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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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  • Unity3D - Projection matrix camera frustum

    - by MulletDevil
    I've used off centre projection to create a custom projection matrix for my camera. When I run the game I can see the scene correctly in the game view but in the editor view the camera frustum is not correct. It still shows the original frustum shape not the new one. It also appears that Unity is using the original frustum for frustum culling and not the new one as I can see object being culled which are visible to the new frustum but would not be visible in the old one. Am I wrong in thinking that a custom projection matrix would alter the view frustum? Or am I missing something else?

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  • Arbitrary projection matrix from 6 arbitrary frustum planes

    - by Doub
    A projection matrix represent a tranformation from the camera view space to the rendering system clip space. In other words, it defines the transormation between a 6-sided frustum to the clip cube. The glOrtho and glFrustum use only 6 parameter to define such a projection, but impose several constraints on the frustum that will get projected to the clip cube: the near and far planes are parallel, the left and right planes intersect on a vertical line, and the top and bottom planes intersect on a horizontal lines, both lines being parallel to the near and far planes. I'd like to lift these restrictions. So, from the definition of the 6 frustum side planes (in whatever representation you see fit), how can I compute a general projection matrix?

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  • projection / view matrix: the object is bigger than it should and depth does not affect vertices

    - by Francesco Noferi
    I'm currently trying to write a C 3D software rendering engine from scratch just for fun and to have an insight on what OpenGL does behind the scene and what 90's programmers had to do on DOS. I have written my own matrix library and tested it without noticing any issues, but when I tried projecting the vertices of a simple 2x2 cube at 0,0 as seen by a basic camera at 0,0,10, the cube seems to appear way bigger than the application's window. If I scale the vertices' coordinates down by 8 times I can see a proper cube centered on the screen. This cube doesn't seem to be in perspective: wheen seen from the front, the back vertices pe rfectly overlap with the front ones, so I'm quite sure it's not correct. this is how I create the view and projection matrices (vec4_initd initializes the vectors with w=0, vec4_initw initializes the vectors with w=1): void mat4_lookatlh(mat4 *m, const vec4 *pos, const vec4 *target, const vec4 *updirection) { vec4 fwd, right, up; // fwd = norm(pos - target) fwd = *target; vec4_sub(&fwd, pos); vec4_norm(&fwd); // right = norm(cross(updirection, fwd)) vec4_cross(updirection, &fwd, &right); vec4_norm(&right); // up = cross(right, forward) vec4_cross(&fwd, &right, &up); // orientation and translation matrices combined vec4_initd(&m->a, right.x, up.x, fwd.x); vec4_initd(&m->b, right.y, up.y, fwd.y); vec4_initd(&m->c, right.z, up.z, fwd.z); vec4_initw(&m->d, -vec4_dot(&right, pos), -vec4_dot(&up, pos), -vec4_dot(&fwd, pos)); } void mat4_perspectivefovrh(mat4 *m, float fovdegrees, float aspectratio, float near, float far) { float h = 1.f / tanf(ftoradians(fovdegrees / 2.f)); float w = h / aspectratio; vec4_initd(&m->a, w, 0.f, 0.f); vec4_initd(&m->b, 0.f, h, 0.f); vec4_initw(&m->c, 0.f, 0.f, -far / (near - far)); vec4_initd(&m->d, 0.f, 0.f, (near * far) / (near - far)); } this is how I project my vertices: void device_project(device *d, const vec4 *coord, const mat4 *transform, int *projx, int *projy) { vec4 result; mat4_mul(transform, coord, &result); *projx = result.x * d->w + d->w / 2; *projy = result.y * d->h + d->h / 2; } void device_rendervertices(device *d, const camera *camera, const mesh meshes[], int nmeshes, const rgba *color) { int i, j; mat4 view, projection, world, transform, projview; mat4 translation, rotx, roty, rotz, transrotz, transrotzy; int projx, projy; // vec4_unity = (0.f, 1.f, 0.f, 0.f) mat4_lookatlh(&view, &camera->pos, &camera->target, &vec4_unity); mat4_perspectivefovrh(&projection, 45.f, (float)d->w / (float)d->h, 0.1f, 1.f); for (i = 0; i < nmeshes; i++) { // world matrix = translation * rotz * roty * rotx mat4_translatev(&translation, meshes[i].pos); mat4_rotatex(&rotx, ftoradians(meshes[i].rotx)); mat4_rotatey(&roty, ftoradians(meshes[i].roty)); mat4_rotatez(&rotz, ftoradians(meshes[i].rotz)); mat4_mulm(&translation, &rotz, &transrotz); // transrotz = translation * rotz mat4_mulm(&transrotz, &roty, &transrotzy); // transrotzy = transrotz * roty = translation * rotz * roty mat4_mulm(&transrotzy, &rotx, &world); // world = transrotzy * rotx = translation * rotz * roty * rotx // transform matrix mat4_mulm(&projection, &view, &projview); // projview = projection * view mat4_mulm(&projview, &world, &transform); // transform = projview * world = projection * view * world for (j = 0; j < meshes[i].nvertices; j++) { device_project(d, &meshes[i].vertices[j], &transform, &projx, &projy); device_putpixel(d, projx, projy, color); } } } this is how the cube and camera are initialized: // test mesh cube = &meshlist[0]; mesh_init(cube, "Cube", 8); cube->rotx = 0.f; cube->roty = 0.f; cube->rotz = 0.f; vec4_initw(&cube->pos, 0.f, 0.f, 0.f); vec4_initw(&cube->vertices[0], -1.f, 1.f, 1.f); vec4_initw(&cube->vertices[1], 1.f, 1.f, 1.f); vec4_initw(&cube->vertices[2], -1.f, -1.f, 1.f); vec4_initw(&cube->vertices[3], -1.f, -1.f, -1.f); vec4_initw(&cube->vertices[4], -1.f, 1.f, -1.f); vec4_initw(&cube->vertices[5], 1.f, 1.f, -1.f); vec4_initw(&cube->vertices[6], 1.f, -1.f, 1.f); vec4_initw(&cube->vertices[7], 1.f, -1.f, -1.f); // main camera vec4_initw(&maincamera.pos, 0.f, 0.f, 10.f); maincamera.target = vec4_zerow; and, just to be sure, this is how I compute matrix multiplications: void mat4_mul(const mat4 *m, const vec4 *va, vec4 *vb) { vb->x = m->a.x * va->x + m->b.x * va->y + m->c.x * va->z + m->d.x * va->w; vb->y = m->a.y * va->x + m->b.y * va->y + m->c.y * va->z + m->d.y * va->w; vb->z = m->a.z * va->x + m->b.z * va->y + m->c.z * va->z + m->d.z * va->w; vb->w = m->a.w * va->x + m->b.w * va->y + m->c.w * va->z + m->d.w * va->w; } void mat4_mulm(const mat4 *ma, const mat4 *mb, mat4 *mc) { mat4_mul(ma, &mb->a, &mc->a); mat4_mul(ma, &mb->b, &mc->b); mat4_mul(ma, &mb->c, &mc->c); mat4_mul(ma, &mb->d, &mc->d); }

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  • Building View Matrix in Direct3D11

    - by Balls
    Am I doing it right? I converted this. m_ViewMatrix = XMMatrixLookAtLH(XMLoadFloat3(&m_Position), lookAtVector, upVector); to this one. XMVECTOR vz = XMVector3Normalize( lookAtVector - XMLoadFloat3(&m_Position) ); XMVECTOR vx = XMVector3Normalize( XMVector3Cross( upVector, vz ) ); XMVECTOR vy = XMVector3Cross( vz, vx ); m_ViewMatrix.r[0] = vx; m_ViewMatrix.r[1] = vy; m_ViewMatrix.r[2] = vz; m_ViewMatrix.r[3] = XMLoadFloat3(&m_Position); m_ViewMatrix.r[0].m128_f32[3] = 0.0f; m_ViewMatrix.r[1].m128_f32[3] = 0.0f; m_ViewMatrix.r[2].m128_f32[3] = 0.0f; m_ViewMatrix.r[3].m128_f32[3] = 1.0f; m_ViewMatrix = XMMatrixInverse( &XMMatrixDeterminant(m_ViewMatrix), m_ViewMatrix ); Everything looks fine when I run it. Another question is, I saw on this site(http://webglfactory.blogspot.com/2011/06/how-to-create-view-matrix.html) that he subtracted lookat from position in his vector vz. I tried it but gave me wrong view matrix. Can anyone check my code. I'm studying linear algebra right now. Sucks my course doesn't have one. Thank you, Balls

