OpenGL function

Hey.
I just started out learning openGL and I am trying to make a function to make 3d cubes with + set their color.
However I ran into a little problem that I hope someone can help out with...now..I got this function :

Code:

void cube(char color1[256]) { glColor3f(color1[256]); (+ all the rest for the cube) }

The problem is that my compiler tells me that glColor3f takes 3 parrameters, wich is true, however i just want it to take one, the one my function takes.
Hope someone understand what I mean :)

try

Code:

void cube(unsigned int red, unsigned int blue, unsigned int green) { glColor3f(red, blue, green); }

you need to pass 3 rgb component values to get true color variation (at least i can't think of another way).

Getting a warning (or 3 warnings one for each color I guess) if I do that.. :

conversion from 'unsigned int' to 'float', possible loss of data

However, if I chose to compile and run it anyway it works.

well yea my bad try

Code:

void cube(unsigned float red, unsigned float blue, unsigned float green) { glColor3f(red, blue, green); }

unsigned (if you didn't know) makes it so the variable can only store positive values. anyway, then you'll want to pass values from 0.0 to 1.0 as normal, unless you set it so it excepts values from 1 to 256 (which i assumed you did b/c of the way you declared color[256]). but yeah, just use the above code and it should get rid of those errors.

hmmm several general things i was thinking of. for the box code you may want to try a slightly different approach.

Code:

void creatcorner(unsigned int red, unsigned int blue, unsigned int green, unsigned float cornerx, unsigned float cornery, unsigned float cornerz) { glColor3f(red, blue, green); glVertex3f(cornerx, cornery, cornerz); }

now you can just call this function 4 times to create a cube.

ah yes, very good idea.

But i am still getting a warrning when i try to use it.

"conversion from 'const double' to 'unsigned int', possible loss of data"

Quote:

Originally Posted by Oluf

ah yes, very good idea.

But i am still getting a warrning when i try to use it.

"conversion from 'const double' to 'unsigned int', possible loss of data"

when you use unsigned float it says the above?

sorry im running to my next class, be back in a couple hours lol

yep when I use the :

Code:

void creatcorner( unsigned int red, unsigned int blue, unsigned int green, unsigned float cornerx, unsigned float cornery, unsigned float cornerz) { glColor3f(red, blue, green); glVertex3f(cornerx, cornery, cornerz); }

And then try to create with :

Code:

creatcorner(1.0,0.0,0.0, 1,5,0);

I get the error on the line where I use the function.

Thanks a lot for helping me out, no way I would be able to figure this stuff out myself :)

glColor3fv

Wich does what?

Code:

glBegin(GL_QUADS); createcorner(1.0,0.0,0.0, 0,-5,0); createcorner(1.0,0.0,0.0, 0,7,0); createcorner(1.0,0.0,0.0, -1,7,0); createcorner(1.0,0.0,0.0, -1,-5,0); glEnd();

you have to put the function call inside a glBegin statement. I'm still really not sure how to get rid of the warnings...

Ah yeah of cuase :)

But, something is wrong (sorry, but I am new to this thing hehe)

If i try and copy the code you posted above and run then I just get a black screen, I tryed putting in an other color and make it an other place but still nothing

hmmmm where is your basecode coming from, nehe?

go ahead and post your entire code. ill bet your modelview matrix isn't showing the polygon.

Yep its from Nehe, but i made some edits in some of it.
As you can guess my entire code is kind of long, cant you explain what pit it is you think there is a bug in?

I guess its better to post it all....might be curz i messed around a bit with it all so :

Code:

