Search Results

Search found 278 results on 12 pages for 'triangles'.

Page 2/12 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

  • Triangulation A* (TA*) pathfinding algorithm

    - by hyn
    I need help understanding the Triangle A* (TA*) algorithm that is described by Demyen in his paper Efficient Triangulation-Based Pathfinding, on pages 76-81. He describes how to adapt the regular A* algorithm for triangulation, to search for other possibly more optimal paths, even after the final node is reached/expanded. Regular A* stops when the final node is expanded, but this is not always the best path when used in a triangulated graph. This is exactly the problem I'm having. The problem is illustrated on page 78, Figure 5.4: I understand how to calculate the g and h values presented in the paper (page 80). And I think the search stop condition is: if (currentNode.fCost > shortestDistanceFound) { // stop break; } where currentNode is the search node popped from the open list (priority queue), which has the lowest f-score. shortestDistanceFound is the actual distance of the shortest path found so far. But how do I exclude the previously found paths from future searches? Because if I do the search again, it will obviously find the same path. Do I reset the closed list? I need to modify something, but I don't know what it is I need to change. The paper lacks pseudocode, so that would be helpful.

    Read the article

  • Ray-plane intersection to find the Z of the intersecting point

    - by Jenko
    I have a rectangle in 3d space (p1, p2, p3, p4) and when the mouse rolls over it I need to calculate the exact Z of the point on the rect, given the mouse coordinates (x, y). Would a Ray-plane intersection find the Z of the intersecting point? Edit: Would this one-liner work? .. it returns the t value for the intersection, apparently the Z value. float rayPlane(vector3D planepoint, vector3D normal, vector3D origin, vector3D direction){ return -((origin-planepoint).dot(normal))/(direction.dot(normal)); }

    Read the article

  • How do you calculate UVW coordinates?

    - by Jenko
    I'm working on a 3d engine and I'm calculating UVT coordinates, where U and V represent pixels on the texture measured in 0-1, and T is: T = perspective / Z But I'm trying to use this perspective-correct triangle rasteriser, which requires a W, per vertex. How do I calculate the W for each vertex for the drawPerspectiveTexturedPolygon() function? Hint: The code comments refer to W as the "homogenous coordinate" ... does that mean anything?

    Read the article

  • Point[] and Tri not "could not be found"

    - by Craig Dannehl
    Hi I'm trying to learn how to load a .obj file using OpenTK in windows Forms. I have seen a lot of examples out there, but I do see almost everyone uses List, and Point[]. Code example show these highlighted like there IDE know what these are; for example List<Tri> tris = new List<Tri>(); but mine just returns "The type or namespace name 'Tri' could not be found" is there an include I need to add or a using I am missing. Currently have this using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Drawing; using OpenTK; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL;

    Read the article

  • Grab triangles within a lower triangle

    - by Tyler Rinker
    I have the need to grab all the thee element triangles that make up the lower triangle of a symmetric matrix. I can not think of how to grab all these pieces in the order of far left column working down and then next column to the right and so on. I know that the numbe rof mini triangles inside of the lower triangle is: n = x(x - 1)/2 where: x = nrow(mats[[i]]) Here I've created three matrices with letters (it's easier for me to conceptualize this way) and the elements in the order I'm looking for: FUN <- function(n) { matrix(LETTERS[1:(n*n)], n) } mats <- lapply(3:5, FUN) So this is the output I'd like to get (I put it in code rather than output format) for each of the matrices created above: list(c("B", "C", "F")) list(c("B", "C", "G"), c("C", "D", "H"), c("G", "H", "L")) list(c("B", "C", "H"), c("C", "D", "I"), c("D", "E", "J"), c("H", "I", "N"), c("I", "J", "O"), c("N", "O", "T")) How can I do this task in the fastest manner possible while staying in base R? Not sure if this visual of what I'm after is helpful but it may be:

