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OpenGL help a noobie please

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hi guys, im quite new to opengl and c++ and have been wanting to learn how to make 3d graphics for quite some time. i always wanted to go to university and study game programming but simply cant afford it. anyway long story short i wanted to understand c++/opengl better and found this bit of code for a rubiks cube on the net, ive been told its one of the easier ones to understand :(. its the only code i have found so far that i managed to compile on my computer but the author has no comments. if anyone could put some comments on it for me that would be amazing. thank u in advance, even if u just take a few minutes to help. #include "GL/glut.h" #include "stdlib.h" #include <cmath> #define UP '1' #define DOWN '2' #define LEFT '3' #define RIGHT '4' #define FRONT '5' #define BACK '6' #define UP2 'q' #define DOWN2 'w' #define LEFT2 'e' #define RIGHT2 'r' #define FRONT2 't' #define BACK2 'y' #define UP3 'a' #define DOWN3 's' #define LEFT3 'd' #define RIGHT3 'f' #define FRONT3 'g' #define BACK3 'h' #define SHUFFLE 's' #define CHANGEMOVE '\t' #define CHANGEMOVE2 '`' #define MAKEMOVE 13 //Enter #define MAKEMOVE2 8 //Backspace void OnSize(int x,int y); void OnDraw(); void OnChar(unsigned char k,int x,int y); void OnDrag(int,int); void OnClick(int,int,int,int); int dragstartx,dragstarty; double theta=.35; double phi=.25; double theta0,phi0; bool Shuffling; //bool MoveClick=false; //int mousex,mousey; int CurrentMove=0; class Matrix { public: double l[3][3]; //[row][column] }; class Vector3D { public: Vector3D():x(0),y(0),z(0){} double x,y,z; void MultiplyBy(Matrix m) { double xnew,ynew,znew; xnew=m.l[0][0]*x+m.l[1][0]*y+m.l[2][0]*z; ynew=m.l[0][1]*x+m.l[1][1]*y+m.l[2][1]*z; znew=m.l[0][2]*x+m.l[1][2]*y+m.l[2][2]*z; x=xnew;y=ynew;z=znew; } Vector3D& operator+=(Vector3D p){x+=p.x;y+=p.y;z+=p.z;return *this;} }; class Face { public: void Draw() { glColor3d(r,g,b); glBegin(GL_QUADS); for(int n=0;n<4;++n) glVertex3d(v[n].x,v[n].y,v[n].z); glEnd(); } void MultiplyBy(Matrix m){for(int n=0;n<4;++n)v[n].MultiplyBy(m);} Vector3D Centre() { Vector3D ret; for(int n=0;n<4;++n) ret+=v[n]; return ret; } double r,g,b; Vector3D v[4]; }; class Cube { public: void Draw(){for(int n=0;n<6;++n) face[n].Draw();} Vector3D Centre() { Vector3D ret; for(int n=0;n<6;++n) ret+=face[n].Centre(); return ret; } void MultiplyBy(Matrix m){for(int n=0;n<6;++n)face[n].MultiplyBy(m);} Face face[6]; }; class Rubiks { public: void Reset() { for(int n=0;n<27;++n) { int xi=n%3-1; int yi=((n-xi)/3)%3-1; int zi=((n-xi)/3)/3-1; double x=xi*1.1; double y=yi*1.1; double z=zi*1.1; //Appologies for the intense ugliness of this