Archived

This topic is now archived and is closed to further replies.

exa_einstein

OpenGL multi window with opengl

Recommended Posts

exa_einstein    122
I have created two windows, but my (simple... i hope) problem is to draw into them. Do we have some function to tell OpenGL to render INTO a particular window? (switch between more wnds) possible send HWND or HDC? how? please help, i have no idea...

Share this post


Link to post
Share on other sites
Wildfire    154
As far as I know OpenGL will always render into the window which is in the same thread. Don''t know of any parameters to pass... Never tried what happens if you have two windows in the same thread, but you could just create two threads, give each it''s own window and gl-commands?

Share this post


Link to post
Share on other sites
exa_einstein    122
no, I think that OpenGL library (=dll) is loaded only once for INSTANCE, threads are only using imported funcs.
idea (maybe helpful) what exactly does wglMakeCurrent() and wglCreateContext() and that third wgl_something_()? I never thought about them.

Share this post


Link to post
Share on other sites
Wildfire    154
quote:
from MSDN The wglMakeCurrent function makes a specified OpenGL rendering context the calling thread''s current rendering context. All subsequent OpenGL calls made by the thread are drawn on the device identified by hdc. You can also use wglMakeCurrent to change the calling thread''s current rendering context so it''s no longer current.

So, if you have two threads, each OpenGL call inside the thread will be made to the opengl rendering context of that thread. The other stuff is for creating a rendering context and binding it to a window.

Share this post


Link to post
Share on other sites
Xiachunyi    556
This should help, it renders 4 opengl screens each in an edit control in a dialogbox. Plus this is in Win32 API
What you can basically do with this is create windows within your window, get their DCs and Wiggles then render.

Main Source File

// windowopengl.cpp : Defines the entry point for the application.

//


#include "stdafx.h"
#include "resource.h"
#include <gl\glut.h>
#include <gl\gl.h>
#include <gl\glaux.h>

#define MAX_LOADSTRING 100

// Global Variables:

HINSTANCE hInst; // current instance

TCHAR szTitle[MAX_LOADSTRING]; // The title bar text

TCHAR szWindowClass[MAX_LOADSTRING]; // The title bar text

int TheEnd; // Flag used by thread to end

int xrot; // rotation


// Foward declarations of functions included in this code module:

ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK About(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK OpenGL(HWND, UINT, WPARAM, LPARAM);
DWORD WINAPI InitGL(HWND);
int MySetPixelFormat(HDC hdc);
void RenderScene(int);

int APIENTRY WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
// TODO: Place code here.

MSG msg;
HACCEL hAccelTable;

// Initialize global strings

LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadString(hInstance, IDC_WINDOWOPENGL, szWindowClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);

// Perform application initialization:

if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}

hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_WINDOWOPENGL);

// Main message loop:

while (GetMessage(&msg, NULL, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}

return msg.wParam;
}



//

// FUNCTION: MyRegisterClass()

//

// PURPOSE: Registers the window class.

//

// COMMENTS:

//

// This function and its usage is only necessary if you want this code

// to be compatible with Win32 systems prior to the 'RegisterClassEx'

// function that was added to Windows 95. It is important to call this function

// so that the application will get 'well formed' small icons associated

// with it.

//

ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEX wcex;

wcex.cbSize = sizeof(WNDCLASSEX);

wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = (WNDPROC)WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, (LPCTSTR)IDI_WINDOWOPENGL);
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = (LPCSTR)IDC_WINDOWOPENGL;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL);

return RegisterClassEx(&wcex);
}

//

// FUNCTION: InitInstance(HANDLE, int)

//

// PURPOSE: Saves instance handle and creates main window

//

// COMMENTS:

//

// In this function, we save the instance handle in a global variable and

// create and display the main program window.

//

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
HWND hWnd;

hInst = hInstance; // Store instance handle in our global variable


hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

if (!hWnd)
{
return FALSE;
}

ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);

return TRUE;
}

//

// FUNCTION: WndProc(HWND, unsigned, WORD, LONG)

//

// PURPOSE: Processes messages for the main window.

