Skip to content

Commit

Permalink
Initial commit
Browse files Browse the repository at this point in the history
  • Loading branch information
@Calvin-L
Calvin-L committed Apr 11, 2012
0 parents commit 1064ffe
Show file tree
Hide file tree
Showing 14 changed files with 1,042 additions and 0 deletions.
3 changes: 3 additions & 0 deletions .gitignore
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
.DS_Store
VolumeRenderer.xcodeproj/project.xcworkspace
VolumeRenderer.xcodeproj/xcuserdata
55 changes: 55 additions & 0 deletions Array3D.h
Original file line number Diff line number Diff line change
@@ -0,0 +1,55 @@
//
// Array3D.h
// MarchingCubes
//
// Created by Calvin Loncaric on 6/26/11.
//

#ifndef ARRAY3D_H
#define ARRAY3D_H

#include <cstdlib>

template <class T>
class Array3D
{

private:
size_t _xmult, _ymult;
T* _data;

public:
Array3D(size_t width, size_t height, size_t depth);
~Array3D();
inline void set(size_t x, size_t y, size_t z, const T& value);
inline const T& get(size_t x, size_t y, size_t z);

};

// ========================================================================

template <class T>
Array3D<T>::Array3D(size_t width, size_t height, size_t depth)
:_xmult(width * height), _ymult(height), _data(new T[width*height*depth])
{
}

template <class T>
Array3D<T>::~Array3D()
{
delete[] _data;
}

template <class T>
void Array3D<T>::set(size_t x, size_t y, size_t z, const T& value)
{
_data[x * _xmult + y * _ymult + z] = value;
}

template <class T>
const T& Array3D<T>::get(size_t x, size_t y, size_t z)
{
return _data[x * _xmult + y * _ymult + z];
}

#endif
321 changes: 321 additions & 0 deletions Decimate.cpp
Original file line number Diff line number Diff line change
@@ -0,0 +1,321 @@
//
// Decimator.cpp
// MarchingCubes
//
// Created by Calvin Loncaric on 6/26/11.
//

#include <cassert>
#include <iostream>
#include <cmath>
#include "common.h"
#include GLUT_INCLUDE
#include "Decimate.h"
#include "Array3D.h"

static inline void drawVert(const Isosurface& surface, const point& p1, const point& p2, float isolevel)
{

float v1 = p1.value;
float v2 = p2.value;

float x, y, z;

if (v2 == v1) {
x = (p1.x + p2.x) / 2.0f;
y = (p1.y + p2.y) / 2.0f;
z = (p1.z + p2.z) / 2.0f;
} else {

/*
<----+-----+---+----->
v1 | v2
isolevel
<----+-----+---+----->
0 | 1
interp
*/


// interp == 0: vert should be at p1
// interp == 1: vert should be at p2
float interp = (isolevel - v1) / (v2 - v1);
float oneMinusInterp = 1 - interp;

x = p1.x * oneMinusInterp + p2.x * interp;
y = p1.y * oneMinusInterp + p2.y * interp;
z = p1.z * oneMinusInterp + p2.z * interp;
}

vector normal = surface.gradientAt(x, y, z);

glNormal3f(normal.x, normal.y, normal.z);
glVertex3f(x, y, z);
}

static void drawTetrahedron(const Isosurface& surface, const point p[4], float isolevel)
{

/*
Tetrahedron layout:
0
*
/|\
/ | \
3 *-----* 1
\ | /
\|/
*
2
*/

unsigned char index = 0;
for (int i = 0; i < 4; ++i)
if (p[i].value < isolevel)
index |= (1 << i);

switch (index) {

// we don't do anything if everyone is inside or outside
case 0x00:
case 0x0F:
break;

// only vert 0 is inside
case 0x01:
drawVert(surface, p[0], p[1], isolevel);
drawVert(surface, p[0], p[3], isolevel);
drawVert(surface, p[0], p[2], isolevel);
break;

// only vert 1 is inside
case 0x02:
drawVert(surface, p[1], p[0], isolevel);
drawVert(surface, p[1], p[2], isolevel);
drawVert(surface, p[1], p[3], isolevel);
break;

// only vert 2 is inside
case 0x04:
drawVert(surface, p[2], p[0], isolevel);
drawVert(surface, p[2], p[3], isolevel);
drawVert(surface, p[2], p[1], isolevel);
break;

// only vert 3 is inside
case 0x08:
drawVert(surface, p[3], p[1], isolevel);
drawVert(surface, p[3], p[2], isolevel);
drawVert(surface, p[3], p[0], isolevel);
break;

// verts 0, 1 are inside
case 0x03:
drawVert(surface, p[3], p[0], isolevel);
drawVert(surface, p[2], p[0], isolevel);
drawVert(surface, p[1], p[3], isolevel);

drawVert(surface, p[2], p[0], isolevel);
drawVert(surface, p[2], p[1], isolevel);
drawVert(surface, p[1], p[3], isolevel);
break;

// verts 0, 2 are inside
case 0x05:
drawVert(surface, p[3], p[0], isolevel);
drawVert(surface, p[1], p[2], isolevel);
drawVert(surface, p[1], p[0], isolevel);

drawVert(surface, p[1], p[2], isolevel);
drawVert(surface, p[3], p[0], isolevel);
drawVert(surface, p[2], p[3], isolevel);
break;

