize_Scene;
procedure Init_GL is
use GL;
use GLU;
begin
-- smooth shading
glShadeModel (GL_SMOOTH);
-- black background
glClearColor (0.0, 0.0, 0.0, 0.0);
-- depth buffer setup
glClearDepth (1.0);
-- enable depth testing
glEnable (GL_DEPTH_TEST);
-- type of depth test
glDepthFunc (GL_LEQUAL);
glHint (GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); end Init_GL;
-- Resize and Initialize the GL window
procedure Resize_Handler (Event : in Lumen.Events.Event_Data) is
Height : Natural := Event.Resize_Data.Height;
Width : Natural := Event.Resize_Data.Width;
begin
-- prevent div by zero
if Height = 0 then
Height := 1;
end if;
Resize_Scene (Width, Height); end;
procedure Draw is
use GL;
begin
-- clear screen and depth buffer
glClear (GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
-- reset current modelview matrix
glLoadIdentity;
-- draw triangle
glBegin (GL_TRIANGLES);
glColor3f (1.0, 0.0, 0.0);
glVertex3f ( 0.0, 1.0, 0.0);
glColor3f (0.0, 1.0, 0.0);
glVertex3f (-1.0, -1.0, 0.0);
glColor3f (0.0, 0.0, 1.0);
glVertex3f ( 1.0, -1.0, 0.0);
glEnd;
end Draw;
procedure Frame_Handler (Frame_Delta : in Duration) is
begin
Draw;
Lumen.Window.Swap (The_Window);
end Frame_Handler;
begin
Lumen.Window.Create (Win => The_Window,
Name => "OpenGL Demo",
Width => 640,
Height => 480,
Events => (Lumen.Window.Want_Key_Press => True,
Lumen.Window.Want_Exposure => True,
others => False));
Resize_Scene (640, 480); Init_GL;
Lumen.Events.Animate.Select_Events
(Win => The_Window,
FPS => Lumen.Events.Animate.Flat_Out,
Frame => Frame_Handler'Unrestricted_Access,
Calls => (Lumen.Events.Resized => Resize_Handler'Unrestricted_Access,
Lumen.Events.Close_Window => Quit_Handler'Unrestricted_Access,
others => Lumen.Events.No_Callback));
exception
when Program_Exit =>
null; -- normal termination
end OpenGL;</lang>
AutoHotkey
<lang AutoHotkey>hOpenGL32 := DllCall("LoadLibrary", "Str", "opengl32") Gui, +LastFound +Resize hDC := DllCall("GetDC", "uInt", WinExist())
VarSetCapacity(pfd, 40, 0) NumPut(40, pfd, 0, "uShort") NumPut(1, pfd, 2, "uShort") NumPut(37, pfd, 4, "uInt") NumPut(24, pfd, 9, "uChar") NumPut(16, pfd, 23, "uChar") DllCall("SetPixelFormat", "uInt", hDC, "uInt", DllCall("ChoosePixelFormat", "uInt", hDC, "uInt", &pfd), "uInt", &pfd)
hRC := DllCall("opengl32\wglCreateContext", "uInt", hDC) DllCall("opengl32\wglMakeCurrent", "uInt", hDC, "uInt", hRC) Gui, Show, w640 h480, Triangle OnExit, ExitSub SetTimer, Paint, 50 return
Paint:
DllCall("opengl32\glClearColor", "Float", 0.3, "Float", 0.3, "Float", 0.3, "Float", 0)
DllCall("opengl32\glClear", "uInt", 0x4100) ;GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT
DllCall("opengl32\glShadeModel", "uInt", 0x1D01) ;GL_SMOOTH
DllCall("opengl32\glLoadIdentity") DllCall("opengl32\glTranslatef", "Float", -15, "Float", -15, "Float", 0)
DllCall("opengl32\glBegin", "uInt", 0x0004) ;GL_TRIANGLES DllCall("opengl32\glColor3f", "Float", 1, "Float", 0, "Float", 0) DllCall("opengl32\glVertex2f", "Float", 0, "Float", 0) DllCall("opengl32\glColor3f", "Float", 0, "Float", 1, "Float", 0) DllCall("opengl32\glVertex2f", "Float", 30, "Float", 0) DllCall("opengl32\glColor3f", "Float", 0, "Float", 0, "Float", 1) DllCall("opengl32\glVertex2f", "Float", 0, "Float", 30) DllCall("opengl32\glEnd")
DllCall("SwapBuffers", "uInt", hDC) return
GuiSize:
DllCall("opengl32\glViewport", "Int", 0, "Int", 0, "Int", A_GuiWidth, "Int", A_GuiHeight)
DllCall("opengl32\glMatrixMode", "uInt", 0x1701) ;GL_PROJECTION
DllCall("opengl32\glLoadIdentity")
DllCall("opengl32\glOrtho", "Double", -30, "Double", 30, "Double", -30, "Double", 30, "Double", -30, "Double", 30)
DllCall("opengl32\glMatrixMode", "uInt", 0x1700) ;GL_MODELVIEW
return
GuiClose:
ExitApp
ExitSub:
DllCall("opengl32\wglMakeCurrent", "uInt", 0, "uInt", 0)
DllCall("opengl32\wglDeleteContext", "uInt", hRC)
DllCall("ReleaseDC", "uInt", hDC)
DllCall("FreeLibrary", "uInt", hOpenGL32)
ExitApp</lang>
BBC BASIC
<lang bbcbasic> *FLOAT64
SYS "LoadLibrary", "OPENGL32.DLL" TO opengl%
SYS "GetProcAddress", opengl%, "wglCreateContext" TO `wglCreateContext`
SYS "GetProcAddress", opengl%, "wglDeleteContext" TO `wglDeleteContext`
SYS "GetProcAddress", opengl%, "wglMakeCurrent" TO `wglMakeCurrent`
SYS "GetProcAddress", opengl%, "glMatrixMode" TO `glMatrixMode`
SYS "GetProcAddress", opengl%, "glClear" TO `glClear`
SYS "GetProcAddress", opengl%, "glBegin" TO `glBegin`
SYS "GetProcAddress", opengl%, "glColor3dv" TO `glColor3dv`
SYS "GetProcAddress", opengl%, "glVertex2dv" TO `glVertex2dv`
SYS "GetProcAddress", opengl%, "glEnd" TO `glEnd`
MODE 8
PFD_MAIN_PLANE = 0
PFD_TYPE_RGBA = 0
PFD_DOUBLEBUFFER = 1
PFD_DRAW_TO_WINDOW = 4
PFD_SUPPORT_OPENGL = &20
GL_MODELVIEW = &1700
GL_TRIANGLES = 4
GL_DEPTH_BUFFER_BIT = &00000100
GL_COLOR_BUFFER_BIT = &00004000
ON CLOSE PROCcleanup : QUIT
ON ERROR PROCcleanup : SYS "MessageBox", @hwnd%, REPORT$, 0, 48 : QUIT
DIM GLcolor{r#, g#, b#}, GLvertex{x#, y#}
DIM pfd{nSize{l&,h&}, nVersion{l&,h&}, dwFlags%, iPixelType&, cColorBits&, \
\ cRedBits&, cRedShift&, cGreenBits&, cGreenShift&, cBlueBits&, cBlueShift&, \
\ cAlphaBits&, cAlphaShift&, cAccumBits&, cAccumRedBits&, cAccumGreenBits&, \
\ cAccumBlueBits&, cAccumAlphaBits&, cDepthBits&, cStencilBits&, cAuxBuffers&, \
\ iLayerType&, bReserved&, dwLayerMask%, dwVisibleMask%, dwDamageMask%}
pfd.nSize.l& = DIM(pfd{})
pfd.nVersion.l& = 1
pfd.dwFlags% = PFD_DRAW_TO_WINDOW OR PFD_SUPPORT_OPENGL OR PFD_DOUBLEBUFFER
pfd.dwLayerMask% = PFD_MAIN_PLANE
pfd.iPixelType& = PFD_TYPE_RGBA
pfd.cColorBits& = 24
pfd.cDepthBits& = 16
SYS "GetDC", @hwnd% TO ghDC%
SYS "ChoosePixelFormat", ghDC%, pfd{} TO pixelformat%
IF pixelformat% = 0 ERROR 100, "ChoosePixelFormat failed"
SYS "SetPixelFormat", ghDC%, pixelformat%, pfd{} TO res%
IF res% = 0 ERROR 100, "SetPixelFormat failed"
SYS `wglCreateContext`, ghDC% TO ghRC%
SYS `wglMakeCurrent`, ghDC%, ghRC%
SYS `glMatrixMode`, GL_MODELVIEW
REPEAT
WAIT 2
SYS `glClear`, GL_COLOR_BUFFER_BIT OR GL_DEPTH_BUFFER_BIT
SYS `glBegin`, GL_TRIANGLES
GLcolor.r# = 1.0 : GLcolor.g# = 0.0 : GLcolor.b# = 0.0
SYS `glColor3dv`, GLcolor{}
GLvertex.x# = 0.0 : GLvertex.y# = 0.8
SYS `glVertex2dv`, GLvertex{}
GLcolor.r# = 0.0 : GLcolor.g# = 1.0 : GLcolor.b# = 0.0
SYS `glColor3dv`, GLcolor{}
GLvertex.x# = 0.8 : GLvertex.y# = -0.8
SYS `glVertex2dv`, GLvertex{}
GLcolor.r# = 0.0 : GLcolor.g# = 0.0 : GLcolor.b# = 1.0
SYS `glColor3dv`, GLcolor{}
GLvertex.x# = -0.8 : GLvertex.y# = -0.8
SYS `glVertex2dv`, GLvertex{}
SYS `glEnd`
SYS "SwapBuffers", ghDC%
UNTIL FALSE
END
DEF PROCcleanup
ON ERROR OFF
ghRC% += 0 : IF ghRC% SYS `wglDeleteContext`, ghRC% : ghRC% = 0
ghDC% += 0 : IF ghDC% SYS "ReleaseDC", @hwnd%, ghDC% : ghDC% = 0
ENDPROC</lang>
C
In this example, we use GLUT to create a window and handle the main loop in a portable way. Windowing systems like MS Windows and X11 have their own platform-specific ways of handling these things.
