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  • Per-pixel displacement mapping GLSL

    - by Chris
    Im trying to implement a per-pixel displacement shader in GLSL. I read through several papers and "tutorials" I found and ended up with trying to implement the approach NVIDIA used in their Cascade Demo (http://www.slideshare.net/icastano/cascades-demo-secrets) starting at Slide 82. At the moment I am completly stuck with following problem: When I am far away the displacement seems to work. But as more I move closer to my surface, the texture gets bent in x-axis and somehow it looks like there is a little bent in general in one direction. EDIT: I added a video: click I added some screen to illustrate the problem: Well I tried lots of things already and I am starting to get a bit frustrated as my ideas run out. I added my full VS and FS code: VS: #version 400 layout(location = 0) in vec3 IN_VS_Position; layout(location = 1) in vec3 IN_VS_Normal; layout(location = 2) in vec2 IN_VS_Texcoord; layout(location = 3) in vec3 IN_VS_Tangent; layout(location = 4) in vec3 IN_VS_BiTangent; uniform vec3 uLightPos; uniform vec3 uCameraDirection; uniform mat4 uViewProjection; uniform mat4 uModel; uniform mat4 uView; uniform mat3 uNormalMatrix; out vec2 IN_FS_Texcoord; out vec3 IN_FS_CameraDir_Tangent; out vec3 IN_FS_LightDir_Tangent; void main( void ) { IN_FS_Texcoord = IN_VS_Texcoord; vec4 posObject = uModel * vec4(IN_VS_Position, 1.0); vec3 normalObject = (uModel * vec4(IN_VS_Normal, 0.0)).xyz; vec3 tangentObject = (uModel * vec4(IN_VS_Tangent, 0.0)).xyz; //vec3 binormalObject = (uModel * vec4(IN_VS_BiTangent, 0.0)).xyz; vec3 binormalObject = normalize(cross(tangentObject, normalObject)); // uCameraDirection is the camera position, just bad named vec3 fvViewDirection = normalize( uCameraDirection - posObject.xyz); vec3 fvLightDirection = normalize( uLightPos.xyz - posObject.xyz ); IN_FS_CameraDir_Tangent.x = dot( tangentObject, fvViewDirection ); IN_FS_CameraDir_Tangent.y = dot( binormalObject, fvViewDirection ); IN_FS_CameraDir_Tangent.z = dot( normalObject, fvViewDirection ); IN_FS_LightDir_Tangent.x = dot( tangentObject, fvLightDirection ); IN_FS_LightDir_Tangent.y = dot( binormalObject, fvLightDirection ); IN_FS_LightDir_Tangent.z = dot( normalObject, fvLightDirection ); gl_Position = (uViewProjection*uModel) * vec4(IN_VS_Position, 1.0); } The VS just builds the TBN matrix, from incoming normal, tangent and binormal in world space. Calculates the light and eye direction in worldspace. And finally transforms the light and eye direction into tangent space. FS: #version 400 // uniforms uniform Light { vec4 fvDiffuse; vec4 fvAmbient; vec4 fvSpecular; }; uniform Material { vec4 diffuse; vec4 ambient; vec4 specular; vec4 emissive; float fSpecularPower; float shininessStrength; }; uniform sampler2D colorSampler; uniform sampler2D normalMapSampler; uniform sampler2D heightMapSampler; in vec2 IN_FS_Texcoord; in vec3 IN_FS_CameraDir_Tangent; in vec3 IN_FS_LightDir_Tangent; out vec4 color; vec2 TraceRay(in float height, in vec2 coords, in vec3 dir, in float mipmap){ vec2 NewCoords = coords; vec2 dUV = - dir.xy * height * 0.08; float SearchHeight = 1.0; float prev_hits = 0.0; float hit_h = 0.0; for(int i=0;i<10;i++){ SearchHeight -= 0.1; NewCoords += dUV; float CurrentHeight = textureLod(heightMapSampler,NewCoords.xy, mipmap).r; float first_hit = clamp((CurrentHeight - SearchHeight - prev_hits) * 499999.0,0.0,1.0); hit_h += first_hit * SearchHeight; prev_hits += first_hit; } NewCoords = coords + dUV * (1.0-hit_h) * 10.0f - dUV; vec2 Temp = NewCoords; SearchHeight = hit_h+0.1; float Start = SearchHeight; dUV *= 0.2; prev_hits = 0.0; hit_h = 0.0; for(int i=0;i<5;i++){ SearchHeight -= 0.02; NewCoords += dUV; float CurrentHeight = textureLod(heightMapSampler,NewCoords.xy, mipmap).r; float first_hit = clamp((CurrentHeight - SearchHeight - prev_hits) * 499999.0,0.0,1.0); hit_h += first_hit * SearchHeight; prev_hits += first_hit; } NewCoords = Temp + dUV * (Start - hit_h) * 50.0f; return NewCoords; } void main( void ) { vec3 fvLightDirection = normalize( IN_FS_LightDir_Tangent ); vec3 fvViewDirection = normalize( IN_FS_CameraDir_Tangent ); float mipmap = 0; vec2 NewCoord = TraceRay(0.1,IN_FS_Texcoord,fvViewDirection,mipmap); //vec2 ddx = dFdx(NewCoord); //vec2 ddy = dFdy(NewCoord); vec3 BumpMapNormal = textureLod(normalMapSampler, NewCoord.xy, mipmap).xyz; BumpMapNormal = normalize(2.0 * BumpMapNormal - vec3(1.0, 1.0, 1.0)); vec3 fvNormal = BumpMapNormal; float fNDotL = dot( fvNormal, fvLightDirection ); vec3 fvReflection = normalize( ( ( 2.0 * fvNormal ) * fNDotL ) - fvLightDirection ); float fRDotV = max( 0.0, dot( fvReflection, fvViewDirection ) ); vec4 fvBaseColor = textureLod( colorSampler, NewCoord.xy,mipmap); vec4 fvTotalAmbient = fvAmbient * fvBaseColor; vec4 fvTotalDiffuse = fvDiffuse * fNDotL * fvBaseColor; vec4 fvTotalSpecular = fvSpecular * ( pow( fRDotV, fSpecularPower ) ); color = ( fvTotalAmbient + (fvTotalDiffuse + fvTotalSpecular) ); } The FS implements the displacement technique in TraceRay method, while always using mipmap level 0. Most of the code is from NVIDIA sample and another paper I found on the web, so I guess there cannot be much wrong in here. At the end it uses the modified UV coords for getting the displaced normal from the normal map and the color from the color map. I looking forward for some ideas. Thanks in advance! Edit: Here is the code loading the heightmap: glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, mWidth, mHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, mImageData); glGenerateMipmap(GL_TEXTURE_2D); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); Maybe something wrong in here?