bit.... cube[n].face[0].r=.8; cube[n].face[0].g=cube[n].face[0].b=0; cube[n].face[0].v[0].x=x-.5; cube[n].face[0].v[0].y=y-.5; cube[n].face[0].v[0].z=z-.5; cube[n].face[0].v[1].x=x+.5; cube[n].face[0].v[1].y=y-.5; cube[n].face[0].v[1].z=z-.5; cube[n].face[0].v[2].x=x+.5; cube[n].face[0].v[2].y=y+.5; cube[n].face[0].v[2].z=z-.5; cube[n].face[0].v[3].x=x-.5; cube[n].face[0].v[3].y=y+.5; cube[n].face[0].v[3].z=z-.5; cube[n].face[1].r=1; cube[n].face[1].g=.75; cube[n].face[1].b=0; cube[n].face[1].v[0].x=x-.5; cube[n].face[1].v[0].y=y-.5; cube[n].face[1].v[0].z=z+.5; cube[n].face[1].v[1].x=x+.5; cube[n].face[1].v[1].y=y-.5; cube[n].face[1].v[1].z=z+.5; cube[n].face[1].v[2].x=x+.5; cube[n].face[1].v[2].y=y+.5; cube[n].face[1].v[2].z=z+.5; cube[n].face[1].v[3].x=x-.5; cube[n].face[1].v[3].y=y+.5; cube[n].face[1].v[3].z=z+.5; cube[n].face[2].r=cube[n].face[2].b=cube[n].face[2].g=.9; cube[n].face[2].v[0].x=x-.5; cube[n].face[2].v[0].y=y-.5; cube[n].face[2].v[0].z=z-.5; cube[n].face[2].v[1].x=x-.5; cube[n].face[2].v[1].y=y-.5; cube[n].face[2].v[1].z=z+.5; cube[n].face[2].v[2].x=x-.5; cube[n].face[2].v[2].y=y+.5; cube[n].face[2].v[2].z=z+.5; cube[n].face[2].v[3].x=x-.5; cube[n].face[2].v[3].y=y+.5; cube[n].face[2].v[3].z=z-.5; cube[n].face[3].r=cube[n].face[3].g=.95; cube[n].face[3].b=0; cube[n].face[3].v[0].x=x+.5; cube[n].face[3].v[0].y=y-.5; cube[n].face[3].v[0].z=z-.5; cube[n].face[3].v[1].x=x+.5; cube[n].face[3].v[1].y=y-.5; cube[n].face[3].v[1].z=z+.5; cube[n].face[3].v[2].x=x+.5; cube[n].face[3].v[2].y=y+.5; cube[n].face[3].v[2].z=z+.5; cube[n].face[3].v[3].x=x+.5; cube[n].face[3].v[3].y=y+.5; cube[n].face[3].v[3].z=z-.5; cube[n].face[4].b=1; cube[n].face[4].r=cube[n].face[4].g=0; cube[n].face[4].v[0].x=x-.5; cube[n].face[4].v[0].y=y-.5; cube[n].face[4].v[0].z=z-.5; cube[n].face[4].v[1].x=x-.5; cube[n].face[4].v[1].y=y-.5; cube[n].face[4].v[1].z=z+.5; cube[n].face[4].v[2].x=x+.5; cube[n].face[4].v[2].y=y-.5; cube[n].face[4].v[2].z=z+.5; cube[n].face[4].v[3].x=x+.5; cube[n].face[4].v[3].y=y-.5; cube[n].face[4].v[3].z=z-.5; cube[n].face[5].g=.6; cube[n].face[5].b=cube[n].face[5].r=0; cube[n].face[5].v[0].x=x-.5; cube[n].face[5].v[0].y=y+.5; cube[n].face[5].v[0].z=z-.5; cube[n].face[5].v[1].x=x-.5; cube[n].face[5].v[1].y=y+.5; cube[n].face[5].v[1].z=z+.5; cube[n].face[5].v[2].x=x+.5; cube[n].face[5].v[2].y=y+.5; cube[n].face[5].v[2].z=z+.5; cube[n].face[5].v[3].x=x+.5; cube[n].face[5].v[3].y=y+.5; cube[n].face[5].v[3].z=z-.5; for(int f=0;f<6;++f) for(int v=0;v<4;++v) if(fabs(cube[n].face[f].v[v].x)<1 && fabs(cube[n].face[f].v[v].y)<1 && fabs(cube[n].face[f].v[v].z)<1) cube[n].face[f].r=cube[n].face[f].g=cube[n].face[f].b=0; } } void Draw() { for(int n=0;n<27;++n) cube[n].Draw(); } void Shuffle() { Shuffling=true; for(int n=0;n<100;++n) { int r=rand()%6; char k; if(r==0) k=UP; if(r==1) k=DOWN; if(r==2) k=LEFT; if(r==3) k=RIGHT; if(r==4) k=FRONT; if(r==5) k=BACK; MakeMove(k,true); } Shuffling=false; } void MakeMove(char k,bool fast) { Matrix m; for(int x=0;x<3;++x) for(int y=0;y<3;++y) m.l[x][y]=0; double