<lang c>#include <stdlib.h>
- include <GL/gl.h>
- include <GL/glut.h>
void paint(void) {
glClearColor(0.3,0.3,0.3,0.0); glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glShadeModel(GL_SMOOTH);
glLoadIdentity(); glTranslatef(-15.0, -15.0, 0.0);
glBegin(GL_TRIANGLES); glColor3f(1.0, 0.0, 0.0); glVertex2f(0.0, 0.0); glColor3f(0.0, 1.0, 0.0); glVertex2f(30.0, 0.0); glColor3f(0.0, 0.0, 1.0); glVertex2f(0.0, 30.0); glEnd();
glFlush();
}
void reshape(int width, int height) {
glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0); glMatrixMode(GL_MODELVIEW);
}
int main(int argc, char *argv[]) {
glutInit(&argc, argv);
glutInitWindowSize(640, 480);
glutCreateWindow("Triangle");
glutDisplayFunc(paint); glutReshapeFunc(reshape);
glutMainLoop();
return EXIT_SUCCESS;
}</lang>
C#
C# example using the OpenTK library, which is multiplatform and provides C# OpenGL bindings for .Net and Mono. This code creates its own window and draws the triangle into it.
<lang csharp>using OpenTK; using OpenTK.Graphics; namespace OpenGLTest {
class Program
{
static void Main(string[] args)
{
//Create the OpenGL window
GameWindow window = new GameWindow(640, 480, GraphicsMode.Default, "OpenGL Example");
GL.MatrixMode(MatrixMode.Projection);
GL.LoadIdentity();
GL.Ortho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0);
GL.MatrixMode(MatrixMode.Modelview);
//Add event handler to render to the window when called
window.RenderFrame += new RenderFrameEvent(a_RenderFrame);
//Starts the window's updating/rendering events
window.Run();
}
static void a_RenderFrame(GameWindow sender, RenderFrameEventArgs e)
{
GL.ClearColor(0.3f, 0.3f, 0.3f, 0f);
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
GL.ShadeModel(ShadingModel.Smooth);
GL.LoadIdentity();
GL.Translate(-15.0f, -15.0f, 0.0f);
GL.Begin(BeginMode.Triangles);
GL.Color3(1.0f, 0.0f, 0.0f);
GL.Vertex2(0.0f, 0.0f);
GL.Color3(0.0f, 1.0f, 0.0f);
GL.Vertex2(30f, 0.0f);
GL.Color3(0.0f, 0.0f, 1.0f);
GL.Vertex2(0.0f, 30.0f);
GL.End();
//Swaps the buffers on the window so that what we draw becomes visible
sender.SwapBuffers();
}
}
}</lang>
Clojure
In this example, we use Penumbra, which is an idiomatic wrapper for OpenGL. <lang lisp>(use 'penumbra.opengl) (require '[penumbra.app :as app])
(defn init [state]
(app/title! "Triangle") (clear-color 0.3 0.3 0.3 0) (shade-model :smooth) state)
(defn reshape [[x y w h] state]
(ortho-view -30 30 -30 30 -30 30) (load-identity) (translate -15 -15) state)
(defn display [[dt time] state]
(draw-triangles (color 1 0 0) (vertex 0 0) (color 0 1 0) (vertex 30 0) (color 0 0 1) (vertex 0 30)))
(app/start {:display display, :reshape reshape, :init init} {})</lang>
D
opengl_sample.d: <lang d>module opengl_sample; // file name + directory import dglut.core, dglut.window, dglut.opengl;
void main() {
with (new Canvas) {
setName("Triangle");
map;
onResize = (Canvas self) { // A delegate literal that takes a parameter.
with (self) glViewport(0, 0, width, height);
MatrixMode.Projection.Identity; // For functions without parameters, the () can be omitted.
glOrtho(-30, 30, -30, 30, -30, 30);
MatrixMode.Modelview;
};
onDisplay=(Canvas self) {
scope(exit) self.swap; // Scope guards ease exception-safe programming
glClearColor(0.3f, 0.3f, 0.3f, 0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity;
// A convenience wrapper around glTranslatef. Supports numbers, arrays and vectors.
Translate(-15, -15, 0);
// This is a delegate literal as well. Triangles is a wrapper around glBegin and glEnd.
Triangles = {
Color(1f, 0f, 0f); Vertex(0, 0);
Color(0f, 1f, 0f); Vertex(30, 0);
Color(0f, 0f, 1f); Vertex(0, 30);
};
};
}
loop;
}</lang>
Common Lisp
The user may change the :type argument in draw-update to 'right, and re-evaluate to see the change take effect in realtime.
<lang lisp>(defun draw-triangle (x y &key (z 0) (type 'right))
(case type
(right
(gl:with-primitive :triangles
(gl:color 0 0 1)
(gl:vertex x y z)
(gl:color 0 1 0)
(gl:vertex x (- y 1) z)
(gl:color 1 0 0)
(gl:vertex (+ x 1) (1- y) z)))
(equilateral
(gl:with-primitive :triangles
(gl:color 0 0 1)
(gl:vertex (+ x 0.5) y z)
(gl:color 1 0 0)
(gl:vertex (- x 0.5) (- y 1) z)
(gl:color 0 1 0)
(gl:vertex (+ x 1.5) (- y 1) z)))))
(defun draw-update ()
(gl:clear :color-buffer :depth-buffer :color-buffer-bit) (gl:matrix-mode :modelview) (gl:load-identity)
(gl:color 1.0 1.0 1.0) (gl:translate 0 0 -2)
(draw-triangle -0.5 0.5 :type 'equilateral))
(defun main-loop ()
(sdl:with-events ()
(:quit-event () t)
(:key-down-event (:key key)
(cond ((sdl:key= key :sdl-key-escape)
(sdl:push-quit-event))))
(:idle ()
(draw-update)
(sdl:update-display))))
(defun setup-gl (w h)
(gl:clear-color 0.5 0.5 0.5 1) (gl:clear-depth 1)
(gl:viewport 0 0 w h)
(gl:depth-func :lequal) (gl:hint :perspective-correction-hint :nicest) (gl:shade-model :smooth) (gl:enable :depth-test :cull-face)
(gl:matrix-mode :projection) (gl:load-identity) (glu:perspective 45 (/ w (max h 1)) 0.1 20)
(gl:matrix-mode :modelview) (gl:load-identity))
(defun triangle (&optional (w 640) (h 480))
(sdl:with-init ()
(sdl:set-gl-attribute :SDL-GL-DEPTH-SIZE 16)
(sdl:window w h
:bpp 32
:flags sdl:sdl-opengl
:title-caption "Rosettacode.org OpenGL Demo")
(setup-gl w h)
(setf (sdl:frame-rate) 2)
(main-loop)))</lang>
eC
<lang C>#include <GL/gl.h> import "ecere"
class GLTriangle : Window {
text = "Triangle";
displayDriver = "OpenGL";
background = activeBorder;
nativeDecorations = true;
borderStyle = sizable;
hasMaximize = true, hasMinimize = true, hasClose = true;
size = { 640, 480 };
void OnRedraw(Surface surface)
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-30, 30, -30, 30, -30, 30);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(-15, -15, 0);
glShadeModel(GL_SMOOTH);
glBegin(GL_TRIANGLES);
glColor3f(1, 0, 0);
glVertex2f(0, 0);
glColor3f(0, 1, 0);
glVertex2f(30, 0);
glColor3f(0, 0, 1);
glVertex2f(0, 30);
glEnd();
}
}
GLTriangle window {};</lang>
Euphoria
Adapted from NeHe tutorial #3 nehe.gamedev.net <lang euphoria> include get.e include dll.e include machine.e include msgbox.e include constants.ew include GLfunc.ew include GLconst.ew
without warning
atom hRC, hDC, hWnd, hInstance, ClassName sequence keys keys = repeat(0,256) -- array to hold key presses
integer active, fullscreen, retval active = TRUE fullscreen = TRUE hRC = NULL hDC = NULL hWnd = NULL hInstance = NULL
