Currently I am trying to illuminate an object with a light source and change the color of the object based on GL_COLOR_MATERIAL. For some reason, I am only able to see ONE light source being projected on to the model. I've tried various different positions and combination of light sources and I have noticed only GL_LIGHT0 functions.
I've also tried different combination of ambient/diffuse/materials with no success.
static const GLfloat ambient[4] = {0.1f, 0.1f, 0.1f, 1.0f};
static const GLfloat diffuse[4] = {0.5f, 1.0f, 1.0f, 1.0f};
static const GLfloat position0[4] = {0.0f, 0.0f, 20.0f, 0.0f};
static const GLfloat position1[4] = {0.0f, 0.0f, -20.0f, 0.0f};
static const GLfloat front_mat_shininess[1] = {60.0f};
static const GLfloat front_mat_specular[4] = {0.2f, 0.2f, 0.2f, 1.0f};
static const GLfloat front_mat_diffuse[4] = {0.5f, 0.28f, 0.38f, 1.0f};
static const GLfloat lmodel_ambient[4] = {1.0f, 1.0f, 1.0f, 1.0f};
static const GLfloat lmodel_twoside[1] = {GL_FALSE};
glDisable(GL_LIGHTING);
glDisable(GL_COLOR_MATERIAL);
///Enable lighting if item is a solid model
if(wireFlag == 1)
{
glEnable(GL_LIGHTING);
glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse);
glLightfv(GL_LIGHT0, GL_POSITION, position0);
glEnable(GL_LIGHT0);
glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
glLightfv(GL_LIGHT1, GL_POSITION, position1);
glEnable(GL_LIGHT1);
glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
glLightModelfv(GL_LIGHT_MODEL_TWO_SIDE, lmodel_twoside);
glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, front_mat_shininess);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, front_mat_specular);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, front_mat_diffuse);
glEnable(GL_DEPTH_TEST);
glEnable(GL_COLOR_MATERIAL);
}
Any help would be greatly appreciated!
There are several parameters (eg GL_DIFFUSE) which default to 0,0,0,0 for GL_LIGHT1 .. GL_LIGHT7 but something else (eg 1,1,1,1) for GL_LIGHT0. I don't know which one you've missed, but I bet you're relying on a default for both lights and it's "off" for GL_LIGHT1.
Related
I have a spotlight in my OpenGL project, the light currently shines down the -z axis like a ceiling light, towards the floor, which is just a big quad.
I currently have a cube at the origin of the light, that follows the light around, so I can see exactly where the light is at all times.
My problem is that there is another brighter spotlight that follows the main light, it starts at the origin, or the bottom left corner of the floor.
I'd like to remove this white light, as I don't know what's causing it, or how to remove it.
I have tried to play around with some of the variables and see their impact, but I've had little to no success.
Any assistance would be greatly appreciated.
The error:
//ceiling light
GLfloat Light_Ambient[] = { 1.0f, 1.0f, 1.0f, 1.0f };
GLfloat Light_Diffuse[] = { 0.0f, 0.0f, 0.0f, 1.0f };
GLfloat Light_Position[] = { Sun.X, Sun.Y, Sun.Z, 1.0f };
GLfloat Spot_Direction[] = { 0.0f, 0.0f, -1.0f };
//ambient
GLfloat Light_Ambient1[] = { 0.4f, 0.4f, 0.4f, 1.0f };
GLfloat Light_Diffuse1[] = { 1.0f, 1.0f, 1.0f, 0.0f };
GLfloat Light_Position1[] = { Sun.X, Sun.Y, Sun.Z, 1.0f };
//ceiling light
glLightfv(GL_LIGHT0, GL_AMBIENT, Light_Ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, Light_Diffuse);
glLightfv(GL_LIGHT0, GL_POSITION, Light_Position);
glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 55);
glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, Spot_Direction);
glLightf(GL_LIGHT0, GL_SPOT_EXPONENT, 5);
glEnable(GL_LIGHT0);
//ambient
glLightfv(GL_LIGHT1, GL_AMBIENT, Light_Ambient1);
glLightfv(GL_LIGHT1, GL_DIFFUSE, Light_Diffuse1);
glLightfv(GL_LIGHT1, GL_POSITION, Light_Position1);
glEnable(GL_LIGHT1);
I changed some things around and I seem to have solved it.
