OpenGL drawing with lighting disabled loses its "depth" - c++

Question

Currently, I'm drawing a big room, and it's all good and pretty:
But, it's blue, so I figure, ok, I'll just disable lighting first, and then draw the room, re-enable it later, and it'll work out fine, right?
I suppose not... It loses its "depth" entirely.
Can I not simply do:
glDisable(GL_LIGHTING);
glColor3f(51/255.0, 25/255.0,0.0);
drawstuffhere
glEnable(GL_LIGHTING);
Or is this influenced by my initial lighting setup?
glClearColor(0.0, 0.0, 0.0, 0.0);
glEnable(GL_DEPTH_TEST); // Enable depth testing.
// Turn on OpenGL lighting.
glEnable(GL_LIGHTING);
// Light property vectors.
float lightAmb[] = { 0.0, 0.0, 0.0, 1.0 };
float lightDifAndSpec0[] = { 1.0, 1.0, 1.0, 1.0 };
float lightDifAndSpec1[] = { 1.0, 1.0, 0.0, 1.0 };
float globAmb[] = { 0.2, 0.2, 0.2, 1.0 };
// Light0 properties.
glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmb);
glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDifAndSpec0);
glLightfv(GL_LIGHT0, GL_SPECULAR, lightDifAndSpec0);
// Light1 properties.
glLightfv(GL_LIGHT1, GL_AMBIENT, lightAmb);
glLightfv(GL_LIGHT1, GL_DIFFUSE, lightDifAndSpec1);
glLightfv(GL_LIGHT1, GL_SPECULAR, lightDifAndSpec1);
glEnable(GL_LIGHT0); // Enable particular light source.
glEnable(GL_LIGHT1); // Enable particular light source.
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, globAmb); // Global ambient light.
glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_TRUE); // Enable local viewpoint
// Cull back faces.
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
EDIT: Source code: http://pastebin.com/DKGpWiFB
///////////////////////////////////////////////////////////////////////////////////////////
// main.cpp
//
///////////////////////////////////////////////////////////////////////////////////////////
#include <iostream>
#include <fstream>
#ifdef __APPLE__
# include <GLUT/glut.h>
#else
# include <GL/glut.h>
#endif
using namespace std;
//Structures
struct perspectives {
float ex,ey,ez,cx,cy,cz;
int x, y, z;
};
struct coordinates {
float x, y, z;
};
// Globals.
static float a = .1; // Blue ambient reflectance.
static float d = 1.0; // Blue diffuse reflectance.
static float s = 1.0; // White specular reflectance.
static float h = 50.0; // Shininess.
static float e = 0.0; // Blue emittance.
static float t = 0.0; // Quadratic attenuation factor.
static float zMove = 0.0; // z-direction component.
static char theStringBuffer[10]; // String buffer.
static long font = (long)GLUT_BITMAP_8_BY_13; // Font selection.
static bool cameraRotate = false;
struct perspectives camera = {0,0,12,0,0,0,0,1,0};
struct coordinates key = {0,0,11};
// Routine to draw a bitmap character string.
void writeBitmapString(void *font, char *string)
{
char *c;
for (c = string; *c != '\0'; c++) glutBitmapCharacter(font, *c);
}
// Routine to convert floating point to char string.
void floatToString(char * destStr, int precision, float val)
{
sprintf(destStr,"%f",val);
destStr[precision] = '\0';
}
//Routine to draw a ball of light
void drawMoon()
{//TODO
// Light position vectors.
float lightPos[] = { 3, 4, -.2, 1.0 };
glDisable(GL_LIGHTING);
// Light0 and its sphere positioned.