atom rtri, rquad rtri = 0.0 rquad = 0.0
integer dmScreenSettings, WindowRect
procedure ReSizeGLScene(integer width, integer height)
if height = 0 then
height = 1
end if
c_proc(glViewport,{0,0,width,height})
c_proc(glMatrixMode,{GL_PROJECTION})
c_proc(glLoadIdentity,{})
c_proc(gluPerspective,{45.0,width/height,0.1,100.0})
c_proc(glMatrixMode,{GL_MODELVIEW})
c_proc(glLoadIdentity,{})
end procedure
procedure InitGL()
c_proc(glShadeModel,{GL_SMOOTH})
c_proc(glClearColor,{0.0,0.0,0.0,0.0})
c_proc(glClearDepth,{1.0})
c_proc(glEnable,{GL_DEPTH_TEST})
c_proc(glDepthFunc,{GL_LEQUAL})
c_proc(glHint,{GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST})
end procedure
function DrawGLScene()
c_proc(glClear, {or_bits(GL_COLOR_BUFFER_BIT,GL_DEPTH_BUFFER_BIT)})
c_proc(glLoadIdentity, {})
c_proc(glTranslatef, {-1.5,0.0,-6.0})
c_proc(glRotatef, {rtri,0.0,1.0,0.0})
c_proc(glBegin, {GL_TRIANGLES})
c_proc(glColor3f, {1.0,0.0,0.0})
c_proc(glVertex3f, {0.0,1.0,0.0})
c_proc(glColor3f, {0.0,1.0,0.0})
c_proc(glVertex3f, {-1.0,-1.0,0.0})
c_proc(glColor3f, {0.0,0.0,1.0})
c_proc(glVertex3f, {1.0,-1.0,0.0})
c_proc(glEnd, {})
c_proc(glLoadIdentity, {})
c_proc(glTranslatef, {1.5,0.0,-6.0})
c_proc(glRotatef, {rquad,1.0,0.0,0.0})
c_proc(glColor3f, {0.5,0.5,1.0})
c_proc(glBegin, {GL_QUADS})
c_proc(glVertex3f, {1.0,1.0,0.0})
c_proc(glVertex3f, {-1.0,1.0,0.0})
c_proc(glVertex3f, {-1.0,-1.0,0.0})
c_proc(glVertex3f, {1.0,-1.0,0.0})
c_proc(glEnd, {})
rtri += 0.2
rquad -= 0.15
return TRUE
end function
procedure KillGLWindow()
if fullscreen then
if c_func(ChangeDisplaySettingsA,{NULL,0}) then end if
if c_func(ShowCursor,{TRUE}) then end if
end if
if hRC then
if c_func(wglMakeCurrent,{NULL,NULL}) then end if
if c_func(wglDeleteContext,{hRC}) then end if
hRC = NULL
end if
if hRC and not c_func(ReleaseDC,{hWnd,hDC}) then
hDC = NULL
end if
if hWnd and not c_func(DestroyWindow,{hWnd}) then
hWnd = NULL
end if
if dmScreenSettings then
free(dmScreenSettings)
end if
free(WindowRect)
end procedure
function WndProc(atom hWnd, integer uMsg, atom wParam, atom lParam)
if uMsg = WM_ACTIVATE then
if not floor(wParam/#10000) then
active = TRUE
else
active = FALSE
end if
elsif uMsg = WM_SYSCOMMAND then
if wParam = SC_SCREENSAVE then end if
if wParam = SC_MONITORPOWER then end if
elsif uMsg = WM_CLOSE then
c_proc(PostQuitMessage,{0})
elsif uMsg = WM_KEYDOWN then
keys[wParam] = TRUE
elsif uMsg = WM_KEYUP then
keys[wParam] = FALSE
elsif uMsg = WM_SIZE then
ReSizeGLScene(and_bits(lParam,#FFFF),floor(lParam/#10000))
end if
return c_func(DefWindowProcA,{hWnd, uMsg, wParam, lParam})
end function
integer wc wc = allocate(40) function ClassRegistration() integer WndProcAddress, id
id = routine_id("WndProc")
if id = -1 then
puts(1, "routine_id failed!\n")
abort(1)
end if
WndProcAddress = call_back(id)
hInstance = c_func(GetModuleHandleA,{NULL})
ClassName = allocate_string("OpenGL")
poke4(wc,or_all({CS_HREDRAW, CS_VREDRAW, CS_OWNDC}))
poke4(wc+4,WndProcAddress)
poke4(wc+8,0)
poke4(wc+12,0)
poke4(wc+16,hInstance)
poke4(wc+20,c_func(LoadIconA,{NULL,IDI_WINLOGO}))
poke4(wc+24,c_func(LoadCursorA,{NULL, IDC_ARROW}))
poke4(wc+28,NULL)
poke4(wc+32,NULL)
poke4(wc+36,ClassName)
if not c_func(RegisterClassA,{wc}) then
retval = message_box("Failed to register class","Error", or_bits(MB_OK,MB_ICONINFORMATION))
return FALSE
else
return TRUE
end if
end function
integer regd regd = FALSE procedure CreateGLWindow(atom title, integer width, integer height, integer bits, integer fullscreenflag)
atom PixelFormat, pfd, dwExStyle, dwStyle
sequence s
if regd = FALSE then
if ClassRegistration() then
regd = TRUE
end if
end if
fullscreen = fullscreenflag
if fullscreen then
dmScreenSettings = allocate(156)
mem_set(dmScreenSettings,0,156)
s = int_to_bytes(156)
poke(dmScreenSettings + 36,{s[1],s[2]})
poke4(dmScreenSettings + 40,or_all({DM_BITSPERPEL,DM_PELSWIDTH,DM_PELSHEIGHT}))
poke4(dmScreenSettings + 104, bits)
poke4(dmScreenSettings + 108, width)
poke4(dmScreenSettings + 112, height)
if c_func(ChangeDisplaySettingsA,{dmScreenSettings,CDS_FULLSCREEN}) != DISP_CHANGE_SUCCESSFUL then
if message_box("The requested fullscreen mode is not supported by\nyour video card. " &
"Use windowed mode instead?","Error", or_bits(MB_YESNO,MB_ICONEXCLAMATION)) = IDYES then
else
retval = message_box("Program will now close","Error",or_bits(MB_OK,MB_ICONSTOP))
end if
end if
else
dmScreenSettings = NULL
end if
if fullscreen then
dwExStyle = WS_EX_APPWINDOW
dwStyle = WS_POPUP
if c_func(ShowCursor,{FALSE}) then end if
else
dwExStyle = or_bits(WS_EX_APPWINDOW,WS_EX_WINDOWEDGE)
dwStyle = WS_OVERLAPPEDWINDOW
end if
WindowRect = allocate(16)
poke4(WindowRect,0)
poke4(WindowRect + 4,width)
poke4(WindowRect + 8, 0)
poke4(WindowRect + 12, height)
if c_func(AdjustWindowRectEx,{WindowRect, dwStyle, FALSE, dwExStyle}) then end if
hWnd = c_func(CreateWindowExA,{dwExStyle, --extended window style
ClassName, --class
title, --window caption
or_all({WS_CLIPSIBLINGS,WS_CLIPCHILDREN,dwStyle}), --window style
0,
0,
peek4u(WindowRect + 4) - peek4u(WindowRect),
peek4u(WindowRect + 12) - peek4u(WindowRect + 8),
NULL,
NULL,
hInstance,
NULL})
if hWnd = NULL then
KillGLWindow()
retval = message_box("Window creation error","Error",or_bits(MB_OK,MB_ICONEXCLAMATION))
end if
pfd = allocate(40) --PIXELFORMATDESCRIPTOR
mem_set(pfd,0,40)
poke(pfd, 40) --size of pfd structure
poke(pfd + 2, 1) --version
poke4(pfd + 4, or_all({PFD_DRAW_TO_WINDOW,PFD_SUPPORT_OPENGL,PFD_DOUBLEBUFFER})) --properties flags
poke(pfd + 8, PFD_TYPE_RGBA) --request an rgba format
poke(pfd + 9, 24) --select color depth
poke(pfd + 23, 24) --32bit Z-buffer
hDC = c_func(GetDC,{hWnd}) --create GL device context to match window device context
if not hDC then
KillGLWindow()
retval = message_box("Can't create a GL device context","Error",or_bits(MB_OK,MB_ICONEXCLAMATION))
end if
PixelFormat = c_func(ChoosePixelFormat,{hDC,pfd}) --find a pixel format matching PIXELFORMATDESCRIPTOR
if not PixelFormat then
KillGLWindow()
retval = message_box("Can't find a suitable pixel format","Error",or_bits(MB_OK,MB_ICONEXCLAMATION))
end if
if not (c_func(SetPixelFormat,{hDC,PixelFormat,pfd})) then --set the pixel format
KillGLWindow()
retval = message_box("Can't set the pixel format","Error",or_bits(MB_OK,MB_ICONEXCLAMATION))
end if
if not c_func(DescribePixelFormat, {hDC,PixelFormat,40,pfd}) then
