glNormal(?)

OpenGL OpenGL: Basic Coding
1

Hi.
I have created two textured quads to act somewhat like a floor and ceiling like this

glBegin(GL_QUADS);
//TOP QUAD
glTexCoord2f(0,0); glVertex3f( 10.0f,0.9f, 0.0f); //BL
glTexCoord2f(1,0); glVertex3f(-10.0f,0.9f, 0.0f); //BR
glTexCoord2f(1,1); glVertex3f(-10.0f,0.9f,-20.0f); //TR
glTexCoord2f(0,1); glVertex3f( 10.0f,0.9f,-20.0f); //TL

//BOTTOM QUAD
glTexCoord2f(0,0); glVertex3f(-10.0f,-0.9f, 0.0f); //BL
glTexCoord2f(1,0); glVertex3f( 10.0f,-0.9f, 0.0f); //BR
glTexCoord2f(1,1); glVertex3f( 10.0f,-0.9f,-20.0f); //TR
glTexCoord2f(0,1); glVertex3f(-10.0f,-0.9f,-20.0f); //TL
glEnd();

now i dont know how to set the normals for them i have tried all kind of different settings but the light just turns out wierd or everything turns black

some help would be appriciated.

2

This tutorial explains this precisely: http://nehe.gamedev.net/tutorials/lesson07.asp

3

Well i have read the tutorial before and i thought i knew how to do it but i dosent work

i tohught my ceiling would have -y and the floor +y but this just turns out black

4

Maybe you should post the lighting setup code and the rendering code with normals.

5

//GLOBALS////////////////////////////////////
float LightAmbient[] = {0.5f, 0.5f, 0.5f, 1.0f};
float LightDiffuse[] = {1.0f, 1.0f, 1.0f, 1.0f};
float LightPosition[] = {0.0f, 0.0f,1.0f, 1.0f};

//INITGL/////////////////////////////////////
glLightfv(GL_LIGHT1,GL_AMBIENT,LightAmbient);
glLightfv(GL_LIGHT1,GL_DIFFUSE,LightDiffuse);
glLightfv(GL_LIGHT1,GL_POSITION,LightPosition);
glEnable(GL_LIGHT1);
glEnable(GL_LIGHTING);
glShadeModel(GL_SMOOTH);

//DRAW SCENE////////////////////////////////
glBegin(GL_QUADS);
//TOP QUAD
glNormal3f(0.0f,-1.0f,0.0f);
glTexCoord2f(0,0); glVertex3f( 10.0f,0.9f, 0.0f); //BL
glTexCoord2f(1,0); glVertex3f(-10.0f,0.9f, 0.0f); //BR
glTexCoord2f(1,1); glVertex3f(-10.0f,0.9f,-20.0f); //TR
glTexCoord2f(0,1); glVertex3f( 10.0f,0.9f,-20.0f); //TL

//BOTTOM QUAD
glNormal3f(0.0f,1.0f,0.0f);
glTexCoord2f(0,0); glVertex3f(-10.0f,-0.9f, 0.0f); //BL
glTexCoord2f(1,0); glVertex3f( 10.0f,-0.9f, 0.0f); //BR
glTexCoord2f(1,1); glVertex3f( 10.0f,-0.9f,-20.0f); //TR
glTexCoord2f(0,1); glVertex3f(-10.0f,-0.9f,-20.0f); //TL
glEnd();

6

I just can’t get it to work so i’ll post more of my code to see if anyone can help me

//GLOBALS
float LightAmbient[] = {0.5f, 0.5f, 0.5f, 1.0f};
float LightDiffuse[] = {1.0f, 1.0f, 1.0f, 1.0f};
float LightPosition[] = {0.0f, 0.0f,20.0f, 1.0f};

//INITGL
int InitGL(int w,int h)
{

glViewport(0, 0, w, h);

glClearColor(0.0f,0.0f,0.0f,0.5f);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();

gluPerspective(45.0f,(float)w/(float)h,1.0,100.0);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();

LoadGLTextures();
glEnable(GL_TEXTURE_2D);

glLightfv(GL_LIGHT1,GL_AMBIENT,LightAmbient);
glLightfv(GL_LIGHT1,GL_DIFFUSE,LightDiffuse);
glLightfv(GL_LIGHT1,GL_POSITION,LightPosition);
glEnable(GL_LIGHT1);
glEnable(GL_LIGHTING);
glShadeModel(GL_SMOOTH);

glClearDepth(1.0f);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);

glHint(GL_PERSPECTIVE_CORRECTION_HINT,GL_NICEST);

return TRUE;

}

//RENDERSCENE
int RenderGLScene()
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glLoadIdentity();

glBindTexture(GL_TEXTURE_2D,Texture[0]);

glBegin(GL_QUADS);
	//TOP QUAD
	glNormal3f(0.0f,-1.0f,0.0f);
	glTexCoord2f(0,0); glVertex3f( 10.0f,0.9f, 0.0f);	//BL
	glTexCoord2f(1,0); glVertex3f(-10.0f,0.9f, 0.0f);	//BR
	glTexCoord2f(1,1); glVertex3f(-10.0f,0.9f,-20.0f);	//TR
	glTexCoord2f(0,1); glVertex3f( 10.0f,0.9f,-20.0f);	//TL

	//BOTTOM QUAD
	glNormal3f(0.0f,1.0f,0.0f);
	glTexCoord2f(0,0); glVertex3f(-10.0f,-0.9f, 0.0f);	//BL
	glTexCoord2f(1,0); glVertex3f( 10.0f,-0.9f, 0.0f);	//BR
	glTexCoord2f(1,1); glVertex3f( 10.0f,-0.9f,-20.0f);	//TR
	glTexCoord2f(0,1); glVertex3f(-10.0f,-0.9f,-20.0f);	//TL
glEnd();

return TRUE;

}

7

Hi, are you seeing the textures when you turn
off lighting?
I tried your code and it works over here…

8

Yes I see the textures if i turn the light off.
The light shows up(but not correct)
if i set the normals to any x or z value its real strange