I created a small scene in C and OpenGL. It is a plane with a small tunnel over it. I'm trying to move the OpenGL "camera" inside this tunnel. However, I've been having some difficult to configure perspective and the objects disapear as I translate the object (my idea was to rotate and translate the scene to enter the tunnel).
I'm trying not to use additional lybraies, such as GLUT.
Can someone help?
#include <windows.h>
#include <gl/gl.h>
#define sizeX 0.05f
#define sizeY 0.75f
#define incr 0.1
double xyz[3] = {0,0,0};
int op = 0;
void incrAxis(int v){
if(v != 0)
xyz[op] += incr;
else
xyz[op] -= incr;
printf("%f %f %f\n",xyz[0],xyz[1],xyz[2]);
}
void changeAxis(int v){
op = op + v;
if(op == 3)
op = 0;
else
if(op < 0)
op = 2;
}
void draw(){
double alt = -0.1;
glBegin(GL_QUADS);
glColor3f(0.5f, 0.5f, 0.5f); // black plane
glVertex3f( 0.275, 0.275, alt);
glVertex3f( 0.275,-0.275, alt);
glVertex3f(-0.275,-0.275, alt);
glVertex3f(-0.275, 0.275, alt);
glEnd();
glBegin(GL_QUADS);
glColor3f(1.0f, 1.0f, 1.0f); // plane
glVertex3f( 0.75, 0.75, 0.0f);
glVertex3f( 0.75,-0.75, 0.0f);
glVertex3f(-0.75,-0.75, 0.0f);
glVertex3f(-0.75, 0.75, 0.0f);
glEnd();
glBegin(GL_QUADS);
glColor3f(0.0f, 1.0f, 0.0f);
glVertex3f( sizeX, sizeY, -sizeX);
glVertex3f( sizeX,-sizeY, -sizeX);
glVertex3f(-sizeX,-sizeY, -sizeX);
glVertex3f(-sizeX, sizeY, -sizeX);
glEnd();
glBegin(GL_QUADS);
glColor3f(0.0f, 0.0f, 1.0f);
glVertex3f(-sizeX, -sizeY, 0.0f);
glVertex3f(-sizeX, -sizeY, -sizeX);
glVertex3f(-sizeX, sizeY, -sizeX);
glVertex3f(-sizeX, sizeY, 0.0f);
glEnd();
glBegin(GL_QUADS);
glColor3f(1.0f, 0.0f, 0.0f);
glVertex3f(sizeX, -sizeY, 0.0f);
glVertex3f(sizeX, -sizeY, -sizeX);
glVertex3f(sizeX, sizeY, -sizeX);
glVertex3f(sizeX, sizeY, 0.0f);
glEnd();
glBegin(GL_QUADS);
glColor3f(1.0f, 1.0f, 0.0f);
glVertex3f(-sizeX, sizeY, 0.0f);
glVertex3f(-sizeX, sizeY, -sizeX);
glVertex3f( sizeX, sizeY, -sizeX);
glVertex3f( sizeX, sizeY, 0.0f);
glEnd();
}
LRESULT CALLBACK WindowProc(HWND, UINT, WPARAM, LPARAM);
void EnableOpenGL(HWND hwnd, HDC*, HGLRC*);
void DisableOpenGL(HWND, HDC, HGLRC);
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
WNDCLASSEX wcex;
HWND hwnd;
HDC hDC;
HGLRC hRC;
MSG msg;
BOOL bQuit = FALSE;
/* register window class */
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_OWNDC;
wcex.lpfnWndProc = WindowProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = "GLSample";
wcex.hIconSm = LoadIcon(NULL, IDI_APPLICATION);;
if (!RegisterClassEx(&wcex))
return 0;
/* create main window */
hwnd = CreateWindowEx(0,
"GLSample",
"OpenGL Sample",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
512,
512,
NULL,
NULL,
hInstance,
NULL);
ShowWindow(hwnd, nCmdShow);
/* enable OpenGL for the window */
EnableOpenGL(hwnd, &hDC, &hRC);
/* program main loop */
while (!bQuit)
{
/* check for messages */
if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
/* handle or dispatch messages */
if (msg.message == WM_QUIT)
{
bQuit = TRUE;
}
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
else
{
/* OpenGL animation code goes here */
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glTranslatef(xyz[0],xyz[1],xyz[2]);
glRotatef(89, 1.0f, 0.0f, 0.0f);
glRotatef(50, 0.0f, 1.0f, 0.0f);
//glRotatef(5, 0.0f, 0.0f, 1.0f);
draw();
glPopMatrix();
SwapBuffers(hDC);
Sleep (1);
}
}
/* shutdown OpenGL */
DisableOpenGL(hwnd, hDC, hRC);
/* destroy the window explicitly */
DestroyWindow(hwnd);
return msg.wParam;
}
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_CLOSE:
PostQuitMessage(0);
break;
case WM_DESTROY:
return 0;
case WM_KEYDOWN:
{
switch (wParam)
{
case VK_ESCAPE:
PostQuitMessage(0);
break;
case VK_RIGHT:
changeAxis(+1);
break;
case VK_DOWN:
incrAxis(0);
break;
case VK_LEFT:
changeAxis(-1);
break;
case VK_UP:
incrAxis(1);
break;
}
}
break;
default:
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
return 0;
}
void EnableOpenGL(HWND hwnd, HDC* hDC, HGLRC* hRC)
{
PIXELFORMATDESCRIPTOR pfd;
int iFormat;
/* get the device context (DC) */
*hDC = GetDC(hwnd);
/* set the pixel format for the DC */
ZeroMemory(&pfd, sizeof(pfd));
pfd.nSize = sizeof(pfd);
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW |
PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 24;
pfd.cDepthBits = 16;
pfd.iLayerType = PFD_MAIN_PLANE;
iFormat = ChoosePixelFormat(*hDC, &pfd);
SetPixelFormat(*hDC, iFormat, &pfd);
/* create and enable the render context (RC) */
*hRC = wglCreateContext(*hDC);
wglMakeCurrent(*hDC, *hRC);
glShadeModel(GL_SMOOTH); // Enables Smooth Color Shading
glClearDepth(1.0); // Depth Buffer Setup
glEnable(GL_DEPTH_TEST); // Enables Depth Testing
glDepthFunc(GL_LESS); // The Type Of Depth Test To Do
glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);//Realy Nice perspective calculations
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum(-10, 10, -10, 10, -100, 100);
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
}
void DisableOpenGL (HWND hwnd, HDC hDC, HGLRC hRC)
{
wglMakeCurrent(NULL, NULL);
wglDeleteContext(hRC);
ReleaseDC(hwnd, hDC);
}