retval = message_box("Can't describe the pixel format","Error",or_bits(MB_OK,MB_ICONEXCLAMATION))
end if
hRC = c_func(wglCreateContext,{hDC}) --create GL rendering context
if not hRC then
KillGLWindow()
retval = message_box("Can't create a GL rendering context","Error",or_bits(MB_OK,MB_ICONEXCLAMATION))
end if
if not (c_func(wglMakeCurrent,{hDC,hRC})) then --make the GL rendering context active
KillGLWindow()
retval = message_box("Can't activate the GL rendering context","Error",or_bits(MB_OK,MB_ICONEXCLAMATION))
end if
retval = c_func(ShowWindow,{hWnd,SW_SHOW}) --show the window
retval = c_func(SetForegroundWindow,{hWnd}) --set it to always be in foreground
retval = c_func(SetFocus,{hWnd}) --give it focus
ReSizeGLScene(width, height) --draw the GL scene to match the window size
InitGL() --initialize OpenGL
end procedure
integer MSG MSG = allocate(28) integer title title = allocate_string("OpenGL") procedure WinMain() integer done, msg_message
done = FALSE
if message_box("Would you like to run in fullscreen mode?","Start Fullscreen?",or_bits(MB_YESNO,MB_ICONQUESTION)) = IDNO then
fullscreen = FALSE
else
fullscreen = TRUE
end if
CreateGLWindow(title,640,480,24,fullscreen)
while not done do
if c_func(PeekMessageA,{MSG,NULL,0,0,PM_REMOVE}) then
msg_message = peek4u(MSG+4)
if msg_message = WM_QUIT then
done = TRUE
else
retval = c_func(TranslateMessage,{MSG})
retval = c_func(DispatchMessageA,{MSG})
end if
else
if ((active and not DrawGLScene()) or keys[VK_ESCAPE]) then
done = TRUE
else
retval = c_func(SwapBuffers,{hDC})
if keys[VK_F1] then
keys[VK_F1] = FALSE
KillGLWindow()
if fullscreen = 0 then
fullscreen = 1
else
fullscreen = 0
end if
CreateGLWindow(title,640,480,24,fullscreen)
end if
end if
end if
end while
KillGLWindow()
end procedure
WinMain() </lang>
Factor
Translated from C <lang factor>USING: kernel math math.rectangles opengl.gl sequences ui ui.gadgets ui.render ; IN: rosettacode.opengl
TUPLE: triangle-gadget < gadget ;
- reshape ( width height -- )
[ 0 0 ] 2dip glViewport GL_PROJECTION glMatrixMode glLoadIdentity -30.0 30.0 -30.0 30.0 -30.0 30.0 glOrtho GL_MODELVIEW glMatrixMode ;
- paint ( -- )
0.3 0.3 0.3 0.0 glClearColor GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT bitor glClear GL_SMOOTH glShadeModel glLoadIdentity -15.0 -15.0 0.0 glTranslatef GL_TRIANGLES glBegin 1.0 0.0 0.0 glColor3f 0.0 0.0 glVertex2f 0.0 1.0 0.0 glColor3f 30.0 0.0 glVertex2f 0.0 0.0 1.0 glColor3f 0.0 30.0 glVertex2f glEnd glFlush ;
M: triangle-gadget pref-dim* drop { 640 480 } ; M: triangle-gadget draw-gadget*
rect-bounds nip first2 reshape paint ;
- triangle-window ( -- )
[ triangle-gadget new "Triangle" open-window ] with-ui ;
MAIN: triangle-window </lang>
Forth
triangle.fs: <lang forth>import glconst import float glconst also float also opengl also</lang>
triangle.m: <lang forth>#! xbigforth \ automatic generated code \ do not edit
also editor also minos also forth
include triangle.fs component class triangle public:
early widget early open early dialog early open-app ( [varstart] ) ( [varend] )
how:
: open new DF[ 0 ]DF s" Triangle" open-component ; : dialog new DF[ 0 ]DF s" Triangle" open-dialog ; : open-app new DF[ 0 ]DF s" Triangle" open-application ;
class;
triangle implements
( [methodstart] ) ( [methodend] )
: widget ( [dumpstart] )
GL[ ^ glcanvas with
0 0 w @ h @ glViewport GL_PROJECTION glMatrixMode glLoadIdentity -30e 30e -30e 30e -30e 30e glOrtho GL_MODELVIEW glMatrixMode 0.3e 0.3e 0.3e 0.0e glClearColor GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT or glClear GL_SMOOTH glShadeModel glLoadIdentity -15e -15e 0e glTranslatef GL_TRIANGLES glBegin 1e 0e 0e glColor3f 0e 0e glVertex2f 0e 1e 0e glColor3f 30e 0e glVertex2f 0e 0e 1e glColor3f 0e 30e glVertex2f glEnd glFlush endwith ]GL ( MINOS ) ^^ CK[ ( x y b n -- ) 2drop 2drop ]CK ( MINOS ) $280 $1 *hfil $1E0 $1 *vfil glcanvas new
&1 vabox new ( [dumpend] ) ; : init ^>^^ assign widget 1 :: init ;
class;
- main
triangle open-app $1 0 ?DO stop LOOP bye ;
script? [IF] main [THEN] previous previous previous</lang>
Go
The win package used in this example is a simple wrapper around GLFW.
<lang go>// triangle displays a smooth shaded triangle with OpenGL. package main
import ( "log" "runtime" "time"
gl "github.com/chsc/gogl/gl21" "github.com/mewmew/glfw/win" )
// Window dimensions. const ( Width = 640 Height = 480 )
func main() { // OpenGL requires a dedicated OS thread. runtime.LockOSThread() defer runtime.UnlockOSThread()
// Open window with the specified dimensions. err := win.Open(Width, Height) if err != nil { log.Fatalln(err) } defer win.Close()
// Initiate viewport. resize(Width, Height)
// Register that we are interested in receiving close and resize events. win.EnableCloseChan() win.EnableResizeChan()
// 60 frames per second. c := time.Tick(time.Second / 60)
// Event loop. for { select { case <-win.CloseChan: return case e := <-win.ResizeChan: resize(e.Width, e.Height) case <-c: draw() } } }
// resize resizes the window to the specified dimensions. func resize(width, height int) { gl.Viewport(0, 0, gl.Sizei(width), gl.Sizei(height)) gl.MatrixMode(gl.PROJECTION) gl.LoadIdentity() gl.Ortho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0) gl.MatrixMode(gl.MODELVIEW) }
// draw draws the triangle. func draw() { gl.ClearColor(0.3, 0.3, 0.3, 0.0) gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
gl.ShadeModel(gl.SMOOTH)
gl.LoadIdentity() gl.Translatef(-15.0, -15.0, 0.0)
gl.Begin(gl.TRIANGLES)
gl.Color3f(1.0, 0.0, 0.0) gl.Vertex2f(0.0, 0.0)
gl.Color3f(0.0, 1.0, 0.0) gl.Vertex2f(30.0, 0.0)
gl.Color3f(0.0, 0.0, 1.0) gl.Vertex2f(0.0, 30.0)
gl.End()
win.SwapBuffers() } </lang>
Haskell
<lang haskell>import Graphics.Rendering.OpenGL import Graphics.UI.GLUT
main = do
getArgsAndInitialize
createWindow "Triangle"
displayCallback $= display
matrixMode $= Projection
loadIdentity
ortho2D 0 30 0 30
matrixMode $= Modelview 0
mainLoop
display = do
clear [ColorBuffer]
renderPrimitive Triangles $ do
corner 1 0 0 5 5
corner 0 1 0 25 5
corner 0 0 1 5 25
swapBuffers
corner r g b x y = do color (Color3 r g b :: Color3 GLfloat)
vertex (Vertex2 x y :: Vertex2 GLfloat)</lang>
J
This version assumes J6.02 (but should work on earlier versions). This will not work with any of the new IDEs from J7 because wd emulation has not been ported to them yet.
