height map mesh

Contributed Library Questions

jaunders

in Contributed Library Questions • 2 years ago

hi guys

Im super new to this but im trying to make a mesh terrain model using a hieght map and the un lekker 3dmesh,

here is my code but i cant seem to get it to work can any one help me ?

import peasy.org.apache.commons.math.*;
import peasy.*;
import peasy.org.apache.commons.math.geometry.*;
import processing.opengl.*;
import unlekker.util.*;
import unlekker.geom.*;
import unlekker.data.*;
// 2-dimensional array of 3D vector objects to contain our mesh
Vec3 mesh[][];
// num will decide the mesh dimensions
int numX;
int numY;
// use the CTRL key for interface
boolean ctrlDown=false;
// translation the Z direction
float xUnit, yUnit, zTrans;
float rotX, rotY, amplitude;
PImage extrude;
int[][] values;
void setup() {
size(1200, 1000, OPENGL);
// allocate space for the mesh and fill it with empty vectors
numX=200;
numY=200;
mesh=new Vec3[numX][numY];
meshPlane();
xUnit=width/(float)numX;
yUnit=height/(float)numY;
rotX=30;
rotY=0;
amplitude=200;
zTrans=-width/2;
extrude = loadImage("ystone08.jpg");
extrude.loadPixels();
values = new int[extrude.width][extrude.height];
for (int y = 0; y < extrude.height; y++) {
    for (int x = 0; x < extrude.width; x++) {
      color pixel = extrude.get(x, y);
      values[x][y] = int(brightness(pixel));
    }
}
}
void draw() {
background(0);
// translate to center of screen and use mouse movement
// to rotate the scene
translate(width/2, height/2, zTrans);
rotateX(rotX);
rotateY(rotY);
stroke(255, 255, 255, 50);
noFill();
drawMesh();
}
void keyPressed() {
// check for CTRL key
if (key == CODED && keyCode==CONTROL) {
ctrlDown=true;
println("ctrlDown "+ctrlDown);
}
}
void keyReleased() {
// check for CTRL key to see if it has been released
if (key == CODED && keyCode==CONTROL) {
ctrlDown=false;
}
}
void mouseDragged() {
// if CTRL key is down, then adjust amplitude
if (ctrlDown) {
    amplitude=((float)mouseY/(float)height)*height;
    println("amplitude "+amplitude);
}
// else rotate the viewport
else {
    rotX=((float)mouseX/(float)width)*2*PI;
    rotY=((float)mouseY/(float)height)*2*PI;
}
}
// drawMesh is a custom method that takes care of drawing the
// mesh using beginShape() / endShape()
void drawMesh() {
for (int i=0; i<numX-1; i++) {
    beginShape(QUAD_STRIP);
    for (int j=0; j<numY; j++) {
      vertex(mesh[j][i].x, mesh[j][i].y * amplitude, mesh[j][i].z);
      vertex(mesh[j][i+1].x, mesh[j][i+1].y * amplitude, mesh[j][i+1].z);
    }
    endShape();
}
}
// sets the mesh to an even grid plane
void meshPlane() {
for (int y = 0; y < extrude.width-1; y++) {
    for (int x = 0; x < extrude.height-1; x++) {

          mesh[y][x]=new Vec3((x-numX/2)*10, 0, (-values[x][y]));
    }
}
    }

Replies(4)

kooogy

don't know what you've done to your code when pasting it but it's very hard to use as it is

also " i cant seem to get it to work " is the kind of thing that gets no help. how doesn't it work? where's the error? what are you expecting? if there's a null pointer or any other warning (and there is) tell us where it is.

also, don't use unnecessary libraries - the more you use the less people will be able to help. as it is you aren't using peasycam at all and are only using Vec3 from unlekker which can be replaced with PVector which is in the core processing code.

and link to any images you use, or tell us what they should be like ("any 200x200 image")

after all that:
you're using extrude.width in meshPlane BEFORE you've loaded your image into it. null pointer exception.

just move meshPlane() to the end of startup and that should be ok.

toxmeister

Re: height map mesh

2 years ago

Sorry, can't help you with the unlekker lib, but here's a small demo using toxiclibs:

import toxi.geom.*;
import toxi.geom.mesh.*;
import toxi.processing.*;
int DIM=20;
float NOISE_SCALE=0.15;
TriangleMesh mesh;
ToxiclibsSupport gfx;
void setup() {
size(640, 480, P3D);
Terrain terrain = new Terrain(DIM, DIM, 16);
// populate elevation data
float[] el = new float[DIM*DIM];
noiseSeed(23);
for (int z = 0, i = 0; z < DIM; z++) {
for (int x = 0; x < DIM; x++) {
el[i++] = noise(x * NOISE_SCALE, z * NOISE_SCALE) * 100;
}
}
terrain.setElevation(el);
// create mesh
mesh = new TriangleMesh();
terrain.toMesh(mesh,-10);
// attach drawing utils
gfx = new ToxiclibsSupport(this);
}
void draw() {
background(0);
lights();
translate(width/2,height/2,0);
rotateX(mouseY*0.01);
rotateY(mouseX*0.01);
noStroke();
gfx.mesh(mesh);
}

http://postspectacular.com | http://toxiclibs.org

toxmeister

Re: Re: height map mesh

2 years ago

Also, if you want to export the mesh as STL do this at the end of setup:

mesh.saveAsSTL(sketchPath("mesh.stl"));

aufsess

Re: height map mesh

1 year ago

How would you convert a triangulated mesh to a heightmap / terrain? I'm trying to take my mesh and use the blob detection library to make contours. Do I need to just create meshes that have equally distributed points (in a grid)?

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height map mesh

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