ang=fast?3.14159265/10.0:3.14159265/50.0; switch(k) { case(LEFT): case(LEFT2): case(LEFT3): m.l[0][0]=1; m.l[1][1]=cos(ang); m.l[1][2]=sin(ang); m.l[2][1]=-sin(ang); m.l[2][2]=cos(ang); break; case(RIGHT): case(RIGHT2): case(RIGHT3): m.l[0][0]=1; m.l[1][1]=cos(ang); m.l[1][2]=-sin(ang); m.l[2][1]=sin(ang); m.l[2][2]=cos(ang); break; case(UP): case(UP2): case(UP3): m.l[2][2]=1; m.l[0][0]=cos(ang); m.l[0][1]=-sin(ang); m.l[1][0]=sin(ang); m.l[1][1]=cos(ang); break; case(DOWN): case(DOWN2): case(DOWN3): m.l[2][2]=1; m.l[0][0]=cos(ang); m.l[0][1]=sin(ang); m.l[1][0]=-sin(ang); m.l[1][1]=cos(ang); break; case(FRONT): case(FRONT2): case(FRONT3): m.l[1][1]=1; m.l[0][0]=cos(ang); m.l[0][2]=sin(ang); m.l[2][0]=-sin(ang); m.l[2][2]=cos(ang); break; case(BACK): case(BACK2): case(BACK3): m.l[1][1]=1; m.l[0][0]=cos(ang); m.l[0][2]=-sin(ang); m.l[2][0]=sin(ang); m.l[2][2]=cos(ang); break; } long t0=glutGet(GLUT_ELAPSED_TIME); for(int t=0;t<(fast?5:25);++t) { for(int n=0;n<27;++n) switch(k) { case(LEFT): case(RIGHT3): if(cube[n].Centre().x<-1) cube[n].MultiplyBy(m); break; case(RIGHT): case(LEFT3): if(cube[n].Centre().x>+1) cube[n].MultiplyBy(m); break; case(LEFT2): case(RIGHT2): if(cube[n].Centre().x>-1 && cube[n].Centre().x<+1) cube[n].MultiplyBy(m); break; case(UP): case(DOWN3): if(cube[n].Centre().z>+1) cube[n].MultiplyBy(m); break; case(DOWN): case(UP3): if(cube[n].Centre().z<-1) cube[n].MultiplyBy(m); break; case(UP2): case(DOWN2): if(cube[n].Centre().z<+1 && cube[n].Centre().z>-1) cube[n].MultiplyBy(m); break; case(FRONT): case(BACK3): if(cube[n].Centre().y<-1) cube[n].MultiplyBy(m); break; case(BACK): case(FRONT3): if(cube[n].Centre().y>+1) cube[n].MultiplyBy(m); break; case(FRONT2): case(BACK2): if(cube[n].Centre().y<+1 && cube[n].Centre().y>-1) cube[n].MultiplyBy(m); break; } OnDraw(); while(glutGet(GLUT_ELAPSED_TIME)<t0+t*10); } } Cube cube[27]; } RCube; int main(int argc,char** argv) { glutInit(&argc,argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB); glutInitWindowSize(500,500); glutCreateWindow("Rubik's Cube"); glutReshapeFunc(OnSize); glutDisplayFunc(OnDraw); glutKeyboardFunc(OnChar); glutMotionFunc(OnDrag); glutMouseFunc(OnClick); RCube.Reset(); glutMainLoop(); return 0; } void OnSize(int x,int y) { if(x!=500 || y!=500) { glutReshapeWindow(500,500); return; } glViewport(0,0,x,y); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45,1,1,100); glMatrixMode(GL_MODELVIEW); glEnable(GL_DEPTH_TEST); // glDrawBufffer(GL_BACK); } void OnDraw() { glClearColor(.75,.75,.75,0); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); gluLookAt(7*sin(phi)*cos(theta),-7*cos(phi)*cos(theta),7*sin(theta),0,0,0,0,0,1); glPushMatrix(); glLineWidth(3); glColor3d(0,0,0); if(CurrentMove<3) { glScaled(1.1,3.6,3.6); glTranslated(CurrentMove-1,0,0); glBegin(GL_LINES); glVertex3d(0,-.25,.6); //Little pointy arrows glVertex3d(0,+.25,.6); glVertex3d(0,-.25,.6); glVertex3d(.1,-.15,.6); glVertex3d(0,-.25,.6); glVertex3d(-.1,-.15,.6); glVertex3d(0,-.25,-.6); glVertex3d(0,+.25,-.6); glVertex3d(0,+.25,-.6); glVertex3d(.1,+.15,-.6); glVertex3d(0,+.25,-.6); glVertex3d(-.1,+.15,-.6); glVertex3d(0,.6,-.25); glVertex3d(0,.6,+.25); glVertex3d(0,.6,+.25); glVertex3d(.1,.6,+.15); glVertex3d(0,.6,+.25); glVertex3d(-.1,.6,+.15); glVertex3d(0,-.6,-.25); glVertex3d(0,-.6,+.25); glVertex3d(0,-.6,-.25); glVertex3d(.1,-.6,-.15); glVertex3d(0,-.6,-.25); glVertex3d(-.1,-.6,-.15); glEnd(); } if(CurrentMove>=3 && CurrentMove<6) { glScaled(3.6,1.1,3.6); glTranslated(0,CurrentMove-4,0); glBegin(GL_LINES); glVertex3d(-.25,0,.6); //Little pointy arrows glVertex3d(+.25,0,.6); glVertex3d(-.25,0,.6); glVertex3d(-.15,.1,.6); glVertex3d(-.25,0,.6); glVertex3d(-.15,-.1,.6); glVertex3d(-.25,0,-.6); glVertex3d(+.25,0,-.6); glVertex3d(+.25,0,-.6); glVertex3d(+.15,.1,-.6); glVertex3d(+.25,0,-.6); glVertex3d(+.15,-.1,-.6); glVertex3d(.6,0,-.25); glVertex3d(.6,0,+.25); glVertex3d(.6,0,+.25); glVertex3d(.6,.1,+.15); glVertex3d(.6,0,+.25); glVertex3d(.6,-.1,+.15); glVertex3d(-.6,0,-.25); glVertex3d(-.6,0,+.25); glVertex3d(-.6,0,-.25); glVertex3d(-.6,.1,-.15); glVertex3d(-.6,0,-.25); glVertex3d(-.6,-.1,-.15); glEnd(); } if(CurrentMove>=6) { glScaled(3.6,3.6,1.1); glTranslated(0,0,CurrentMove-7); glBegin(GL_LINES); glVertex3d(-.25,.6,0); //Little pointy arrows glVertex3d(+.25,.6,0); glVertex3d(-.25,.6,0); glVertex3d(-.15,.6,.1); glVertex3d(-.25,.6,0); glVertex3d(-.15,.6,-.1); glVertex3d(-.25,-.6,0); glVertex3d(+.25,-.6,0); glVertex3d(+.25,-.6,0); glVertex3d(+.15,-.6,.1); glVertex3d(+.25,-.6,0); glVertex3d(+.15,-.6,-.1); glVertex3d(.6,-.25,0); glVertex3d(.6,+.25,0); glVertex3d(.6,+.25,0); glVertex3d(.6,+.15,.1); glVertex3d(.6,+.25,0); glVertex3d(.6,+.15,-.1); glVertex3d(-.6,-.25,0); glVertex3d(-.6,+.25,0); glVertex3d(-.6,-.25,0); glVertex3d(-.6,-.15,.1); glVertex3d(-.6,-.25,0); glVertex3d(-.6,-.15,-.1); glEnd(); } glutWireCube(1); glPopMatrix(); RCube.Draw(); glutSwapBuffers(); } void OnChar(unsigned char k,int x,int y) { if(k==SHUFFLE){RCube.Shuffle();return;} if(k==CHANGEMOVE) { ++CurrentMove; CurrentMove%=9; glutPostRedisplay(); return; } if(k==CHANGEMOVE2) { --CurrentMove; if(CurrentMove<0) CurrentMove=8; glutPostRedisplay(); return; } if(k==MAKEMOVE) { if(CurrentMove==0) RCube.MakeMove(LEFT,false); if(CurrentMove==1) RCube.MakeMove(LEFT2,false); if(CurrentMove==2) RCube.MakeMove(LEFT3,false); if(CurrentMove==3) RCube.MakeMove(FRONT,false); if(CurrentMove==4) RCube.MakeMove(FRONT2,false); if(CurrentMove==5) RCube.MakeMove(FRONT3,false); if(CurrentMove==6) RCube.MakeMove(DOWN,false); if(CurrentMove==7) RCube.MakeMove(DOWN2,false); if(CurrentMove==8) RCube.MakeMove(DOWN3,false); return; } if(k==MAKEMOVE2) { if(CurrentMove==0) RCube.MakeMove(RIGHT3,false); if(CurrentMove==1) RCube.MakeMove(RIGHT2,false); if(CurrentMove==2) RCube.MakeMove(RIGHT,false); if(CurrentMove==3) RCube.MakeMove(BACK3,false); if(CurrentMove==4) RCube.MakeMove(BACK2,false); if(CurrentMove==5) RCube.MakeMove(BACK,false); if(CurrentMove==6) RCube.MakeMove(UP3,false); if(CurrentMove==7) RCube.MakeMove(UP2,false); if(CurrentMove==8) RCube.MakeMove(UP,false); return; } } void OnDrag(int x,int y) { theta=(y-dragstarty)/100.0+theta0; phi=(dragstartx-x)/50.0+phi0; if(theta<-1.57) theta=-1.57; if(theta>1.57) theta=1.57; glutPostRedisplay(); } void OnClick(int b,int s,int x,int y) { if(s==GLUT_DOWN) { theta0=theta; phi0=phi; dragstartx=x; dragstarty=y; } }