Additionally, if you are using 64 bit windows, to get opengl working on J602 you will need to copy jzopengl_win.ijs to jzopengl_win_64.ijs in system/classes/opengl/.
<lang J>coclass 'example' (coinsert[require) 'jzopengl'
create=:3 :0
ogl=: conew'jzopengl' wd 'pc p;cc c isigraph opengl rightmove bottommove;pas 0 0;pshow;'
)
p_close=: destroy=:3 :0
destroy__ogl wd'pclose' codestroy
)
corner=:4 :0
glColor3d x glVertex2d y
)
p_c_paint=:3 :0
rc__ogl glClear GL_COLOR_BUFFER_BIT glBegin GL_TRIANGLES 1 0 0 corner 0 0-0.5 0 1 0 corner 1 0-0.5 0 0 1 corner 0 1-0.5 glEnd show__ogl
)
conew~'example'</lang>
Note: OpenGL's initial state is well defined by the OpenGL standard.
Java
This example uses LWJGL, a game library which has an OpenGL binding for Java <lang Java>import org.lwjgl.LWJGLException; import org.lwjgl.opengl.Display; import org.lwjgl.opengl.DisplayMode; import static org.lwjgl.opengl.GL11.*;
public class OpenGlExample {
public void run() throws LWJGLException { Display.setDisplayMode(new DisplayMode(640, 480)); Display.create();
glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-30, 30, -30, 30, -30, 30); glMatrixMode(GL_MODELVIEW);
while(!Display.isCloseRequested()) { render();
Display.update(); }
Display.destroy(); }
public void render() {
glClearColor(0.3f, 0.3f, 0.3f, 0.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glShadeModel(GL_SMOOTH);
glLoadIdentity(); glTranslatef(-15.0f, -15.0f, 0.0f);
glBegin(GL_TRIANGLES); glColor3f(1.0f, 0.0f, 0.0f); glVertex2f(0.0f, 0.0f); glColor3f(0.0f, 1.0f, 0.0f); glVertex2f(30f, 0.0f); glColor3f(0.0f, 0.0f, 1.0f); glVertex2f(0.0f, 30.0f); glEnd();
}
public static void main(String[] args) { OpenGlExample openGlExmpl = new OpenGlExample(); try { openGlExmpl.run(); } catch(LWJGLException e) { System.err.println(e); } }
}
</lang>
JavaScript (WebGL)
Unfortunately for comparison with the other examples on this page, WebGL provides only OpenGL ES, which removes the classic “fixed-function pipeline” and glVertex() in favor of requiring you to write vertex shaders and fragment shaders, and use vertex arrays. It is not hard to write shader programs to emulate as much of the fixed-function pipeline as you need, but it does mean more verbosity as you have to explicitly define all of the data you're going to communicate to your shader.
In the interest of brevity and not depending on an external matrix library, this example omits matrix operations entirely, as OpenGL ES requires you to add those features yourself if you want them. Examples which show how to implement the classic OpenGL matrix stack are available at Learning WebGL (which this code was derived from).
<lang html><html style="margin: 0;">
<head>
<title>Minimal WebGL Example</title>
<script id="shader-fs" type="x-shader/x-fragment">
precision highp float;
varying vec4 v_color;
void main(void) {
// "Varying" variables are implicitly interpolated across triangles.
gl_FragColor = v_color;
}
</script>
<script id="shader-vs" type="x-shader/x-vertex">
attribute vec3 a_position;
attribute vec4 a_color;
varying vec4 v_color;
void main(void) {
gl_Position = vec4(a_position, 1.0);
v_color = a_color;
}
</script>
<script type="text/javascript">
function getShader(gl, id) {
var scriptElement = document.getElementById(id);
// Create shader object
var shader;
if (scriptElement.type == "x-shader/x-fragment")
shader = gl.createShader(gl.FRAGMENT_SHADER);
else if (scriptElement.type == "x-shader/x-vertex")
shader = gl.createShader(gl.VERTEX_SHADER);
else
throw new Error("unknown shader script type");
// Compile shader from source
gl.shaderSource(shader, scriptElement.textContent);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS))
throw new Error(gl.getShaderInfoLog(shader));
return shader;
}
</script>
</head>
<body style="margin: 0;">
<canvas id="glcanvas" style="border: none; margin: auto; display: block;" width="640" height="480"></canvas>
<script type="text/javascript">
var canvas = document.getElementById("glcanvas");
// Get WebGL context.
var gl = canvas.getContext("webgl")
|| canvas.getContext("experimental-webgl");
if (!gl)
throw new Error("WebGL context not found");
// Create shader program from vertex and fragment shader code.
var shaderProgram = gl.createProgram();
gl.attachShader(shaderProgram, getShader(gl, "shader-vs"));
gl.attachShader(shaderProgram, getShader(gl, "shader-fs"));
gl.linkProgram(shaderProgram);
if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS))
throw new Error(gl.getProgramInfoLog(shaderProgram));
// Specify to render using that program.
gl.useProgram(shaderProgram);
// Get the indexes to communicate vertex attributes to the program.
var positionAttr = gl.getAttribLocation(shaderProgram, "a_position");
var colorAttr = gl.getAttribLocation(shaderProgram, "a_color");
// And specify that we will be actually delivering data to those attributes.
gl.enableVertexAttribArray(positionAttr);
gl.enableVertexAttribArray(colorAttr);
// Store vertex positions and colors in array buffer objects.
var vertices;
var positionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices = [
-0.5, -0.5, 0,
+0.5, -0.5, 0,
-0.5, +0.5, 0
]), gl.STATIC_DRAW);
var colorBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, colorBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
1, 0, 0, 1,
0, 1, 0, 1,
0, 0, 1, 1
]), gl.STATIC_DRAW);
var numVertices = vertices.length / 3; // 3 coordinates per vertex
// Set GL state
gl.clearColor(0.3, 0.3, 0.3, 1.0);
gl.enable(gl.DEPTH_TEST);
gl.viewport(0, 0, gl.drawingBufferWidth || canvas.width,
gl.drawingBufferHeight || canvas.height);
// Draw scene.
// If this were an animation, everything after this point would go in a main loop.
// Clear frame.
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
// Specify the array data to render.
// 3 and 4 are the lengths of the vectors (3 for XYZ, 4 for RGBA).
gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
gl.vertexAttribPointer(positionAttr, 3, gl.FLOAT, false, 0, 0);
gl.bindBuffer(gl.ARRAY_BUFFER, colorBuffer);
gl.vertexAttribPointer(colorAttr, 4, gl.FLOAT, false, 0, 0);
// Draw triangles using the specified arrays.
gl.drawArrays(gl.TRIANGLES, 0, numVertices);
// Check for errors.
var e;
while (e = gl.getError())
console.log("GL error", e);
</script>
</body>
</html></lang>
Kotlin
<lang scala>// Kotlin Native version 0.3
import kotlinx.cinterop.* import opengl.*
fun paint() {
glClearColor(0.3f, 0.3f, 0.3f, 0.0f) glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT) glShadeModel(GL_SMOOTH) glLoadIdentity() glTranslatef(-15.0f, -15.0f, 0.0f) glBegin(GL_TRIANGLES) glColor3f(1.0f, 0.0f, 0.0f) glVertex2f(0.0f, 0.0f) glColor3f(0.0f, 1.0f, 0.0f) glVertex2f(30.0f, 0.0f) glColor3f(0.0f, 0.0f, 1.0f) glVertex2f(0.0f, 30.0f) glEnd()
glFlush()
}
fun reshape(width: Int, height: Int) {
glViewport(0, 0, width, height) glMatrixMode(GL_PROJECTION) glLoadIdentity() glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0) glMatrixMode(GL_MODELVIEW)
}
fun main(args: Array<String>) {
memScoped {
val argc = alloc<IntVar>().apply { value = 0 }
glutInit(argc.ptr, null)
}
glutInitWindowSize(640, 480)
glutCreateWindow("Triangle")
glutDisplayFunc(staticCFunction(::paint))
glutReshapeFunc(staticCFunction(::reshape))
glutMainLoop()
}</lang>
- Output:
Same as C entry
Lua
Note that GL functions that take constants in LuaGL can take either the numbers representing those flags (ie. gl.XXX + gl.YYY) or a comma-separated string of those flags (ie. "XXX,YYY"). This example uses strings.