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  • Trying to detect collision between two polygons using Separating Axis Theorem

    - by Holly
    The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(vertices[0]); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(vertices[i]); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if( other.x <= y || other.y >= x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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  • Error in my Separating Axis Theorem collision code

    - by Holly
    The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; int x; int y; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } public void update(int xPos, int yPos){ x = xPos; y = yPos; } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(new Vect(vertices[0].x+x, vertices[0].y+y)); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(new Vect(vertices[i].x+x, vertices[i].y+y)); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if(y > other.x && other.y > x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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  • Mail "Can't continue" for a AppleScript function

    - by Paul J. Lucas
    I'm trying to write an AppleScript for use with Mail (on Snow Leopard) to save image attachments of messages to a folder. The main part of the AppleScript is: property ImageExtensionList : {"jpg", "jpeg"} property PicturesFolder : path to pictures folder as text property SaveFolderName : "Fetched" property SaveFolder : PicturesFolder & SaveFolderName tell application "Mail" set theMessages to the selection repeat with theMessage in theMessages repeat with theAttachment in every mail attachment of theMessage set attachmentFileName to theAttachment's name if isImageFileName(attachmentFileName) then set attachmentPathName to SaveFolder & attachmmentFileName save theAttachment in getNonexistantFile(attachmentPathName) end if end repeat end repeat end tell on isImageFileName(theFileName) set dot to offset of "." in theFileName if dot > 0 then set theExtension to text (dot + 1) thru -1 of theFileName return theExtension is in ImageExtensionList end if return false end isImageFileName When run, I get the error: error "Mail got an error: Can’t continue isImageFileName." number -1708 where error -1708 is: Event wasnt handled by an Apple event handler. However, if I copy/paste the isImageFileName() into another script like: property imageExtensionList : {"jpg", "jpeg"} on isImageFileName(theFileName) set dot to offset of "." in theFileName if dot > 0 then set theExtension to text (dot + 1) thru -1 of theFileName return theExtension is in ImageExtensionList end if return false end isImageFileName if isImageFileName("foo.jpg") then return true else return false end if it works fine. Why does Mail complain about this?

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  • formula for replicating glTexGen in opengl es 2.0 glsl

