Jump to content

  • Log In with Google      Sign In   
  • Create Account

Interested in a FREE copy of HTML5 game maker Construct 2?

We'll be giving away three Personal Edition licences in next Tuesday's GDNet Direct email newsletter!

Sign up from the right-hand sidebar on our homepage and read Tuesday's newsletter for details!


We're also offering banner ads on our site from just $5! 1. Details HERE. 2. GDNet+ Subscriptions HERE. 3. Ad upload HERE.


Need some suggestion about lighting and shading


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
6 replies to this topic

#1 jenny_wui   Members   -  Reputation: 196

Like
0Likes
Like

Posted 01 April 2013 - 02:13 PM

Hello, I have somehow built a model (partial) which looks like a stadium. I have attached the picture for your kind perusal. The field ground has been textured. Now for a particular position, my model looks too much lighted as you can see the far half of the seats look totally white. I am a bit new in modeling lighting. If I don't consider the specular parameter, my model looks dull and seats are not properly outlined. So I added some specular component of light and shininess to the model. But the far half of the model looks too much lighted. I found textured portion is unaffected by lighting. Could any one explain why?
Could any one suggest how can I adjust the lighting parameters so that model does not look too shiny and seats around the field are also properly outlined.

I am using simple OpenGL, no GLSL.

Thanks in advance to all.

Attached Thumbnails

  • image.png


Sponsor:

#2 GeneralQuery   Crossbones+   -  Reputation: 1263

Like
0Likes
Like

Posted 01 April 2013 - 02:24 PM

Show us the relevant code you're using so we can see your configuration.

Edited by GeneralQuery, 01 April 2013 - 02:25 PM.


#3 jenny_wui   Members   -  Reputation: 196

Like
0Likes
Like

Posted 01 April 2013 - 05:30 PM

void initGL(){

	static const GLfloat light_model_ambient[] = {1.0f, 1.0f, 1.0f, 1.0f};
	
	glLightModelfv(GL_LIGHT_MODEL_AMBIENT, light_model_ambient);
	 
	glShadeModel(GL_SMOOTH);
	glEnable(GL_DEPTH_TEST);
	

	float diffuse[]  = {1.0f, 1.0f, 1.0f, 1.0f};
	float position[] = {5.0f, 5.0f, 5.0f, 1.0f};
	float specular[] = {1.0f, 1.0f, 1.0f, 1.0f};

	glEnable(GL_LIGHTING);
	glEnable( GL_LIGHT0);
	glLightfv(GL_LIGHT0, GL_DIFFUSE,  diffuse);
	glLightfv(GL_LIGHT0, GL_POSITION, position);
	glLightfv(GL_LIGHT0, GL_SPECULAR, specular);

	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

	float shininess = 5.0f;
	glEnable(GL_COLOR_MATERIAL);
	glMaterialf( GL_FRONT_AND_BACK, GL_SHININESS, shininess);
       glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR,  specular);

	pTextureLoader->SetHighQualityTextures(TRUE);
	pTextureLoader->SetMipMapping(TRUE);
	pTextureLoader->SetTextureFilter(txTrilinear);
	pTextureLoader->LoadTextureFromDisk("grass.jpg", &m_MyLogoTexture);

}

void drawSceneGraphics()
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);           

	//Render the checked floor.
	glEnable(GL_BLEND);
	glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
	renderAll();
	
	glDisable(GL_BLEND);
}


void renderAll(){
	
	glPushMatrix();

      //Render the middle textured field

	glEnable(GL_TEXTURE_2D);   
	renderField(size);
	glDisable(GL_TEXTURE_2D);
	glPopMatrix();
				
	// Render track 1 (red color)
   
       glPushMatrix();
	renderTexturedTrack_1(size);
	glPopMatrix();

      // Render Track 2 (blue color)

	glPushMatrix();
	renderTexturedTrack_2(size);
       glPopMatrix();

      // Render seats

	glPushMatrix();
	drawModel();			
	glPopMatrix();

	return;
}


Thanks in advance to all.
void glutReshape(int width, int height)
{
	
	static const double kPI = 3.1415926535897932384626433832795;
	static const double kFovY = 45;

	double nearDist, farDist, aspect;
	

	width =  glutGet(GLUT_WINDOW_WIDTH);
	height = glutGet(GLUT_WINDOW_HEIGHT);