<lang lua>local gl = require "luagl" local iup = require "iuplua" require "iupluagl"
local function paint()
gl.ClearColor(0.3,0.3,0.3,0.0) gl.Clear"COLOR_BUFFER_BIT,DEPTH_BUFFER_BIT"
gl.ShadeModel"SMOOTH"
gl.LoadIdentity() gl.Translate(-15.0, -15.0, 0.0)
gl.Begin"TRIANGLES" gl.Color(1.0, 0.0, 0.0) gl.Vertex(0.0, 0.0) gl.Color(0.0, 1.0, 0.0) gl.Vertex(30.0, 0.0) gl.Color(0.0, 0.0, 1.0) gl.Vertex(0.0, 30.0) gl.End()
gl.Flush()
end
local function reshape(width, height)
gl.Viewport(0, 0, width, height) gl.MatrixMode"PROJECTION" gl.LoadIdentity() gl.Ortho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0) gl.MatrixMode"MODELVIEW"
end
local glc = iup.glcanvas{rastersize="640x480"} function glc:action() paint() end function glc:resize_cb(w,h) reshape(w,h) end function glc:map_cb() iup.GLMakeCurrent(self) end
local dlg = iup.dialog{title="Triangle", shrink="yes"; glc} dlg:show()
iup.MainLoop() </lang>
Liberty BASIC
<lang lb>nomainwin
struct rect, x as long, y as long, x2 as long, y2 as long
struct PFD, Size as word, Version as word, Flags as long,_
PixelType as char[1], ColorBits as char[1], RedBits as char[1],_
RedShift as char[1], GreenBits as char[1], GreenShift as char[1],_
BlueBits as char[1], BlueShift as char[1], AlphaBits as char[1],_
AlphaShift as char[1],AccumBits as char[1], AccumRedBits as char[1],_
AccumGreenBits as char[1], AccumBlueBits as char[1], AccumAlphaBits as char[1],_
DepthBits as char[1], StencilBits as char[1], AuxBuffers as char[1],_
LayerType as char[1], Reserved as char[1], LayerMask as long,_
VisibleMask as long, DamageMask as long
PFD.Version.struct=1
PFD.ColorBits.struct=24
PFD.DepthBits.struct=16
PFD.Size.struct=len(PFD.struct)
PFD.Flags.struct=37
GlColorBufferBit=16384
open "opengl32.dll" for dll as #gl
open "glu32.dll" for dll as #glu
WindowWidth=500
WindowHeight=500
UpperLeftX=1
UpperLeftY=1
open "Triangle" for window_nf as #main
print #main,"trapclose [quit]"
MainH=hwnd(#main)
calldll #user32,"GetDC", MainH as ulong, MainDC as ulong
calldll #gdi32,"ChoosePixelFormat", MainDC as ulong, PFD as struct, ret as long
calldll #gdi32, "SetPixelFormat", MainDC as ulong, ret as long, PFD as struct, t as long
calldll #gl,"wglCreateContext", MainDC as ulong, GLContext as ulong
calldll #gl,"wglMakeCurrent", MainDC as ulong, GLContext as ulong, ret as long
calldll #gl,"glClear", GlColorBufferBit as long, ret as long
calldll #gl,"glRotated", 0 as double, 0 as double, 0 as double, 0 as double, ret as long
calldll #gl,"glBegin", 4 as long, ret as long
calldll #gl,"glColor3d", 0 as double, 0 as double, 255 as double, ret as long
calldll #gl,"glVertex3i", -1 as long, -1 as long, 0 as long, ret as long
calldll #gl,"glColor3d", 255 as double, 0 as double, 0 as double, ret as long
calldll #gl,"glVertex3i", 0 as long, 1 as long, 0 as long, ret as long
calldll #gl,"glColor3d", 0 as double, 255 as double, 0 as double, ret as long
calldll #gl,"glVertex3i", 1 as long, -1 as long, 0 as long, ret as long
calldll #gl,"glEnd", ret as void
calldll #gdi32,"SwapBuffers", MainDC as ulong, ret as long
wait
[quit]
calldll #gl,"wglMakeCurrent", 0 as ulong, 0 as ulong, ret as long calldll #gl,"wglDeleteContext", GLContext as ulong, ret as long calldll #user32, "ReleaseDC", MainH as ulong, MainDC as ulong,ret as long close #main close #glu close #gl end</lang>
MAXScript
The choice of OpenGL or D3D in MAX is a user configuration setting. All MAXScript code is platform independent. <lang maxscript>newMesh = mesh numVerts:3 numFaces:1 setMesh newMesh vertices:#([-100, -100, 0], [100, -100, 0], [-100, 100, 0]) faces:#([1, 2, 3]) defaultVCFaces newMesh setVertColor newMesh 1 red setVertColor newMesh 2 green setVertColor newMesh 3 blue setCVertMode newMesh true update newMesh viewport.setType #view_top max tool maximize viewport.SetRenderLevel #smoothhighlights</lang>
Mercury
Translated from C. <lang>:- module opengl.
- - interface.
- - import_module io.
- - pred main(io::di, io::uo) is det.
- - implementation.
- - import_module list, glut, glut.callback, glut.window, mogl.
main(!IO) :-
glut.init_window_size(640, 480, !IO),
glut.window.create("Triangle", !IO),
glut.callback.display_func(opengl.paint, !IO),
glut.callback.reshape_func(opengl.reshape, !IO),
glut.main_loop(!IO).
- - pred paint(io::di, io::uo) is det.
paint(!IO) :-
mogl.clear_color(0.3, 0.3, 0.3 , 0.0, !IO), mogl.clear([color, depth], !IO),
mogl.shade_model(smooth, !IO),
mogl.load_identity(!IO), mogl.translate(-15.0, -15.0, 0.0, !IO),
mogl.begin(triangles, !IO),
mogl.color3(1.0, 0.0, 0.0, !IO),
mogl.vertex2(0.0, 0.0, !IO),
mogl.color3(0.0, 1.0, 0.0, !IO),
mogl.vertex2(30.0, 0.0, !IO),
mogl.color3(0.0, 0.0, 1.0, !IO),
mogl.vertex2(0.0, 30.0, !IO),
mogl.end(!IO),
mogl.flush(!IO).
- - pred reshape(int::in, int::in, io::di, io::uo) is det.
reshape(Width, Height, !IO) :-
mogl.viewport(0, 0, Width, Height, !IO), mogl.matrix_mode(projection, !IO), mogl.load_identity(!IO), mogl.ortho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0, !IO), mogl.matrix_mode(modelview, !IO).</lang>
Nim
<lang nim>import opengl, glut
proc paint() {.cdecl.} =
glClearColor(0.3,0.3,0.3,0.0) glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT)
glShadeModel(GL_SMOOTH)
glLoadIdentity() glTranslatef(-15.0, -15.0, 0.0)
glBegin(GL_TRIANGLES) glColor3f(1.0, 0.0, 0.0) glVertex2f(0.0, 0.0) glColor3f(0.0, 1.0, 0.0) glVertex2f(30.0, 0.0) glColor3f(0.0, 0.0, 1.0) glVertex2f(0.0, 30.0) glEnd()
glFlush()
proc reshape(width, height: cint) {.cdecl.} =
glViewport(0, 0, width, height) glMatrixMode(GL_PROJECTION) glLoadIdentity() glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0) glMatrixMode(GL_MODELVIEW)
enableAutoGlErrorCheck(false) loadExtensions() glutInit() glutInitWindowSize(640, 480) discard glutCreateWindow("Triangle")
glutDisplayFunc(paint) glutReshapeFunc(reshape)
glutMainLoop()</lang>
OxygenBasic
<lang oxygenbasic>
title="Rotating Triangle" include "OpenglSceneFrame.inc"
sub Initialize(sys hWnd) '======================= SetTimer hWnd,1,10,NULL end sub ' sub Scene(sys hWnd) '================== ' static single ang1,angi1=1 ' glClearColor 0.3, 0.3, 0.5, 0 glClear GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT ' glLoadIdentity ' ' gltranslatef 0.0, 0.0, -4.0 glrotatef ang1, 0.0, 0.0, 1.0 ' glBegin GL_TRIANGLES glColor3f 1.0, 0.0, 0.0 : glVertex3f 0.0, 1.0, 0.0 glColor3f 0.0, 1.0, 0.0 : glVertex3f -1.0, -1.0, 0.0 glColor3f 0.0, 0.0, 1.0 : glVertex3f 1.0, -1.0, 0.0 glEnd ' 'UPDATE ROTATION ANGLES ' ang1+=angi1 if ang1>360 then ang1-=360 ' end sub
sub Release(sys hwnd) '==================== killTimer hwnd, 1 end sub
</lang>
OCaml
<lang ocaml>open GL open Glut
let display() =
glClearColor 0.3 0.3 0.3 0.0; glClear[GL_COLOR_BUFFER_BIT; GL_DEPTH_BUFFER_BIT];
glShadeModel GL_SMOOTH;
glLoadIdentity(); glTranslate (-15.0) (-15.0) (0.0);
glBegin GL_TRIANGLES; glColor3 1.0 0.0 0.0; glVertex2 0.0 0.0; glColor3 0.0 1.0 0.0; glVertex2 30.0 0.0; glColor3 0.0 0.0 1.0; glVertex2 0.0 30.0; glEnd();
glFlush();
let reshape ~width ~height =
glViewport 0 0 width height; glMatrixMode GL_PROJECTION; glLoadIdentity(); glOrtho(-30.0) 30.0 (-30.0) 30.0 (-30.0) 30.0; glMatrixMode GL_MODELVIEW;
let () =
ignore(glutInit Sys.argv); glutInitWindowSize 640 480; ignore(glutCreateWindow "Triangle");
glutDisplayFunc ~display; glutReshapeFunc ~reshape;
glutMainLoop();
- </lang>
Pascal
Ported from the C example. <lang pascal>Program OpenGLDemo;
uses
SysUtils, ctypes, gl, Glut;
procedure paint; cdecl; begin
glClearColor(0.3,0.3,0.3,0.0); glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT); glShadeModel(GL_SMOOTH); glLoadIdentity(); glTranslatef(-15.0, -15.0, 0.0); glBegin(GL_TRIANGLES); glColor3f(1.0, 0.0, 0.0); glVertex2f(0.0, 0.0); glColor3f(0.0, 1.0, 0.0); glVertex2f(30.0, 0.0); glColor3f(0.0, 0.0, 1.0); glVertex2f(0.0, 30.0); glEnd(); glFlush();
end;
procedure reshape(width, height: cint); cdecl; begin
glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0); glMatrixMode(GL_MODELVIEW);
end;
begin
glutInit(@argc, @argv);
glutInitWindowSize(640, 480);
glutCreateWindow('Triangle');
glutDisplayFunc(@paint);
glutReshapeFunc(@reshape);
glutMainLoop();
end.
