OpenGL lighting appears to be clamping

Question

I'm experiencing an odd problem where everything placed in front of my light appears black in my scene. This happens on multiple axes. I've searched the depths of the internet to find a solution, but I can't seem to find anything. It's also important to note that this is only happening to my models; the model's normals are fine and dandy. The rest of the scene renders as expected...

Here's how it looks:

Here's how my light is initialized:

GLfloat light_ambient[] =
{ 0.2, 0.2, 0.2, 1.0 };
GLfloat light_diffuse[] =
{ 0.8, 0.8, 0.8, 1.0 };
GLfloat light_specular[] =
{ 1.0, 1.0, 1.0, 1.0 };
GLfloat light_position[] =
{ 15.0, 11.0, 10.0, 1.0 };

glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);

glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.4);
glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.1);
glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, 0.0);

glEnable(GL_LIGHT0);
glEnable(GL_LIGHTING);

Here's how my light's position is set:

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(60, (double)g_window1Width / g_window1Height, 1.0, 300.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslated(0.0, 0.0, -player.camera.Dist);
glRotated(player.camera.Angle-90, 1.0, 0.0, 0.0);
glRotated(player.camera.Rot, 0.0, 0.0, 1.0);
glTranslated(-player.camera.TgtX, player.camera.TgtY, -player.camera.TgtZ);
glScaled(1.0, -1.0, 1.0);
glEnable(GL_POLYGON_OFFSET_LINE);
glPolygonOffset(g_offset[0], g_offset[1]);

glClearColor(0.0, 0.0, 0.0, 0.0);
glClearStencil(0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

glm::vec4 light_position;
light_position.x = player.mouseMapPos.x - 1;
light_position.y = player.mouseMapPos.y - 1;
light_position.z = player.mouseMapPos.z + 0.5;
light_position.w = 1.0f;

glLightfv(GL_LIGHT0, GL_POSITION, glm::value_ptr(light_position));

I can supply more code and information as needed...

Answer 1

Your main issue is that you need to fix your normals. If you want to calculate smooth normals correctly please check my answers here and here. Also make sure that your normals are normalized.

Your second issue is your attenuation values, I often get better results with one attenuation type. So try to use one type of attenuation and try to modify its value until you get satisfactory results.

Answer 2

The normals facing away from the camera are shaded black in your setup.

Add more lights into the scene that are shining on parts you want lit up, or set up the lighting with a brighter minimum brightness.

Answer 3

This should be a comment but I cant make them :(.

Anyhow it looks like a normals problem with your model. If you look at the bottom flower in the first picture the lighting is wrong and it looks like the light is coming from behind and above the flower instead of in front it. Try to set the color of each pixel to the value of normal to see if the normals are correct. I do not know how to do this with the fixed pipeline unfortunately.

Answer 4

I'm not sure, but you probably should move code that sets color of light to update frame. As I understand you initialize light color only once at start of program, but it needs to be updated each frame, in accordance with this question.