	


	if (width && height)
	{
		glViewport(0, 0, width, height);

		// Compute the viewing parameters based on a fixed fov and viewing
		// a canonical box centered at the origin.

		nearDist = 15.0 / tan((kFovY / 2.0) * kPI / 180.0);
		farDist = nearDist + 70.0;
		aspect = (double) width / height;

		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		gluPerspective(kFovY, aspect, 0.1, 140);

		// Place the camera down the Z axis looking at the origin.

		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();            
		
		gluLookAt(0, 25.0, nearDist + 35.0, 0, 0.0, 0, 0, 1, 0.0);
	

	}
}

I have attached some part of my code. Please provide me some suggestions so that I can fix the lighting parameters.

 

Thanks again in advance.



#4 GeneralQuery   Crossbones+   -  Reputation: 1263

Like
0Likes
Like

Posted 02 April 2013 - 03:16 AM

Your lighting terms don't look right. From a brief skim of your code:

Why is the ambient term at full intensity? It shouldn't be otherwise you have no dynamic range to work with (hence the washed out lighting). Try a lower value like 0.2f.

Your specular shininess is very broad. A low number such as the one you are using will wash out a lot of your model, especially with vertex lighting (which you are using). Try a higher value like 64.0f or 128.0f.

Your specular term is very bright. This may be contributing to your problem so try a lower value like 0.8f.

#5 jenny_wui   Members   -  Reputation: 196

Like
0Likes
Like

Posted 02 April 2013 - 10:04 AM

Hi, thank you very much for taking time to answer my question. As per your suggestion I have changed the lighting parameters as follows:

The attached picture is for a shininess value of 128.0f. Setting the value at 64.0f does not make much difference in output.

void initGL()
{
	static const GLfloat light_model_ambient[] = {0.2f, 0.2f, 0.2f, 1.0f};
	
	glLightModelfv(GL_LIGHT_MODEL_AMBIENT, light_model_ambient);
	 
	glShadeModel(GL_SMOOTH);
	glEnable(GL_DEPTH_TEST);

	float diffuse[]  = {1.0f, 1.0f, 1.0f, 1.0f};
	float position[] = {5.0f, 5.0f, 5.0f, 1.0f};
	float specular[] = {0.8f, 0.8f, 0.8f, 1.0f};

	glEnable(GL_LIGHTING);
	glEnable( GL_LIGHT0);
	glLightfv(GL_LIGHT0, GL_DIFFUSE,  diffuse);
	glLightfv(GL_LIGHT0, GL_POSITION, position);
	glLightfv(GL_LIGHT0, GL_SPECULAR, specular);

	glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

	float shininess = 128.0f;
	glEnable(GL_COLOR_MATERIAL);
	glMaterialf( GL_FRONT_AND_BACK, GL_SHININESS, shininess);
    glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR,  specular);


	pTextureLoader->SetHighQualityTextures(TRUE);
	pTextureLoader->SetMipMapping(TRUE);
	pTextureLoader->SetTextureFilter(txTrilinear);
	pTextureLoader->LoadTextureFromDisk("grass.jpg", &m_MyLogoTexture);

}

 

 

Could you suggest me what is going wrong with my code.

 

Thanks again an advance.

Attached Thumbnails

  • image1.png


#6 jenny_wui   Members   -  Reputation: 196

Like
0Likes
Like

Posted 02 April 2013 - 06:29 PM

I have been able to get better output by adding the following:

glEnable(GL_NORMALIZE);

 

Thank you for sharing ideas. But I have one question why textured portion remains unaffected by lighting?

 

Thanks again.



#7 Sik_the_hedgehog   Crossbones+   -  Reputation: 1811

Like
0Likes
Like

Posted 03 April 2013 - 08:11 AM

You probably have the textures set to decal instead of modulate.


Don't pay much attention to "the hedgehog" in my nick, it's just because "Sik" was already taken =/ By the way, Sik is pronounced like seek, not like sick.




Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS