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improved the API slightly, by passing the metasurface object pointer …
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callbacks, and adding getters for all parameters.
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@jtsiomb
jtsiomb committed Aug 24, 2015
1 parent 78c6613 commit dbe29dc
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Showing 6 changed files with 119 additions and 54 deletions.
10 changes: 8 additions & 2 deletions README
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Original file line number Diff line number Diff line change
Expand Up @@ -20,19 +20,25 @@ sphere, centered around the origin.
/* initialization */
ms = msurf_create();
msurf_eval_func(ms, eval);
msurf_vertex_func(ms, glVertex3f);
msurf_vertex_func(ms, vertex);

/* drawing */
glBegin(GL_TRIANGLES);
msurf_polygonize(ms);
glEnd();

/* evaluator */
float eval(float x, float y, float z)
float eval(struct metasurface *ms, float x, float y, float z)
{
return (x * x + y * y + z * z) - 1.0;
}

/* vertex generation callback */
float vertex(struct metasurface *ms, float x, float y, float z)
{
glVertex3f(x, y, z);
}

See the examples subdirectory for more examples.

3. License
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24 changes: 12 additions & 12 deletions examples/metaballs/src/metaballs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -30,8 +30,8 @@ struct metaball {

int num_mballs = sizeof mball / sizeof *mball;

float eval(float x, float y, float z);
void vertex(float x, float y, float z);
float eval(struct metasurface *ms, float x, float y, float z);
void vertex(struct metasurface *ms, float x, float y, float z);
void render(void);
void disp(void);
void reshape(int x, int y);
Expand Down Expand Up @@ -107,17 +107,17 @@ int main(int argc, char **argv)
msurf = msurf_create();
msurf_eval_func(msurf, eval);
msurf_vertex_func(msurf, vertex);
msurf_threshold(msurf, threshold);
msurf_resolution(msurf, RES, RES, RES);
msurf_bounds(msurf, -1, -1, -1, 1, 1, 1);
msurf_set_threshold(msurf, threshold);
msurf_set_resolution(msurf, RES, RES, RES);
msurf_set_bounds(msurf, -1, -1, -1, 1, 1, 1);

glClearColor(0.8, 0.8, 0.8, 1.0);

glutMainLoop();
return 0;
}

float eval(float x, float y, float z)
float eval(struct metasurface *ms, float x, float y, float z)
{
int i;
float val = 0.0f;
Expand All @@ -137,12 +137,12 @@ float eval(float x, float y, float z)
return val;
}

void vertex(float x, float y, float z)
void vertex(struct metasurface *ms, float x, float y, float z)
{
const float dt = 0.001;
float dfdx = eval(x - dt, y, z) - eval(x + dt, y, z);
float dfdy = eval(x, y - dt, z) - eval(x, y + dt, z);
float dfdz = eval(x, y, z - dt) - eval(x, y, z + dt);
float dfdx = eval(ms, x - dt, y, z) - eval(ms, x + dt, y, z);
float dfdy = eval(ms, x, y - dt, z) - eval(ms, x, y + dt, z);
float dfdz = eval(ms, x, y, z - dt) - eval(ms, x, y, z + dt);

glNormal3f(dfdx, dfdy, dfdz);
glVertex3f(x, y, z);
Expand Down Expand Up @@ -239,14 +239,14 @@ void keyb(unsigned char key, int x, int y)

case '=':
threshold += 0.05;
msurf_threshold(msurf, threshold);
msurf_set_threshold(msurf, threshold);
printf("threshold: %f\n", threshold);
glutPostRedisplay();
break;

case '-':
threshold -= 0.05;
msurf_threshold(msurf, threshold);
msurf_set_threshold(msurf, threshold);
printf("threshold: %f\n", threshold);
glutPostRedisplay();
break;
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27 changes: 20 additions & 7 deletions examples/simple/simple.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,9 @@

