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Basic 3D ShapesMore on perspective projectionLeft- vs. Ri ht-handed coordinate

systems.

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Glut has many different preset 3d shapes foruse in OpenGL.

Both solid and wireframe versions for eachshape.

For a cube: glutSolidCube(GLdouble size); glutWireCube(GLdouble size);

Render a solid or wireframe cube respectively. Thecube is centered at the modeling coordinates origin

with sides of length size. Next we will show only the solid version functions,

remember wireframe versions are available too.

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Sphere:

glutSolidSphere(GLdouble radius, GLintslices, GLint stacks);

radius: The radius of the sphere.

slices: The number of subdivisions around the Z

axis (similar to lines of longitude). stacks: The number of subdivisions along the Z axis

(similar to lines of latitude).

Cone:

glutSolidCone(GLdouble base, GLdouble

height, GLint slices, GLint stacks);

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Torus (doughnut) glutSolidTorus(GLdouble innerRadius,

GLdouble outerRadius, GLint nsides, GLint

rings);

innerRadius: Inner radius of the torus..

nsides: Number of sides for each radial section. rings Number of radial divisions for the torus.

TeapotglutSolidTeapot(GLdouble size);

size: Relative size of the teapot.

& some other shapes as well

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glFrustum( GLdouble left, GLdouble right,

GLdouble bottom, GLdouble top, GLdouble

near, GLdouble far);

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gluPerspective( GLdouble fovy, GLdouble

aspect, GLdouble near, GLdouble far);

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gluPerspectivegluPerspectivegluPerspectivegluPerspective()()()() requires only 4 parameters.

Can produce a symmetrical viewing volume only.

you have to use glFrustumglFrustumglFrustumglFrustum()()()() directly if you need tocreate a non-symmetrical viewing volume.

if ou want to render a wide scene into 2 ad oinin

screens, you can break down the frustum into 2asymmetric frustums (left and right). Then, renderthe scene with each frustum.

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It is very important to remember thatgluPerspectivegluPerspectivegluPerspectivegluPerspective,,,, glOrthoglOrthoglOrthoglOrtho andandandand glFrustumglFrustumglFrustumglFrustum are lefthanded.

It is easier if you think ofzNearzNearzNearzNearand zFarzFarzFarzFarasdistances from view oint ( oint where the camera

is placed, using the glulookAt function). Everything else is right handed, including the

vertices to be rendered.

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Refer to the attached code. Notice the difference between orthographic

and perspective projections. Try changing the parameters of the

ro ection functions calls, and the luLookAt

function call. Two OpenGL programs (with their source

code) are attached as well, they will help youbetter understand how to adjust theparameters passed to the projection andtransformation functions.