</lang>
Perl
<lang perl>use OpenGL;
sub triangle {
glBegin GL_TRIANGLES; glColor3f 1.0, 0.0, 0.0; glVertex2f 5.0, 5.0; glColor3f 0.0, 1.0, 0.0; glVertex2f 25.0, 5.0; glColor3f 0.0, 0.0, 1.0; glVertex2f 5.0, 25.0; glEnd;
};
glpOpenWindow; glMatrixMode GL_PROJECTION; glLoadIdentity; gluOrtho2D 0.0, 30.0, 0.0, 30.0; glMatrixMode GL_MODELVIEW;
glClear GL_COLOR_BUFFER_BIT; triangle; glpFlush;
glpMainLoop;</lang>
<lang perl>use SDL::App; use SDL::Event; use SDL::OpenGL;
$app = SDL::App->new(
-gl => 1,
);
sub triangle {
glBegin(GL_TRIANGLES); glColor(1.0, 0.0, 0.0); glVertex(5.0, 5.0); glColor(0.0, 1.0, 0.0); glVertex(25.0, 5.0); glColor(0.0, 0.0, 1.0); glVertex(5.0, 25.0); glEnd();
}
glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0.0, 30.0, 0.0, 30.0); glMatrixMode(GL_MODELVIEW); glClear(GL_COLOR_BUFFER_BIT); triangle(); $app->sync; $app->loop ({
SDL_QUIT() => sub { exit; },
});</lang>
Phix
Adapted from the included demo\Arwen32dibdemo\shadepol.exw, draws the same thing as the image at the top of this page, but (as per the talk page) does not use openGL, just windows api (BitBlt etc) and some low-level fully open source routines (all included). <lang Phix>include demo\Arwen32dibdemo\a32dpoly.ew
a32Dib0 screen_dib = 0 integer dx = 0, dy = 0, dw = 0, dh = 0
constant win = create(Window, "Arwen32Dib bitmap shaded triangle demo", 0, 0, Default, Default, 480, 300, 0)
function winHandler(integer id, integer msg, atom wParam, object lParam) sequence rect
if id or object(lParam) then end if -- suppress warnings
if msg=WM_PAINT then
if sequence(screen_dib) then
clearDib(screen_dib, {0, 0, 0})
drawShadedPolygonToDib(screen_dib, {{dx, dy}, {dx, dh-dy}, {dw-dx, dh-dy}}, {{255, 0, 0}, {0, 0, 255}, {0, 255, 0}})
drawDib(win, screen_dib, 0, 0, 0, 0, screen_dib[DibWidth]-1, screen_dib[DibHeight]-1)
end if
elsif msg=WM_SIZE then
rect = getClientRect(win)
dw = rect[3]
dh = rect[4]
dx = floor(dw/4)+1
dy = floor(dh/4)+1
if sequence(screen_dib) then killDib(screen_dib) end if
screen_dib = newDib(dw, dh)
elsif msg=WM_CHAR
and wParam=VK_ESCAPE then
closeWindow(win)
end if
return 0
end function setHandler(win, routine_id("winHandler"))
WinMain(win, SW_NORMAL)
if sequence(screen_dib) then killDib(screen_dib) end if</lang> And here is a proper openGL version, translated from Lua, and included in the distro as demo\pGUI\triangle.exw:
<lang Phix>include pGUI.e include opengl.e
function resize_cb(Ihandle /*ih*/, integer width, integer height)
glViewport(0, 0, width, height) glMatrixMode(GL_PROJECTION) glLoadIdentity() glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0) glMatrixMode(GL_MODELVIEW) return IUP_DEFAULT
end function
function action(Ihandle /*ih*/)
glClearColor(0.3,0.3,0.3,0.0) glClear(GL_COLOR_BUFFER_BIT+GL_DEPTH_BUFFER_BIT) glShadeModel(GL_SMOOTH) glLoadIdentity() glTranslate(-15.0, -15.0, 0.0) glBegin(GL_TRIANGLES) glColor(1.0, 0.0, 0.0) glVertex(0.0, 0.0) glColor(0.0, 1.0, 0.0) glVertex(30.0, 0.0) glColor(0.0, 0.0, 1.0) glVertex(0.0, 30.0) glEnd() glFlush()
return IUP_DEFAULT
end function
Ihandle dialog, canvas
function map_cb(Ihandle /*ih*/)
IupGLMakeCurrent(canvas)
integer {width, height} = IupGetIntInt(dialog, "RASTERSIZE")
{} = resize_cb(dialog, width, height)
return IUP_DEFAULT
end function
IupOpen() IupGLCanvasOpen()
canvas = IupGLCanvas(Icallback("action"), "RASTERSIZE=640x480") IupSetCallback(canvas, "RESIZE_CB", Icallback("resize_cb"))
dialog = IupDialog(canvas, "MAP_CB", Icallback("map_cb"), "TITLE=Triangle, SHRINK=YES")
IupShow(dialog) IupMainLoop() IupDestroy(dialog) IupClose()</lang>
PicoLisp
This is for the 64-bit version. <lang PicoLisp>(load "@lib/openGl.l")
(glutInit) (glutInitWindowSize 400 300) (glutCreateWindow "Triangle")
(displayPrg
(glClearColor 0.3 0.3 0.3 0.0) (glClear (| GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT)) (glShadeModel GL_SMOOTH) (glLoadIdentity) (glTranslatef -15.0 -15.0 0.0) (glBegin GL_TRIANGLES) (glColor3f 1.0 0.0 0.0) (glVertex2f 0.0 0.0) (glColor3f 0.0 1.0 0.0) (glVertex2f 30.0 0.0) (glColor3f 0.0 0.0 1.0) (glVertex2f 0.0 30.0) (glEnd) (glFlush) )
(reshapeFunc
'((Width Height)
(glViewport 0 0 Width Height)
(glMatrixMode GL_PROJECTION)
(glLoadIdentity)
(glOrtho -30.0 30.0 -30.0 30.0 -30.0 30.0)
(glMatrixMode GL_MODELVIEW) ) )
- Exit upon mouse click
(mouseFunc '((Btn State X Y) (bye)))
(glutMainLoop)</lang>
Pike
Uses GLUE to create the window. Rendering code is based on the C example. <lang pike>int main() { GLUE.init(([ "fullscreen": 0, "resolution": ({ 640, 480 }), ]));
while (1) { GL.glViewport(0, 0, 640, 480); GL.glMatrixMode(GL.GL_PROJECTION); GL.glLoadIdentity(); GL.glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0); GL.glMatrixMode(GL.GL_MODELVIEW);
GL.glClearColor(0.3,0.3,0.3,0.0); GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
GL.glShadeModel(GL.GL_SMOOTH);
GL.glLoadIdentity(); GL.glTranslate(-15.0, -15.0, 0.0);
GL.glBegin(GL.GL_TRIANGLES); GL.glColor(1.0, 0.0, 0.0); GL.glVertex(0.0, 0.0); GL.glColor(0.0, 1.0, 0.0); GL.glVertex(30.0, 0.0); GL.glColor(0.0, 0.0, 1.0); GL.glVertex(0.0, 30.0); GL.glEnd();
GL.glFlush();
GLUE.swap_buffers(); Pike.DefaultBackend(0.0); sleep(0.01); } }</lang>
PureBasic
<lang Purebasic>
XIncludeFile "OpenGL.pbi"
pfd.PIXELFORMATDESCRIPTOR
FlatMode = 0 ; Enable Or disable the 'Flat' rendering
WindowWidth = 800 ; The window & GLViewport dimensions
WindowHeight = 600
hWnd = OpenWindow(0, 0, 0, WindowWidth, WindowHeight, "OpenGL Triangle", #PB_Window_SystemMenu)