//

// WM_COMMAND - process the application menu

// WM_PAINT - Paint the main window

// WM_DESTROY - post a quit message and return

//

//

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
int wmId, wmEvent;
PAINTSTRUCT ps;
HDC hdc;
TCHAR szHello[MAX_LOADSTRING];
LoadString(hInst, IDS_HELLO, szHello, MAX_LOADSTRING);

switch (message)
{
case WM_COMMAND:
wmId = LOWORD(wParam);
wmEvent = HIWORD(wParam);
// Parse the menu selections:

switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
case IDM_OPENGL:
DialogBox(hInst, (LPCTSTR)IDD_OPENGL, hWnd, (DLGPROC)OpenGL);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
break;
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code here...

RECT rt;
GetClientRect(hWnd, &rt);
DrawText(hdc, szHello, strlen(szHello), &rt, DT_CENTER);
EndPaint(hWnd, &ps);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}

// Mesage handler for about box.

LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_INITDIALOG:
return TRUE;

case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return TRUE;
}
break;
}
return FALSE;
}

// Mesage handler for OpenGL box.

LRESULT CALLBACK OpenGL(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
static HANDLE hOpenGL;
static DWORD lpThreadId;

switch (message)
{
case WM_INITDIALOG:
return TRUE;

case WM_COMMAND:
if (LOWORD(wParam) == IDOK)
{
TheEnd=1;
Sleep(500);
EndDialog(hDlg, LOWORD(wParam));
return TRUE;
}
if (LOWORD(wParam) == IDRENDER)
{

EnableWindow(GetDlgItem(hDlg,IDRENDER),FALSE);
hOpenGL=CreateThread(NULL,NULL,(LPTHREAD_START_ROUTINE)InitGL,hDlg,0,&lpThreadId);

}
break;
}
return FALSE;
}


// Here, we do the regular initialization of OpenGL

DWORD WINAPI InitGL(HWND hDlg)
{
HDC hDC1,hDC2,hDC3,hDC4;
HWND hEdit1,hEdit2,hEdit3,hEdit4;
HGLRC hglrc1,hglrc2,hglrc3,hglrc4;

// First, let's get the handle to all the window we created in the Dialog

// with the resource editor

hEdit1=GetDlgItem(hDlg,IDC_EDIT1);
hEdit2=GetDlgItem(hDlg,IDC_EDIT2);
hEdit3=GetDlgItem(hDlg,IDC_EDIT3);
hEdit4=GetDlgItem(hDlg,IDC_EDIT4);

// For every window, we get the HDC

hDC1=GetDC(hEdit1);
hDC2=GetDC(hEdit2);
hDC3=GetDC(hEdit3);
hDC4=GetDC(hEdit4);

// OpenGL Initialization

glShadeModel(GL_SMOOTH); // Enable Smooth Shading

glClearColor(0.0f, 0.0f, 0.0f, 0.5f); // Black Background

glClearDepth(1.0f); // Depth Buffer Setup

glEnable(GL_DEPTH_TEST); // Enables Depth Testing

glDepthFunc(GL_LEQUAL); // The Type Of Depth Testing To Do

glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // Really Nice Perspective Calculations


MySetPixelFormat(hDC1);
MySetPixelFormat(hDC2);
MySetPixelFormat(hDC3);
MySetPixelFormat(hDC4);

hglrc1 = wglCreateContext(hDC1);
hglrc2 = wglCreateContext(hDC2);
hglrc3 = wglCreateContext(hDC3);
hglrc4 = wglCreateContext(hDC4);

//render here

while(TheEnd !=1 )
{

// Select first Window as the rendering context and draw to it

wglMakeCurrent(hDC1, hglrc1);
RenderScene(1);
SwapBuffers(hDC1);

// Select second Window as the rendering context and draw to it

wglMakeCurrent(hDC2, hglrc2);
RenderScene(2);
SwapBuffers(hDC2);

// Select third Window as the rendering context and draw to it

wglMakeCurrent(hDC3, hglrc3);
RenderScene(2);
SwapBuffers(hDC3);

// Select fourth Window as the rendering context and draw to it

wglMakeCurrent(hDC4, hglrc4);
RenderScene(1);
SwapBuffers(hDC4);

// Throttle the loop. If we don't put a sleep here, the thread will use 100% cpu

Sleep(1);
}

wglMakeCurrent(NULL, NULL);

// Cleanup

ReleaseDC (hDlg, hDC1) ;
ReleaseDC (hDlg, hDC2) ;
ReleaseDC (hDlg, hDC3) ;
ReleaseDC (hDlg, hDC4) ;

wglDeleteContext(hglrc1);
wglDeleteContext(hglrc2);
wglDeleteContext(hglrc3);
wglDeleteContext(hglrc4);

return TRUE;
}

// Set up the pixel format

int MySetPixelFormat(HDC hdc)
{


PIXELFORMATDESCRIPTOR pfd = {
sizeof(PIXELFORMATDESCRIPTOR), // size of this pfd

1, // version number

PFD_DRAW_TO_WINDOW | // support window

PFD_SUPPORT_OPENGL | // support OpenGL

PFD_DOUBLEBUFFER, // double buffered

PFD_TYPE_RGBA, // RGBA type

24, // 24-bit color depth

0, 0, 0, 0, 0, 0, // color bits ignored

0, // no alpha buffer

0, // shift bit ignored

0, // no accumulation buffer

0, 0, 0, 0, // accum bits ignored

32, // 32-bit z-buffer

0, // no stencil buffer

0, // no auxiliary buffer

PFD_MAIN_PLANE, // main layer

0, // reserved

0, 0, 0 // layer masks ignored

};

int iPixelFormat;

// get the device context's best, available pixel format match

if((iPixelFormat = ChoosePixelFormat(hdc, &pfd)) == 0)
{
MessageBox(NULL, "ChoosePixelFormat Failed", NULL, MB_OK);
return 0;
}

// make that match the device context's current pixel format

if(SetPixelFormat(hdc, iPixelFormat, &pfd) == FALSE)
{
MessageBox(NULL, "SetPixelFormat Failed", NULL, MB_OK);
return 0;
}

return 1;
}


// This is where we render, in this case, we will draw a simple 3D-Triangle

void RenderScene(int axis)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();

if(axis==1) glRotatef(xrot,1.0f,0.0f,0.0f);
if(axis==2) glRotatef(xrot,0.0f,1.0f,0.0f);

glBegin(GL_TRIANGLES);
glColor3f(1, 0, 0);
glVertex3f(0, 0.8f, 0); //top

glColor3f(0, 1, 0);
glVertex3f(-0.5, -0.5, 0.5); //left

glColor3f(0, 0,1);
glVertex3f(0.5, -0.5, 0.5); //right



glColor3f(1.0f,0.0f,0.0f); // Red

glVertex3f( 0.0f, 0.8f, 0.0f); // Top Of Triangle (Right)

glColor3f(0.0f,0.0f,1.0f); // Blue

glVertex3f( .5f,-.5f, .5f); // Left Of Triangle (Right)

glColor3f(0.0f,0.5f,0.0f); // Green

glVertex3f( 0.5f,-0.5f, -0.5f); // Right Of Triangle (Right)


glColor3f(1.0f,0.0f,0.0f); // Red

glVertex3f( 0.0f, 0.8f, 0.0f); // Top Of Triangle (Back)

glColor3f(0.0f,1.0f,0.0f); // Green

glVertex3f( 0.5f,-0.5f, -0.5f); // Left Of Triangle (Back)

glColor3f(0.0f,0.0f,1.0f); // Blue

glVertex3f(-0.5f,-0.5f, -0.5f); // Right Of Triangle (Back)


glColor3f(1.0f,0.0f,0.0f); // Red

glVertex3f( 0.0f, 0.8f, 0.0f); // Top Of Triangle (Left)

glColor3f(0.0f,0.0f,1.0f); // Blue

glVertex3f(-0.5f,-0.5f,-0.5f); // Left Of Triangle (Left)

glColor3f(0.0f,1.0f,0.0f); // Green

glVertex3f(-0.5f,-0.5f, 0.5f); // Right Of Triangle (Left)


glEnd();

xrot+=1.5f;

}


Resource ID file

//{{NO_DEPENDENCIES}}

// Microsoft Developer Studio generated include file.

