# All Questions

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### How is orthographic projection used in computer graphics technically classified as a projection?

I'm wondering why the orthographic projection we use in computer graphics is called a projection, if all it does is just scale and translate a mesh? According to wiki orthographic projection is ...
14 views

### Perspective correct interpolation z-buffer

While I was deriving expressions for perspective-correct linear interpolation on triangles, I reached the conclusion that the interpolation may be kept linear only if view-space $Z$ is available. ...
42 views

### The ploygon width parallel to the x axis as a function of the y ordonate?

Considering a polygon with n vertices as input. I need to calculate the integral of the form $\int_A p(y) dA$ where $p(y)$ is a piecewise polynomial function of $y$. May be if I could find the ...
35 views

### How to scale signed distance field fonts properly?

I have a setup where I'm rendering a bunch of characters on a canvas with an SDF font. The users can zoom in to see the details of the smaller texts, but currently the smaller characters are quite ...
21 views

### Interactive point cloud

I’m trying to build an interactive point cloud renderer in Panda3D. I want to render a point cloud and be able to select a group of points and change their colors, maybe with a rectangular selector or ...
28 views

### Fast and exact Geodesics on meshes, Backtracking confusion

The following is an excerpt from a 2005 paper on geodesics on triangular meshes, taken from section 3.5 In this case $p$ is a point on some arbitrary face in a mesh, $p'$ is a point on one of the 3 ...
27 views

### Compose ViewMatrix and ProjectionMatrix

As the title says, you are able to compose the ViewMatrix and the ProjectionMatrix into one instead of multiplying a vector by the individual matrices. Instead of doing this at run time for each item: ...
45 views

### Which perspective projection matrix to use

I've seen two diffrent perspective projection matrix being used but i want to know which one of these are the best i think that they both output the same but i'm not sure so if anyone can help me ...
44 views

### OpenGL/D3D11 offscreen render multiple buffering

Recently I've been looking at Vulkan, and one thing that I noticed is that the application is responsible for choosing which buffer to render to in the case of multiple buffering. This got me thinking:...
84 views

### Reducing artificial rings in mean curvature of mesh

I have an isosurface/mesh (generated via marching cubes) of a micro-CT scan. Originally the surface looks very noisy, which becomes prevalent when the mean curvature is visualized: To reduce the ...
89 views

### Dynamic Ray-Triangle Intersection

I am working on a small simulation software which has a 3D Renderer that is using OpenGL. I render objects to the screen as triangle meshes. To be able to select the triangles on the screen, I have ...
43 views

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### Using Bresenham's circle algorithm (or another alternative algorithm) to draw an arc

I'm trying to create some graphic functions for a ZX Spectrum (Z80) machine in assembler. I already have the basics except for the arc. I need a fast algorithm to draw an arc, ideally one that uses ...
40 views

### How are digital painting canvas rendered?

Digital painting and raster graphics software like Krita and Photoshop have a canvas where you can paint with brushes. From a programming perspective, how is this canvas rendered? Can it be included ...
56 views

I am trying to get up to speed with the NV_mesh_shader extension from NVidia (on my RTX2080). Samples are rare, so I tried to come up with my own small sample. I am rendering a sphere (20 triangles) ...
45 views

### Force int array to compact memory

I have following structure which i use as an uniform buffer object. ...
37 views

### How to use PCA to reconstruct 3D Mesh？

Given a set of human body mesh {S_i}, for each S_i, the points are N*3, we can do PCA on that. We can use PCA to reduce the dimension of {S_i}, for example to k dimension. Let the main direction of ...
78 views

### Has anyone found an analytic solution to the product of spherical gaussians from Xu et al?

In section 4.2 of this paper: http://cseweb.ucsd.edu/~ravir/274/15/papers/a209-xu.pdf Xu et al approximate the product of 2 anisotropic Gaussian distributions. I want to know if someone has found not ...
46 views

### Converting Vertex and Index buffers to a File Format

I have many sets of vertex and index buffers that I’d like to render on to the screen. Ideally each model in different locations with-in world space. I’m actually doing a statistical study on spatial ...
48 views

### Why does processing dense geometry consume less power than simple geometry?

In The Road to PS5, Mark Cerny states: It's counter-intuitive, but processing dense geometry typically consumes less power than processing simple geometry. Why is this the case?
48 views

### Do you have to group and optimize your draw and shader calls in Vulkan?

This is in reference and contrast to the discipline (or more or less requirement) of opengl to group draws that use the same materials together, to minimize making many draw calls or many switch ...
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### How to measure the reflectance of a material without using a Spectralon

I am trying to measure the reflectance% of a surface (it is made of Teflon and is very white). I am using a line spectrometer. I believe the piece can replace an expensive Spectralon for some ...
35 views

### Calculate the position and rotation needed to have a camera look at a certain region

I have a 2D region defined by 4 points in 3D space. I want to position my camera so that it looks at the region, with a settable variable determining which side it looks at, where looks at means that ...
29 views

### Per-object screen space uv issue

I am currently trying to sample a texture in screen space. This works well : ...