/* * This Code Was Created By Jeff Molofee 2000 * A HUGE Thanks To Fredric Echols For Cleaning Up * And Optimizing The Base Code, Making It More Flexible! * If You've Found This Code Useful, Please Let Me Know. * Visit My Site At nehe.gamedev.net */ #include <windows.h> // Header File For Windows #include <gl\gl.h> // Header File For The OpenGL32 Library #include <gl\glu.h> // Header File For The GLu32 Library #include <gl\glaux.h> // Header File For The Glaux Library #include "functions.h" HDC hDC=NULL; // Private GDI Device Context HGLRC hRC=NULL; // Permanent Rendering Context HWND hWnd=NULL; // Holds Our Window Handle HINSTANCE hInstance; // Holds The Instance Of The Application bool keys[256]; // Array Used For The Keyboard Routine bool active=TRUE; // Window Active Flag Set To TRUE By Default bool fullscreen=TRUE; // Fullscreen Flag Set To Fullscreen Mode By Default double rotate1=1.0; GLfloat rtri; // Angle For The Triangle ( NEW ) GLfloat rquad; // Angle For The Quad ( NEW ) GLfloat rtriup; //up GLfloat rtridown; //Down GLfloat rtrileft; LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); // Declaration For WndProc GLvoid ReSizeGLScene(GLsizei width, GLsizei height) // Resize And Initialize The GL Window { if (height==0) // Prevent A Divide By Zero By { height=1; // Making Height Equal One } glViewport(0,0,width,height); // Reset The Current Viewport glMatrixMode(GL_PROJECTION); // Select The Projection Matrix glLoadIdentity(); // Reset The Projection Matrix // Calculate The Aspect Ratio Of The Window gluPerspective(45.0f,(GLfloat)width/(GLfloat)height,0.1f,100.0f); glMatrixMode(GL_MODELVIEW); // Select The Modelview Matrix glLoadIdentity(); // Reset The Modelview Matrix } int InitGL(GLvoid) // All Setup For OpenGL Goes Here { 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 return TRUE; // Initialization Went OK } //All the fun stuff go here <---------- int DrawGLScene(GLvoid) // Here's Where We Do All The Drawing { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear Screen And Depth Buffer glLoadIdentity(); // Reset The Current Modelview Matrix glTranslatef(-1.5f,0.0f,-6.0f); // Move Left 1.5 Units And Into The Screen 6.0 glRotatef(rtri,0.0f,1.0f,0.0f); // Rotate The Triangle On The Y axis ( NEW ) glRotatef(rtriup,1.0f,0.0f,0.0f); glRotatef(rtridown, -1.0f,0.0f,0.0f); glRotatef(rtrileft, 0.0f, -1.0f,0.0f); glBegin(GL_TRIANGLES); // Start Drawing A Triangle glColor3f(1.0f,0.0f,0.0f); // Red glVertex3f( 0.0f, 1.0f, 0.0f); // Top Of Triangle (Front) glColor3f(0.0f,1.0f,0.0f); // Green glVertex3f(-1.0f,-1.0f, 1.0f); // Left Of Triangle (Front) glColor3f(0.0f,0.0f,1.0f); // Blue glVertex3f( 1.0f,-1.0f, 1.0f); // Right Of Triangle (Front) glColor3f(1.0f,0.0f,0.0f); // Red glVertex3f( 0.0f, 1.0f, 0.0f); // Top Of Triangle (Right) glColor3f(0.0f,0.0f,1.0f); // Blue glVertex3f( 1.0f,-1.0f, 1.0f); // Left Of Triangle (Right) glColor3f(0.0f,1.0f,0.0f); // Green glVertex3f( 1.0f,-1.0f, -1.0f); // Right Of Triangle (Right) glColor3f(1.0f,0.0f,0.0f); // Red glVertex3f( 0.0f, 1.0f, 0.0f); // Top Of Triangle (Back) glColor3f(0.0f,1.0f,0.0f); // Green glVertex3f( 1.0f,-1.0f, -1.0f); // Left Of Triangle (Back) glColor3f(0.0f,0.0f,1.0f); // Blue glVertex3f(-1.0f,-1.0f, -1.0f); // Right Of Triangle (Back) glColor3f(1.0f,0.0f,0.0f); // Red glVertex3f( 0.0f, 1.0f, 0.0f); // Top Of Triangle (Left) glColor3f(0.0f,0.0f,1.0f); // Blue glVertex3f(-1.0f,-1.0f,-1.0f); // Left Of Triangle (Left) glColor3f(0.0f,1.0f,0.0f); // Green glVertex3f(-1.0f,-1.0f, 1.0f); // Right Of Triangle (Left) glEnd(); // Done Drawing The Pyramid glLoadIdentity(); // Reset The Current Modelview Matrix glTranslatef(1.5f,0.0f,-7.0f); // Move Right 1.5 Units And Into The Screen 7.0 glRotatef(rquad,1.0f,1.0f,1.0f); // Rotate The Quad On The X axis ( NEW ) glBegin(GL_QUADS); createcorner(1.0,0.0,0.0, 0,-5,0); createcorner(1.0,0.0,0.0, 