    - by visualjc
    I also posted this on the main StackExchange, but this seems like a better place, but for give me for the double post if it shows up twice. I have been trying for several hours to implement a GLSL replacement for glTexGen with GL_OBJECT_LINEAR. For OpenGL ES 2.0. In Ogl GLSL there is the gl_TextureMatrix that makes this easier, but thats not available on OpenGL ES 2.0 / OpenGL ES Shader Language 1.0 Several sites have mentioned that this should be "easy" to do in a GLSL vert shader. But I just can not get it to work. My hunch is that I'm not setting the planes up correctly, or I'm missing something in my understanding. I've pored over the web. But most sites are talking about projected textures, I'm just looking to create UV's based on planar projection. The models are being built in Maya, have 50k polygons and the modeler is using planer mapping, but Maya will not export the UV's. So I'm trying to figure this out. I've looked at the glTexGen manpage information: g = p1xo + p2yo + p3zo + p4wo What is g? Is g the value of s in the texture2d call? I've looked at the site: http://www.opengl.org/wiki/Mathematics_of_glTexGen Another size explains the same function: coord = P1*X + P2*Y + P3*Z + P4*W I don't get how coord (an UV vec2 in my mind) is equal to the dot product (a scalar value)? Same problem I had before with "g". What do I set the plane to be? In my opengl c++ 3.0 code, I set it to [0, 0, 1, 0] (basically unit z) and glTexGen works great. I'm still missing something. My vert shader looks basically like this: WVPMatrix = World View Project Matrix. POSITION is the model vertex position. varying vec4 kOutBaseTCoord; void main() { gl_Position = WVPMatrix * vec4(POSITION, 1.0); vec4 sPlane = vec4(1.0, 0.0, 0.0, 0.0); vec4 tPlane = vec4(0.0, 1.0, 0.0, 0.0); vec4 rPlane = vec4(0.0, 0.0, 0.0, 0.0); vec4 qPlane = vec4(0.0, 0.0, 0.0, 0.0); kOutBaseTCoord.s = dot(vec4(POSITION, 1.0), sPlane); kOutBaseTCoord.t = dot(vec4(POSITION, 1.0), tPlane); //kOutBaseTCoord.r = dot(vec4(POSITION, 1.0), rPlane); //kOutBaseTCoord.q = dot(vec4(POSITION, 1.0), qPlane); } The frag shader precision mediump float; uniform sampler2D BaseSampler; varying mediump vec4 kOutBaseTCoord; void main() { //gl_FragColor = vec4(kOutBaseTCoord.st, 0.0, 1.0); gl_FragColor = texture2D(BaseSampler, kOutBaseTCoord.st); } I've tried texture2DProj in frag shader Here are some of the other links I've looked up http://www.gamedev.net/topic/407961-texgen-not-working-with-glsl-with-fixed-pipeline-is-ok/ Thank you in advance.

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  • Redhat Kernel patching advice

    - by AndyM
    An audit has pointed out that a RHEL server I manage has not had the latest kernel patches applied. I'm confused about kernel patching and within RHEL in relation to RHEL dot releases i.e 5.2 , 5.3 ,5.4 ..... Can someone answer these questions ? If I want to stay at a dot release of RHEL, say 5.4, can apply just updates to the 5.4 kernel or will applying kernel updates bring the server to a later dot release by default? The reason for this question is that I have applications that are only supported on say RHEL5.4 and going to a more recent dot release of RHEL 5 would break the support. I have some HP psp hba drivers compiled against the currently installed kernel, will applying a kernel update break these drivers as they were complied against the orginal kernel ? Anything else I need to look out for with regards to kernel patching ?

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  • DVI splitter not working as expected/confusion between DVI-D and -I

    - by Freakishly
    Hey guys, thanks for looking. I have an ATI FirePro™ V3700 in my desktop machine, and I have been running a dual-monitor setup quite effortlessly, thanks to the two DVI ports on the card. I came upon a third monitor, and wanted to extend my desktop to 3 screens, so I purchased a DVI splitter from Amazon. Now, I can only duplicate the second monitor onto the third, not extend it. I've tried all possible combinations of input to no avail. Here's the setup: The ATI FirePro™ V3700 has two Dual-Link DVI-I outputs The splitter splits a single Dual-Link DVI-I port into two Dual-Link DVI-I outputs Two of the monitors are NEC E222W, and the third monitor is a Dell 2001FP. Each monitor has one D-Sub and one Dual-Link DVI-D input. Cables going from the video card to the monitors are two Dual-Link DVI-D to the NECs and one Single-Link DVI-D to the Dell. Is the problem likely with the DVI-D/DVI-I mismatch? Or is it with the cable on the Dell that is only a Single-Link? The cables are easily replaceable, the monitors not so much. Thanks for your time, I really appreciate it. http://www.amd.com/us/products/workstation/graphics/ati-firepro-3d/v3700/Pages/v3700-specs.aspx http://www.amazon.com/Cables-Unlimited-DVI-D-Splitter-PCM-2260/product-reviews/B000H09RFM/ref=dp_top_cm_cr_acr_txt?ie=UTF8&showViewpoints=1 www dot newegg dot com/Product/Product.aspx?Item=N82E16824002495 accessories dot us dot dell dot com/sna/PopupProductDetail.aspx?cs=19&l=en&c=us&sku=320-1578 Apologies for the fudged links, I'm new here and they won't let me post more than two :P

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  • Point inside Oriented Bounding Box?