hdc = GetDC_(hWnd)
pfd\nSize = SizeOf(PIXELFORMATDESCRIPTOR)
pfd\nVersion = 1
pfd\dwFlags = #PFD_SUPPORT_OPENGL | #PFD_DOUBLEBUFFER | #PFD_DRAW_TO_WINDOW
pfd\dwLayerMask = #PFD_MAIN_PLANE
pfd\iPixelType = #PFD_TYPE_RGBA
pfd\cColorBits = 24
pfd\cDepthBits = 16
pixformat = ChoosePixelFormat_(hdc, pfd)
SetPixelFormat_(hdc, pixformat, pfd)
hrc = wglCreateContext_(hdc)
wglMakeCurrent_(hdc,hrc)
glViewport_ (0, 0, WindowWidth-30, WindowHeight-30)
glPushMatrix_()
glMatrixMode_(#GL_MODELVIEW)
glBegin_(#GL_TRIANGLES );
glColor3f_(1.0, 0.0, 0.0 )
glVertex2f_( 0.0, 1.0 )
glColor3f_( 0.0, 1.0, 0.0 )
glVertex2f_( 0.87, -0.5 );
glColor3f_( 0.0, 0.0, 1.0 )
glVertex2f_( -0.87, -0.5 );
glEnd_()
glPopMatrix_()
glFinish_()
SwapBuffers_(hdc)
While Quit = 0
Repeat
EventID = WindowEvent()
Select EventID
Case #PB_Event_CloseWindow
Quit = 1
EndSelect
Until EventID = 0
Wend
</lang>
Python
<lang python>#!/usr/bin/env python
- -*- coding: utf-8 -*-
from OpenGL.GL import * from OpenGL.GLUT import *
def paint():
glClearColor(0.3,0.3,0.3,0.0) glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
glShadeModel(GL_SMOOTH)
glLoadIdentity() glTranslatef(-15.0, -15.0, 0.0)
glBegin(GL_TRIANGLES) glColor3f(1.0, 0.0, 0.0) glVertex2f(0.0, 0.0) glColor3f(0.0, 1.0, 0.0) glVertex2f(30.0, 0.0) glColor3f(0.0, 0.0, 1.0) glVertex2f(0.0, 30.0) glEnd()
glFlush()
def reshape(width, height):
glViewport(0, 0, width, height) glMatrixMode(GL_PROJECTION) glLoadIdentity() glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0) glMatrixMode(GL_MODELVIEW)
if __name__ == '__main__':
glutInit(1, 1)
glutInitWindowSize(640, 480)
glutCreateWindow("Triangle")
glutDisplayFunc(paint) glutReshapeFunc(reshape)
glutMainLoop()</lang>
R
<lang R>library(rgl) x <- c(-1, -1, 1) y <- c(0, -1, -1) z <- c(0, 0, 0) M <- cbind(x,y,z) rgl.bg(color="gray15") triangles3d(M, col=rainbow(8))</lang>
Racket
This example features C-style OpenGL api, that's not racket-idiomatic but offer more capabilites.
Note: your system may miss some support libraries. If OpenGL context creation fails please consult Racket documentation
<lang racket>
- lang racket/gui
(require sgl/gl)
(define (resize w h)
(glViewport 0 0 w h))
(define (draw-opengl)
(glClearColor 0.0 0.0 0.0 0.0) (glClear GL_COLOR_BUFFER_BIT)
(glShadeModel GL_SMOOTH)
(glMatrixMode GL_PROJECTION) (glLoadIdentity) (glOrtho 0.0 1.0 0.0 1.0 -1.0 1.0) (glMatrixMode GL_MODELVIEW) (glLoadIdentity)
(glBegin GL_TRIANGLES) (glColor3f 1 0 0) (glVertex3d 0.25 0.25 0.0) (glColor3f 0 1 0) (glVertex3d 0.75 0.25 0.0) (glColor3f 0 0 1) (glVertex3d 0.75 0.75 0.0) (glEnd))
(define my-canvas%
(class* canvas% ()
(inherit with-gl-context swap-gl-buffers)
(define/override (on-paint)
(with-gl-context (λ() (draw-opengl) (swap-gl-buffers))))
(define/override (on-size width height)
(with-gl-context (λ() (resize width height))))
(super-instantiate () (style '(gl)))))
(define win (new frame% [label "Racket Rosetta Code OpenGL example"]
[min-width 200] [min-height 200]))
(define gl (new my-canvas% [parent win]))
(send win show #t) </lang>
Ruby
<lang ruby>require 'rubygems' require 'gl' require 'glut'
include Gl include Glut
paint = lambda do
glClearColor(0.3,0.3,0.3,0.0) glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glShadeModel(GL_SMOOTH) glLoadIdentity glTranslatef(-15.0, -15.0, 0.0) glBegin(GL_TRIANGLES) glColor3f(1.0, 0.0, 0.0) glVertex2f(0.0, 0.0) glColor3f(0.0, 1.0, 0.0) glVertex2f(30.0, 0.0) glColor3f(0.0, 0.0, 1.0) glVertex2f(0.0, 30.0) glEnd glFlush
end
reshape = lambda do |width, height|
glViewport(0, 0, width, height) glMatrixMode(GL_PROJECTION) glLoadIdentity glOrtho(-30.0, 30.0, -30.0, 30.0, -30.0, 30.0) glMatrixMode(GL_MODELVIEW)
end
glutInit glutInitWindowSize(640, 480) glutCreateWindow("Triangle")
glutDisplayFunc(paint) glutReshapeFunc(reshape)
glutMainLoop</lang>
Scala
<lang Scala>import org.lwjgl.opengl.{ Display, DisplayMode } import org.lwjgl.opengl.GL11._
object OpenGlExample extends App {
def render() {
glClearColor(0.3f, 0.3f, 0.3f, 0.0f) glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
glShadeModel(GL_SMOOTH)
glLoadIdentity() glTranslatef(-15.0f, -15.0f, 0.0f)
glBegin(GL_TRIANGLES) glColor3f(1.0f, 0.0f, 0.0f) glVertex2f(0.0f, 0.0f) glColor3f(0.0f, 1.0f, 0.0f) glVertex2f(30f, 0.0f) glColor3f(0.0f, 0.0f, 1.0f) glVertex2f(0.0f, 30.0f) glEnd() }
Display.setDisplayMode(new DisplayMode(640, 480)) Display.create()
glMatrixMode(GL_PROJECTION) glLoadIdentity() glOrtho(-30, 30, -30, 30, -30, 30) glMatrixMode(GL_MODELVIEW)
while (!Display.isCloseRequested()) {
render()
Display.update()
Thread.sleep(1000)
}
}</lang>
Tcl
<lang Tcl>package require Tk package require tcl3d
proc resizedWin {win w h} {
glViewport 0 0 $w $h glMatrixMode GL_PROJECTION glLoadIdentity glOrtho -30.0 30.0 -30.0 30.0 -30.0 30.0 glMatrixMode GL_MODELVIEW
} proc paintShape {win} {
glClearColor 0.0 0.0 0.0 0.5
glClear [expr {$::GL_COLOR_BUFFER_BIT+$::GL_DEPTH_BUFFER_BIT}]
glShadeModel GL_SMOOTH
glLoadIdentity
glTranslatef -15.0 -15.0 0.0
glBegin GL_TRIANGLES
glColor3f 1.0 0.0 0.0
glVertex2f 5.0 5.0
glColor3f 0.0 1.0 0.0
glVertex2f 25.0 5.0
glColor3f 0.0 0.0 1.0
glVertex2f 5.0 25.0
glEnd
$win swapbuffers
}
togl .surface -width 640 -height 480 -double true -depth true \
-displayproc paintShape -reshapeproc resizedWin
pack .surface -fill both -expand 1</lang>Most of this code should be very familiar to anyone looking at the C version above, or with normal Tk applications.