0,7,0); createcorner(1.0,0.0,0.0, -2,7,0); createcorner(1.0,0.0,0.0, -2,-5,0); glEnd(); rquad-=0.15f; // Decrease The Rotation Variable For The Quad ( NEW ) return TRUE; // Keep Going } GLvoid KillGLWindow(GLvoid) // Properly Kill The Window { if (fullscreen) // Are We In Fullscreen Mode? { ChangeDisplaySettings(NULL,0); // If So Switch Back To The Desktop ShowCursor(TRUE); // Show Mouse Pointer } if (hRC) // Do We Have A Rendering Context? { if (!wglMakeCurrent(NULL,NULL)) // Are We Able To Release The DC And RC Contexts? { MessageBox(NULL,"Release Of DC And RC Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); } if (!wglDeleteContext(hRC)) // Are We Able To Delete The RC? { MessageBox(NULL,"Release Rendering Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); } hRC=NULL; // Set RC To NULL } if (hDC && !ReleaseDC(hWnd,hDC)) // Are We Able To Release The DC { MessageBox(NULL,"Release Device Context Failed.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); hDC=NULL; // Set DC To NULL } if (hWnd && !DestroyWindow(hWnd)) // Are We Able To Destroy The Window? { MessageBox(NULL,"Could Not Release hWnd.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); hWnd=NULL; // Set hWnd To NULL } if (!UnregisterClass("OpenGL",hInstance)) // Are We Able To Unregister Class { MessageBox(NULL,"Could Not Unregister Class.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); hInstance=NULL; // Set hInstance To NULL } } /* This Code Creates Our OpenGL Window. Parameters Are: * * title - Title To Appear At The Top Of The Window * * width - Width Of The GL Window Or Fullscreen Mode * * height - Height Of The GL Window Or Fullscreen Mode * * bits - Number Of Bits To Use For Color (8/16/24/32) * * fullscreenflag - Use Fullscreen Mode (TRUE) Or Windowed Mode (FALSE) */ BOOL CreateGLWindow(char* title, int width, int height, int bits, bool fullscreenflag) { GLuint PixelFormat; // Holds The Results After Searching For A Match WNDCLASS wc; // Windows Class Structure DWORD dwExStyle; // Window Extended Style DWORD dwStyle; // Window Style RECT WindowRect; // Grabs Rectangle Upper Left / Lower Right Values WindowRect.left=(long)0; // Set Left Value To 0 WindowRect.right=(long)width; // Set Right Value To Requested Width WindowRect.top=(long)0; // Set Top Value To 0 WindowRect.bottom=(long)height; // Set Bottom Value To Requested Height fullscreen=fullscreenflag; // Set The Global Fullscreen Flag hInstance = GetModuleHandle(NULL); // Grab An Instance For Our Window wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC; // Redraw On Size, And Own DC For Window. wc.lpfnWndProc = (WNDPROC) WndProc; // WndProc Handles Messages wc.cbClsExtra = 0; // No Extra Window Data wc.cbWndExtra = 0; // No Extra Window Data wc.hInstance = hInstance; // Set The Instance wc.hIcon = LoadIcon(NULL, IDI_WINLOGO); // Load The Default Icon wc.hCursor = LoadCursor(NULL, IDC_ARROW); // Load The Arrow Pointer wc.hbrBackground = NULL; // No Background Required For GL wc.lpszMenuName = NULL; // We Don't Want A Menu wc.lpszClassName = "OpenGL"; // Set The Class Name if (!RegisterClass(&wc)) // Attempt To Register The Window Class { MessageBox(NULL,"Failed To Register The Window Class.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } if (fullscreen) // Attempt Fullscreen Mode? { DEVMODE dmScreenSettings; // Device Mode memset(&dmScreenSettings,0,sizeof(dmScreenSettings)); // Makes Sure Memory's Cleared dmScreenSettings.dmSize=sizeof(dmScreenSettings); // Size Of The Devmode Structure dmScreenSettings.dmPelsWidth = width; // Selected Screen Width dmScreenSettings.dmPelsHeight = height; // Selected Screen Height dmScreenSettings.dmBitsPerPel = bits; // Selected Bits Per Pixel dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT; // Try To Set Selected Mode And Get Results. NOTE: CDS_FULLSCREEN Gets Rid Of Start Bar. if (ChangeDisplaySettings(&dmScreenSettings,CDS_FULLSCREEN)!=DISP_CHANGE_SUCCESSFUL) { // If The Mode Fails, Offer Two Options. Quit Or Use Windowed Mode. 