    - by Milo
    I have an OBB2D class based on SAT. This is my point in OBB method: public boolean pointInside(float x, float y) { float newy = (float) (Math.sin(angle) * (y - center.y) + Math.cos(angle) * (x - center.x)); float newx = (float) (Math.cos(angle) * (x - center.x) - Math.sin(angle) * (y - center.y)); return (newy > center.y - (getHeight() / 2)) && (newy < center.y + (getHeight() / 2)) && (newx > center.x - (getWidth() / 2)) && (newx < center.x + (getWidth() / 2)); } public boolean pointInside(Vector2D v) { return pointInside(v.x,v.y); } Here is the rest of the class; the parts that pertain: public class OBB2D { private Vector2D projVec = new Vector2D(); private static Vector2D projAVec = new Vector2D(); private static Vector2D projBVec = new Vector2D(); private static Vector2D tempNormal = new Vector2D(); private Vector2D deltaVec = new Vector2D(); private ArrayList<Vector2D> collisionPoints = new ArrayList<Vector2D>(); // Corners of the box, where 0 is the lower left. private Vector2D corner[] = new Vector2D[4]; private Vector2D center = new Vector2D(); private Vector2D extents = new Vector2D(); private RectF boundingRect = new RectF(); private float angle; //Two edges of the box extended away from corner[0]. private Vector2D axis[] = new Vector2D[2]; private double origin[] = new double[2]; public OBB2D(float centerx, float centery, float w, float h, float angle) { for(int i = 0; i < corner.length; ++i) { corner[i] = new Vector2D(); } for(int i = 0; i < axis.length; ++i) { axis[i] = new Vector2D(); } set(centerx,centery,w,h,angle); } public OBB2D(float left, float top, float width, float height) { for(int i = 0; i < corner.length; ++i) { corner[i] = new Vector2D(); } for(int i = 0; i < axis.length; ++i) { axis[i] = new Vector2D(); } set(left + (width / 2), top + (height / 2),width,height,0.0f); } public void set(float centerx,float centery,float w, float h,float angle) { float vxx = (float)Math.cos(angle); float vxy = (float)Math.sin(angle); float vyx = (float)-Math.sin(angle); float vyy = (float)Math.cos(angle); vxx *= w / 2; vxy *= (w / 2); vyx *= (h / 2); vyy *= (h / 2); corner[0].x = centerx - vxx - vyx; corner[0].y = centery - vxy - vyy; corner[1].x = centerx + vxx - vyx; corner[1].y = centery + vxy - vyy; corner[2].x = centerx + vxx + vyx; corner[2].y = centery + vxy + vyy; corner[3].x = centerx - vxx + vyx; corner[3].y = centery - vxy + vyy; this.center.x = centerx; this.center.y = centery; this.angle = angle; computeAxes(); extents.x = w / 2; extents.y = h / 2; computeBoundingRect(); } //Updates the axes after the corners move. Assumes the //corners actually form a rectangle. private void computeAxes() { axis[0].x = corner[1].x - corner[0].x; axis[0].y = corner[1].y - corner[0].y; axis[1].x = corner[3].x - corner[0].x; axis[1].y = corner[3].y - corner[0].y; // Make the length of each axis 1/edge length so we know any // dot product must be less than 1 to fall within the edge. for (int a = 0; a < axis.length; ++a) { float l = axis[a].length(); float ll = l * l; axis[a].x = axis[a].x / ll; axis[a].y = axis[a].y / ll; origin[a] = corner[0].dot(axis[a]); } } public void computeBoundingRect() { boundingRect.left = JMath.min(JMath.min(corner[0].x, corner[3].x), JMath.min(corner[1].x, corner[2].x)); boundingRect.top = JMath.min(JMath.min(corner[0].y, corner[1].y),JMath.min(corner[2].y, corner[3].y)); boundingRect.right = JMath.max(JMath.max(corner[1].x, corner[2].x), JMath.max(corner[0].x, corner[3].x)); boundingRect.bottom = JMath.max(JMath.max(corner[2].y, corner[3].y),JMath.max(corner[0].y, corner[1].y)); } public void set(RectF rect) { set(rect.centerX(),rect.centerY(),rect.width(),rect.height(),0.0f); } // Returns true if other overlaps one dimension of this. private boolean overlaps1Way(OBB2D other) { for (int a = 0; a < axis.length; ++a) { double t = other.corner[0].dot(axis[a]); // Find the extent of box 2 on axis a double tMin = t; double tMax = t; for (int c = 1; c < corner.length; ++c) { t = other.corner[c].dot(axis[a]); if (t < tMin) { tMin = t; } else if (t > tMax) { tMax = t; } } // We have to subtract off the origin // See if [tMin, tMax] intersects [0, 1] if ((tMin > 1 + origin[a]) || (tMax < origin[a])) { // There was no intersection along this dimension; // the boxes cannot possibly overlap. return false; } } // There was no dimension along which there is no intersection. // Therefore the boxes overlap. return true; } public void moveTo(float centerx, float centery) { float cx,cy; cx = center.x; cy = center.y; deltaVec.x = centerx - cx; deltaVec.y = centery - cy; for (int c = 0; c < 4; ++c) { corner[c].x += deltaVec.x; corner[c].y += deltaVec.y; } boundingRect.left += deltaVec.x; boundingRect.top += deltaVec.y; boundingRect.right += deltaVec.x; boundingRect.bottom += deltaVec.y; this.center.x = centerx; this.center.y = centery; computeAxes(); } // Returns true if the intersection of the boxes is non-empty. public boolean overlaps(OBB2D other) { if(right() < other.left()) { return false; } if(bottom() < other.top()) { return false; } if(left() > other.right()) { return false; } if(top() > other.bottom()) { return false; } if(other.getAngle() == 0.0f && getAngle() == 0.0f) { return true; } return overlaps1Way(other) && other.overlaps1Way(this); } public Vector2D getCenter() { return center; } public float getWidth() { return extents.x * 2; } public float getHeight() { return extents.y * 2; } public void setAngle(float angle) { set(center.x,center.y,getWidth(),getHeight(),angle); } public float getAngle() { return angle; } public void setSize(float w,float h) { set(center.x,center.y,w,h,angle); } public float left() { return boundingRect.left; } public float right() { return boundingRect.right; } public float bottom() { return boundingRect.bottom; } public float top() { return boundingRect.top; } public RectF getBoundingRect() { return boundingRect; } public boolean overlaps(float left, float top, float right, float bottom) { if(right() < left) { return false; } if(bottom() < top) { return false; } if(left() > right) { return false; } if(top() > bottom) { return false; } return true; } public static float distance(float ax, float ay,float bx, float by) { if (ax < bx) return bx - ay; else return ax - by; } public Vector2D project(float ax, float ay) { projVec.x = Float.MAX_VALUE; projVec.y = Float.MIN_VALUE; for (int i = 0; i < corner.length; ++i) { float dot = Vector2D.dot(corner[i].x,corner[i].y,ax,ay); projVec.x = JMath.min(dot, projVec.x); projVec.y = JMath.max(dot, projVec.y); } return projVec; } public Vector2D getCorner(int c) { return corner[c]; } public int getNumCorners() { return corner.length; } public boolean pointInside(float x, float y) { float newy = (float) (Math.sin(angle) * (y - center.y) + Math.cos(angle) * (x - center.x)); float newx = (float) (Math.cos(angle) * (x - center.x) - Math.sin(angle) * (y - center.y)); return (newy > center.y - (getHeight() / 2)) && (newy < center.y + (getHeight() / 2)) && (newx > center.x - (getWidth() / 2)) && (newx < center.x + (getWidth() / 2)); } public boolean pointInside(Vector2D v) { return pointInside(v.x,v.y); } public ArrayList<Vector2D> getCollsionPoints(OBB2D b) { collisionPoints.clear(); for(int i = 0; i < corner.length; ++i) { if(b.pointInside(corner[i])) { collisionPoints.add(corner[i]); } } for(int i = 0; i < b.corner.length; ++i) { if(pointInside(b.corner[i])) { collisionPoints.add(b.corner[i]); } } return collisionPoints; } }; What could be wrong? When I getCollisionPoints for 2 OBBs I know are penetrating, it returns no points. Thanks