    Read the article

  • Opengl problem with texture in model from obj

    - by subSeven
    Hello! I writing small program in OpenGL, and I have problem ( textures are skew, and I dont know why, this model work in another obj viewer) What I have: http://img696.imageshack.us/i/obrazo.png/ What I want http://img88.imageshack.us/i/obraz2d.jpg/ This code where I load texture: bool success; ILuint texId; GLuint image; ilGenImages(1, &texId); ilBindImage(texId); success = ilLoadImage((WCHAR*)fileName.c_str()); if(success) { success = ilConvertImage(IL_RGB, IL_UNSIGNED_BYTE); if(!success) { return false; } } else { return false; } glGenTextures(1, &image); glBindTexture(GL_TEXTURE_2D, image); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexImage2D(GL_TEXTURE_2D, 0, ilGetInteger(IL_IMAGE_BPP), ilGetInteger(IL_IMAGE_WIDTH), ilGetInteger(IL_IMAGE_HEIGHT), 0, ilGetInteger(IL_IMAGE_FORMAT), GL_UNSIGNED_BYTE, ilGetData()); ilDeleteImages(1, &texId); Code to load obj: triangles.clear(); std::ifstream in; std::string cmd; in.open (fileName.c_str()); if (in.is_open()) { while(!in.eof()) { in>>cmd; if(cmd=="v") { Vector3d vector; in>>vector.x; in>>vector.y; in>>vector.z; points.push_back(vector); } if(cmd=="vt") { Vector2d texcord; in>>texcord.x; in>>texcord.y; texcords.push_back(texcord); } if(cmd=="vn") { Vector3d normal; in>>normal.x; in>>normal.y; in>>normal.z; normals.push_back(normal); } if(cmd=="f") { Triangle triangle; std::string str; std::string str1,str2,str3; std::string delimeter("/"); int pos; int n; std::stringstream ss (std::stringstream::in | std::stringstream::out); in>>str; pos = str.find(delimeter); str1 = str.substr(0,pos); str2 = str.substr(pos+delimeter.length()); pos = str2.find(delimeter); str3 = str2.substr(pos+delimeter.length()); str2 = str2.substr(0,pos); ss<<str1; ss>>n; triangle.a= n-1; ss.clear(); ss<<str3; ss>>n; triangle.an =n-1; ss.clear(); ss<<str2; ss>>n; ss.clear(); triangle.atc = n-1; in>>str; pos = str.find(delimeter); str1 = str.substr(0,pos); str2 = str.substr(pos+delimeter.length()); pos = str2.find(delimeter); str3 = str2.substr(pos+delimeter.length()); str2 = str2.substr(0,pos); ss<<str1; ss>>n; triangle.b= n-1; ss.clear(); ss<<str3; ss>>n; triangle.bn =n-1; ss.clear(); ss<<str2; ss>>n; ss.clear(); triangle.btc = n-1; in>>str; pos = str.find(delimeter); str1 = str.substr(0,pos); str2 = str.substr(pos+delimeter.length()); pos = str2.find(delimeter); str3 = str2.substr(pos+delimeter.length()); str2 = str2.substr(0,pos); ss<<str1; ss>>n; triangle.c= n-1; ss.clear(); ss<<str3; ss>>n; triangle.cn =n-1; ss.clear(); ss<<str2; ss>>n; ss.clear(); triangle.ctc = n-1; triangles.push_back(triangle); } cmd = ""; } in.close(); return true; } return false; Code to draw model: glEnable(GL_TEXTURE_2D); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL); glBindTexture(GL_TEXTURE_2D,image); glBegin(GL_TRIANGLES); for(int i=0;i<triangles.size();i++) { glTexCoord2f(texcords[triangles[i].ctc].x, texcords[triangles[i].ctc].y); glNormal3f(normals[triangles[i].cn].x, normals[triangles[i].cn].y, normals[triangles[i].cn].z); glVertex3f( points[triangles[i].c].x, points[triangles[i].c].y, points[triangles[i].c].z); glTexCoord2f(texcords[triangles[i].btc].x, texcords[triangles[i].btc].y); glNormal3f(normals[triangles[i].bn].x, normals[triangles[i].bn].y, normals[triangles[i].bn].z); glVertex3f( points[triangles[i].b].x, points[triangles[i].b].y, points[triangles[i].b].z); glTexCoord2f(texcords[triangles[i].atc].x, texcords[triangles[i].atc].y); glNormal3f(normals[triangles[i].an].x, normals[triangles[i].an].y, normals[triangles[i].an].z); glVertex3f( points[triangles[i].a].x, points[triangles[i].a].y, points[triangles[i].a].z); } glEnd(); glDisable(GL_TEXTURE_2D); Mayby someone find mistake in this

    Read the article

  • how to tesselate bezier triangles?

    - by Cheery
    My concern are quadratic bezier triangles which I'm trying to tesselate for rendering them. I've managed to implement this by subdividing the triangle recursively like described in a wikipedia page. Though I'd like to get more precision to subdivision. The problem is that I'll either get too few subdivisions or too many because the amount of surfaces doubles on every iteration of that algorithm. In particular I would need an adaptive tesselation algorithm that allows me to define the amount of segments at the edges. I'm not sure whether I can get that though so I'd also like to hear about uniform tesselation techniques. Hardest trouble I have trouble with calculating normals for a point in bezier surface, which I'm not sure whether I need, but been trying to solve out.

    Read the article

  • Creating triangles using borders

    - by Interstellar_Coder
    I recently needed to create speech bubbles. To create the little tip at the end of the speech bubble, i used a css technique where the element is given a 0 width and 0 height and given borders. Making certain borders transparent would create diagonals. This works great, and i am able to manipulate different borders to create triangles/shapes to my liking. The problem is, i don't fully understand why this works. I understand that it all starts out with a rectangle and as you set one or more of the borders to transparent it creates a diagonal. My question is how does this work ? And why does it create a diagonal in the first place ? EDIT: To clarify, i would like to know the theory behind why this technique works.