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; // Windowed Mode Selected. Fullscreen = FALSE } else { // Pop Up A Message Box Letting User Know The Program Is Closing. MessageBox(NULL,"Program Will Now Close.","ERROR",MB_OK|MB_ICONSTOP); return FALSE; // Return FALSE } } } if (fullscreen) // Are We Still In Fullscreen Mode? { dwExStyle=WS_EX_APPWINDOW; // Window Extended Style dwStyle=WS_POPUP; // Windows Style ShowCursor(FALSE); // Hide Mouse Pointer } else { dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE; // Window Extended Style dwStyle=WS_OVERLAPPEDWINDOW; // Windows Style } AdjustWindowRectEx(&WindowRect, dwStyle, FALSE, dwExStyle); // Adjust Window To True Requested Size // Create The Window if (!(hWnd=CreateWindowEx( dwExStyle, // Extended Style For The Window "OpenGL", // Class Name title, // Window Title dwStyle | // Defined Window Style WS_CLIPSIBLINGS | // Required Window Style WS_CLIPCHILDREN, // Required Window Style 0, 0, // Window Position WindowRect.right-WindowRect.left, // Calculate Window Width WindowRect.bottom-WindowRect.top, // Calculate Window Height NULL, // No Parent Window NULL, // No Menu hInstance, // Instance NULL))) // Dont Pass Anything To WM_CREATE { KillGLWindow(); // Reset The Display MessageBox(NULL,"Window Creation Error.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } static PIXELFORMATDESCRIPTOR pfd= // pfd Tells Windows How We Want Things To Be { sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor 1, // Version Number PFD_DRAW_TO_WINDOW | // Format Must Support Window PFD_SUPPORT_OPENGL | // Format Must Support OpenGL PFD_DOUBLEBUFFER, // Must Support Double Buffering PFD_TYPE_RGBA, // Request An RGBA Format bits, // Select Our 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, // Accumulation Bits Ignored 16, // 16Bit Z-Buffer (Depth Buffer) 0, // No Stencil Buffer 0, // No Auxiliary Buffer PFD_MAIN_PLANE, // Main Drawing Layer 0, // Reserved 0, 0, 0 // Layer Masks Ignored }; if (!(hDC=GetDC(hWnd))) // Did We Get A Device Context? { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Create A GL Device Context.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } if (!(PixelFormat=ChoosePixelFormat(hDC,&pfd))) // Did Windows Find A Matching Pixel Format? { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Find A Suitable PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } if(!SetPixelFormat(hDC,PixelFormat,&pfd)) // Are We Able To Set The Pixel Format? { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Set The PixelFormat.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } if (!(hRC=wglCreateContext(hDC))) // Are We Able To Get A Rendering Context? { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Create A GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } if(!wglMakeCurrent(hDC,hRC)) // Try To Activate The Rendering Context { KillGLWindow(); // Reset The Display MessageBox(NULL,"Can't Activate The GL Rendering Context.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } ShowWindow(hWnd,SW_SHOW); // Show The Window SetForegroundWindow(hWnd); // Slightly Higher Priority SetFocus(hWnd); // Sets Keyboard Focus To The Window ReSizeGLScene(width, height); // Set Up Our Perspective GL Screen if (!InitGL()) // Initialize Our Newly Created GL Window { KillGLWindow(); // Reset The Display MessageBox(NULL,"Initialization Failed.","ERROR",MB_OK|MB_ICONEXCLAMATION); return FALSE; // Return FALSE } return TRUE; // Success } LRESULT CALLBACK WndProc( HWND hWnd, // Handle For This Window UINT uMsg, // Message For This Window WPARAM wParam, // Additional Message Information LPARAM lParam) // Additional Message Information { switch (uMsg) // Check For Windows Messages { case WM_ACTIVATE: // Watch For Window Activate Message { // LoWord Can Be WA_INACTIVE, WA_ACTIVE, WA_CLICKACTIVE, // The High-Order Word Specifies The Minimized State Of The Window Being Activated Or Deactivated. // A NonZero Value Indicates The Window Is Minimized. if ((LOWORD(wParam) != WA_INACTIVE) && !