primitives - a collection of object primitives for SIPP.

#include <primitives.h> [g]cc [flags] files -lsipp -lm [ libraries ]

SIPP gives the user access to a number of rather low level functions to create polygons, surfaces and objects. This manual describes a set of functions that use the low level functions in SIPP to create geometric primitives. Each primitive is a complete SIPP object. Each object primitive has a last argument that describes what kind of texture coordinates should be assigned to the surface of the object. This texture parameter should be one of: NATURAL, CYLINDRICAL, SPHERICAL or WORD. See the user manual for a detailed description of the meaning of the different values.

Object *sipp_torus(bigradius, smallradius, res1, res2, surface, shader, texture)

double bigradius;

double smallradius;

int res1;

int res2;

void *surface;

Shader *shader;

int texture; sipp_torus() creates a torus centered about the origin and with the z-axis pointing up through the ring. NATURAL texture mapping is a two dimensional mapping with the x coordinate going around the "small" circle and the y coordinate going around the "large" circle.

Object *sipp_cone(bot_rad, ,top_rad, length, resolution, surface, shader, texture)

double bot_rad;

double top_rad;

double length;

int resolution;

void *surface;

Shader *shader;

int texture; sipp_cone() creates a, possibly truncated, cone centered about the origin and with the z-axis along the cones main axis. NATURAL texture mapping is CYLINDRICAL.

Object *sipp_cylinder(radius, length, resolution, surface, shader, texture)

double radius;

double length;

int resolution;

void *surface;

Shader *shader;

int texture; sipp_cylinder() creates a cylinder centered about the origin and with the z-axis along the cylinders main axis. NATURAL texture mapping is CYLINDRICAL.

Object *sipp_ellipsoid(x_rad, y_rad, z_rad, resolution, surface, shader, texture)

double x_rad;

double y_rad;

double z_rad;

int resolution;

void *surface;

Shader *shader;

int texture; sipp_ellipsoid() creates a ellipsoid centered about the origin. NATURAL texture mapping is SPHERICAL.

Object *sipp_sphere(radius, resolution, surface, shader, texture)

double radius;

int resolution;

void *surface;

Shader *shader;

int texture; sipp_sphere() creates a sphere centered about the origin. NATURAL texture mapping is SPHERICAL.

Object *sipp_prism(num_points, points, length, surface, shader, texture)

int num_points;

Vector *points;

double length;

void *surface;

Shader *shader;

int texture; sipp_prism() creates a prism defined by the polygon in points. Only the x and y values are used and the prism will ascend and descend equally far (length / 2.0) from the x-y plane along the z axis. NATURAL texture mapping is similar to CYLINDRICAL but the x coordinate is not taken from projection on a cylinder but is evenly distributed around the perimeter. An odd thing in all the 2D mappings for the prism is that the top face will have texture coordinates (0.0, 1.0) while the bottom will get (0.0, 0.0).

Object *sipp_block(x_size, y_size, z_size, surface, shader, texture)

double x_size;

double y_size;

double z_size;

void *surface;

Shader *shader;

int texture; sipp_block() creates a rectangular block with the size defined by x_size, z_size and z_size. The block is centered about the origin. NATURAL texture mapping is similar to CYLINDRICAL but the x coordinate is not taken from projection on a cylinder but is evenly distributed around the perimeter. An odd thing in all the 2D mappings for the block is that the top face will have texture coordinates (0.0, 1.0) while the bottom will get (0.0, 0.0).

Object *sipp_cube(side, surface, shader, texture)

double side;

void *surface;

Shader *shader;

int texture; sipp_cube() creates a cube with the side of length side. The cube is centered about the origin. NATURAL texture mapping is similar to CYLINDRICAL but the x coordinate is not taken from projection on a cylinder but is evenly distributed around the perimeter. An odd thing in all the 2D mappings for the cube is that the top face will have texture coordinates (0.0, 1.0) while the bottom will get (0.0, 0.0).

Object *sipp_bezier_patch(num_vertex, vertex, num_patch, vx_index, res, surface, shader, texture)

int num_vertex;

Vector vertex[];

int num_patch;

int vx_index[];

int res;

void *surface;

Shader *shader;

int texture; This function creates one or more bezier patches. All created patches in a call will belong to the same surface. The texture coordinates are a bit special for the bezier patches. CYLINDRICAL and SPHERICAL coordinates are not applicable, if they are specified, SIPP will use NATURAL anyway. The NATURAL mapping is a two dimensional mapping using the surface parameters u and v. Note that these parameters range from 0 to 1 within each patch!

Object *sipp_bezier_rotcurve(num_vertex, vertex, num_curve, vx_index, res, surface, shader, texture)

int num_vertex;

Vector vertex[];

int num_curve;

int vx_index[];

int res;

void *surface;

Shader *shader;

int texture; This function creates a surface by rotating one or more bezier curves about the world z-axis. The texture coordinates are a bit special for these surfaces. SPHERICAL and CYLINDRICAL mappings are not applicable, and NATURAL mapping will apply to the peace of surface created by each bezier curve separately. The NATURAL mapping uses the curve parameter u along each curve as x coordinate and goes from 0 to 1 around the perimeter of the rotational surface on the other axis

Object *sipp_bezier_file(file, res, surface, shader, texture)

FILE *file;

int res;

void *surface;

Shader *shader;

int texture; sipp_bezier_file() reads a file containing descriptions of a set of bezier patches or bezier curves. See the user manual for a detailed description of the format of the definition file. Texture coordinates are assigned in the same way as in sipp_bezier_patch() and sipp_bezier_rotcurve().

Object *sipp_teapot(resolution, surface, shader, texture)

int resolution;

void *surface;

Shader *shader;

int texture; sipp_teapot() creates a model of the famous "Utah Teapot". It is built as a combined object of four subobjects: body, lid, handle and spout (no, there is no bottom). Each of these subobjects are also available as separate primitive objects. The body and lid are created as Bezier rotation curves while the spout and handle are created as sets Bezier patches. Texture coordinates are assigned in the same way as for these primitives (i.e. sipp_bezier_rotcurve() and sipp_bezier_patch().

Object *sipp_teapot_body(resolution, surface, shader, texture)

int resolution;

void *surface;

Shader *shader;

int texture; Create the body of the "Utah Teapot" as a separate object. See sipp_teapot() for a more detailed description.

Object *sipp_teapot_lid(resolution, surface, shader, texture)

int resolution;

void *surface;

Shader *shader;

int texture; Create the lid of the "Utah Teapot" as a separate object. See sipp_teapot() for a more detailed description.

Object *sipp_teapot_handle(resolution, surface, shader, texture)

int resolution;

void *surface;

Shader *shader;

int texture; Create the handle of the "Utah Teapot" as a separate object. See sipp_teapot() for a more detailed description.

Object *sipp_teapot_spout(resolution, surface, shader, texture)

int resolution;

void *surface;

Shader *shader;

int texture; Create the spout of the "Utah Teapot" as a separate object. See sipp_teapot() for a more detailed description.

sipp(3) - simple polygon processor, a 3d-graphics library

sipp_shaders(3) - a collection of shaders for SIPP.

sipp_geometric(3) - Vector and matrix functions for SIPP.

sipp_pixmap(3) - pixmap handling code for SIPP.

sipp_bitmap(3) - bitmap handling code for SIPP.

Jonas Yngvesson (jonas-y@isy.liu.se)

Inge Wallin (ingwa@isy.liu.se)

The format for the bezier patches and curves is prohibitively ugly.