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  • Matrix.CreateBillboard centre rotation problem

    - by Chris88
    I'm having an issue with Matrix.CreateBillboard and a textured Quad where the center axis seems to be positioned incorrectly to the quad object which is rotating around a center point: Using: BasicEffect quadEffect; Drawing the quad shape: Left = Vector3.Cross(Normal, Up); Vector3 uppercenter = (Up * height / 2) + origin; LowerLeft = uppercenter + (Left * width / 2); LowerRight = uppercenter - (Left * width / 2); UpperLeft = LowerLeft - (Up * height); UpperRight = LowerRight - (Up * height); Where height and width are float values passed in (it draws a square) Draw method: quadEffect.View = camera.view; quadEffect.Projection = camera.projection; quadEffect.World = Matrix.CreateBillboard(Origin, camera.cameraPosition, Vector3.Up, camera.cameraDirection); GraphicsDevice.BlendState = BlendState.Additive; foreach (EffectPass pass in quadEffect.CurrentTechnique.Passes) { pass.Apply(); GraphicsDevice.DrawUserIndexedPrimitives <VertexPositionNormalTexture>( PrimitiveType.TriangleList, Vertices, 0, 4, Indexes, 0, 2); } GraphicsDevice.BlendState = BlendState.Opaque; In the screenshots below i draw the image at Vector3(32f, 0f, 32f) The screenshots below show you the position of the quad in relation to the red cross. The red cross shows where it should be drawn http://i.imgur.com/YwRYj.jpg http://i.imgur.com/ZtoHL.jpg It rotates around the red cross position

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  • Simple 3x3 matrix inverse code (C++)

    - by batty
    What's the easiest way to compute a 3x3 matrix inverse? I'm just looking for a short code snippet that'll do the trick for non-singular matrices, possibly using Cramer's rule. It doesn't need to be highly optimized. I'd prefer simplicity over speed. I'd rather not link in additional libraries. Primarily I was hoping to have this on Stack Overflow so that I wouldn't have to hunt around for it or rewrite from scratch again next time.

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  • What is Chain Matrix Multiplication ?

    - by Hellnar
    Hello, I am trying to understand what is a chain matrix multiplication and how it is different from a regular multiplication. I have checked several sourcers yet all seem to be very academically explained for me to understand. I guess it is a form of dynamic programming algorithm to achieve the operation in an optimised way but I didn't go any further. Thanks

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  • WebGL First Person Camera - Matrix issues

    - by Ryan Welsh
    I have been trying to make a WebGL FPS camera.I have all the inputs working correctly (I think) but when it comes to applying the position and rotation data to the view matrix I am a little lost. The results can be viewed here http://thistlestaffing.net/masters/camera/index.html and the code here var camera = { yaw: 0.0, pitch: 0.0, moveVelocity: 1.0, position: [0.0, 0.0, -70.0] }; var viewMatrix = mat4.create(); var rotSpeed = 0.1; camera.init = function(canvas){ var ratio = canvas.clientWidth / canvas.clientHeight; var left = -1; var right = 1; var bottom = -1.0; var top = 1.0; var near = 1.0; var far = 1000.0; mat4.frustum(projectionMatrix, left, right, bottom, top, near, far); viewMatrix = mat4.create(); mat4.rotateY(viewMatrix, viewMatrix, camera.yaw); mat4.rotateX(viewMatrix, viewMatrix, camera.pitch); mat4.translate(viewMatrix, viewMatrix, camera.position); } camera.update = function(){ viewMatrix = mat4.create(); mat4.rotateY(viewMatrix, viewMatrix, camera.yaw); mat4.rotateX(viewMatrix, viewMatrix, camera.pitch); mat4.translate(viewMatrix, viewMatrix, camera.position); } //prevent camera pitch from going above 90 and reset yaw when it goes over 360 camera.lockCamera = function(){ if(camera.pitch > 90.0){ camera.pitch = 90; } if(camera.pitch < -90){ camera.pitch = -90; } if(camera.yaw <0.0){ camera.yaw = camera.yaw + 360; } if(camera.yaw >360.0){ camera.yaw = camera.yaw - 0.0; } } camera.translateCamera = function(distance, direction){ //calculate where we are looking at in radians and add the direction we want to go in ie WASD keys var radian = glMatrix.toRadian(camera.yaw + direction); //console.log(camera.position[3], radian, distance, direction); //calc X coord camera.position[0] = camera.position[0] - Math.sin(radian) * distance; //calc Z coord camera.position[2] = camera.position [2] - Math.cos(radian) * distance; console.log(camera.position [2] - (Math.cos(radian) * distance)); } camera.rotateUp = function(distance, direction){ var radian = glMatrix.toRadian(camera.pitch + direction); //calc Y coord camera.position[1] = camera.position[1] + Math.sin(radian) * distance; } camera.moveForward = function(){ if(camera.pitch!=90 && camera.pitch!=-90){ camera.translateCamera(-camera.moveVelocity, 0.0); } camera.rotateUp(camera.moveVelocity, 0.0); } camera.moveBack = function(){ if(camera.pitch!=90 && camera.pitch!=-90){ camera.translateCamera(-camera.moveVelocity, 180.0); } camera.rotateUp(camera.moveVelocity, 180.0); } camera.moveLeft = function(){ camera.translateCamera(-camera.moveVelocity, 270.0); } camera.moveRight = function(){ camera.translateCamera(-camera.moveVelocity, 90.0); } camera.lookUp = function(){ camera.pitch = camera.pitch + rotSpeed; camera.lockCamera(); } camera.lookDown = function(){ camera.pitch = camera.pitch - rotSpeed; camera.lockCamera(); } camera.lookLeft = function(){ camera.yaw= camera.yaw - rotSpeed; camera.lockCamera(); } camera.lookRight = function(){ camera.yaw = camera.yaw + rotSpeed; camera.lockCamera(); } . If there is no problem with my camera then I am doing some matrix calculations within my draw function where a problem might be. //position cube 1 worldMatrix = mat4.create(); mvMatrix = mat4.create(); mat4.translate(worldMatrix, worldMatrix, [-20.0, 0.0, -30.0]); mat4.multiply(mvMatrix, worldMatrix, viewMatrix); setShaderMatrix(); gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer); gl.vertexAttribPointer(shaderProgram.attPosition, 3, gl.FLOAT, false, 8*4,0); gl.vertexAttribPointer(shaderProgram.attTexCoord, 2, gl.FLOAT, false, 8*4, 3*4); gl.vertexAttribPointer(shaderProgram.attNormal, 3, gl.FLOAT, false, 8*4, 5*4); gl.activeTexture(gl.TEXTURE0); gl.bindTexture(gl.TEXTURE_2D, myTexture); gl.uniform1i(shaderProgram.uniSampler, 0); gl.useProgram(shaderProgram); gl.drawArrays(gl.TRIANGLES, 0, vertexBuffer.numItems); //position cube 2 worldMatrix = mat4.create(); mvMatrix = mat4.create(); mat4.multiply(mvMatrix, worldMatrix, viewMatrix); mat4.translate(worldMatrix, worldMatrix, [40.0, 0.0, -30.0]); setShaderMatrix(); gl.drawArrays(gl.TRIANGLES, 0, vertexBuffer.numItems); //position cube 3 worldMatrix = mat4.create(); mvMatrix = mat4.create(); mat4.multiply(mvMatrix, worldMatrix, viewMatrix); mat4.translate(worldMatrix, worldMatrix, [20.0, 0.0, -100.0]); setShaderMatrix(); gl.drawArrays(gl.TRIANGLES, 0, vertexBuffer.numItems); camera.update();

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  • How to create projection/view matrix for hole in the monitor effect

    - by Mr Bell
    Lets say I have my XNA app window that is sized at 640 x 480 pixels. Now lets say I have a cube model with its poly's facing in to make a room. This cube is sized 640 units wide by 480 units high by 480 units deep. Lets say the camera is somewhere in front of the box looking at it. How can I set up the view and projection matrices such that the front edge of the box lines up exactly with the edges of the application window? It seems like this should probably involve the Matrix.CreatePerspectiveOffCenter method, but I don't fully understand how the parameters translate on to the screen. For reference, the end result will be something like Johhny Lee's wii head tracking demo: http://www.youtube.com/watch?v=Jd3-eiid-Uw&feature=player_embedded P.S. I realize that his source code is available, but I am afraid I haven't been able to make heads or tails out of it.