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  • Huge google impression drop after cleaning html

    - by olgatorresfoundation
    Good morning, I am the webmaster of a non-profit organization that donates grants to colorectal cancer research projects and funds various colorectal cancer information campaigns. We have three domains: www.fundacioolgatorres dot org (Catalan) www.fundacionolgatorres dot org (Spanish) www.olgatorresfoundation dot org (English) So what happened? I redesigned olgatorresfoundation on the 20th and the fundacionolgatorres on the 30th of May. In both cases, exactly two days later, the number of impressions on both dropped to a halt. Granted, we did not have the traffic of Microsoft, but a 90% decrease a disaster of incredible proportions for us. My only real changes were cleaning up the old ineffective HTML to a cleaner form (mostly moving away from redundant table construction to a table-less view). Here is a before and after snapshot of what the change looks like: Before: http://www.fundacioolgatorres.org/aparell_digestiu/introduccio/ (unchanged page in Catalan) After: http://www.olgatorresfoundation.org/digestive_system/introduction/ (changed page in English) Anybody has a clue to what just happened? Why should a normal, sane html improvement be punished and so dramatically? No URLs have been changed, neither have page names or descriptions. Possible secondary question: If it is so that Google sees it as a major overhaul and decides to drop the pagerank sharply, does it come back to pre-change levels if the content "checks out" or will the page start over from scratch earning those pagerank points (which would mean that we would have to wait 6 months for the pages to recover to the level they had two weeks ago)? (duplicated from productforums.google dot com/forum/#!category-topic/webmasters/crawling-indexing--ranking/YsnyX0JzOpY, hoping to reach a wider audience)

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  • Implementing Circle Physics in Java