// Used by windowopengl.rc

//

#define IDC_MYICON 2
#define IDD_WINDOWOPENGL_DIALOG 102
#define IDD_ABOUTBOX 103
#define IDS_APP_TITLE 103
#define IDM_ABOUT 104
#define IDM_EXIT 105
#define IDS_HELLO 106
#define IDI_WINDOWOPENGL 107
#define IDI_SMALL 108
#define IDC_WINDOWOPENGL 109
#define IDR_MAINFRAME 128
#define IDD_OPENGL 129
#define IDC_EDIT1 1000
#define IDRENDER 1001
#define IDC_EDIT2 1002
#define IDC_EDIT3 1003
#define IDC_EDIT4 1004
#define IDM_OPENGL 32771
#define IDC_STATIC -1

// Next default values for new objects

//

#ifdef APSTUDIO_INVOKED
#ifndef APSTUDIO_READONLY_SYMBOLS
#define _APS_NEXT_RESOURCE_VALUE 130
#define _APS_NEXT_COMMAND_VALUE 32772
#define _APS_NEXT_CONTROL_VALUE 1002
#define _APS_NEXT_SYMED_VALUE 110
#endif
#endif


Resource File

//Microsoft Developer Studio generated resource script.

//

#include "resource.h"

#define APSTUDIO_READONLY_SYMBOLS
/////////////////////////////////////////////////////////////////////////////

//

// Generated from the TEXTINCLUDE 2 resource.

//

#define APSTUDIO_HIDDEN_SYMBOLS
#include "windows.h"
#undef APSTUDIO_HIDDEN_SYMBOLS
#include "resource.h"

/////////////////////////////////////////////////////////////////////////////

#undef APSTUDIO_READONLY_SYMBOLS

/////////////////////////////////////////////////////////////////////////////

// English (U.S.) resources


#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
#ifdef _WIN32
LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
#pragma code_page(1252)
#endif //_WIN32


/////////////////////////////////////////////////////////////////////////////

//

// Icon

//


// Icon with lowest ID value placed first to ensure application icon

// remains consistent on all systems.

IDI_WINDOWOPENGL ICON DISCARDABLE "windowopengl.ICO"
IDI_SMALL ICON DISCARDABLE "SMALL.ICO"

/////////////////////////////////////////////////////////////////////////////

//

// Menu

//


IDC_WINDOWOPENGL MENU DISCARDABLE
BEGIN
POPUP "&File"
BEGIN
MENUITEM "E&xit", IDM_EXIT
END
MENUITEM "&OpenGL", IDM_OPENGL
POPUP "&Help"
BEGIN
MENUITEM "&About ...", IDM_ABOUT
END
END


/////////////////////////////////////////////////////////////////////////////

//

// Accelerator

//


IDC_WINDOWOPENGL ACCELERATORS MOVEABLE PURE
BEGIN
"?", IDM_ABOUT, ASCII, ALT
"/", IDM_ABOUT, ASCII, ALT
END


/////////////////////////////////////////////////////////////////////////////

//

// Dialog

//


IDD_ABOUTBOX DIALOG DISCARDABLE 22, 17, 230, 75
STYLE DS_MODALFRAME | WS_CAPTION | WS_SYSMENU
CAPTION "About"
FONT 8, "System"
BEGIN
ICON IDI_WINDOWOPENGL,IDC_MYICON,14,9,16,16
LTEXT "windowopengl Version 1.0",IDC_STATIC,49,10,119,8,
SS_NOPREFIX
LTEXT "Copyright (C) 2001",IDC_STATIC,49,20,119,8
DEFPUSHBUTTON "OK",IDOK,195,6,30,11,WS_GROUP
END

