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gtcmesh.h File Reference

Simple meshes and vector math. More...

#include <gtcutils.h>

Go to the source code of this file.

Compounds
struct	gtcSimpleMesh
	Basic 3d mesh. More...
Typedefs
typedef gtcReal (*	I_dont_know_all_I_need_to_know )[4][4]
	How do you say that a function returns a pointer to an array without a typedef?
Functions
void	gtc_put_mesh (int f[][3], gtcReal v[][3], gtcReal n[][3], int texid, gtcReal t[][2], int numf)
	Low-level functionality without the gtcSimpleMesh structure.
void	gtc_put_simple_mesh_wremap (gtcSimpleMesh *m, gtcReal(*A[])[4][4], gtcReal(*An[])[4][4])
	Puts a mesh with warping remap. More...
void	gtc_put_simple_mesh (gtcSimpleMesh *m, gtcReal A[][4][4])
	Puts a mesh (with perhaps warping). More...
I_dont_know_all_I_need_to_know	gtc_prep_An (int numw, gtcReal A[][4][4])
	Given a matrix A, which is to be applied to vertices, this computes An, to be applied to a normal vector.
void	gtc_put_simple_mesh_easy (gtcSimpleMesh *m, gtcReal A[4][4])
	If m->numw=0 or 1, then you can use this instead of gtc_put_simple_mesh().
void	gtc_normalize_mesh (gtcReal v[][3], int numv)
	Centers the mesh about the origin and scales it so that its radius is roughly one.
void	gtc_normalize_simple_mesh (gtcSimpleMesh *m)
	Same as gtc_normalize_mesh(), but for simple meshes.
gtcSimpleMesh*	gtc_simple_mesh_new (char *name, int numf, int numv)
	Create a new mesh, no texture, no weights.
gtcSimpleMesh*	gtc_simple_mesh_tex_new (char *name, int numf, int numv)
	Create a new mesh, texture, no weights.
gtcSimpleMesh*	gtc_simple_mesh_w_new (char *name, int numf, int numv, int numw)
	Create a new mesh, no texture, weights.
gtcSimpleMesh*	gtc_simple_mesh_wtex_new (char *name, int numf, int numv, int numw)
	Create a new mesh, texture, weights.
void	gtc_simple_texcoord (gtcSimpleMesh *m)
	Assigns debugging texture coordinates to the mesh.
void	gtc_simple_mesh_free (gtcSimpleMesh *m)
	Deallocates all memory for a gtcSimpleMesh.
gtcReal	gtc_dot (gtcReal a[], gtcReal b[], int n)
	vector dot product (n-dimensional).
void	gtc_cross (gtcReal a[3], gtcReal b[3], gtcReal r[3])
	vector cross product.
void	gtc_add (gtcReal a[], gtcReal b[], gtcReal r[], int n)
	vector addition (n-dimensional) r=a+b.
void	gtc_sub (gtcReal a[], gtcReal b[], gtcReal r[], int n)
	vector subtraction (n-dimensional) r=a-b.
gtcReal	gtc_norm (gtcReal a[], int n)
	vector norm (n-dimensional).
void	gtc_addscale (gtcReal s, gtcReal a[], gtcReal r[], int n)
	r+=s*a (n-dimensional).
void	gtc_zero (gtcReal z[], int n)
	zero vector (n-dimensional).
void	gtc_copy (gtcReal a[], gtcReal r[], int n)
	copy vector (really thin, maybe I should remove this).
void	gtc_cum_face (int f[3], gtcReal v[][3], gtcReal n[][3])
	Private function.
void	gtc_set_normals (int f[][3], gtcReal v[][3], gtcReal n[][3], int numf, int numv)
	Private function.
void	gtc_make_face (int f[], int a, int b, int c)
	Private function.
void	gtc_tetrahedron (gtcReal v[4][3], int f[4][3])
	Make a tetrahedron out of the given vertices -- simple sets the output array f.
void	gtc_simple_GL_setup (void)
	Initializes OpenGL for simple use -- note that you still must use glxdemo.h or something.
void	gtc_GL_setup (int normalize, int smooth, int lighting, int cull, int clear, gtcReal near, gtcReal far, gtcReal fov, gtcReal w_div_h)
	Reasonable GL setup. More...
void	gtc_GL_setupall (gtcReal w_div_h)
	gtc_GL_setup with all reasonable flags on.
void	gtc_apply (gtcReal A[4][4], gtcReal v[3], gtcReal r[3])
	Apply given affine transform to the vector v, getting r.
void	gtc_xform_pos (gtcReal A[4][4], gtcReal v[][3], gtcReal r[][3], int numv)
	Apply an affine transform to an array of vertices v, getting r.
void	gtc_combine (gtcReal a[4][4], gtcReal b[4][4], gtcReal r[4][4])
	r=a*b (* is affine transform composition).
void	gtc_rot (gtcReal x, gtcReal y, gtcReal z, gtcReal theta, gtcReal R[4][4])
	Get a rotation matrix about vector (x,y,z) of given angle (radians), result is in R.
void	gtc_redress (gtcReal r[4][4])
	The input matrix is made into a rotation matrix.
void	gtc_xlat (gtcReal x, gtcReal y, gtcReal z, gtcReal T[4][4])
	Translation matrix (by (x,y,z)) goes into T.
void	gtc_ident (gtcReal I[4][4])
	Identity matrix goes into I.
void	gtcaffinecopy (gtcReal A[4][4], gtcReal R[4][4])
	Copies A onto R.
gtcReal	gtc_determinant_3 (gtcReal A[4][4])
	Computes the determinant of the linear part of the affine matrix.
void	gtc_invert (gtcReal A[4][4], gtcReal R[4][4])
	Inverts the affine transform.
int	gtc_check_ortho (gtcReal A[4][4], gtcReal epsilon)
	Checks if A is orthonormal, error threshold is epsilon.
int	gtc_check_rot (gtcReal A[4][4], gtcReal epsilon)
	Checks if A is orthonormal of determinant 1 (error threshold epsilon).
char*	gtc_first_tok (char *s)
	Internal function.
char*	gtc_next_tok (char *s)
	Internal function.
void	gtc_quaternion_to_matrix (gtcReal Q[4], gtcReal M[4][4])
	Convert a quaternion to a matrix.
void	gtc_matrix_to_quaternion (gtcReal M[4][4], gtcReal Q[4])
	Convert a matrix to a quaternion in an error tolerant way.
gtcSimpleMesh*	gtc_stars (void)
	Make a cube to be used for texture mapped stars.

