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View Full Version : Light not apearing?



colinisinhere
07-15-2002, 03:49 PM
I want a light in the middle of that square and i want it to stay there when i move the camera... but why wont it apear where i put it?



#include <windows.h>
#include <gl\gl.h>
#include <gl\glu.h>
#include <gl\glaux.h>

HDC hDC=NULL;
HGLRC hRC=NULL;
HWND hWnd=NULL;
HINSTANCE hInstance;

bool keys[256];
bool active=TRUE;
bool fullscreen=TRUE;

GLfloat yrot;

GLfloat tranx;

GLfloat LightAmbient[]= { 0.3f, 0.3f, 0.3f, 1.0f };
GLfloat LightDiffuse[]= { 0.8f, 1.0f, 0.8f, 1.0f };
GLfloat LightPosition[]= { 0.0f, 2.0f, 0.0f, 1.0f };

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

GLvoid ReSizeGLScene(GLsizei width, GLsizei height)
{
if (height==0)
{
height=1;
}

glViewport(0,0,width,height);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();

// Calculate The Aspect Ratio Of The Window
gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

int InitGL(GLvoid)
{
glShadeModel(GL_SMOOTH);
glClearColor(0.0f, 0.0f, 0.2f, 0.5f);
glClearDepth(1.0f);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmbient);
glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDiffuse);
glLightfv(GL_LIGHT1, GL_POSITION,LightPosition);
glEnable(GL_LIGHT1);
glEnable(GL_LIGHTING);
return TRUE;
}

int DrawGLScene(GLvoid)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt(0.0f, 3.0f, -40.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f);

glBegin(GL_QUADS);
glVertex3f(-20.0f, -1.0f, -20.0f);
glVertex3f(-20.0f, -1.0f, 20.0f);
glVertex3f(20.0f, -1.0f, 20.0f);
glVertex3f(20.0f, -1.0f, -20.0f);
glEnd();
yrot += 5.0f;
if (keys[VK_RIGHT])
{
yrot += 5.0f;
}

if (keys[VK_LEFT])
{
yrot -= 5.0f;
}
if (keys[VK_UP])
{
tranx -= 2.0f;
}

return TRUE;
}

GLvoid KillGLWindow(GLvoid)
{
if (fullscreen)
{
ChangeDisplaySettings(NULL,0);
ShowCursor(TRUE);
}

if (hRC)
{
if (!wglMakeCurrent(NULL,NULL))
{
MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
}

if (!wglDeleteContext(hRC))
{
MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
}
hRC=NULL;
}

if (hDC &amp;&amp; !ReleaseDC(hWnd,hDC))
{
MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hDC=NULL;
}

if (hWnd &amp;&amp; !DestroyWindow(hWnd))
{
MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hWnd=NULL;
}

if (!UnregisterClass("OpenGL",hInstance))
{
MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION);
hInstance=NULL;
}
}


BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag)
{
GLuint PixelFormat;
WNDCLASS wc;
DWORD dwExStyle;
DWORD dwStyle;
RECT WindowRect;
WindowRect.left=(long)0;
WindowRect.right=(long)width;
WindowRect.top=(long)0;
WindowRect.bottom=(long)height;

fullscreen=fullscreenflag;

hInstance = GetModuleHandle(NULL);
wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
wc.lpfnWndProc = (WNDPROC) WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = NULL;
wc.lpszMenuName = NULL;
wc.lpszClassName = "OpenGL";

if (!RegisterClass(&amp;wc))
{
MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

if (fullscreen)
{
DEVMODE dmScreenSettings;
memset(&amp;dmScreenSettings,0,sizeof(dmScreenSettings ));
dmScreenSettings.dmSize=sizeof(dmScreenSettings);
dmScreenSettings.dmPelsWidth = width;
dmScreenSettings.dmPelsHeight = height;
dmScreenSettings.dmBitsPerPel = bits;
dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWID TH|DM_PELSHEIGHT;


if (ChangeDisplaySettings(&amp;dmScreenSettings,CDS_FULLS CREEN)!=DISP_CHANGE_SUCCESSFUL)
{

if (MessageBox(NULL,"The Requested Fullscreen Mode Is Not Supported By\nYour Video Card. Use Windowed Mode Instead?","NeHe GL",MB_YESNO|MB_ICONEXCLAMATION)==IDYES)
{
fullscreen=FALSE;
}
else
{

MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP);
return FALSE;
}
}
}

if (fullscreen)
{
dwExStyle=WS_EX_APPWINDOW;
dwStyle=WS_POPUP;
ShowCursor(FALSE);
}
else
{
dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;
dwStyle=WS_OVERLAPPEDWINDOW;
}

AdjustWindowRectEx(&amp;WindowRect, dwStyle, FALSE, dwExStyle);

// Create The Window
if (!(hWnd=CreateWindowEx( dwExStyle,
"OpenGL",
title,
dwStyle |
WS_CLIPSIBLINGS |
WS_CLIPCHILDREN,
0, 0,
WindowRect.right-WindowRect.left,
WindowRect.bottom-WindowRect.top,
NULL,
NULL,
hInstance,
NULL)))
{
KillGLWindow();
MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

static PIXELFORMATDESCRIPTOR pfd=
{
sizeof(PIXELFORMATDESCRIPTOR),
1,
PFD_DRAW_TO_WINDOW |
PFD_SUPPORT_OPENGL |
PFD_DOUBLEBUFFER,
PFD_TYPE_RGBA,
bits,
0, 0, 0, 0, 0, 0,
0,
0,
0,
0, 0, 0, 0,
16,
0,
0,
PFD_MAIN_PLANE,
0,
0, 0, 0
};

if (!(hDC=GetDC(hWnd)))
{
KillGLWindow();
MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

if (!(PixelFormat=ChoosePixelFormat(hDC,&amp;pfd)))
{
KillGLWindow();
MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

if(!SetPixelFormat(hDC,PixelFormat,&amp;pfd))
{
KillGLWindow();
MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

if (!(hRC=wglCreateContext(hDC)))
{
KillGLWindow();
MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

if(!wglMakeCurrent(hDC,hRC))
{
KillGLWindow();
MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

ShowWindow(hWnd,SW_SHOW);
SetForegroundWindow(hWnd);
SetFocus(hWnd);
ReSizeGLScene(width, height);

if (!InitGL())
{
KillGLWindow();
MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

return TRUE;
}

LRESULT CALLBACK WndProc( HWND hWnd,
UINT uMsg,
WPARAM wParam,
LPARAM lParam)
{
switch (uMsg)
{
case WM_ACTIVATE:
{
if (!HIWORD(wParam))
{
active=TRUE;
}
else
{
active=FALSE;
}

return 0;
}

case WM_SYSCOMMAND:
{
switch (wParam)
{
case SC_SCREENSAVE:
case SC_MONITORPOWER:
return 0;
}
break;
}

case WM_CLOSE:
{
PostQuitMessage(0);
return 0;
}

case WM_KEYDOWN:
{
keys[wParam] = TRUE;
return 0;
}

case WM_KEYUP:
{
keys[wParam] = FALSE;
return 0;
}

case WM_SIZE:
{
ReSizeGLScene(LOWORD(lParam),HIWORD(lParam));
return 0;
}
}

// Pass All Unhandled Messages To DefWindowProc
return DefWindowProc(hWnd,uMsg,wParam,lParam);
}

int WINAPI WinMain( HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
MSG msg;
BOOL done=FALSE;

// Ask The User Which Screen Mode They Prefer
if (MessageBox(NULL,"Would You Like To Run In Fullscreen Mode?", "Start FullScreen?",MB_YESNO|MB_ICONQUESTION)==IDNO)
{
fullscreen=FALSE;
}

// Create Our OpenGL Window
if (!CreateGLWindow("NeHe's OpenGL Framework",640,480,16,fullscreen))
{
return 0;
}

while(!done)
{
if (PeekMessage(&amp;msg,NULL,0,0,PM_REMOVE))
{
if (msg.message==WM_QUIT)
{
done=TRUE;
}
else
{
TranslateMessage(&amp;msg);
DispatchMessage(&amp;msg);
}
}
else
{

if (active)
{
if (keys[VK_ESCAPE])
{
done=TRUE;
}
else
{
DrawGLScene();
SwapBuffers(hDC);
}
}

if (keys[VK_F1])
{
keys[VK_F1]=FALSE;
KillGLWindow();
fullscreen=!fullscreen;
// Recreate Our OpenGL Window
if (!CreateGLWindow("NeHe's OpenGL Framework",640,480,16,fullscreen))
{
return 0;
}
}
}
}

// Shutdown
KillGLWindow();
return (msg.wParam);
}

chowe6685
07-15-2002, 04:46 PM
Position the light each frame after you call glulookat

Deiussum
07-16-2002, 04:48 AM
You should also be aware that OpenGL lighting is a per-vertex operation. This means that the color of each vertex of a face will be computed based on how the light will affect that location, and then the color of the rest of the face is interpolated from those vertices.

So for example say you have a large quad, and the light shines in the center in such a way that none of the four vertices are affected by the light. In this example, you won't see any lighting effects at all.