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Please post your source code inside source tags, but I doubt anybody here will comment this code for you:

(left brace)source(right brace)
...code goes here...

(left brace)/source(right brace)

I would start with something much simpler to understand. While not difficult this application is also not entry level. If you're not familiar with 3D coding, go to http://nehe.gamedev.net and run through all the tutorials, that should get up and running with openGL. If you're not familiar with C++ then there are several good tutorials on the net (some even on this site) to help you. The information is out there, you just need to find it and then work through it.

If you really want to go to university, don't let lack of money stop you. There are plenty of programs (at least in most countries) to help people go to school. Some you have to pay back, others you don't. My personal choice was work my ass off.

Cheers,

Bob

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I agree with Scourage, I'm afraid no-one here will just comment your code. However, I would urge you to go to University.

I see that you're based in London, the University of Westminster (where I went) does a fantastic Games Design & Programming degree, based in Harrow. In terms of the money you can get a student loan from the government to help pay for your tuition fees (£3000/year) and also get money towards your rent and food bills etc (I think, you can get about £5000/year).

Now after a 3 or 4 year degree this can mount up. However, you do not have to start paying this back until you are earning over £15,000 and they take 9% of your total gross earnings.

I would definitely encourage you to go to University to study it if you are serious about doing it.

Also, nehe.gamedev.net are good tutorials to get you started, however they are a bit dated. So as long s you bear that in mind, and just use to base your 3D graphics theory on then you should be well on your way.

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I would take the time to comment this for yourself. You'll learn as you go by having to explain each line of code, if even in 1 sentence. Consider this a good exercise. Also, you've picked a fairly sophisticated example to begin with. Try something simpler like a spinning cube.


Here's a Windows only example. See if you can figure it out and then move on to your example :

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

#define NON_REALTIME 0

char *className = "OpenGL";
char *windowName = "OpenGL Cube";
int winX = 0, winY = 0;
int winWidth = 300, winHeight = 300;

HDC hDC;
HGLRC hGLRC;
HPALETTE hPalette;

void init(void)
{
/* set viewing projection */
glMatrixMode(GL_PROJECTION);
glFrustum(-0.5F, 0.5F, -0.5F, 0.5F, 1.0F, 3.0F);

/* position viewer */
glMatrixMode(GL_MODELVIEW);
glTranslatef(0.0F, 0.0F, -2.0F);

/* position object */
glRotatef(30.0F, 1.0F, 0.0F, 0.0F);
glRotatef(30.0F, 0.0F, 1.0F, 0.0F);

glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
}

void redraw(void)
{
/* clear color and depth buffers */
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