#include "metasurf.h"

float eval(float x, float y, float z);
float eval(struct metasurface *ms, float x, float y, float z);
void vertex(struct metasurface *ms, float x, float y, float z);
void normal(struct metasurface *ms, float x, float y, float z);
void disp(void);
void reshape(int x, int y);
void keyb(unsigned char key, int x, int y);
Expand Down Expand Up @@ -39,14 +41,13 @@ int main(int argc, char **argv)

ms = msurf_create();
/* consider anything below the threshold (0 by default) to be inside */
msurf_inside(ms, MSURF_LESS);
msurf_set_inside(ms, MSURF_LESS);
/* set the evaluation callback */
msurf_eval_func(ms, eval);
/* pass any vertices and normals generated directly to OpenGL */
msurf_vertex_func(ms, glVertex3f);
msurf_normal_func(ms, glNormal3f);
msurf_vertex_func(ms, vertex);
msurf_normal_func(ms, normal);
/* slightly increase the bounds to avoid clipping the unit sphere */
msurf_bounds(ms, -1.1, -1.1, -1.1, 1.1, 1.1, 1.1);
msurf_set_bounds(ms, -1.1, -1.1, -1.1, 1.1, 1.1, 1.1);

glutMainLoop();
return 0;
Expand All @@ -55,11 +56,23 @@ int main(int argc, char **argv)
/* the unit sphere is implicitly defined as the locus of points in R3 satisfying
* the equation: x^2 + y^2 + z^2 - 1 = 0
*/
float eval(float x, float y, float z)
float eval(struct metasurface *ms, float x, float y, float z)
{
return (x * x + y * y + z * z) - 1.0;
}

void vertex(struct metasurface *ms, float x, float y, float z)
{
/* pass any vertices generated directly to OpenGL */
glVertex3f(x, y, z);
}

void normal(struct metasurface *ms, float x, float y, float z)
{
/* pass any normals generated directly to OpenGL */
glNormal3f(x, y, z);
}

void disp(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
Expand Down
24 changes: 12 additions & 12 deletions examples/volume/src/volume.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,8 @@
#include "cam.h"
#include "metasurf.h"

float eval(float x, float y, float z);
void vertex(float x, float y, float z);
float eval(struct metasurface *ms, float x, float y, float z);
void vertex(struct metasurface *ms, float x, float y, float z);
void render(void);
void disp(void);
void reshape(int x, int y);
Expand Down Expand Up @@ -100,9 +100,9 @@ int main(int argc, char **argv)
msurf = msurf_create();
msurf_eval_func(msurf, eval);
msurf_vertex_func(msurf, vertex);
msurf_threshold(msurf, threshold);
msurf_resolution(msurf, xres, yres, num_slices);
msurf_bounds(msurf, -1, -1, -1, 1, 1, 1);
msurf_set_threshold(msurf, threshold);
msurf_set_resolution(msurf, xres, yres, num_slices);
msurf_set_bounds(msurf, -1, -1, -1, 1, 1, 1);

glClearColor(0.6, 0.6, 0.6, 1.0);

Expand All @@ -112,7 +112,7 @@ int main(int argc, char **argv)
return 0;
}

float eval(float x, float y, float z)
float eval(struct metasurface *ms, float x, float y, float z)
{
int px, py, slice;
struct img_pixmap *img;
Expand All @@ -134,14 +134,14 @@ float eval(float x, float y, float z)
return *((unsigned char*)img->pixels + py * img->width + px) / 255.0;
}

void vertex(float x, float y, float z)
void vertex(struct metasurface *ms, float x, float y, float z)
{
float dx = 1.0 / xres;
float dy = 1.0 / yres;
float dz = 1.0 / num_slices;
float dfdx = eval(x - dx, y, z) - eval(x + dx, y, z);
float dfdy = eval(x, y - dy, z) - eval(x, y + dy, z);
float dfdz = eval(x, y, z - dz) - eval(x, y, z + dz);
float dfdx = eval(ms, x - dx, y, z) - eval(ms, x + dx, y, z);
float dfdy = eval(ms, x, y - dy, z) - eval(ms, x, y + dy, z);
float dfdz = eval(ms, x, y, z - dz) - eval(ms, x, y, z + dz);