    - by Shijima
    I am working on a simple physics based game where 2 balls bounce off each other. I am following a tutorial, 2-Dimensional Elastic Collisions Without Trigonometry, for the collision reactions. I am using Vector2 from the LIBGDX library to handle vectors. I am a bit confused on how to implement step 6 in Java from the tutorial. Below is my current code, please note that the code strictly follows the tutorial and there are redundant pieces of code which I plan to refactor later. Note: refrences to this refer to ball 1, and ball refers to ball 2. /* * Step 1 * * Find the Normal, Unit Normal and Unit Tangential vectors */ Vector2 n = new Vector2(this.position[0] - ball.position[0], this.position[1] - ball.position[1]); Vector2 un = n.normalize(); Vector2 ut = new Vector2(-un.y, un.x); /* * Step 2 * * Create the initial (before collision) velocity vectors */ Vector2 v1 = this.velocity; Vector2 v2 = ball.velocity; /* * Step 3 * * Resolve the velocity vectors into normal and tangential components */ float v1n = un.dot(v1); float v1t = ut.dot(v1); float v2n = un.dot(v2); float v2t = ut.dot(v2); /* * Step 4 * * Find the new tangential Velocities after collision */ float v1tPrime = v1t; float v2tPrime = v2t; /* * Step 5 * * Find the new normal velocities */ float v1nPrime = v1n * (this.mass - ball.mass) + (2 * ball.mass * v2n) / (this.mass + ball.mass); float v2nPrime = v2n * (ball.mass - this.mass) + (2 * this.mass * v1n) / (this.mass + ball.mass); /* * Step 6 * * Convert the scalar normal and tangential velocities into vectors??? */

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  • Making particle bounce off a line with friction

    - by Dlaor
    So I'm making a game and I need a particle to bounce off a line. I've got this so far: public static Vector2f Reflect(this Vector2f vec, Vector2f axis) //vec is velocity { Vector2f result = vec - 2f * axis * axis.Dot(vec); return result; } Which works fine, but then I decided I wanted to be able to change the bounciness and friction of the bounce. I got bounciness down... public static Vector2f Reflect(this Vector2f vec, Vector2f axis, float bounciness) //Bounciness goes from 0 to 1, 0 being not bouncy and 1 being perfectly bouncy { var reflect = (1 + bounciness); //2f Vector2f result = vec - reflect * axis * axis.Dot(vec); return result; } But when I tried to add friction, everything went to hell and back... public static Vector2f Reflect(this Vector2f vec, Vector2f axis, float bounciness, float friction) //Does not work at all! { var reflect = (1 + bounciness); //2f Vector2f subtract = reflect * axis * axis.Dot(vec); Vector2f subtract2 = axis * axis.Dot(vec); Vector2f result = vec - subtract; result -= axis.PerpendicularLeft() * subtract2.Length() * friction; return result; } Any physics guys willing to help me out with this? (if you're not sure what I mean with the friction of a bounce see this: http://www.metanetsoftware.com/technique/diagrams/A-1_particle_collision.swf)

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  • What is causing this behavior with the movement of Pong Ball in 2D? [closed]

    - by thegermanpole
    //edit after running it through the debugger it turned out i had the display function set to x,x...TIL how to use a debugger I've been trying to teach myself C++ SDL with the lazyfoo tutorial and seem to have run into a roadblock. The code below is the movement function of my Dot class, which controls the ball. The ball seems to ignore yvel and moves with xvel to the bottom right. The code should be pretty readable, the rest of the relevant facts are: All variables are names Constants are in caps dotrad is the radius of my dot yvel and xvel are set to 5 in the constructor The dot is created at x and y equal to 100 When I comment out the x movement block it doesn't move, but if i comment out the y movement block, it keeps on going down to the right. void Dot::move() { if(((y+yvel+dotrad) <= SCREEN_HEIGHT) && (0 <= (y-dotrad+yvel))) { y+=yvel; } else { yvel = -1*yvel; } if(((x+xvel+dotrad) <= SCREEN_WIDTH) && (0 <= (x-dotrad+xvel))) { x +=xvel; } else { xvel = -1*xvel; } }

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  • COM INTEROP Support - which is better? C# or VB

    - by dot
    I keep hearing that c# is "better" than vb... but as far as I can see, aside from syntactical differences, both compile down to the same IL. I've found some good articles by googling that explain what the differences are between the two and so I feel comfortable in "diffusing" conversations between developers arguing over vb / c#. =) But I did read an article that said vb.net 2005 had better support for com interop stuff. But i'm wondering if this is still the case? This is of interest to me because we are in the middle of redesigning an old vb6 app that communicates with some older COM components. Does anyone have recent experience with .NET and COM interop? Thanks.

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  • Configurable tables in sql database

    - by dot
    I have the following tables in my database: Config Table: ====================================== Start_Range | End Range | Config_id 10 | 15 | 1 ====================================== Available_UserIDs ========================== ID | UserID | Used_YN | 1 | 10 | t | 1 | 11 | f | 1 | 12 | f | 1 | 13 | f | 1 | 14 | f | 1 | 15 | f | ========================== Users ========================== UserId | FName | LName | 10 |John | Doe | ========================== This is used in a reservation system of sorts... which lets an administrator specify a range of numbers that will be assigned to users in the config table. Once the range has been defined, the system then populates the Available_userIDs table with all the numbers in between the range, and sets the Used_YN flag to false As users sign up, they grab the next user_id number that's not in use... and reserve it. Then the system adds a record to the Users table. Once the admin has specified a range, it is possible that they can change it. For example, they can start with 10-15... and then when the range is used up, they should be able to specify another range like 16 - 99. I've put a unique constraint on the Available_UserIDs table, as well as on the Users table - to ensure that UserIds can't be duplicated. My questions are as follows: What's the best way to prevent the admins from using a range that's already in use? I thought of the following options: -- check either the Users table to see if the start range or ending range numbers are being used. If they are, assume that all the numbers in between are in use too, and reject the range. -- let them specify whatever they want, try to populate the Available_UserIDs table. If there are duplicates, just ignore that specific error message from the database and continue on. How do I find gaps in the number ranges? For example, if they specify 10-15, and then 20-25, it'd be nice to be able to somehow suggest on my web page that 16-19 is currently available. I found this article: http://stackoverflow.com/questions/1312101/how-to-find-a-gap-in-running-counter-with-sql But it only seems to return the first available number... so in my example above, it would only return the number 16. I'm sure there's a simpler way to do things that I'm overlooking!

