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I start with a ground surface. It has to be 3-dimensional so
I use a box. It's dimensions and position in the world are
given by the positions of the diagonally opposite corners.
It needs a color so I create a green texture and attach it
to the box. Then I add the box to the scene.
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Box* ground = new Box(Position(-100.,-1.,100.),
Position(100.,0.,-100.));
Texture* groundTxt = new Texture(ForestGreen);
ground->setTexture(groundTxt);
pScene->add(ground);
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I create a simple ornament which is a Union (ie, a
collection) of a ball and a stem.
The ball is a sphere. It gets a chrome finish texture except
I change the color to red.
The ball is added to the ornament.
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Union* ornament = new Union;
Sphere* ball = new Sphere(Origin, 7.);
Texture* ballTxt = new Texture(T_Chrome_5E);
ballTxt->surfaceColor = Red;
ball->setTexture(ballTxt);
ornament->add(ball);
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The stem is also a Union
containing a ring to hang the ornament from and a collar
where the ring and the ball join.
The collar is a cylinder positioned so that it sticks up out of the
top of the sphere.
It is added to the stem.
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Union* stem = new Union;
Cylinder* collar = new Cylinder(Position(0.,6.,0.),
Position(0.,8.5,0.), 1.);
stem->add(collar);
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The ring is another
cylinder lying horizontally across the top of the collar.
The ring is made hollow (a tube) to allow a hook to pass through it
and I turn it a little so it's easier to see.
The ring is added to the stem.
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Cylinder* ring = new Cylinder(Position(0.,9.,-.5),
Position(0.,9.,.5), 1.);
ring->setInterior(GeoObject::hollow);
ring->rotate(0.,RADIANS(60.), 0.);
stem->add(ring);
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I made the stem because I
can change the texture, position or other characteristic of
both the collar and the ring together by referring to the
stem alone.
The stem is given a shiny gold color (which the collar and ring inherit).
The stem is added to the ornament.
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Texture* stemTxt = new Texture(T_Gold_5E);
stem->setTexture(stemTxt);
ornament->add(stem);
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Now that there's one ornament, it's a simple matter to clone
two more. Initially they all share the same characteristics
including position. I move them apart and raise them off
the ground. I add them to the scene (which is just another
Union).
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Union* ornament2 = new Union(ornament);
Union* ornament3 = new Union(ornament);
ornament->move(-6.5, 10., 0.);
pScene->add(ornament);
ornament2->move(6., 12., -40.);
pScene->add(ornament2);
ornament3->move(-32., 15., -80.);
pScene->add(ornament3);
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Point light sources, spotlights and directional lighting
affect the shading of a scene but they don't
have any physical presence in the scene and have no shape.
Lights are defined in the camera settings and are not
part of the scene description.
I want a rectangular light reflected in the ornaments.
To make any light source visible, it needs
to be realized by a shape which acts as proxy for the light
source. The named light and its proxy shape are associated
by the meta object, ProxyLight, which is added to the scene.
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Light* lightEmitter;
if (lightEmitter = pCam->lights->getNamedLight("boxlight")) {
Box* lightBox = new Box(Position(-40, 0, 40),
Position(40, 2, -40));
ProxyLight* boxLight = new ProxyLight(lightEmitter,
lightBox);
boxLight->setAreaLight();
pScene->add(boxLight);
}
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After the image of the scene was rendered, I added the
text using an image editing program.
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The camera settings are chosen interactively at rendering time. Below are
screenshots of the camera dialog box used to create the image above.
Click on a thumbnail image to see a larger view. Use your BACK button to
return here.