glNormal3f(dfdx, dfdy, dfdz);
glVertex3f(x, y, z);
Expand Down Expand Up @@ -256,15 +256,15 @@ void keyb(unsigned char key, int x, int y)

case '=':
threshold += 0.05;
msurf_threshold(msurf, threshold);
msurf_set_threshold(msurf, threshold);
printf("threshold: %f\n", threshold);
glutPostRedisplay();
need_update = 1;
break;

case '-':
threshold -= 0.05;
msurf_threshold(msurf, threshold);
msurf_set_threshold(msurf, threshold);
printf("threshold: %f\n", threshold);
glutPostRedisplay();
need_update = 1;
Expand Down
65 changes: 52 additions & 13 deletions src/metasurf.c
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
/*
metasurf - a library for implicit surface polygonization
Copyright (C) 2011 John Tsiombikas <nuclear@member.fsf.org>
Copyright (C) 2011-2015 John Tsiombikas <nuclear@member.fsf.org>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
Expand Down Expand Up @@ -37,6 +37,7 @@ struct metasurface {
msurf_eval_func_t eval;
msurf_vertex_func_t vertex;
msurf_normal_func_t normal;
void *udata;

float dx, dy, dz;
int flip;
Expand Down Expand Up @@ -79,6 +80,7 @@ static int msurf_init(struct metasurface *ms)
ms->eval = 0;
ms->vertex = 0;
ms->normal = 0;
ms->udata = 0;
ms->min[0] = ms->min[1] = ms->min[2] = -1.0;
ms->max[0] = ms->max[1] = ms->max[2] = 1.0;
ms->res[0] = ms->res[1] = ms->res[2] = 40;
Expand All @@ -90,7 +92,17 @@ static int msurf_init(struct metasurface *ms)
return 0;
}

void msurf_inside(struct metasurface *ms, int inside)
void msurf_set_user_data(struct metasurface *ms, void *udata)
{
ms->udata = udata;
}

void *msurf_get_user_data(struct metasurface *ms)
{
return ms->udata;
}

void msurf_set_inside(struct metasurface *ms, int inside)
{
switch(inside) {
case MSURF_GREATER:
Expand All @@ -106,6 +118,11 @@ void msurf_inside(struct metasurface *ms, int inside)
}
}

int msurf_get_inside(struct metasurface *ms)
{
return ms->flip ? MSURF_LESS : MSURF_GREATER;
}

void msurf_eval_func(struct metasurface *ms, msurf_eval_func_t func)
{
ms->eval = func;
Expand All @@ -121,7 +138,7 @@ void msurf_normal_func(struct metasurface *ms, msurf_normal_func_t func)
ms->normal = func;
}

void msurf_bounds(struct metasurface *ms, float xmin, float ymin, float zmin, float xmax, float ymax, float zmax)
void msurf_set_bounds(struct metasurface *ms, float xmin, float ymin, float zmin, float xmax, float ymax, float zmax)
{
ms->min[0] = xmin;
ms->min[1] = ymin;
Expand All @@ -131,18 +148,40 @@ void msurf_bounds(struct metasurface *ms, float xmin, float ymin, float zmin, fl
ms->max[2] = zmax;
}

void msurf_resolution(struct metasurface *ms, int xres, int yres, int zres)
void msurf_get_bounds(struct metasurface *ms, float *xmin, float *ymin, float *zmin, float *xmax, float *ymax, float *zmax)
{
*xmin = ms->min[0];
*ymin = ms->min[1];
*zmin = ms->min[2];
*xmax = ms->max[0];
*ymax = ms->max[1];
*zmax = ms->max[2];
}

void msurf_set_resolution(struct metasurface *ms, int xres, int yres, int zres)
{
ms->res[0] = xres;
ms->res[1] = yres;
ms->res[2] = zres;
}

void msurf_threshold(struct metasurface *ms, float thres)
void msurf_get_resolution(struct metasurface *ms, int *xres, int *yres, int *zres)
{
*xres = ms->res[0];
*yres = ms->res[1];
*zres = ms->res[2];
}

void msurf_set_threshold(struct metasurface *ms, float thres)
{
ms->thres = thres;
}

float msurf_get_threshold(struct metasurface *ms)
{
return ms->thres;
}


int msurf_polygonize(struct metasurface *ms)
{
Expand Down Expand Up @@ -211,7 +250,7 @@ static void process_cell(struct metasurface *ms, vec3 pos, vec3 sz)
p[i][1] = pos[1] + sz[1] * offs[i][1];
p[i][2] = pos[2] + sz[2] * offs[i][0];

val[i] = ms->eval(p[i][0], p[i][1], p[i][2]);
val[i] = ms->eval(ms, p[i][0], p[i][1], p[i][2]);
}

#ifdef USE_MTETRA
Expand Down Expand Up @@ -266,20 +305,20 @@ static void process_cube(struct metasurface *ms, vec3 *pos, float *val)

if(ms->normal) {
float dfdx, dfdy, dfdz;
dfdx = ms->eval(v[0] - ms->dx, v[1], v[2]) - ms->eval(v[0] + ms->dx, v[1], v[2]);
dfdy = ms->eval(v[0], v[1] - ms->dy, v[2]) - ms->eval(v[0], v[1] + ms->dy, v[2]);
dfdz = ms->eval(v[0], v[1], v[2] - ms->dz) - ms->eval(v[0], v[1], v[2] + ms->dz);
dfdx = ms->eval(ms, v[0] - ms->dx, v[1], v[2]) - ms->eval(ms, v[0] + ms->dx, v[1], v[2]);
dfdy = ms->eval(ms, v[0], v[1] - ms->dy, v[2]) - ms->eval(ms, v[0], v[1] + ms->dy, v[2]);
dfdz = ms->eval(ms, v[0], v[1], v[2] - ms->dz) - ms->eval(ms, v[0], v[1], v[2] + ms->dz);

if(ms->flip) {
dfdx = -dfdx;
dfdy = -dfdy;
dfdz = -dfdz;
}
ms->normal(dfdx, dfdy, dfdz);
ms->normal(ms, dfdx, dfdy, dfdz);
}

/* TODO multithreadied polygon emmit */
ms->vertex(v[0], v[1], v[2]);
ms->vertex(ms, v[0], v[1], v[2]);
}
}
}
Expand Down Expand Up @@ -394,7 +433,7 @@ static void emmit(struct metasurface *ms, float v0, float v1, vec3 p0, vec3 p1,
for(i=0; i<3; i++) {
p[i] = p0[i] + (p1[i] - p0[i]) * t;
}
ms->vertex(p[0], p[1], p[2]);
ms->vertex(ms, p[0], p[1], p[2]);

/*for(i=0; i<3; i++) {
ms->vbuf[ms->nverts][i] = p0[i] + (p1[i] - p0[i]) * t;
Expand All @@ -405,7 +444,7 @@ static void emmit(struct metasurface *ms, float v0, float v1, vec3 p0, vec3 p1,
for(i=0; i<3; i++) {
int idx = rev ? (2 - i) : i;
ms->vertex(ms->vbuf[idx][0], ms->vbuf[idx][1], ms->vbuf[idx][2]);
ms->vertex(ms, ms->vbuf[idx][0], ms->vbuf[idx][1], ms->vbuf[idx][2]);
}
}*/
}
Expand Down
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