((BOOL)HIWORD(wParam))) active=TRUE; // Program Is Active else active=FALSE; // Program Is No Longer Active return 0; // Return To The Message Loop } case WM_SYSCOMMAND: // Intercept System Commands { switch (wParam) // Check System Calls { case SC_SCREENSAVE: // Screensaver Trying To Start? case SC_MONITORPOWER: // Monitor Trying To Enter Powersave? return 0; // Prevent From Happening } break; // Exit } case WM_CLOSE: // Did We Receive A Close Message? { PostQuitMessage(0); // Send A Quit Message return 0; // Jump Back } case WM_KEYDOWN: // Is A Key Being Held Down? { keys[wParam] = TRUE; // If So, Mark It As TRUE return 0; // Jump Back } case WM_KEYUP: // Has A Key Been Released? { keys[wParam] = FALSE; // If So, Mark It As FALSE return 0; // Jump Back } case WM_SIZE: // Resize The OpenGL Window { ReSizeGLScene(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height return 0; // Jump Back } } // Pass All Unhandled Messages To DefWindowProc return DefWindowProc(hWnd,uMsg,wParam,lParam); } int WINAPI WinMain( HINSTANCE hInstance, // Instance HINSTANCE hPrevInstance, // Previous Instance LPSTR lpCmdLine, // Command Line Parameters int nCmdShow) // Window Show State { MSG msg; // Windows Message Structure BOOL done=FALSE; // Bool Variable To Exit Loop // 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; // Windowed Mode } // Create Our OpenGL Window if (!CreateGLWindow("NeHe's Solid Object Tutorial",640,480,16,fullscreen)) { return 0; // Quit If Window Was Not Created } while(!done) // Loop That Runs While done=FALSE { if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is There A Message Waiting? { if (msg.message==WM_QUIT) // Have We Received A Quit Message? { done=TRUE; // If So done=TRUE } else // If Not, Deal With Window Messages { TranslateMessage(&msg); // Translate The Message DispatchMessage(&msg); // Dispatch The Message } } else // If There Are No Messages { // Draw The Scene. Watch For ESC Key And Quit Messages From DrawGLScene() if ((active && !DrawGLScene()) || keys[VK_ESCAPE]) // Active? Was There A Quit Received? { done=TRUE; // ESC or DrawGLScene Signalled A Quit } else // Not Time To Quit, Update Screen { SwapBuffers(hDC); // Swap Buffers (Double Buffering) } if (keys[VK_F1]) // Is F1 Being Pressed? { keys[VK_F1]=FALSE; // If So Make Key FALSE KillGLWindow(); // Kill Our Current Window fullscreen=!fullscreen; // Toggle Fullscreen / Windowed Mode // Recreate Our OpenGL Window if (!CreateGLWindow("NeHe's Solid Object Tutorial",640,480,16,fullscreen)) { return 0; // Quit If Window Was Not Created } } if (keys[VK_RIGHT]) { rtri=rtri++; } if (keys[VK_UP]) { rtriup+= 1.0f; } if (keys[VK_DOWN]) { rtridown-=-1.0f; } if (keys[VK_LEFT]) { rtrileft++; } } } // Shutdown KillGLWindow(); // Kill The Window return (msg.wParam); // Exit The Program }

Quote:

Wich does what?

check out:
msdn.microsoft.com

im not going to solve this problem for you

Of curz not silvercord :)

I just had no idea that you could check opengl stuff on msdn. thanks i will have a look for it right now

oops, I didn't know that you didnt' know :)

but now you do. I use msdn a lot.

damn...pointers...I hate them...however I know they are useful :)

This is what you mean I should be looking for right silver?

Code:

void glColor3fv( const GLfloat *v );

I know you want me to think myself (And I want to think for myself hehe) But I dont really get what this *v is a pointer too. Tryed a few things but its not really working....

Your "quad" has constant x and constant y values. ie.) its not a quad, your drawing four co-linear points.

the *v is the starting memory address of three floating point values that represent the x y and z coordinates of a single vertex in 3d space. you need to call glVertex3fv four times when you draw the quad