    Read the article

  • circles and triangles problem

    - by Faken
    Hello everyone, I have an interesting problem here I've been trying to solve for the last little while: I have 3 circles on a 2D xy plane, each with the same known radius. I know the coordinates of each of the three centers (they are arbitrary and can be anywhere). What is the largest triangle that can be drawn such that each vertice of the triangle sits on a separate circle, what are the coordinates of those verticies? I've been looking at this problem for hours and asked a bunch of people but so far only one person has been able to suggest a plausible solution (though i have no way of proving it). The solution that we have come up with involves first creating a triangle about the three circle centers. Next we look at each circle individually and calculate the equation of a line that passes through the circle's center and is perpendicular to the opposite edge. We then calculate two intersection points of the circle. This is then done for the next two circles with a result of 6 points. We iterate over the 8 possible 3 point triangles that these 6 points create (the restriction is that each point of the big triangle must be on a separate circle) and find the maximum size. The results look reasonable (at least when drawn out on paper) and it passes the special case of when the centers of the circles all fall on a straight line (gives a known largest triangle). Unfortunate i have no way of proving this is correct or not. I'm wondering if anyone has encountered a problem similar to this and if so, how did you solve it? Note: I understand that this is mostly a math question and not programming, however it is going to be implemented in code and it must be optimized to run very fast and efficient. In fact, I already have the above solution in code and tested to be working, if you would like to take a look, please let me know, i chose not to post it because its all in vector form and pretty much impossible to figure out exactly what is going on (because it's been condensed to be more efficient). Lastly, yes this is for school work, though it is NOT a homework question/assignment/project. It's part of my graduate thesis (abet a very very small part, but still technically is part of it). Thanks for your help.

    Read the article

  • 3D terrain map with Hexagon Grids

    - by Rob
    I'm working on a hobby project (I'm a web/backend developer by day) and I want to create a 3D Tile (terrain) engine. I'm using XNA, but I can use MonoGame, OpenGL, or straight DirectX, so the answer does not have to be XNA specific. I'm more looking for some high level advice on how to approach this problem. I know about creating height maps and such, there are thousands of references out there on the net for that, this is a bit more specific. I'm more concerned with is the approach to get a 3D hexagon tile grid out of my terrain (since the terrain, and all 3d objects, are basically triangles). The first approach I thought about is to basically draw the triangles on the screen in the following order (blue numbers) to give me the triangles for terrain (black triangles) and then make hexes out of the triangles (red hex). This approach seems complicated to me since i'm basically having to draw 4 different types of triangles. The next approach I thought of was to use the existing triangles like I did for a square grid and get my hexes from 6 triangles as follows This seems like the easier approach to me since there are only 2 types of triangles (i would have to play with the heights and widths to get a "perfect" hexagon, but the idea is the same. So I'm looking for: 1) Any suggestions on which approach I should take, and why. 2) How would I translate mouse position to a hexagon grid position (especially when moving the camera around), for example in the second image if the mouse pointer were the green circle, how would I determine to highlight that hexagon and then translating that into grid coordinates (assuming it is 0,0)? 3) Any references, articles, books, etc - to get me going in the right direction. Note: I've done hex grid's and mouse-grid coordinate conversion before in 2d. looking for some pointers on how to do the same in 3d. The result I would like to achieve is something similar to this video.

    Read the article

  • Saving new indicies, triangles and normals after WPF 3D transform

    - by sklitzz
    Hi, I have a 3D model which is lying flat currently, I wish for it to be rotated 90 degrees around the X axis. I have no problem doing this with the transforms. But to my knowledge all the transforms are a bunch of matrices multiplied. I would like to have the transform really alter all the coordinates of the indicies of the model. Is there a way to "save changes" after I apply a transform?

    Read the article

  • Concept: Mapping irregular shapes (cartoons, sprites) to triangles in OpenGL ES

    - by Moshe
    I understand how mapping a triangle texture to a triangle works, but how do you map other things? I can't see myself mapping a circle onto a triangle. If it were a quad (square), I could see it happening, but why would a graphic not get warped on a triangle? EDIT: Bonus question: What are some good OpenGL ES tutorials online? Videos and articles count. (I've seen the Stanford University stuff on iTunes U and think it's excellent, but I want more.)

    Read the article

  • What is the best way to implement collision detection using Bullet physics engine and a track generated from a curve?

    - by tigrou
    I am developing a small racing game were the track is generated from a curve. As said above, the track is generated, but not infinite. The track of one level could fit with no problem in memory and will contain a reasonably small amount of triangles. For collisions, I would like to use Bullet physics engine and know what is the best way to handle collisions with the track efficiently. NOTE : The track will be stored as a static rigid body (mass = 0). The player will be represented by a sphere shape for collisions. Here is some possibilities i have in mind : Create one rigid body, then, put all triangles of the track (except non collidable stuff) into it. Result : 1 body with many triangles (eg : 30000 triangles) Split the track into several sections (eg: 10 sections). Then, for each section, create a rigid body and put corresponding triangles in it. Result : small amount of bodies with relatively small amount of triangles (eg : 1500 triangles per section). Split the track into many sub-sections (eg : 1200 sections). Here one subsection = very small step when generating the curve. Again for each sub-section, create a body and put triangles in it. Result : many bodies with very small amount of triangles (eg : 20 triangles). Advantage : it could be possible to "extra data" to each of the subsection, that could be used when handling collisions. Same as 2, but only put sections N and N+1 in physics engine (where N = current section where the player is). When player reach section N+1, unload section N and load section N+2 and so on... Issue : harder to implement, problems if the player suddenly "jump" from one section to another (eg : player fly away from section N, and fall on section N + 4 that was underneath : no collision handled, player will fall into void ) Same as 4, but with many sub-sections. Issues : since subsections are very small there will be constantly new bodies added and removed to physics engine at runtime. Possibilities for player to accidently skip some sections and fall into the void are higher than 4.

    Read the article

  • Is there any hueristic to polygonize a closed 2d-raster shape with n triangles?

    - by Arthur Wulf White
    Lets say we have a 2d image black on white that shows a closed geometric shape. Is there any (not naive brute force) algorithm that approximates that shape as closely as possible with n triangles? If you want a formal definition for as closely as possible: Approximate the shape with a polygon that when rendered into a new 2d image will match the largest number of pixels possible with the original image.

    Read the article

  • 3D terrain map with Hexagon Grids (XNA)

    - by Rob
    I'm working on a hobby project (I'm a web/backend developer by day) and I want to create a 3D Tile (terrain) engine. I'm using XNA, but I can use MonoGame, OpenGL, or straight DirectX, so the answer does not have to be XNA specific. I'm more looking for some high level advice on how to approach this problem. I know about creating height maps and such, there are thousands of references out there on the net for that, this is a bit more specific. I'm more concerned with is the approach to get a 3D hexagon tile grid out of my terrain (since the terrain, and all 3d objects, are basically triangles). The first approach I thought about is to basically draw the triangles on the screen in the following order (blue numbers) to give me the triangles for terrain (black triangles) and then make hexes out of the triangles (red hex). http://screencast.com/t/ebrH2g5V This approach seems complicated to me since i'm basically having to draw 4 different types of triangles. The next approach I thought of was to use the existing triangles like I did for a square grid and get my hexes from 6 triangles as follows http://screencast.com/t/w9b7qKzVJtb8 This seems like the easier approach to me since there are only 2 types of triangles (i would have to play with the heights and widths to get a "perfect" hexagon, but the idea is the same. So I'm looking for: 1) Any suggestions on which approach I should take, and why. 2) How would I translate mouse position to a hexagon grid position (especially when moving the camera around), for example in the second image if the mouse pointer were the green circle, how would I determine to highlight that hexagon and then translating that into grid coordinates (assuming it is 0,0)? 3) Any references, articles, books, etc - to get me going in the right direction. Note: I've done hex grid's and mouse-grid coordinate conversion before in 2d. looking for some pointers on how to do the same in 3d. The result I would like to achieve is something similar to the following: http :// www. youtube .com / watch?v=Ri92YkyC3fw (sorry about the youtube link, but it will only let me post 2 links in this post... same rep problem i mention below...) Thanks for any help! P.S. Sorry for not posting the images inline, I apparently don't have enough rep on this stack exchange site.