glPushMatrix();
glLightfv(GL_LIGHT1, GL_POSITION, lightPos);
glTranslatef(lightPos[0], lightPos[1], lightPos[2]);
glColor3f(1.0, 1.0, 1.0);
glutSolidSphere(2, 20, 20);
glPopMatrix();
glEnable(GL_LIGHTING);
}
//Routine to draw starry sky
void drawStars()
{
//TODO
}
void drawPumpkin()
{
//TODO
}
void drawKey()
{
//TODO
}
//Routine to draw walls
void drawWalls()
{
//glDisable(GL_LIGHTING);
glColor3f(51/255.0,25/255.0,0);
glPushMatrix();
//glRotatef(0,0,0,1);
glScalef(1,1,3);
glBegin(GL_QUADS);
/* Floor */
glVertex3f(-1,-1,-1);
glVertex3f(-1,-1,1);
glVertex3f(1,-1,1);
glVertex3f(1,-1,-1);
/* Ceiling */
glVertex3f(-1,1,-1);
glVertex3f(1,1,-1);
glVertex3f(1,1,1);
glVertex3f(-1,1,1);
/* Walls */
/* front outer */
/* left half */
glVertex3f(-1,-1,1);
glVertex3f(-.45,-1,1);
glVertex3f(-.45,1,1);
glVertex3f(-1,1,1);
/* right half */
glVertex3f(.45,-1,1);
glVertex3f(1,-1,1);
glVertex3f(1,1,1);
glVertex3f(.45,1,1);
/* top half */
glVertex3f(-1,.5,1);
glVertex3f(1,.5,1);
glVertex3f(1,1,1);
glVertex3f(-1,1,1);
/* end front outer */
/* front door */
//TODO
/* end front door */
/* back inner */
/* left half */
glVertex3f(-1,-1,-1);
glVertex3f(-.45,-1,-1);
glVertex3f(-.45,1,-1);
glVertex3f(-1,1,-1);
/* right half */
glVertex3f(.45,-1,-1);
glVertex3f(1,-1,-1);
glVertex3f(1,1,-1);
glVertex3f(.45,1,-1);
/* top half */
glVertex3f(-1,.5,-1);
glVertex3f(1,.5,-1);
glVertex3f(1,1,-1);
glVertex3f(-1,1,-1);
/* end inner */
glVertex3f(1,1,1);
glVertex3f(1,1,-1);
glVertex3f(1,-1,-1);
glVertex3f(1,-1,1);
glVertex3f(-1,1,1);
glVertex3f(-1,-1,1);
glVertex3f(-1,-1,-1);
glVertex3f(-1,1,-1);
glEnd();
glPopMatrix();
//glEnable(GL_LIGHTING);
}
void drawLight()
{
// Light position vectors.
float lightPos0[] = { 0.0, .75, -.5, 1.0 };
glDisable(GL_LIGHTING);
// Light0 and its sphere positioned.
glPushMatrix();
glLightfv(GL_LIGHT0, GL_POSITION, lightPos0);
glTranslatef(lightPos0[0], lightPos0[1], lightPos0[2]);
glColor3f(1.0, 1.0, 1.0);
glutWireSphere(0.05, 8, 8);
glPopMatrix();
glEnable(GL_LIGHTING);
}
// Initialization routine.
void setup(void)
{
//Set globals
a = 1- abs(camera.ez/15.0);
glClearColor(0.0, 0.0, 0.0, 0.0);
glEnable(GL_DEPTH_TEST); // Enable depth testing.
// Turn on OpenGL lighting.
glEnable(GL_LIGHTING);
// Light property vectors.
float lightAmb[] = { 0.0, 0.0, 0.0, 1.0 };
float lightDifAndSpec0[] = { 1.0, 1.0, 1.0, 1.0 };
float lightDifAndSpec1[] = { 1.0, 1.0, 0.0, 1.0 };
float globAmb[] = { 0.2, 0.2, 0.2, 1.0 };
// Light0 properties.
glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmb);
glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDifAndSpec0);
glLightfv(GL_LIGHT0, GL_SPECULAR, lightDifAndSpec0);
// Light1 properties.
glLightfv(GL_LIGHT1, GL_AMBIENT, lightAmb);
glLightfv(GL_LIGHT1, GL_DIFFUSE, lightDifAndSpec1);
glLightfv(GL_LIGHT1, GL_SPECULAR, lightDifAndSpec1);
glEnable(GL_LIGHT0); // Enable particular light source.
glEnable(GL_LIGHT1); // Enable particular light source.
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, globAmb); // Global ambient light.
glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_TRUE); // Enable local viewpoint
// Cull back faces.
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
}
// Drawing routine.
void drawScene()
{
// Material property vectors.
float matAmb[] = {0.0, 0.0, a, 1.0};
float matDif[] = {0.0, 0.0, d, 1.0};
float matSpec[] = { s, s, s, 1.0 };
float matShine[] = { h };
float matEmission[] = {0.0, 0.0, e, 1.0};
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
// Light quadratic attenuation factor.
glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, t);
glLightf(GL_LIGHT1, GL_QUADRATIC_ATTENUATION, t);
//gluLookAt(0.0, ey, ez, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
gluLookAt(camera.ex,camera.ey, camera.ez,
camera.cx,camera.cy,camera.cz,
camera.x,camera.y,camera.z);
//gluLookAt(0,0,0,0,0,0,0,1,0);
// Draw light source spheres after disabling lighting.
drawLight();
// Material properties of sphere.
glMaterialfv(GL_FRONT, GL_AMBIENT, matAmb);
glMaterialfv(GL_FRONT, GL_DIFFUSE, matDif);
glMaterialfv(GL_FRONT, GL_SPECULAR, matSpec);
glMaterialfv(GL_FRONT, GL_SHININESS, matShine);
glMaterialfv(GL_FRONT, GL_EMISSION, matEmission);
// Sphere.
glTranslatef(0.0, 0.0, zMove); // Move the sphere.
//glutSolidCube(1.5);
drawWalls();
drawMoon();
glutSwapBuffers();
}
// OpenGL window reshape routine.
void resize (int w, int h)
{
glViewport (0, 0, (GLsizei)w, (GLsizei)h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity();
gluPerspective(60.0, (float)w/(float)h, 1.0, 100.0);
glMatrixMode(GL_MODELVIEW);
}
// Keyboard input processing routine.
void keyInput(unsigned char key, int x, int y)
{
int mod = glutGetModifiers();
if (mod!=0)
{
switch(mod)
{
//Shift key
case 1 : cameraRotate=true; break;
//ALT key
case 4 : ; break;
mod = 0;
}
}
switch (key)
{
case 27:
exit(0);
break;
case 'a':
if (a > 0.0) a -= 0.05;
glutPostRedisplay();
break;
case 'A':
if (a < 1.0) a += 0.05;
glutPostRedisplay();
break;
case 'd':
if (d > 0.0) d -= 0.05;
glutPostRedisplay();
break;
case 'D':
if (d < 1.0) d += 0.05;
glutPostRedisplay();
break;
case 's':
if (s > 0.0) s -= 0.05;
glutPostRedisplay();
break;
case 'S':
if (s < 1.0) s += 0.05;
glutPostRedisplay();
break;
case 'e':
if (e > 0.0) e -= 0.05;
glutPostRedisplay();
break;
case 'E':
if (e < 1.0) e += 0.05;
glutPostRedisplay();
break;
case 'h':
if (h > 0.0) h -= 1.0;
glutPostRedisplay();
break;
case 'H':
if (h < 128.0) h += 1.0;
glutPostRedisplay();
break;
case 't':
if (t > 0.0) t -= 0.005;
glutPostRedisplay();
break;
case 'T':
t += 0.005;
glutPostRedisplay();
break;
default:
break;
}
}
// Callback routine for non-ASCII key entry.
void specialKeyInput(int key, int x, int y)
{
if (key == GLUT_KEY_UP){
if(camera.ez - .1 >= 0)
{camera.ez += -0.1;
camera.ex += 0;}
}
if (key == GLUT_KEY_DOWN){
camera.ez += 0.1;
camera.ex += 0;
}
if (key == GLUT_KEY_LEFT){
camera.cx -= .1;
}
if (key == GLUT_KEY_RIGHT){
camera.cx += .1;
}
printf("This is my ez %f\n", camera.ez);
a = 1- abs(camera.ez/5.0);
glutPostRedisplay();
}
// Routine to output interaction instructions to the C++ window.
void printInteraction(void)
{
}
// Main routine.
int main(int argc, char **argv)
{
printInteraction();
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize (600, 600);
glutInitWindowPosition (100, 100);
glutCreateWindow ("scaryRoom.cpp");
setup();
glutDisplayFunc(drawScene);
glutReshapeFunc(resize);
glutKeyboardFunc(keyInput);
glutSpecialFunc(specialKeyInput);
glutMainLoop();
return 0;
}

Answer 1

OpenGL is a state based drawing API. Once you've drawn something OpenGL doesn't remember it. Everything happens at the time of drawing, and if there's no lighting setup at the moment of drawing, that's it.
I have no idea why your room comes out blue; I'd have to see the full code for that. However I can give you the advice, that you should not try to "initialize" things at a certain time, and then "live" with that. OpenGL is a state machine, meant to have every attribute that matters being set right before you actually need it. So I suggest you move the lighting and color setup as close to the actual drawing as possible.
Update
You're setting material state in your drawScene function. Those will effect on everything drawn after setting those states until you change them. You intended them to affect only the sphere, but it will affect also the other stuff. Take note that glColor won't have an effect on illuminated drawing, unless you enable and set a so called color material state.
However I strongly suggest you don't bother with the arcane fixed function pipeline at all. You've run into a few pitfalls already :) I suggest you learn modern OpenGL, which also avoids all those weird peculiarities. A very good tutorial can be found at http://arcsynthesis.org/gltut