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  • Rotate view matrix based on touch coordinates

    - by user1055947
    I'm working on an Android game where I need to rotate the camera around the origin based on the user dragging their finger. My view matrix has initial position of sitting on the negative z and facing origin. I have succeeded in moving the camera through rotation left or right, up or down based on the user dragging the finger, but my problem is obviously that after I drag my finger up/down and rotate say 90 degrees so my intial position of -z is now +y and still facing origin, if I drag my finger left/right I want to rotate from +y to +x, but what happens is it rotates around the pole +y. This is to be expected as I am mapping 2D touch drag coords to 3D space, but I dont know where to start trying to do what I want. Perhaps someone can point me in the right direction, I've been googling for a while now but I don't know what I want to do is called! Edit __ What I was looking for is called an ArcBall, google it for lots of info on it.

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  • Restoring projection matrix

    - by brainydexter
    I am learning to use FBOs and one of the things that I need to do when rendering something onto user defined FBO, I have to setup the projection, modelview and viewport for it. Once I am done rendering to the FBO, I need to restore these matrices. I found: glPushAttrib(GL_VIEWPORT_BIT); glPopAttrib(); to restore the viewport to its old state. Is there a way to restore the projection and modelview matrix to whatever it was earlier ? Tech: C++/OpenGL Thanks!

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  • Unity3d vector and matrix operations

    - by brandon
    I have the following three vectors: posA: (1,2,3) normal: (0,1,0) offset: (2,3,1) I want to get the vector representing the position which is offset in the direction of the normal from posA. I know how to do this by cheating (not using matrix operations): Vector3 result = new Vector3(posA.x + normal.x*offset.x posA.y + normal.y*offset.y, posA.z + normal.z*offset.z); I know how to do this mathematically Note: [] indicates a column vector, {} indicates a row vector result = [1,2,3] + {2,3,1}*{[0,0,0],[0,1,0],[0,0,0]} What I don't know is which is better to use and if it's the latter how do I do this in unity? I only know of 4x4 matrices in unity. I don't like the first option because you are instantiating a new vector instead of just modifying the original. Suggestions? Note: by asking which is better, I am asking for a quantifiable reason, not just a preference.

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  • convert orientation vec3 to a rotation matrix

    - by lapin
    I've got a normalized vec3 that represents an orientation. Each frame of animation, an object's orientation changes slightly, so I add a delta vector to the orientation vector and then normalize to find the new orientation. I'd like to convert the vec3 that represents an orientation into a rotation matrix that I can use to orient my object. If it helps, my object is a cone, and I'd like to rotate it about the pointy end, not from its center :) PS I know I should use quaternions because of the gimbal lock problem. If someone can explain quats too, that'd be great :)

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  • Transformation matrix that maps a window

    - by gbhall
    I'm currently learning OpenGL at uni, and they give us questions to help us learn (these are not worth anything), however I'm stuck on this one question and would have to travel over an hour and a half to uni for an answer. How do I do this question? Please include as many steps as you can, I want to be able to follow exactly how to do this. Find the transformation that maps a window whose lower left corner is at (1,1) and upper right corner is at (3,5) onto: The entire device screen whose dimension is (600, 500) A viewport that has lower left corner at (100,100) and upper right corner at (400,400) Edit: Damn sorry I should have added I am meant to find the matrix, so no code.

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  • Optimizing hierarchical transform

    - by Geotarget
    I'm transforming objects in 3D space by transforming each vector with the object's 4x4 transform matrix. In order to achieve hierarchical transform, I transform the child by its own matrix, and then the child by the parent matrix. This becomes costly because objects deeper in the display tree have to be transformed by all the parent objects. This is what's happening, in summary: Root -- transform its verts by Root matrix Parent -- transform its verts by Parent, Root matrix Child -- transform its verts by Child, Parent, Root matrix Is there a faster way to transform vertices to achieve hierarchical transform? What If I first concatenated each transform matrix with the parent matrices, and then transform verts by that final resulting matrix, would that work and wouldn't that be faster? Root -- transform its verts by Root matrix Parent -- concat Parent, Root matrices, transform its verts by Concated matrix Child -- concat Child, Parent, Root matrices, transform its verts by Concated matrix

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  • Transform coordinates from 3d to 2d without matrix or built in methods

    - by Thomas
    Not to long ago i started to create a small 3D engine in javascript to combine this with an html5 canvas. One of the issues I run into is how can you transform 3d to 2d coords. Since I cannot use matrices or built in transformation methods I need another way. I've tried implementing the next explanation + pseudo code: http://freespace.virgin.net/hugo.elias/routines/3d_to_2d.htm Unfortunately no luck there. I've replace all the input variables with data from my own camera and object classes. I have the following data: An object with a rotation, position vector and an array of 4 3d coords (its just a plane) a camera with a position and rotation vector the viewport - a square 600 x 600 surface. The example uses a zoom factor which I've set as 1 Most hits on google use either matrix calculations or don't implement camera rotation. Basic transformation should be like this: screen.x = x / z * zoom screen.y = y / z * zoom Can anyone point me in the right direction or explain to me howto achieve this? edit: Thanks for all your posts, I haven't been able to apply all this to my project yet but I hope to do this soon.

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  • C Programming matrix

    - by Bilal Khan
    In this program the user enters the # of columns of the matrix and then the entries of the matrix. So, for example, if the user enters 2 for column # and 1 2 3 4 for entries then the program develops a 2 by 2 matrix with 1 2 3 4 as entries. My program works perfectly in such a case. However, if the user for example had only entered 1 2 3 then my program makes a matrix with garbage values. I would like the program in such a case to exit the program. It is a simple question, but it has me baffled. #include<stdio.h> #include<stdlib.h> int main() { int m,x, n, c = 0, d,k, matrix[10][10], transpose[10][10], product[10][10]; printf("Enter the number of columns of matrix "); scanf("%d",&m); if(m<=0){ printf("You entered a invalid value."); exit(0); } else{ printf("Enter the elements of matrix \n"); for( c = 0 ; c < 10 ; c++ ) { for( d = 0 ; d < m ; d++ ) { scanf("%d",&matrix[c][d]); if (matrix[c][d] == 99) // 'x' is character variable I declared to use as a break break; // c = c+1; } if (matrix[c][d] == 99) break; } } printf("\nHere is your matrix:\n"); int i; for(i=0;i<c;i++) { for(d=0;d<m;d++) { printf("%3d ",matrix[i][d]); } printf("\n"); }

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  • Flip rotation matrix

    - by azer89
    right now i'm doing character control with kinect. Basically i need to mirror the joint orientation because the character faces the player. Somehow by googling through internet i've done it and everything works very well. But i have little idea about how the math works, here's my code: //------------------------------------------------------------------------------------- Ogre::Quaternion JointOrientationCalculator::buildQuaternion(Ogre::Vector3 xAxis, Ogre::Vector3 yAxis, Ogre::Vector3 zAxis) { Ogre::Matrix3 mat; if(isMirror) { mat = Ogre::Matrix3(xAxis.x, yAxis.x, zAxis.x, xAxis.y, yAxis.y, zAxis.y, xAxis.z, yAxis.z, zAxis.z); Ogre::Matrix3 flipMat(1, 0, 0, 0, 1, 0, 0, 0, -1); mat = flipMat * mat * flipMat; } else { mat = Ogre::Matrix3(xAxis.x, -yAxis.x, zAxis.x, -xAxis.y, yAxis.y, -zAxis.y, xAxis.z, -yAxis.z, zAxis.z); } Ogre::Quaternion q; q.FromRotationMatrix(mat); return q; } when i need to mirror/flip it by axes z i calculate mat = flipMat * mat * flipMat; but i don't understand how this equation works.

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  • the easiest way to convert matrix to one row vector

    - by niko
    Hi, Does anyone know what is the best way to create one row matrix (vector) from M x N matrix by putting all rows, from 1 to M, of the original matrix into first row of new matrix the following way: A = [row1; row2, ..., rowM] B = [row1, row2, ..., rowM] Example: A = [1 1 0 0; 0 1 0 1] B = [1 1 0 0 0 1 0 1] I would be very thankful if anyone suggested any simple method or perhaps points out a function if it already exists that could generate matrix B from original matrix A.

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  • How does a template class inherit another template class?

    - by hkBattousai
    I have a "SquareMatrix" template class which inherits "Matrix" template class, like below: SquareMatrix.h: #ifndef SQUAREMATRIX_H #define SQUAREMATRIX_H #include "Matrix.h" template <class T> class SquareMatrix : public Matrix<T> { public: T GetDeterminant(); }; template <class T> // line 49 T SquareMatrix<T>::GetDeterminant() { T t = 0; // Error: Identifier "T" is undefined // line 52 return t; // Error: Expected a declaration // line 53 } // Error: Expected a declaration // line 54 #endif I commented out all other lines, the files contents are exactly as above. I receive these error messages: LINE 49: IntelliSense: expected a declaration LINE 52: IntelliSense: expected a declaration LINE 53: IntelliSense: expected a declaration LINE 54: error C2039: 'GetDeterminant' : is not a member of 'SquareMatrix' LINE 54: IntelliSense: expected a declaration So, what is the correct way of inheriting a template class? And what is wrong with this code? The "Matrix" class: template <class T> class Matrix { public: Matrix(uint64_t unNumRows = 0, uint64_t unNumCols = 0); void GetDimensions(uint64_t & unNumRows, uint64_t & unNumCols) const; std::pair<uint64_t, uint64_t> GetDimensions() const; void SetDimensions(uint64_t unNumRows, uint64_t unNumCols); void SetDimensions(std::pair<uint64_t, uint64_t> Dimensions); uint64_t GetRowSize(); uint64_t GetColSize(); void SetElement(T dbElement, uint64_t unRow, uint64_t unCol); T & GetElement(uint64_t unRow, uint64_t unCol); //Matrix operator=(const Matrix & rhs); // Compiler generate this automatically Matrix operator+(const Matrix & rhs) const; Matrix operator-(const Matrix & rhs) const; Matrix operator*(const Matrix & rhs) const; Matrix & operator+=(const Matrix & rhs); Matrix & operator-=(const Matrix & rhs); Matrix & operator*=(const Matrix & rhs); T& operator()(uint64_t unRow, uint64_t unCol); const T& operator()(uint64_t unRow, uint64_t unCol) const; static Matrix Transpose (const Matrix & matrix); static Matrix Multiply (const Matrix & LeftMatrix, const Matrix & RightMatrix); static Matrix Add (const Matrix & LeftMatrix, const Matrix & RightMatrix); static Matrix Subtract (const Matrix & LeftMatrix, const Matrix & RightMatrix); static Matrix Negate (const Matrix & matrix); // TO DO: static bool IsNull(const Matrix & matrix); static bool IsSquare(const Matrix & matrix); static bool IsFullRowRank(const Matrix & matrix); static bool IsFullColRank(const Matrix & matrix); // TO DO: static uint64_t GetRowRank(const Matrix & matrix); static uint64_t GetColRank(const Matrix & matrix); protected: std::vector<T> TheMatrix; uint64_t m_unRowSize; uint64_t m_unColSize; bool DoesElementExist(uint64_t unRow, uint64_t unCol); };

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  • Blender - creating bones from transform matrices

    - by user975135
    Notice: this is for the Blender 2.5/2.6 API. Back in the old days in the Blender 2.4 API, you could easily create a bone from a transform matrix in your 3d file as EditBones had an attribute named "matrix", which was an armature-space matrix you could access and modify. The new 2.5+ API still has the "matrix" attribute for EditBones, but for some unknown reason it is now read-only. So how to create EditBones from transform matrices? I could only find one thing: a new "transform()" function, which takes a Matrix too. Transform the the bones head, tail, roll and envelope (when the matrix has a scale component). Perfect, but you already need to have some values (loc/rot/scale) for your bone, otherwise transforming with a matrix like this will give you nothing, your bone will be a zero-sized bone which will be deleted by Blender. if you create default bone values first, like this: bone.tail = mathutils.Vector([0,1,0]) Then transform() will work on your bone and it might seem to create correct bones, but setting a tail position actually generates a matrix itself, use transform() and you don't get the matrix from your model file on your EditBone, but the multiplication of your matrix with the bone's existing one. This can be easily proven by comparing the matrices read from the file with EditBone.matrix. Again it might seem correct in Blender, but now export your model and you see your animations are messed up, as the bind pose rotations of the bones are wrong. I've tried to find an alternative way to assign the transformation matrix from my file to my EditBone with no luck.

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  • Java Matrix Transpose strangeness going on

    - by user1459976
    ok so im making my own Matrix class. and i have a transpose method that transposes a matrix. this is the block in the main method Matrix m1 = new Matrix(4,2); m1.fillMatrix(1,2,3,4,5,6,7,8); System.out.println("before " + m1.toString()); m1.transpose(); System.out.println("after " + m1.toString()); this is where it gets messed up, at m1.transpose(); in the transpose() method public Matrix transpose() { if(isMatrix2) { Matrix tempMatrix = new Matrix(row, col); // matrix2 contents are emptied once this line is executed for(int i=0; i < row; i++) { for(int j=0; j < col; j++) tempMatrix.matrix2[i][j] = matrix2[i][j]; } so for some reason, the tempMatrix.matrix2 has the same id as this.matrix2. so when the codes executes Matrix tempMatrix = new Matrix(row,col); then the contents of this.matrix2 is emptied. anyone know what might be going on here?

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  • iPhone OpenGL ES: How do I use gravity vector to correctly transform scene for augmented reality

    - by gpdawson
    I'm trying figure out how to get an OpenGL specified object to be displayed correctly according to the device orientation (ie. according to the gravity vector from the accelerometer, and heading from compass). The GLGravity sample project has an example which is almost like this (despite ignoring heading), but it has some glitches. For example, the teapot jumps 180deg as the device viewing angle crosses the horizon, and it also rotates spuriously if you tilt the device from portrait into landscape. This is fine for the context of this app, as it just shows off an object and it doesn't matter that it does these things. But it means that the code just doesn't work when you attempt to emulate real life viewing of an OpenGL object according to the device's orientation. What happens is that it almost works, but the heading rotation you apply from the compass gets "corrupted" by the spurious additional rotations seen in the GLGravity example project. Can anyone provide sample code that shows how to adjust correctly for the device orientation (ie. gravity vector), or to fix the GLGravity example so that it doesn't include spurious heading changes? //Clear matrix to be used to rotate from the current referential to one based on the gravity vector bzero(matrix, sizeof(matrix)); matrix[3][3] = 1.0; //Setup first matrix column as gravity vector matrix[0][0] = accel[0] / length; matrix[0][1] = accel[1] / length; matrix[0][2] = accel[2] / length; //Setup second matrix column as an arbitrary vector in the plane perpendicular to the gravity vector {Gx, Gy, Gz} defined by by the equation "Gx * x + Gy * y + Gz * z = 0" in which we arbitrarily set x=0 and y=1 matrix[1][0] = 0.0; matrix[1][1] = 1.0; matrix[1][2] = -accel[1] / accel[2]; length = sqrtf(matrix[1][0] * matrix[1][0] + matrix[1][1] * matrix[1][1] + matrix[1][2] * matrix[1][2]); matrix[1][0] /= length; matrix[1][1] /= length; matrix[1][2] /= length; //Setup third matrix column as the cross product of the first two matrix[2][0] = matrix[0][1] * matrix[1][2] - matrix[0][2] * matrix[1][1]; matrix[2][1] = matrix[1][0] * matrix[0][2] - matrix[1][2] * matrix[0][0]; matrix[2][2] = matrix[0][0] * matrix[1][1] - matrix[0][1] * matrix[1][0]; //Finally load matrix glMultMatrixf((GLfloat*)matrix);

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