//ceiling light
GLfloat Light_Ambient[] = { 1.0f, 1.0f, 1.0f, 1.0f };
GLfloat Light_Diffuse[] = { 0.0f, 0.0f, 0.0f, 1.0f };
GLfloat Light_Position[] = { Sun.X, Sun.Y, Sun.Z, 1.0f };
GLfloat Spot_Direction[] = { 0.0f, 0.0f, -1.0f };
//ambient
GLfloat Light_Ambient1[] = { 0.6f, 0.6f, 0.6f, 1.0f };
GLfloat Light_Diffuse1[] = { 1.0f, 1.0f, 1.0f, 0.0f };
GLfloat Light_Position1[] = { 0, 0, 0, 0.0f };
//ceiling light
glLightfv(GL_LIGHT0, GL_AMBIENT, Light_Ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, Light_Diffuse);
glLightfv(GL_LIGHT0, GL_POSITION, Light_Position);
glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 55);
glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, Spot_Direction);
glLightf(GL_LIGHT0, GL_SPOT_EXPONENT, 20);
glEnable(GL_LIGHT0);
//ambient
glLightfv(GL_LIGHT1, GL_AMBIENT, Light_Ambient1);
glLightfv(GL_LIGHT1, GL_DIFFUSE, Light_Diffuse1);
glLightfv(GL_LIGHT1, GL_POSITION, Light_Position1);
glEnable(GL_LIGHT1);
UPDATE:
I'm returning to edit this months later simply because I feel that this answer may help a lot of people with OpenGL and this confusion with lights.
If your lights are broken (like mine were) there's actually a good chance there's nothing wrong with your lights at all, but how you're rendering the world. It's worthwhile to remember that opengl looks a little like this:
https://imgur.com/a/saYxy
What I was actually doing wrong, as you can see from my initial question i was convinced that the Z was the Y and the Y was the Z, and vice versa, this broke all of my lighting calculations back then. If your lights look like mine do, there's a good chance that you're confusing your axis, it isn't that hard to do this when moving from 2d to 3D opengl.
I have a problem with spotlight in OpenGL library. A scene is black, light is unseen if the GL_SPOT_CUTOFF is less than 125. I supposed that issue concerns direction of the light source but I have tried plenty of options both for position and direction of spotlight. Here is my code:
const GLfloat light_ambient[] = { 0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat light_diffuse[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
glPushMatrix();
glLoadIdentity();
GLfloat spot_direction[] = { 0.0, -1.0, 0.0 ,0.0};
GLfloat spot_position[] = { 1.0,1.0,0.0,1.0 };
glLightfv(GL_LIGHT1, GL_POSITION, spot_position);
glLightfv(GL_LIGHT1, GL_AMBIENT, light_ambient);
glLightfv(GL_LIGHT1, GL_DIFFUSE, light_diffuse);
glLightfv(GL_LIGHT1, GL_SPECULAR, light_specular);
glLightf(GL_LIGHT1, GL_SPOT_CUTOFF, 60);
glLightfv(GL_LIGHT1, GL_SPOT_DIRECTION, spot_direction);
glLightf(GL_LIGHT1, GL_SPOT_EXPONENT, 100);
glPopMatrix();
glEnable(GL_LIGHT1);
Solved. Problem was with too high GL_SPOT_EXPONENT factor (light was too much focused) and with direction of the light stream.
I have a problem when I draw a scaled (with glScale) gluSphere.
The Color changes after Scaling and the darker faces are not as dark as they should be...
This is how I set up the light:
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_COLOR_MATERIAL);
glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
GLfloat LAmbient[4] = {0.2f, 0.2f, 0.2f, 1.0};
GLfloat LDiffuse[4] = {1.0f, 1.0f, 1.0f, 1.f};
GLfloat LSpecular[4] = {1.0f, 1.0f, 1.0f, 0.0f};
GLfloat LPosition[4] = {100.0f, -200.0f, -50.0f, 0.0f};
GLfloat LSpotDirec[3] = {0.0,0.0,0.0};
GLfloat LSpotCutOff = 180.0f;
GLfloat LSpotExponent = 0.0f;
GLfloat LAttenuationConst = 1.0f;
GLfloat LAttenuationLinear = 0.0f;
GLfloat LAttenuationQuadrat = 0.0f;
glLightfv(GL_LIGHT0, GL_AMBIENT, LAmbient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, LDiffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, LSpecular);
glLightfv(GL_LIGHT0, GL_POSITION, LPosition);
glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION, LSpotDirec);
glLightfv(GL_LIGHT0, GL_SPOT_CUTOFF, &LSpotCutOff);
glLightfv(GL_LIGHT0, GL_SPOT_EXPONENT, &LSpotExponent);
glLightfv(GL_LIGHT0, GL_CONSTANT_ATTENUATION, &LAttenuationConst);
glLightfv(GL_LIGHT0, GL_LINEAR_ATTENUATION, &LAttenuationLinear);
glLightfv(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, &LAttenuationQuadrat);
Here is my code, that sets up a new glList, where the glu Sphere is drawn:
//Sphere
GLUquadric * pSphere = gluNewQuadric();
glNewList(LIST_SPHERE, GL_COMPILE);//'LIST_SPHERE' is defined above
gluQuadricTexture(pSphere, GL_FALSE);
gluQuadricOrientation(pSphere, GLU_OUTSIDE);
gluQuadricDrawStyle(pSphere, GLU_FILL);
gluQuadricNormals(pSphere, GLU_SMOOTH);
gluQuadricCallback(pSphere, GLU_ERROR, NULL);
gluSphere(pSphere, 1.0f, 20, 10);
glEndList();
and here is the code, where the List is called:
glPushMatrix();
//drawing a white Sphere with a radius of 6
glColor3f(1.0f, 1.0f, 1.0f);
glScalef(6.f,6.f,6.f);
glCallList(LIST_SPHERE);
glPopMatrix();
Sphere drawn with 'glScalef(1.0f, 1.0f, 1.0f)' (no scale)
Sphere drawn with 'glScalef(6.0f, 6.0f, 6.0f)'
I hope you have any Idea, why things are not working probably.
The normals are not being scaled correctly (they are non-unit length after scaling).
You have two options to solve this:
GL_NORMALIZE -- This will renormalize your normals, which is costly.
GL_RESCALE_NORMAL -- This will simply rescale them.
Option #2 is what you want here, since you applied a uniform scale (6.0x in every direction). If you had applied a non-uniform scale (e.g. glScalef (1.0f, 6.0f, 3.0f)) then this would not be a valid option and you would have to resort to option #1.
In either case, all you need to do is enable GL_NORMALIZE or GL_RESCALE_NORMAL to solve this problem.
I need a rendering platform to show the result of my mesh processing algorithm, it's quite basic and easy, I've had it done, except that the default lighting from OpenGL is a little weird.
My rendering result is like:
And the lighting parameter in OpenGL is like:
// Lights properties
float ambientProperties[] = {0.4f, 0.4f, 0.4f, 1.0f};
float diffuseProperties[] = {0.8f, 0.8f, 0.8f, 1.0f};
float specularProperties[] = {1.0f, 1.0f, 1.0f, 1.0f};
float lightPosition[] = {0.2f, -0.3f, -0.3f, 0.0f};
glLightfv(GL_LIGHT0, GL_AMBIENT, ambientProperties);
glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseProperties);
glLightfv(GL_LIGHT0, GL_SPECULAR, specularProperties);
glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
glLightModelf(GL_LIGHT_MODEL_TWO_SIDE, 1.0);
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE);
// Material Properties
float MatAmbient[] = {0.3f, 0.3f, 0.3f, 1.0f};
float MatDiffuse[] = {0.7f, 0.7f, 0.7f, 1.0f};
float MatSpecular[] = {0.8f, 0.8f, 0.8, 1.0f};
float MatShininess[] = { 64 };
float MatEmission[] = {0.0f, 0.0f, 0.0f, 1.0f};
glMaterialfv(GL_FRONT, GL_AMBIENT, MatAmbient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, MatDiffuse);
glMaterialfv(GL_FRONT, GL_SPECULAR, MatSpecular);
glMaterialfv(GL_FRONT, GL_SHININESS, MatShininess);
glMaterialfv(GL_FRONT, GL_EMISSION, MatEmission);
What I want is something like this:
hand http://iparla.inria.fr/publications/2007/BS07b/sketch_teaser.jpg
I've changed the full resolution version of mine rendering results to vertex normal and added a simplified version, to make the comparison more convincing. We can see that the latter ones are apparently more vividly lighted, ignoring the color.
Can the default OpenGL lighting be parameter-tuned like the results that I want?? Or how can I retrieve codes for some high-quality GLSL shaders for lighting?? I'm only new to graphics rendering, and I think such a lighting routines is not rare.
I'd like to enable lighting in my openGL program, i already works for objects drawn with GLUT.
but when i draw my cuuboid
glBegin(5);
glVertex3f((x_+(b/2)),y_,(z_-(l/2)));
glVertex3f((x_+(b/2)),y_,(z_+(l/2)));
glVertex3f((x_-(b/2)),y_,(z_-(l/2)));
glVertex3f((x_-(b/2)),y_,(z_+(l/2)));
glVertex3f((x_+(b/2)),y_t,(z_-(l/2)));
glVertex3f((x_+(b/2)),y_t,(z_+(l/2)));
glVertex3f((x_-(b/2)),y_t,(z_-(l/2)));
glVertex3f((x_-(b/2)),y_t,(z_+(l/2)));
glVertex3f((x_+(b/2)),y_,(z_-(l/2)));
glVertex3f((x_+(b/2)),y_t,(z_-(l/2)));
glVertex3f((x_+(b/2)),y_,(z_+(l/2)));
glVertex3f((x_+(b/2)),y_t,(z_+(l/2)));
glVertex3f((x_-(b/2)),y_,(z_-(l/2)));
glVertex3f((x_-(b/2)),y_t,(z_-(l/2)));
glVertex3f((x_-(b/2)),y_,(z_+(l/2)));
glVertex3f((x_-(b/2)),y_t,(z_+(l/2)));
glVertex3f((x_-(b/2)),y_,(z_-(l/2)));
glVertex3f((x_-(b/2)),y_t,(z_-(l/2)));
glVertex3f((x_+(b/2)),y_,(z_-(l/2)));
glVertex3f((x_+(b/2)),y_t,(z_-(l/2)));
glVertex3f((x_-(b/2)),y_,(z_+(l/2)));
glVertex3f((x_-(b/2)),y_t,(z_+(l/2)));
glVertex3f((x_+(b/2)),y_,(z_+(l/2)));
glVertex3f((x_+(b/2)),y_t,(z_+(l/2)));
glEnd();
with
glColor3f(6,0,0);
lightning isn't applied on its surfaces. (the cuboid is drawn correct)
my lighning is set up like this:
glEnable(GL_DEPTH_TEST);
glEnable(GL_LIGHT0);
glEnable(GL_NORMALIZE);
glEnable(GL_COLOR_MATERIAL);
glEnable(GL_LIGHTING);
const GLfloat light_ambient[] = { 0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat light_diffuse[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_position[] = { 2.0f, 5.0f, 1.0, 1.0f };
const GLfloat mat_ambient[] = { 0.7f, 0.7f, 0.7f, 1.0f };
const GLfloat mat_diffuse[] = { 0.8f, 0.8f, 0.8f, 1.0f };
const GLfloat mat_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat high_shininess[] = { 100.0f };
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);
glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);
does anyone know the flaw i make?
You didn't give it any normals. You need to use glNormal3f to specify the normals.
glBegin(GL_TRIANGLE_STRIP);
glNormal3f(0,1,0);
glVertex3f((x_+(b/2)),y_,(z_-(l/2)));
glVertex3f((x_+(b/2)),y_,(z_+(l/2)));
glVertex3f((x_-(b/2)),y_,(z_-(l/2)));
glVertex3f((x_-(b/2)),y_,(z_+(l/2)));
glNormal3f(-1,0,0);
// etc.