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  • install android sdk on kubuntu

    - by dot
    I'm trying to follow the instructions for installing the android sdk found here: http://developer.android.com/sdk/installing/adding-packages.html After i've unpackaged and i run the android program under tools, I don't get all the options that I'm supposed to. The only 2 folders that show up are tools, and extras. Under tools, it only shows the "Android SDK Tools" with the status "Installed". Under the "extas" folder, I have nothing. I've made sure that my http: proxy settings are correct. And I've checked the logs. there are no errors. According to the android developer site, I'm supposed to install the SDK platform tools. has anyone tried this on ubuntu? I also checked and saw others were instructed to do an apt-get install ia32-libs but it failed for me. Besides which, I am running the 32bit os... so I don't think i would need to install that... ?? I've also tried following the instructions found here: http://forums.team-nocturnal.com/showthread.php/772 But... I can't seem to add the personal archive nilarimogard without getting an error message. when i attempt: sudo add-apt-repository ppa:nilarimogard/webupd8 I get the message: Traceback (most recent call last): File "/usr/bin/add-apt-repository", line 125, in ppa_info = get_ppa_info_from_lp(user, ppa_name) File "/usr/lib/python2.7/dist-packages/softwareproperties/ppa.py", line 80, in get_ppa_info_from_lp curl.perform() pycurl.error: (7, "couldn't connect to host") root@jll:/home/me/Documents# any suggestions? Thanks.

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  • Reporting Solution in PHP / CodeIgniter - Server side logic vs client side

    - by dot
    I'm building a report for an end user. They would like to see a list of all widgets... but then also like to see widgets with missing attributes, like missing names, or missing size. So i was thinking of creating one method that returns json data containing all widgets... and then using javascript to let them filter the data for missing data, instead of requerying the database. Ultimately, they need to be able to save all "reports" (filtered versions of data) inside a csv file. These are the two options I'm mulling over: Design 1 Create 3 separate methods in my controller/model like: get_all_data() get_records_with_missing_names() get_records_with_missing_size() And then when these methods are called, I would display the data on screen and give them a button to save to csv file. Design 2 Create one method called get_all_data() and then somehow, give them tools in the view to filter the json data using tables etc... and then letting them save subsets of the data. The reality is, in order to display all data, I still need to massage the data, and therefore, I know which records are missing attributes. So i'd rather not create separate methods by each filter. I'm not sure how I would do that just yet but at this point, i would like to know some pros/cons of each method. Thanks.

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  • designing solution to dynamically load class

    - by dot
    Background Information I have a web app that allows end users to connect to ssh-enabled devices and manipulate them. Right now, i only support one version of firmware. The logic is something like this: user clicks on a button to run some command on device. web application looks up the class name containing the correct ssh interface for the device, using the device's model name. (because the number of hardware models is so small, i have a list that's hardcoded in my web app) web app creates a new ssh object using the class loaded in step 2. ssh command is run and session closed. command results displayed on web page. This all works fine. Now the end user wants me to be able to support multiple versions of firmware. But the catch is, they don't want to have to document the firmware version anywhere becuase the amount of overhead this will create in maintaining the system database. In other words, I can't look up the firmware version based on the device. The good news is that it sounds like at most, I'll have to support two different versions of firmware per device. One option is to name the the classes like this: deviceX.1.php deviceX.2.php deviceY.1.php deviceY.2.php where "X" and "Y" represent the model names, and 1 and 2 represent the firmware versions. When a user runs a command, I will first try it with one of the class files, if it fails, i can try with the second. I think always try the newer version of firmware first... so let's say in the above example, I would load deviceX.2.php before deviceX.1.php. This will work, but it's not very efficient. But I can't think of another way around this. Any suggestions?

