# 0.7 Textures in processing  (Page 2/2)

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In the code that follows the image representing a broken glass is employed as texture and followed by a color interpolationand the default illumination. The shading of the surfaces, produced by means of the illumination and the colors, ismodulated in a multiplicative way by the colors of the texture. size(400,400,P3D); PImage a = loadImage("vetro.jpg");lights(); textureMode(NORMALIZED);beginShape(TRIANGLE_STRIP); texture(a);fill(240, 0, 0); vertex(40,61, 63, 0, 0); fill(240, 150, 0); vertex(340, 80, 76, 0, 1);fill(250, 250, 0); vertex(150, 176, 100, 1, 1); vertex(110, 170, 180, 1, 0);endShape();

## Texture mapping

It is evident that the mapping operations from a texture image to an object surface, of arbitrary shape, implies some formof interpolation. Similarly to what happens for colors, only the vertices that delimit the surface are mapped onto exactpoints of the texture image. What happens for the internal points has to be established in some way. Actually,Processing and OpenGL behave according to what illustrated in [link] , i.e. by bilinear interpolation: a first linear interpolation over eachboundary segment is cascaded by a linear interpolation on a scan line. If $u$ and $v$ exceed the limits of the texture image, the system (Processing) can assume that this isrepeated periodically and fix it to the values at the border.

A problem that occurs is that a pixel on a display does not necessarly correspond exactly to a texel. One can map morethan one texel on a pixel or, viceversa, a texel can be mapped on several pixels. The first case corresponds to adownsampling that, as seen in Sampling and Quantization , can produce aliasing. The effect of aliasing can be attenuated by means of low pass filtering ofthe texture image. The second case corresponds to upsampling, that in the frequency domain can be interpreted asincreasing the distance between spectral images.

## Texture generation

Textures are not necessarely imported from images, but they can also be generated in an algorithmic fashion. This isparticularly recommended when one wants to generate regular or pseudo-random patterns. For example, the pattern of achess-board can be generated by means of the code PImage textureImg = loadImage("vetro.jpg"); // dummy image colorMode(RGB,1);int biro = 0; int bbiro = 0;int scacco = 5; for (int i=0; i<textureImg.width; i+=scacco) { bbiro = (bbiro + 1)%2; biro = bbiro;for (int j=0; j<textureImg.height; j+=scacco) { for (int r=0; r<scacco; r++) for (int s=0; s<scacco; s++) textureImg.set(i+r,j+s, color(biro));biro = (biro + 1)%2; }} image(textureImg, 0, 0);

The use of the function random, combined with filters of various type, allows a wide flexibility in the production oftextures. For example, the pattern represented in [link] was obtained from a modification of the code generating the chess-board. In particular, we added theline scacco=floor(2+random(5)); within the outer for , and applied an averaging filter.

How could one modify the code [link] in order to make the breaks in the glass more evident?

It is sufficient to consider only a piece of the texture, with calls of the type vertex(150, 176, 0.3, 0.3);

The excercise consists in modifying the code of the generator of the chess-board in [link] in order to generate the texture [link] .

This exercise consists in running and analyzing the following code. Try then to vary the dimensions of the smallsquares and the filtering type. size(200, 100, P3D);PImage textureImg = loadImage("vetro.jpg"); // dummy image colorMode(RGB,1);int biro = 0; int bbiro = 0;int scacco = 5; for (int i=0; i<textureImg.width; i+=scacco) { // scacco=floor(2+random(5));bbiro = (bbiro + 1)%2; biro = bbiro; for (int j=0; j<textureImg.height; j+=scacco) { for (int r=0; r<scacco; r++) for (int s=0; s<scacco; s++) textureImg.set(i+r,j+s, color(biro));biro = (biro + 1)%2; }} image(textureImg, 0, 0);textureMode(NORMALIZED); beginShape(QUADS);texture(textureImg); vertex(20, 20, 0, 0);vertex(80, 25, 0, 0.5); vertex(90, 90, 0.5, 0.5);vertex(20, 80, 0.5, 0); endShape();// ------ filtering ------- PImage tImg = loadImage("vetro.jpg"); // dummy imagefloat val = 1.0/9.0; float[][] kernel = { {val, val, val},{val, val, val}, {val, val, val} };int n2 = 1; int m2 = 1;colorMode(RGB,255); // Convolve the imagefor(int y=0; y<textureImg.height; y++) { for(int x=0; x<textureImg.width/2; x++) { float sum = 0;for(int k=-n2; k<=n2; k++) { for(int j=-m2; j<=m2; j++) { // Reflect x-j to not exceed array boundaryint xp = x-j; int yp = y-k;if (xp<0) { xp = xp + textureImg.width;} else if (x-j>= textureImg.width) { xp = xp - textureImg.width;} // Reflect y-k to not exceed array boundaryif (yp<0) { yp = yp + textureImg.height;} else if (yp>= textureImg.height) { yp = yp - textureImg.height;} sum = sum + kernel[j+m2][k+n2] * red(textureImg.get(xp,yp)); }} tImg.set(x,y, color(int(sum)));} }translate(100, 0);beginShape(QUADS); texture(tImg);vertex(20, 20, 0, 0); vertex(80, 25, 0, 0.5);vertex(90, 90, 0.5, 0.5); vertex(20, 80, 0.5, 0);endShape();

how can chip be made from sand
is this allso about nanoscale material
Almas
are nano particles real
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
no can't
Lohitha
where is the latest information on a no technology how can I find it
William
currently
William
where we get a research paper on Nano chemistry....?
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
how did you get the value of 2000N.What calculations are needed to arrive at it
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