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Detailed Description

Simple meshes and vector math.

This file contains basic functionality for meshes and vector math, implemented on top of OpenGL (http://www.opengl.org/). A basic mesh type, gtcSimpleMesh, is included. This basic mesh type has support for many useful things, including texture mapping and deformable meshes. Also included is various functions for manipulating affine transforms. For instance, gtc_rot() will create a rotation matrix about a given rotation axis with the given angle of rotation, while gtc_xlat() will create a translation matrix with the given translation. In addition, vertices can be transformed (eg, using gtc_apply() or gtc_xform_pos()).

NOTE ON AFFINE TRANSFORMS. It is perhaps counter intuitive that A[i][j] is the ith column of the jth row of the matrix, where matrices multiply from the left.

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Function Documentation

void gtc_GL_setup ( int normalize, int smooth, int lighting, int cull, int clear, gtcReal near, gtcReal far, gtcReal fov, gtcReal w_div_h )

Reasonable GL setup. Assuming you have a window open and glx is set up properly (using, eg, glxdemo.h), you can use this to set up OpenGL itself. The meaning of the parameters are as follow. normalize: use glEnable(GL_NORMALIZE) (0=false, 1=true) -- do this. smooth: use glEnable(GL_SMOOTH) (0=false, 1=true) -- Gouraud shading. lighting: turn lighting on. Do this. cull: backface culling. In most cases you want this. clear: call glClear. If you're doing something multipass, you might not want to do this. near, far: clipping planes. fov: field of view, in degrees. w_div_h: aspect ration (width/height).

void gtc_put_simple_mesh ( gtcSimpleMesh * m, gtcReal A[][4][4] )

Puts a mesh (with perhaps warping). Puts the mesh to the OpenGL pipeline, using the given affine transform(s). The number of affine transforms fed should be equal to m->numw. If this is more than zero, vertices will be transformed not by OpenGL but by GTC. In that case, any geometry acceleration hardware (eg, Impact or GeForce) is useless. If, on the other hand, m->numw=0 then OpenGL is used to transform all the vertices. (The weights are assumed to be one.)

void gtc_put_simple_mesh_wremap ( gtcSimpleMesh * m, gtcReal *[] A[4][4], gtcReal *[] An[4][4] )

Puts a mesh with warping remap. As gtc_put_simple_mesh() except that A and An are arrays of pointers to affine transforms, where An are the matrices to apply to the normals.

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