IDD_OPENGL DIALOG DISCARDABLE 0, 0, 304, 170
STYLE DS_MODALFRAME | WS_POPUP | WS_CAPTION | WS_SYSMENU
CAPTION "Window OpenGL example by Chong Hin Ooi, chongooi@mediaone.net"
FONT 8, "MS Sans Serif"
BEGIN
DEFPUSHBUTTON "Render",IDRENDER,190,149,50,14
PUSHBUTTON "OK",IDOK,247,149,50,14
EDITTEXT IDC_EDIT1,7,7,138,58,ES_AUTOHSCROLL
EDITTEXT IDC_EDIT2,159,7,138,58,ES_AUTOHSCROLL
EDITTEXT IDC_EDIT3,7,78,138,58,ES_AUTOHSCROLL
EDITTEXT IDC_EDIT4,159,78,138,58,ES_AUTOHSCROLL
END


#ifdef APSTUDIO_INVOKED
/////////////////////////////////////////////////////////////////////////////

//

// TEXTINCLUDE

//


2 TEXTINCLUDE DISCARDABLE
BEGIN
"#define APSTUDIO_HIDDEN_SYMBOLS\r\n"
"#include ""windows.h""\r\n"
"#undef APSTUDIO_HIDDEN_SYMBOLS\r\n"
"#include ""resource.h""\r\n"
"\0"
END

3 TEXTINCLUDE DISCARDABLE
BEGIN
"\r\n"
"\0"
END

1 TEXTINCLUDE DISCARDABLE
BEGIN
"resource.h\0"
END

#endif // APSTUDIO_INVOKED



/////////////////////////////////////////////////////////////////////////////

//

// DESIGNINFO

//


#ifdef APSTUDIO_INVOKED
GUIDELINES DESIGNINFO DISCARDABLE
BEGIN
IDD_OPENGL, DIALOG
BEGIN
LEFTMARGIN, 7
RIGHTMARGIN, 297
TOPMARGIN, 7
BOTTOMMARGIN, 163
END
END
#endif // APSTUDIO_INVOKED



/////////////////////////////////////////////////////////////////////////////

//

// String Table

//


STRINGTABLE DISCARDABLE
BEGIN
IDS_APP_TITLE "windowopengl"
IDS_HELLO "Window OpenGL example by Chong Hin Ooi"
IDC_WINDOWOPENGL "WINDOWOPENGL"
END

#endif // English (U.S.) resources

/////////////////////////////////////////////////////////////////////////////




#ifndef APSTUDIO_INVOKED
/////////////////////////////////////////////////////////////////////////////

//

// Generated from the TEXTINCLUDE 3 resource.

//



/////////////////////////////////////////////////////////////////////////////

#endif // not APSTUDIO_INVOKED




Hope that helps.
[edit] Misspelled a tag.

[edited by - Xiachunyi on August 11, 2003 11:59:02 AM]

Share this post


Link to post
Share on other sites
JesusFreak    122
Like the above poster''s example shows... Just create a new OpenGL context for each window and then use wglMakeCurrent and then swap the buffers and then repeat for each window.

Share this post


Link to post
Share on other sites
Dredge-Master    175
the above two are right. my last renderer used 9 windows (VCL)


OpenGL renders in the selected context in the current thread.

If you have two windows and only need to rendere in one of them at a time, create a context for both and then use wglmakecurrent to select which you wish to render in.

if you want to have both windows being rendered into at the same time, you can either swap the current context between the two (a bit dodgey, but hey, it works) or you can do it the better way and create a two threads. In each thread you have a seperate opengl thread that renders to one of the windows.

Either way, under win32 OpenGL always renders into the THREADS current device context.

I have no idea about macos or os2 or solaris or linux or dos though. I never played with opengl that much under them.