/* draw six faces of a cube */
glBegin(GL_QUADS);
glNormal3f( 0.0F, 0.0F, 1.0F);
glVertex3f( 0.5F, 0.5F, 0.5F); glVertex3f(-0.5F, 0.5F, 0.5F);
glVertex3f(-0.5F,-0.5F, 0.5F); glVertex3f( 0.5F,-0.5F, 0.5F);

glNormal3f( 0.0F, 0.0F,-1.0F);
glVertex3f(-0.5F,-0.5F,-0.5F); glVertex3f(-0.5F, 0.5F,-0.5F);
glVertex3f( 0.5F, 0.5F,-0.5F); glVertex3f( 0.5F,-0.5F,-0.5F);

glNormal3f( 0.0F, 1.0F, 0.0F);
glVertex3f( 0.5F, 0.5F, 0.5F); glVertex3f( 0.5F, 0.5F,-0.5F);
glVertex3f(-0.5F, 0.5F,-0.5F); glVertex3f(-0.5F, 0.5F, 0.5F);

glNormal3f( 0.0F,-1.0F, 0.0F);
glVertex3f(-0.5F,-0.5F,-0.5F); glVertex3f( 0.5F,-0.5F,-0.5F);
glVertex3f( 0.5F,-0.5F, 0.5F); glVertex3f(-0.5F,-0.5F, 0.5F);

glNormal3f( 1.0F, 0.0F, 0.0F);
glVertex3f( 0.5F, 0.5F, 0.5F); glVertex3f( 0.5F,-0.5F, 0.5F);
glVertex3f( 0.5F,-0.5F,-0.5F); glVertex3f( 0.5F, 0.5F,-0.5F);

glNormal3f(-1.0F, 0.0F, 0.0F);
glVertex3f(-0.5F,-0.5F,-0.5F); glVertex3f(-0.5F,-0.5F, 0.5F);
glVertex3f(-0.5F, 0.5F, 0.5F); glVertex3f(-0.5F, 0.5F,-0.5F);
glEnd();

/* position object */
// glRotatef(1.0F, 1.0F, 0.0F, 0.0F);
// glRotatef(1.0F, 0.0F, 1.0F, 0.0F);

SwapBuffers(hDC);
}

void resize(void)
{
/* set viewport to cover the window */
glViewport(0, 0, winWidth, winHeight);
}

void setupPixelFormat(HDC hDC)
{
PIXELFORMATDESCRIPTOR pfd = {
sizeof(PIXELFORMATDESCRIPTOR), /* size */
1, /* version */
PFD_SUPPORT_OPENGL |
PFD_DRAW_TO_WINDOW |
PFD_DOUBLEBUFFER, /* support double-buffering */
PFD_TYPE_RGBA, /* color type */
16, /* prefered color depth */
0, 0, 0, 0, 0, 0, /* color bits (ignored) */
0, /* no alpha buffer */
0, /* alpha bits (ignored) */
0, /* no accumulation buffer */
0, 0, 0, 0, /* accum bits (ignored) */
16, /* depth buffer */
0, /* no stencil buffer */
0, /* no auxiliary buffers */
PFD_MAIN_PLANE, /* main layer */
0, /* reserved */
0, 0, 0, /* no layer, visible, damage masks */
};
int pixelFormat;

pixelFormat = ChoosePixelFormat(hDC, &pfd);
if (pixelFormat == 0)
{
MessageBox(WindowFromDC(hDC), "ChoosePixelFormat failed.", "Error",
MB_ICONERROR | MB_OK);
exit(1);
}

if (SetPixelFormat(hDC, pixelFormat, &pfd) != TRUE)
{
MessageBox(WindowFromDC(hDC), "SetPixelFormat failed.", "Error",
MB_ICONERROR | MB_OK);
exit(1);
}
}

void setupPalette(HDC hDC)
{
int pixelFormat = GetPixelFormat(hDC);
PIXELFORMATDESCRIPTOR pfd;
LOGPALETTE* pPal;
int paletteSize;

DescribePixelFormat(hDC, pixelFormat, sizeof(PIXELFORMATDESCRIPTOR), &pfd);

if (pfd.dwFlags & PFD_NEED_PALETTE)
{
paletteSize = 1 << pfd.cColorBits;
}
else
{
return;
}

pPal = (LOGPALETTE*)
malloc(sizeof(LOGPALETTE) + paletteSize * sizeof(PALETTEENTRY));
pPal->palVersion = 0x300;
pPal->palNumEntries = paletteSize;

