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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();

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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.

Algorithmically-generated pattern

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);

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

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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();

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Questions & Answers

Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
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why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
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sciencedirect big data base
Introduction about quantum dots in nanotechnology
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Source:  OpenStax, Media processing in processing. OpenStax CNX. Nov 10, 2010 Download for free at http://cnx.org/content/col10268/1.14
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