    Read the article

  • Problems with SAT Collision Detection

    - by DJ AzKai
    I'm doing a project in one of my modules for college in C++ with SFML and I was hoping someone may be able to help me. I'm using a vector of squares and triangles and I am using the SAT collision detection method to see if objects collide and to make the objects respond to the collision appropriately using the MTV(minimum translation vector) Below is my code: //from the main method int main(){ // Create the main window sf::RenderWindow App(sf::VideoMode(800, 600, 32), "SFML OpenGL"); // Create a clock for measuring time elapsed sf::Clock Clock; srand(time(0)); //prepare OpenGL surface for HSR glClearDepth(1.f); glClearColor(0.3f, 0.3f, 0.3f, 0.f); //background colour glEnable(GL_DEPTH_TEST); glDepthMask(GL_TRUE); //// Setup a perspective projection & Camera position glMatrixMode(GL_PROJECTION); glLoadIdentity(); //set up a 3D Perspective View volume //gluPerspective(90.f, 1.f, 1.f, 300.0f);//fov, aspect, zNear, zFar //set up a orthographic projection same size as window //this mease the vertex coordinates are in pixel space glOrtho(0,800,0,600,0,1); // use pixel coordinates // Finally, display rendered frame on screen vector<BouncingThing*> triangles; for(int i = 0; i < 10; i++) { //instantiate each triangle; triangles.push_back(new BouncingTriangle(Vector2f(rand() % 700, rand() % 500), 3)); } vector<BouncingThing*> boxes; for(int i = 0; i < 10; i++) { //instantiate each box; boxes.push_back(new BouncingBox(Vector2f(rand() % 700, rand() % 500), 4)); } CollisionDetection * b = new CollisionDetection(); // Start game loop while (App.isOpen()) { // Process events sf::Event Event; while (App.pollEvent(Event)) { // Close window : exit if (Event.type == sf::Event::Closed) App.close(); // Escape key : exit if ((Event.type == sf::Event::KeyPressed) && (Event.key.code == sf::Keyboard::Escape)) App.close(); } //Prepare for drawing // Clear color and depth buffer glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Apply some transformations glMatrixMode(GL_MODELVIEW); glLoadIdentity(); for(int i = 0; i < 10; i++) { triangles[i]->draw(); boxes[i]->draw(); triangles[i]->update(Vector2f(800,600)); boxes[i]->draw(); boxes[i]->update(Vector2f(800,600)); } for(int j = 0; j < 10; j++) { for(int i = 0; i < 10; i++) { triangles[j]->setCollision(b->CheckCollision(*(triangles[j]),*(boxes[i]))); } } for(int j = 0; j < 10; j++) { for(int i = 0; i < 10; i++) { boxes[j]->setCollision(b->CheckCollision(*(boxes[j]),*(triangles[i]))); } } for(int i = 0; i < triangles.size(); i++) { for(int j = i + 1; j < triangles.size(); j ++) { triangles[j]->setCollision(b->CheckCollision(*(triangles[j]),*(triangles[i]))); } } for(int i = 0; i < triangles.size(); i++) { for(int j = i + 1; j < triangles.size(); j ++) { boxes[j]->setCollision(b->CheckCollision(*(boxes[j]),*(boxes[i]))); } } App.display(); } return EXIT_SUCCESS; } (ignore this line) //from the BouncingThing.cpp BouncingThing::BouncingThing(Vector2f position, int noSides) : pos(position), pi(3.14), radius(3.14), nSides(noSides) { collided = false; if(nSides ==3) { Vector2f vert1 = Vector2f(-12.0f,-12.0f); Vector2f vert2 = Vector2f(0.0f, 12.0f); Vector2f vert3 = Vector2f(12.0f,-12.0f); verts.push_back(vert1); verts.push_back(vert2); verts.push_back(vert3); } else if(nSides == 4) { Vector2f vert1 = Vector2f(-12.0f,12.0f); Vector2f vert2 = Vector2f(12.0f, 12.0f); Vector2f vert3 = Vector2f(12.0f,-12.0f); Vector2f vert4 = Vector2f(-12.0f, -12.0f); verts.push_back(vert1); verts.push_back(vert2); verts.push_back(vert3); verts.push_back(vert4); } velocity.x = ((rand() % 5 + 1) / 3) + 1; velocity.y = ((rand() % 5 + 1) / 3 ) +1; } void BouncingThing::update(Vector2f screenSize) { Transform t; t.rotate(0); for(int i=0;i< verts.size(); i++) { verts[i]=t.transformPoint(verts[i]); } if(pos.x >= screenSize.x || pos.x <= 0) { velocity.x *= -1; } if(pos.y >= screenSize.y || pos.y <= 0) { velocity.y *= -1; } if(collided) { //velocity.x *= -1; //velocity.y *= -1; collided = false; } pos += velocity; } void BouncingThing::setCollision(bool x){ collided = x; } void BouncingThing::draw() { glBegin(GL_POLYGON); glColor3f(0,1,0); for(int i = 0; i < verts.size(); i++) { glVertex2f(pos.x + verts[i].x,pos.y + verts[i].y); } glEnd(); } vector<Vector2f> BouncingThing::getNormals() { vector<Vector2f> normalVerts; if(nSides == 3) { Vector2f ab = Vector2f((verts[1].x + pos.x) - (verts[0].x + pos.x), (verts[1].y + pos.y) - (verts[0].y + pos.y)); ab = flip(ab); ab.x *= -1; normalVerts.push_back(ab); Vector2f bc = Vector2f((verts[2].x + pos.x) - (verts[1].x + pos.x), (verts[2].y + pos.y) - (verts[1].y + pos.y)); bc = flip(bc); bc.x *= -1; normalVerts.push_back(bc); Vector2f ac = Vector2f((verts[2].x + pos.x) - (verts[0].x + pos.x), (verts[2].y + pos.y) - (verts[0].y + pos.y)); ac = flip(ac); ac.x *= -1; normalVerts.push_back(ac); return normalVerts; } if(nSides ==4) { Vector2f ab = Vector2f((verts[1].x + pos.x) - (verts[0].x + pos.x), (verts[1].y + pos.y) - (verts[0].y + pos.y)); ab = flip(ab); ab.x *= -1; normalVerts.push_back(ab); Vector2f bc = Vector2f((verts[2].x + pos.x) - (verts[1].x + pos.x), (verts[2].y + pos.y) - (verts[1].y + pos.y)); bc = flip(bc); bc.x *= -1; normalVerts.push_back(bc); return normalVerts; } } Vector2f BouncingThing::flip(Vector2f v){ float vyTemp = v.x; float vxTemp = v.y * -1; return Vector2f(vxTemp, vyTemp); } (Ignore this line) CollisionDetection::CollisionDetection() { } vector<float> CollisionDetection::bubbleSort(vector<float> w) { int temp; bool finished = false; while (!finished) { finished = true; for (int i = 0; i < w.size()-1; i++) { if (w[i] > w[i+1]) { temp = w[i]; w[i] = w[i+1]; w[i+1] = temp; finished=false; } } } return w; } class Vector{ public: //static int dp_count; static float dot(sf::Vector2f a,sf::Vector2f b){ //dp_count++; return a.x*b.x+a.y*b.y; } static float length(sf::Vector2f a){ return sqrt(a.x*a.x+a.y*a.y); } static Vector2f add(Vector2f a, Vector2f b) { return Vector2f(a.x + b.y, a.y + b.y); } static sf::Vector2f getNormal(sf::Vector2f a,sf::Vector2f b){ sf::Vector2f n; n=a-b; n/=Vector::length(n);//normalise float x=n.x; n.x=n.y; n.y=-x; return n; } }; bool CollisionDetection::CheckCollision(BouncingThing & x, BouncingThing & y) { vector<Vector2f> xVerts = x.getVerts(); vector<Vector2f> yVerts = y.getVerts(); vector<Vector2f> xNormals = x.getNormals(); vector<Vector2f> yNormals = y.getNormals(); int size; vector<float> xRange; vector<float> yRange; for(int j = 0; j < xNormals.size(); j++) { Vector p; for(int i = 0; i < xVerts.size(); i++) { xRange.push_back(p.dot(xNormals[j], Vector2f(xVerts[i].x, xVerts[i].x))); } for(int i = 0; i < yVerts.size(); i++) { yRange.push_back(p.dot(xNormals[j], Vector2f(yVerts[i].x , yVerts[i].y))); } yRange = bubbleSort(yRange); xRange = bubbleSort(xRange); if(xRange[xRange.size() - 1] < yRange[0] || yRange[yRange.size() - 1] < xRange[0]) { return false; } float x3 = Min(xRange[0], yRange[0]); float y3 = Max(xRange[xRange.size() - 1], yRange[yRange.size() - 1]); float length = Max(x3, y3) - Min(x3, y3); } for(int j = 0; j < yNormals.size(); j++) { Vector p; for(int i = 0; i < xVerts.size(); i++) { xRange.push_back(p.dot(yNormals[j], xVerts[i])); } for(int i = 0; i < yVerts.size(); i++) { yRange.push_back(p.dot(yNormals[j], yVerts[i])); } yRange = bubbleSort(yRange); xRange = bubbleSort(xRange); if(xRange[xRange.size() - 1] < yRange[0] || yRange[yRange.size() - 1] < xRange[0]) { return false; } } return true; } float CollisionDetection::Min(float min, float max) { if(max < min) { min = max; } else return min; } float CollisionDetection::Max(float min, float max) { if(min > max) { max = min; } else return min; } On the screen the objects will freeze for a small amount of time before moving off again. However the problem is is that when this happens there are no collisions actually happening and I would really love to find out where the flaw is in the code. If you need any more information/code please don't hesitate to ask and I'll reply as soon as possible Regards, AzKai