// verts 0, 3 are inside
case 0x09:
drawVert(surface, p[0], p[1], isolevel);
drawVert(surface, p[1], p[3], isolevel);
drawVert(surface, p[0], p[2], isolevel);

drawVert(surface, p[1], p[3], isolevel);
drawVert(surface, p[3], p[2], isolevel);
drawVert(surface, p[0], p[2], isolevel);
break;

// verts 1, 2 are inside
case 0x06:
drawVert(surface, p[0], p[1], isolevel);
drawVert(surface, p[0], p[2], isolevel);
drawVert(surface, p[1], p[3], isolevel);

drawVert(surface, p[1], p[3], isolevel);
drawVert(surface, p[0], p[2], isolevel);
drawVert(surface, p[3], p[2], isolevel);
break;

// verts 2, 3 are inside
case 0x0C:
drawVert(surface, p[1], p[3], isolevel);
drawVert(surface, p[2], p[0], isolevel);
drawVert(surface, p[3], p[0], isolevel);

drawVert(surface, p[2], p[0], isolevel);
drawVert(surface, p[1], p[3], isolevel);
drawVert(surface, p[2], p[1], isolevel);
break;

// verts 1, 3 are inside
case 0x0A:
drawVert(surface, p[3], p[0], isolevel);
drawVert(surface, p[1], p[0], isolevel);
drawVert(surface, p[1], p[2], isolevel);

drawVert(surface, p[1], p[2], isolevel);
drawVert(surface, p[2], p[3], isolevel);
drawVert(surface, p[3], p[0], isolevel);
break;

// verts 0, 1, 2 are inside
case 0x07:
drawVert(surface, p[3], p[0], isolevel);
drawVert(surface, p[3], p[2], isolevel);
drawVert(surface, p[3], p[1], isolevel);
break;

// verts 0, 1, 3 are inside
case 0x0B:
drawVert(surface, p[2], p[1], isolevel);
drawVert(surface, p[2], p[3], isolevel);
drawVert(surface, p[2], p[0], isolevel);
break;

// verts 0, 2, 3 are inside
case 0x0D:
drawVert(surface, p[1], p[0], isolevel);
drawVert(surface, p[1], p[3], isolevel);
drawVert(surface, p[1], p[2], isolevel);
break;

// verts 1, 2, 3 are inside
case 0x0E:
drawVert(surface, p[0], p[1], isolevel);
drawVert(surface, p[0], p[2], isolevel);
drawVert(surface, p[0], p[3], isolevel);
break;

// what is this I don't even
default:
assert(false);
}

}

void decimate(const Isosurface& surface,
float xMin, float xMax,
float yMin, float yMax,
float zMin, float zMax,
float isolevel,
size_t resolution) // resolution indicates # of cubes
{

size_t pointRes = resolution + 1; // indicates the # of points per side

float xrange = xMax - xMin;
float yrange = yMax - yMin;
float zrange = zMax - zMin;

Array3D<float> grid(pointRes, pointRes, pointRes);

for (int i = 0; i <= resolution; ++i) {
float x = (float)i/resolution * xrange + xMin;
for (int j = 0; j <= resolution; ++j) {
float y = (float)j/resolution * yrange + yMin;
for (int k = 0; k <= resolution; ++k) {
float z = (float)k/resolution * zrange + zMin;
float value = surface.valueAt(x, y, z);
grid.set(i, j, k, value);
}
}
}


glBegin(GL_TRIANGLES);
for (int i = 0; i < resolution; ++i) {
float x1 = (float)i/resolution * xrange + xMin;
float x2 = (float)(i+1)/resolution * xrange + xMin;
for (int j = 0; j < resolution; ++j) {
float y1 = (float)j/resolution * yrange + yMin;
float y2 = (float)(j+1)/resolution * yrange + yMin;
for (int k = 0; k < resolution; ++k) {
float z1 = (float)k/resolution * zrange + zMin;
float z2 = (float)(k+1)/resolution * zrange + zMin;

/*
Coordinates:
z
|
|___ y
/
/
x
Cube layout:
4-------7
/| /|
/ | / |
5-------6 |
| 0----|--3
| / | /
|/ |/
1-------2
Tetrahedrons are:
0, 7, 3, 2
0, 7, 2, 6
0, 4, 6, 7
0, 6, 1, 2
0, 6, 1, 4
5, 6, 1, 4
*/

const point v[8] = {
{x1, y1, z1, grid.get(i, j, k )},
{x2, y1, z1, grid.get(i + 1, j, k )},
{x2, y2, z1, grid.get(i + 1, j + 1, k )},
{x1, y2, z1, grid.get(i, j + 1, k )},
{x1, y1, z2, grid.get(i, j, k + 1)},
{x2, y1, z2, grid.get(i + 1, j, k + 1)},
{x2, y2, z2, grid.get(i + 1, j + 1, k + 1)},
{x1, y2, z2, grid.get(i, j + 1, k + 1)}
};

const point tetrahedra[6][4] = {
{ v[0], v[7], v[3], v[2] },
{ v[0], v[7], v[2], v[6] },
{ v[0], v[4], v[7], v[6] },
{ v[0], v[1], v[6], v[2] },
{ v[0], v[4], v[6], v[1] },
{ v[5], v[1], v[6], v[4] }
};

for (int t = 0; t < 6; ++t)
drawTetrahedron(surface, tetrahedra[t], isolevel);

}
}
}
glEnd();

}

Loading

0 comments on commit 1064ffe

Please sign in to comment.