# Search Results

• ### Billboarding restricted to an axis (cylindrical)

##### - by user8709
I have succesfully created a GLSL shader for a billboarding effect. I want to tweak this to restrict the billboarding to an arbitrary axis, i.e. a billboarded quad only rotates itself about the y-axis. I use the y-axis as an example, but essentially I would like this to be an arbitrary axis. Can anyone show me how to modify my existing shader below, or if I need to start from scratch, point me towards some resources that could be helpful? precision mediump float; uniform mat4 u_modelViewProjectionMat; uniform mat4 u_modelMat; uniform mat4 u_viewTransposeMat; uniform vec3 u_axis; // <------------ !!! the arbitrary axis to restrict rotation around attribute vec3 a_position0; attribute vec2 a_texCoord0; varying vec2 v_texCoord0; void main() { vec3 pos = (a_position0.x * u_viewTransposeMat[0] + a_position0.y * u_viewTransposeMat[1]).xyz; vec4 position = vec4(pos, 1.0); v_texCoord0 = a_texCoord0; gl_Position = u_modelViewProjectionMat * position; }

• ### Billboarding + aligning with velocity direction

##### - by roxlu
I'm working on a particle system where I'm orientating the billboard using the inverted orientation matrix of my camera. This works quite well and my quad are rotated correctly towards the camera. But, now I want to to rotate the quads in such a way that they point towards the direction they are going to. In 2D this can be done by normalizing the velocity vector and using that vector for a rotation around the Z-axis (where vel.x = cos(a) and vel.y = sin(a)). But how does this work in 3D? Thanks roxlu

• ### Axis Aligned Billboard: how to make the object look at camera

##### - by user19787
I am trying to make an Axis Aligned Billboard with Pyglet. I have looked at several tutorials, but they only show me how to get the Up,Right,and Look vectors. So far this is what I have: target = cam.pos look = norm( target - billboard.pos ) right = norm( Vector3(0,1,0)*look ) up = look*right gluLookAt( look.x, look.y, look.z, self.pos.x, self.pos.y, self.pos.z, up.x, up.y, up.z ) This does nothing for me visibly. Any idea what I'm doing wrong?

• ### Laser Beam End Points Problems

##### - by user36159
I am building a game in XNA that features colored laser beams in 3D space. The beams are defined as: Segment start position Segment end position Line width For rendering, I am using 3 quads: Start point billboard End point billboard Middle section quad whose forward vector is the slope of the line and whose normal points to the camera The problem is that using additive blending, the end points and middle section overlap, which looks quite jarring. However, I need the endpoints in case the laser is pointing towards the camera! See the blue laser in particular:

• ### How do I implement camera axis aligned billboards?

##### - by user19787
I am trying to make an axis-aligned billboard with Pyglet. I have looked at several tutorials, but they only show me how to get the up, right, and look vectors. So far this is what I have: target = cam.pos look = norm(target - billboard.pos) right = norm(Vector3(0,1,0) * look) up = look * right gluLookAt( look.x, look.y, look.z, self.pos.x, self.pos.y, self.pos.z, up.x, up.y, up.z ) This does nothing for me visibly. Any idea what I'm doing wrong?

• ### Laser Beam End Points Problems (XNA)

##### - by user36159
I am building a game in XNA that features colored laser beams in 3D space. The beams are defined as: Segment start position Segment end position Line width For rendering, I am using 3 quads: Start point billboard End point billboard Middle section quad whose forward vector is the slope of the line and whose normal points to the camera The problem is that using additive blending, the end points and middle section overlap, which looks quite jarring. However, I need the endpoints in case the laser is pointing towards the camera! See the blue laser in particular:

• ### Billboard shader without distortion

##### - by Nick Wiggill
I use the standard approach to billboarding within Unity that is OK, but not ideal: transform.LookAt(camera). The problem is that this introduces distortion toward the edges of the viewport, especially as the field of view angle grows larger. This is unlike the perfect billboarding you'd see in eg. Doom when seeing an enemy from any angle and irrespective of where they are located in screen space. Obviously, there are ways to blit an image directly to the viewport, centred around a single vertex, but I'm not hot on shaders. Does anyone have any samples of this approach (GLSL if possible), or any suggestions as to why it isn't typically done this way (vs. the aforementioned quad transformation method)? EDIT: I was confused, thanks Nathan for the heads up. Of course, Causing the quads to look at the camera does not cause them to be parallel to the view plane -- which is what I need.

• ### Is it possible to billboard a sprite using a transformation matrix?

##### - by Ross
None of the current topics on billboarding seemed to answer this question. But, given a sprite (or quad) that has it's own 4x4 transformation matrix a camera with a view matrix (a standard 4x4 transformation matrix) is it possible to compute a 4x4 transformation matrix such that when the quad's matrix is multiplied with this matrix it has an orientation of looking at the camera? Thank you in advance.

• ### How to Draw texture between 2 Vector3

##### - by Sparky41
My scenario: RTS combat style, 1 unit fires beam on another unit My problem is i want to draw a flat texture between 2 Vector3 points. I have looked at various Billboarding styles but that doesn't give me a proper solution. I looked at this: http://msdn.microsoft.com/en-us/library/bb464051.aspx is BasicEffect and DrawPrimitives the correct solution just stretch the texture to the distance between point of origin to target? I used the quad class they used but i found this it seemed to inflexible So my question to you is how would i go about this sort of problem? Regards