/* build a simple RGB color palette */
{
int redMask = (1 << pfd.cRedBits) - 1;
int greenMask = (1 << pfd.cGreenBits) - 1;
int blueMask = (1 << pfd.cBlueBits) - 1;
int i;

for (i=0; i<paletteSize; ++i)
{
pPal->palPalEntry.peRed =
(((i >> pfd.cRedShift) & redMask) * 255) / redMask;
pPal->palPalEntry.peGreen =
(((i >> pfd.cGreenShift) & greenMask) * 255) / greenMask;
pPal->palPalEntry.peBlue =
(((i >> pfd.cBlueShift) & blueMask) * 255) / blueMask;
pPal->palPalEntry.peFlags = 0;
}
}

hPalette = CreatePalette(pPal);
free(pPal);

if (hPalette)
{
SelectPalette(hDC, hPalette, FALSE);
RealizePalette(hDC);
}
}

LRESULT APIENTRY WndProc (HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CREATE:
/* initialize OpenGL rendering */
hDC = GetDC(hWnd);
setupPixelFormat(hDC);
setupPalette(hDC);
hGLRC = wglCreateContext(hDC);
wglMakeCurrent(hDC, hGLRC);
init();
return 0;
case WM_DESTROY:
/* finish OpenGL rendering */
if (hGLRC)
{
wglMakeCurrent(NULL, NULL);
wglDeleteContext(hGLRC);
}
if (hPalette)
{
DeleteObject(hPalette);
}
ReleaseDC(hWnd, hDC);
PostQuitMessage(0);
return 0;
case WM_SIZE:
/* track window size changes */
if (hGLRC)
{
winWidth = (int) LOWORD(lParam);
winHeight = (int) HIWORD(lParam);
resize();
return 0;
}
case WM_PALETTECHANGED:
/* realize palette if this is *not* the current window */
if (hGLRC && hPalette && (HWND) wParam != hWnd)
{
UnrealizeObject(hPalette);
SelectPalette(hDC, hPalette, FALSE);
RealizePalette(hDC);
redraw();
break;
}
break;
case WM_QUERYNEWPALETTE:
/* realize palette if this is the current window */
if (hGLRC && hPalette)
{
UnrealizeObject(hPalette);
SelectPalette(hDC, hPalette, FALSE);
RealizePalette(hDC);
redraw();
return TRUE;
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
BeginPaint(hWnd, &ps);
if (hGLRC)
{
redraw();
}
EndPaint(hWnd, &ps);
return 0;
}
break;
case WM_CHAR:
/* handle keyboard input */
switch ((int)wParam)
{
case VK_ESCAPE:
DestroyWindow(hWnd);
return 0;
default:
break;
}
break;
default:
break;
}
return DefWindowProc(hWnd, message, wParam, lParam);
}

int APIENTRY WinMain(HINSTANCE hCurrentInst, HINSTANCE hPreviousInst, LPSTR lpszCmdLine, int nCmdShow)
{
WNDCLASS wndClass;
HWND hWnd;
MSG msg;

/* register window class */
wndClass.style = CS_OWNDC | CS_HREDRAW | CS_VREDRAW;
wndClass.lpfnWndProc = WndProc;
wndClass.cbClsExtra = 0;
wndClass.cbWndExtra = 0;
wndClass.hInstance = hCurrentInst;
wndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
wndClass.hbrBackground = (HBRUSH) GetStockObject(BLACK_BRUSH);
wndClass.lpszMenuName = NULL;
wndClass.lpszClassName = className;
RegisterClass(&wndClass);

/* create window */
hWnd = CreateWindow(
className, windowName,
WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN | WS_CLIPSIBLINGS,
winX, winY, winWidth, winHeight,
NULL, NULL, hCurrentInst, NULL);

/* display window */
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);

#if NON_REALTIME
/* process messages */
while (GetMessage(&msg, NULL, 0, 0) == TRUE)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
#else
while (1)
{
if (PeekMessage (&msg, NULL, 0, 0, PM_REMOVE))
{
if (msg.message == WM_QUIT)
break;

TranslateMessage(&msg);
DispatchMessage(&msg);
} /* end if PeekMessage (&msg, NULL, 0, 0, PM_REMOVE)) */

// Real time Main code start here
redraw ();
} /* end while (1) */

#endif
return msg.wParam;

}




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