Share this post


Link to post
Share on other sites

  • Similar Content

    • By pseudomarvin
      I assumed that if a shader is computationally expensive then the execution is just slower. But running the following GLSL FS instead just crashes
      void main() { float x = 0; float y = 0; int sum = 0; for (float x = 0; x < 10; x += 0.00005) { for (float y = 0; y < 10; y += 0.00005) { sum++; } } fragColor = vec4(1, 1, 1 , 1.0); } with unhandled exception in nvoglv32.dll. Are there any hard limits on the number of steps/time that a shader can take before it is shut down? I was thinking about implementing some time intensive computation in shaders where it would take on the order of seconds to compute a frame, is that possible? Thanks.
    • By Arulbabu Donbosco
      There are studios selling applications which is just copying any 3Dgraphic content and regenerating into another new window. especially for CAVE Virtual reality experience. so that the user opens REvite or CAD or any other 3D applications and opens a model. then when the user selects the rendered window the VR application copies the 3D model information from the OpenGL window. 
      I got the clue that the VR application replaces the windows opengl32.dll file. how this is possible ... how can we copy the 3d content from the current OpenGL window.
      anyone, please help me .. how to go further... to create an application like VR CAVE. 
       
      Thanks
    • By cebugdev
      hi all,

      i am trying to build an OpenGL 2D GUI system, (yeah yeah, i know i should not be re inventing the wheel, but this is for educational and some other purpose only),
      i have built GUI system before using 2D systems such as that of HTML/JS canvas, but in 2D system, i can directly match a mouse coordinates to the actual graphic coordinates with additional computation for screen size/ratio/scale ofcourse.
      now i want to port it to OpenGL, i know that to render a 2D object in OpenGL we specify coordiantes in Clip space or use the orthographic projection, now heres what i need help about.
      1. what is the right way of rendering the GUI? is it thru drawing in clip space or switching to ortho projection?
      2. from screen coordinates (top left is 0,0 nd bottom right is width height), how can i map the mouse coordinates to OpenGL 2D so that mouse events such as button click works? In consideration ofcourse to the current screen/size dimension.
      3. when let say if the screen size/dimension is different, how to handle this? in my previous javascript 2D engine using canvas, i just have my working coordinates and then just perform the bitblk or copying my working canvas to screen canvas and scale the mouse coordinates from there, in OpenGL how to work on a multiple screen sizes (more like an OpenGL ES question).
      lastly, if you guys know any books, resources, links or tutorials that handle or discuss this, i found one with marekknows opengl game engine website but its not free,
      Just let me know. Did not have any luck finding resource in google for writing our own OpenGL GUI framework.
      IF there are no any available online, just let me know, what things do i need to look into for OpenGL and i will study them one by one to make it work.
      thank you, and looking forward to positive replies.
    • By fllwr0491
      I have a few beginner questions about tesselation that I really have no clue.
      The opengl wiki doesn't seem to talk anything about the details.
       
      What is the relationship between TCS layout out and TES layout in?
      How does the tesselator know how control points are organized?
          e.g. If TES input requests triangles, but TCS can output N vertices.
             What happens in this case?
      In this article,
      http://www.informit.com/articles/article.aspx?p=2120983
      the isoline example TCS out=4, but TES in=isoline.
      And gl_TessCoord is only a single one.
      So which ones are the control points?
      How are tesselator building primitives?
    • By Orella
      I've been developing a 2D Engine using SFML + ImGui.
      Here you can see an image
      The editor is rendered using ImGui and the scene window is a sf::RenderTexture where I draw the GameObjects and then is converted to ImGui::Image to render it in the editor.
      Now I need to create a 3D Engine during this year in my Bachelor Degree but using SDL2 + ImGui and I want to recreate what I did with the 2D Engine. 
      I've managed to render the editor like I did in the 2D Engine using this example that comes with ImGui. 
      3D Editor preview
      But I don't know how to create an equivalent of sf::RenderTexture in SDL2, so I can draw the 3D scene there and convert it to ImGui::Image to show it in the editor.
      If you can provide code will be better. And if you want me to provide any specific code tell me.
      Thanks!
  • Popular Now