    Read the article

  • Triangles in a C++ STL Vector as an Objective-C member sometimes draws incorrectly in OpenGL ES

    - by Rahil627
    The polygons draw correctly 80% of the time. When it fails, a vertex is dislocated. The polygon is consistently drawn with the wrong vertex. I checked that the vector is correct during initialization, even when it's wrongly drawn. I'm using Cocos2d. The class member: @interface Polygon : CCSprite { std::vector<float> triangleVertices; } The draw function called in [Polygon draw]: + (void)drawTrianglesWithVertices:(const std::vector<float> &)v { //glEnableClientState(GL_VERTEX_ARRAY); glDisable(GL_TEXTURE_2D); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glDisableClientState(GL_COLOR_ARRAY); glVertexPointer(2, GL_FLOAT, 0, &v[0]); glDrawArrays(GL_TRIANGLES, 0, v.size()); //glDisableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_COLOR_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glEnable(GL_TEXTURE_2D); } Any ideas?

    Read the article

  • Get all triangles that are < N dist from you?

    - by CyanPrime
    Does anyone know of a way I could add a radius to this code for p? Like basically saying "this is true if the triangle is < N dist from the point" public boolean isPointInTriangle( Vector3f p, Vector3f a, Vector3f b, Vector3f c ) { return ( pointsAreOnSameSide(p, a, b, c) && pointsAreOnSameSide(p, b, a, c) && pointsAreOnSameSide(p, c, a, b) ); } public boolean pointsAreOnSameSide( Vector3f p1, Vector3f p2, Vector3f a, Vector3f b ) { Vector3f diffba = new Vector3f(0,0,0); Vector3f.sub( b, a, diffba ); Vector3f diffp1a = new Vector3f(0,0,0); Vector3f.sub( p1, a, diffp1a ); Vector3f diffp2a = new Vector3f(0,0,0); Vector3f.sub( p2, a, diffp2a ); Vector3f cross1 = Vector3f.cross(diffba, diffp1a); Vector3f cross2 = Vector3f.cross(diffba, diffp2a); return ( Vector3f.dot( cross1, cross2 ) >= 0 ); }

    Read the article

  • Decal implementation

    - by dreta
    I had issues finding information about decals, so maybe this question will help others. The implementation is for a forward renderer. Could somebody confirm if i got decal implementation right? You define a cube of any dimension that'll define the projection volume in common space. You check for triangle intersection with the defined cube to recieve triangles that the projection will affect. You clip these triangles and save them. You then use matrix tricks to calculate UV coordinates for the saved triangles that'll reference the texture you're projecting. To do this you take the vectors representing height, width and depth of the cube in common space, so that f.e. the bottom left corner is the origin. You put that in a matrix as the i, j, k unit vectors, set the translation for the cube, then you inverse this matrix. You multiply the vertices of the saved triangles by this matrix, that way you get their coordinates inside of a 0 to 1 size cube that you use as the UV coordinates. This way you have the original triangles you're projecting onto and you have UV coordinates for them (the UV coordinates are referencing the texture you're projecting). Then you rerender the saved triangles onto the scene and they overwrite the area of projection with the projected image. Now the questions that i couldn't find answers for. Is the last point right? I've never done software clipping, but it seems error prone enough, due to limited precision, that the'll be some z fighting occuring for the projected texture. Also is the way of getting UV coordinates correct?

    Read the article

  • Trying to draw textured triangles on device fails, but the emulator works. Why?

    - by Dinedal
    I have a series of OpenGL-ES calls that properly render a triangle and texture it with alpha blending on the emulator (2.0.1). When I fire up the same code on an actual device (Droid 2.0.1), all I get are white squares. This suggests to me that the textures aren't loading, but I can't figure out why they aren't loading. All of my textures are 32-bit PNGs with alpha channels, under res/raw so they aren't optimized per the sdk docs. Here's how I am loading my textures: private void loadGLTexture(GL10 gl, Context context, int reasource_id, int texture_id) { //Get the texture from the Android resource directory Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), reasource_id, sBitmapOptions); //Generate one texture pointer... gl.glGenTextures(1, textures, texture_id); //...and bind it to our array gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[texture_id]); //Create Nearest Filtered Texture gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); //Different possible texture parameters, e.g. GL10.GL_CLAMP_TO_EDGE gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT); //Use the Android GLUtils to specify a two-dimensional texture image from our bitmap GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0); //Clean up bitmap.recycle(); } Here's how I am rendering the texture: //Clear gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); //Enable vertex buffer gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer); //Push transformation matrix gl.glPushMatrix(); //Transformation matrices gl.glTranslatef(x, y, 0.0f); gl.glScalef(scalefactor, scalefactor, 0.0f); gl.glColor4f(1.0f,1.0f,1.0f,1.0f); //Bind the texture gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[textureid]); //Draw the vertices as triangles gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer); //Pop the matrix back to where we left it gl.glPopMatrix(); //Disable the client state before leaving gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); And here are the options I have enabled: gl.glShadeModel(GL10.GL_SMOOTH); //Enable Smooth Shading gl.glEnable(GL10.GL_DEPTH_TEST); //Enables Depth Testing gl.glDepthFunc(GL10.GL_LEQUAL); //The Type Of Depth Testing To Do gl.glEnable(GL10.GL_TEXTURE_2D); gl.glEnable(GL10.GL_BLEND); gl.glBlendFunc(GL10.GL_SRC_ALPHA,GL10.GL_ONE_MINUS_SRC_ALPHA); Edit: I just tried supplying a BitmapOptions to the BitmapFactory.decodeResource() call, but this doesn't seem to fix the issue, despite manually setting the same preferredconfig, density, and targetdensity. Edit2: As requested, here is a screenshot of the emulator working. The underlaying triangles are shown with a circle texture rendered onto it, the transparency is working because you can see the black background. Here is a shot of what the droid does with the exact same code on it: Edit3: Here are my BitmapOptions, updated the call above with how I am now calling the BitmapFactory, still the same results as below: sBitmapOptions.inPreferredConfig = Bitmap.Config.RGB_565; sBitmapOptions.inDensity = 160; sBitmapOptions.inTargetDensity = 160; sBitmapOptions.inScreenDensity = 160; sBitmapOptions.inDither = false; sBitmapOptions.inSampleSize = 1; sBitmapOptions.inScaled = false; Here are my vertices, texture coords, and indices: /** The initial vertex definition */ private static final float vertices[] = { -1.0f, -1.0f, 0.0f, 1.0f, -1.0f, 0.0f, -1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f }; /** The initial texture coordinates (u, v) */ private static final float texture[] = { //Mapping coordinates for the vertices 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f }; /** The initial indices definition */ private static final byte indices[] = { //Faces definition 0,1,3, 0,3,2 }; Is there anyway to dump the contents of the texture once it's been loaded into OpenGL ES? Maybe I can compare the emulator's loaded texture with the actual device's loaded texture? I did try with a different texture (the default android icon) and again, it works fine for the emulator but fails to render on the actual phone. Edit4: Tried switching around when I do texture loading. No luck. Tried using a constant offset of 0 to glGenTextures, no change. Is there something that I'm using that the emulator supports that the actual phone does not? Edit5: Per Ryan below, I resized my texture from 200x200 to 256x256, and the issue was NOT resolved. Edit: As requested, added the calls to glVertexPointer and glTexCoordPointer above. Also, here is the initialization of vertexBuffer, textureBuffer, and indexBuffer: ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4); byteBuf.order(ByteOrder.nativeOrder()); vertexBuffer = byteBuf.asFloatBuffer(); vertexBuffer.put(vertices); vertexBuffer.position(0); byteBuf = ByteBuffer.allocateDirect(texture.length * 4); byteBuf.order(ByteOrder.nativeOrder()); textureBuffer = byteBuf.asFloatBuffer(); textureBuffer.put(texture); textureBuffer.position(0); indexBuffer = ByteBuffer.allocateDirect(indices.length); indexBuffer.put(indices); indexBuffer.position(0); loadGLTextures(gl, this.context);

    Read the article

  • (Unity)Getting a mirrored mesh from my data structure

    - by Steve
    Here's the background: I'm in the beginning stages of an RTS game in Unity. I have a procedurally generated terrain with a perlin-noise height map, as well as a function to generate a river. The problem is that the graphical creation of the map is taking the data structure of the map and rotating it by 180 degrees. I noticed this problem when i was creating my rivers. I would set the River's height to flat, and noticed that the actual tiles that were flat in the graphical representation were flipped and mirrored. Here's 3 screenshots of the map from different angles: http://imgur.com/a/VLHHq As you can see, if you flipped (graphically) the river by 180 degrees on the z axis, it would fit where the terrain is flattened. I have a suspicion it is being caused by a misunderstanding on my part of how vertices work. Alas, here is a snippet of the code that is used: This code here creates a new array of Tile objects, which hold the information for each tile, including its type, coordinate, height, and it's 4 vertices public DTileMap (int size_x, int size_y) { this.size_x = size_x; this.size_y = size_y; //Initialize Map_Data Array of Tile Objects map_data = new Tile[size_x, size_y]; for (int j = 0; j < size_y; j++) { for (int i = 0; i < size_x; i++) { map_data [i, j] = new Tile (); map_data[i,j].coordinate.x = (int)i; map_data[i,j].coordinate.y = (int)j; map_data[i,j].vertices[0] = new Vector3 (i * GTileMap.TileMap.tileSize, map_data[i,j].Height, -j * GTileMap.TileMap.tileSize); map_data[i,j].vertices[1] = new Vector3 ((i+1) * GTileMap.TileMap.tileSize, map_data[i,j].Height, -(j) * GTileMap.TileMap.tileSize); map_data[i,j].vertices[2] = new Vector3 (i * GTileMap.TileMap.tileSize, map_data[i,j].Height, -(j-1) * GTileMap.TileMap.tileSize); map_data[i,j].vertices[3] = new Vector3 ((i+1) * GTileMap.TileMap.tileSize, map_data[i,j].Height, -(j-1) * GTileMap.TileMap.tileSize); } } This code sets the river tiles to height 0 foreach (Tile t in map_data) { if (t.realType == "Water") { t.vertices[0].y = 0f; t.vertices[1].y = 0f; t.vertices[2].y = 0f; t.vertices[3].y = 0f; } } And below is the code to generate the actual graphics from the data: public void BuildMesh () { DTileMap.DTileMap map = new DTileMap.DTileMap (size_x, size_z); int numTiles = size_x * size_z; int numTris = numTiles * 2; int vsize_x = size_x + 1; int vsize_z = size_z + 1; int numVerts = vsize_x * vsize_z; // Generate the mesh data Vector3[] vertices = new Vector3[ numVerts ]; Vector3[] normals = new Vector3[numVerts]; Vector2[] uv = new Vector2[numVerts]; int[] triangles = new int[ numTris * 3 ]; int x, z; for (z=0; z < vsize_z; z++) { for (x=0; x < vsize_x; x++) { normals [z * vsize_x + x] = Vector3.up; uv [z * vsize_x + x] = new Vector2 ((float)x / size_x, 1f - (float)z / size_z); } } for (z=0; z < vsize_z; z+=1) { for (x=0; x < vsize_x; x+=1) { if (x == vsize_x - 1 && z == vsize_z - 1) { vertices [z * vsize_x + x] = DTileMap.DTileMap.map_data [x - 1, z - 1].vertices [3]; } else if (z == vsize_z - 1) { vertices [z * vsize_x + x] = DTileMap.DTileMap.map_data [x, z - 1].vertices [2]; } else if (x == vsize_x - 1) { vertices [z * vsize_x + x] = DTileMap.DTileMap.map_data [x - 1, z].vertices [1]; } else { vertices [z * vsize_x + x] = DTileMap.DTileMap.map_data [x, z].vertices [0]; vertices [z * vsize_x + x+1] = DTileMap.DTileMap.map_data [x, z].vertices [1]; vertices [(z+1) * vsize_x + x] = DTileMap.DTileMap.map_data [x, z].vertices [2]; vertices [(z+1) * vsize_x + x+1] = DTileMap.DTileMap.map_data [x, z].vertices [3]; } } } } for (z=0; z < size_z; z++) { for (x=0; x < size_x; x++) { int squareIndex = z * size_x + x; int triOffset = squareIndex * 6; triangles [triOffset + 0] = z * vsize_x + x + 0; triangles [triOffset + 2] = z * vsize_x + x + vsize_x + 0; triangles [triOffset + 1] = z * vsize_x + x + vsize_x + 1; triangles [triOffset + 3] = z * vsize_x + x + 0; triangles [triOffset + 5] = z * vsize_x + x + vsize_x + 1; triangles [triOffset + 4] = z * vsize_x + x + 1; } } // Create a new Mesh and populate with the data Mesh mesh = new Mesh (); mesh.vertices = vertices; mesh.triangles = triangles; mesh.normals = normals; mesh.uv = uv; // Assign our mesh to our filter/renderer/collider MeshFilter mesh_filter = GetComponent<MeshFilter> (); MeshCollider mesh_collider = GetComponent<MeshCollider> (); mesh_filter.mesh = mesh; mesh_collider.sharedMesh = mesh; calculateMeshTangents (mesh); BuildTexture (map); } If this looks familiar to you, its because i got most of it from Quill18. I've been slowly adapting it for my uses. And please include any suggestions you have for my code. I'm still in the very early prototyping stage.

    Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >