r2d.h

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/**************************************************************
 *
 *    r2d.h
 *    
 *    Devon Powell
 *    8 February 2015
 *
 *    Routines for fast, geometrically robust clipping operations
 *    and analytic area/moment computations over convex
 *    polygons in 2D. Includes a wrapper function for 
 *    physically conservative rasterization (area sampling)
 *    of quadrilaterals to a Cartesian grid.
 *    
 *    Copyright (C) 2014 Stanford University.
 *    See License.txt for more information.
 *
 *************************************************************/

#ifndef _R2D_H_
#define _R2D_H_

#include <stdint.h>

#ifdef SINGLE_PRECISION
typedef float r2d_real;
#else
typedef double r2d_real;
#endif

typedef int32_t r2d_int;

typedef int64_t r2d_long;

typedef struct {
    r2d_real x, 
             y; 
} r2d_rvec2;

typedef struct {
    r2d_int i, 
            j; 
} r2d_dvec2;

typedef struct {
    r2d_rvec2 n; 
    r2d_real d; 
} r2d_plane;

typedef struct {
    r2d_real fdist[4]; 
    unsigned char fflags; 
} r2d_orientation;

typedef struct {
    r2d_rvec2 pos; 
    unsigned char pnbrs[2]; 
    r2d_orientation orient; 
} r2d_vertex;

typedef struct {
#define R2D_MAX_VERTS 64
    r2d_vertex verts[R2D_MAX_VERTS]; 
    r2d_int nverts; 
    r2d_int funclip; 
} r2d_poly;

typedef struct {
    r2d_real* moments[6]; 
    r2d_int polyorder; 
    r2d_orientation* orient; 
    r2d_long bufsz; 
    r2d_dvec2 n; 
    r2d_rvec2 d; 
} r2d_dest_grid;

const static r2d_int r2d_num_moments[3] = {1, 3, 6};


void r2d_rasterize_quad(r2d_plane* faces, r2d_dest_grid* grid);

void r2d_clip_quad(r2d_poly* poly, unsigned char andcmp);


void r2d_reduce(r2d_poly* poly, r2d_int polyorder, r2d_real* moments);


void r2du_init_box(r2d_poly* poly, r2d_rvec2 rbounds[2]);


void r2du_faces_from_verts(r2d_rvec2* verts, r2d_int nverts, r2d_plane* faces);

r2d_real r2du_orient(r2d_rvec2 pa, r2d_rvec2 pb, r2d_rvec2 pc);


#endif // _R2D_H_