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  • how to speed up this code? [migrated]

    - by dot
    I have some code that's taking over 3 seconds to complete. I'm just wondering if there's a faster way to do this. I have a string with anywhere from 10 to 70 rows of data. I break it up into an array and then loop through the array to find specific patterns. $this->_data = str_replace(chr(27)," ",$this->_data,$count);//strip out esc character $this->_data = explode("\r\n", $this->_data); $detailsArray = array(); foreach ($this->_data as $details) { $pattern = '/(\s+)([0-9a-z]*)(\s+)(100\/1000T|10|1000SX|\s+)(\s*)(\|)(\s+)(\w+)(\s+)(\w+)(\s+)(\w+)(\s+)(1000FDx|10HDx|100HDx|10FDx|100FDx|\s+)(\s*)(\w+)(\s*)(\w+|\s+)(\s*)(0)/i'; if (preg_match($pattern, $details, $matches)) { array_push($detailsArray, array( 'Port' => $matches[2], 'Type' => $matches[4], 'Alert' => $matches[8], 'Enabled' => $matches[10], 'Status' => $matches[12], 'Mode' => $matches[14], 'MDIMode' => $matches[16], 'FlowCtrl' => $matches[18], 'BcastLimit' => $matches[20])); }//end if }//end for $this->_data = $detailsArray; Just wondering if you think there's a way to make it more efficient. Thanks.

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  • View matrix in opengl

    - by user5584
    Hi! Sorry for my clumsy question. But I don't know where I am wrong at creating view matrix. I have the following code: createMatrix(vec4f(xAxis.x, xAxis.y, xAxis.z, dot(xAxis,eye)), vec4f( yAxis.x_, yAxis.y_, yAxis.z_, dot(yAxis,eye)), vec4f(-zAxis.x_, -zAxis.y_, -zAxis.z_, -dot(zAxis,eye)), vec4f(0, 0, 0, 1)); //column1, column2,... I have tried to transpose it, but with no success. I have also tried to use gluLookAt(...) with success. At the reference page, I watched the remarks about the to-be-created matrix, and it seems the same as mine. Where I am wrong?

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  • What's the most efficient way to find barycentric coordinates?

    - by bobobobo
    In my profiler, finding barycentric coordinates is apparently somewhat of a bottleneck. I am looking to make it more efficient. It follows the method in shirley, where you compute the area of the triangles formed by embedding the point P inside the triangle. Code: Vector Triangle::getBarycentricCoordinatesAt( const Vector & P ) const { Vector bary ; // The area of a triangle is real areaABC = DOT( normal, CROSS( (b - a), (c - a) ) ) ; real areaPBC = DOT( normal, CROSS( (b - P), (c - P) ) ) ; real areaPCA = DOT( normal, CROSS( (c - P), (a - P) ) ) ; bary.x = areaPBC / areaABC ; // alpha bary.y = areaPCA / areaABC ; // beta bary.z = 1.0f - bary.x - bary.y ; // gamma return bary ; } This method works, but I'm looking for a more efficient one!

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  • CW/CCW Rotation of a Vector

    - by user23132
    Considering that I have a vector A, and after an arbitrary rotation I get vector B. I want to use this rotation operation in others vectors as well, but I'm having problems in doing that. My idea do that is to calculate the perpendicular vector C of the plane AB (by calculating AxB). This vector C is the axis that I'll need to rotate. To discover the angle I used the dot product between A and B, the acos of the dot product will return the lowest angle between A and B, the angle ang. The rotation I need to do is then: -rotate *ang*º around the C axis. The problem is that I dont know if this rotation is a CW or CCW rotation, since the cos of the dot product does not give me information of the sign of the angle. There's a tip discover that in 2D ( A.x * B.y - A.y * B.x) that you can use to discover if the vector A is at left/right of vector B. But I dont know how to do this in 3D space. Can anyone help me?

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  • Apress Books - 3 - Pro ASP.NET 4 CMS (ISBN 987-1-4302-2712-0) - Final comments

    - by TATWORTH
    This book is more than just  a book about an ASP.NET CMS system -  it has much practical advice and examples for the Dot Net web developer. I liked the use of JQuery to detect that JavaScript was not enabled. One chapter was about MemCached - this one chapter could justify the price of the book if you run a server farm and need to improve performance. Some links to get you started are: Windows Memcache at http://code.jellycan.com/memcached/ Dot Net Access Library at http://sourceforge.net/projects/memcacheddotnet/ The chapters on scripting, performance analysis and search engne optimisation all provide excellent examples. This certainly is a book that should be part of every Dot Net Web Development team library. Congratulations to the author and to Apress for publishing this book!

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  • How do I install graphviz 2.29 in 12.04?

    - by bidur
    In my ubuntu 12.04, the graphviz is not the latest version(2.29). I need some features available in the latest version of graphviz. I tried to install the graphviz version 2.29, which requires libgraphviz4(=2.18). I anyhow installed libgraphviz4 and installed graphviz 2.29. For that I have to remove packages libcdt4 and libpathplan4. Now whenever I try to generate graph, I get some problems: For e.g.: dot -Kfdp -n -Tpng -o samplePOS.png forcePOS.dot It says: dot: error while loading shared libraries: libgvc.so.6: cannot open shared object file: No such file or directory neato -Tps -o sample_1.ps sourcedot.gv It says: neato: error while loading shared libraries: libgvc.so.6: cannot open shared object file: No such file or directory So, I am looking for some ways so that I can run graphviz 2.29 in my ubuntu 12.04.

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