Questions tagged [interpolation]
The interpolation tag has no usage guidance.
66
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How are mipmap levels computed in Metal?
My question is specifically in regards to Metal, since I don't know if the answer would change for another API.
What I believe I understand so far is this:
A mipmapped texture has precomputed "...
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Is a cubic Lagrange interpolation tensor product the same as bicubic interpolation?
I just implemented some interpolated texture sampling by sampling the 4x4 nearest pixels then doing Lagrange interpolation across the x axis to get four values to use Lagrange interpolation on across ...
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What is bilateral upsampling?
I've worked with various interpolation algorithms including linear, cubic (and bilinear and bicubic), other bezier (and nurbs, etc) based interpolations, lagrange interpolation and some others, but I ...
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How do I use barycentric coordinates to interpolate vertex normal?
Given a triangle and a point inside the triangle in Cartesian coordinate system, I compute the Barycentric coordinate of the point like this:
...
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Image rescaling algorithm
Suppose I have to use bilinear interpolation to rescale image. I more or less understand how enlargement works in case of integer scale factor.
But what to do with non-integer scale and especially ...
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Perspective correct interpolation of normal values
I'm currently writing a software rasterizer and I'm at the point where I can draw arbitrary triangles with vertex colors and perspective correct texture mapping. I do point and directional lighting by ...
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The mathematics of two dimensional interpolation on a quad
I am trying to wrap my head around how exactly the GPU interpolates texture coords on a quad. I realize to the GPU a quad is two triangles but I find thinking in terms of the whole quad to be easiest.
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Is there a way to interpolate color across the line with only integer calculation ?`
Here is my function that does interpolation
...
user3437
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Interpolating vectors on a grid
If you have values on a grid and you want to find the value of a point within one of the cells, you can use techniques like bilinear or bicubic interpolation to get the data at that point.
What ...
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Normal Interpolation for Phong shading
As the title says I have been trying to understand the normal interpolation for the Phong shading/lighting model. I am unsure of the equation to calculate the normal but I have come across this ...
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How to rasterize a line when the background color is not always white?
I've to rasterize a line taking into account not only the background color of the screen, which is white, but also the color of other objects in the scene. In my case, I've just another object, a ...
user4718
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Which interpolation algorithm does MS Paint on Windows 7 use for image rescaling?
I was about to scale this image down to 64x64 pixels:
The result I got on MS Paint on Windows 7 was surprisingly good (i.e. crisp edges):
, whereas scaling it with GIMP resulted in for cubic and ...
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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. ...
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How can you interpolate over an array of say 5 colors?
I have an array of color values. I have an interpolating parameter, t, which varies from 0 to ...
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Linear interpolation on Plane (Marching Cubes)
Let's assume I have the following cube.
Let's assume the isovalue = 0. I would like to draw the resulting triangles of the isosurface.
I know that first I define which values are inside or outside ...
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Fake cubic Hermite spline interpolation with smoothstep
When scaling an image with Bicubic Interpolation, the Cubic Hermite spline interpolation is used. smoothstep is one of the four basis/blend functions of this kind ...
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How to interpolate vertices when clipping?
When we clip in homogeneous clip space, we have to generate a new vertex located at the intersection between the edge and the clip plane. We thus have to interpolate the $(x , y, z , w)$ position of ...
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Screen coordinates, barycentric coordinates and global coordinateas
To continue with this my other question, here's the problem. So, I've a slide, which I'm trying to understand.
Here are my questions.
What are the barycentric coordinates of? From my previous ...
user4718
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MRF and Textures
I am pursuing my research in Texture Interpolation. After digging deep into it, I'm stuck at a point. It is proven that textures can be modeled as Markov Random Fields and that each texture can be ...
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Determining Rational Quadratic Bezier Curve Weights for Circle
I am trying to create a spherical interpolation with 3 points. I'm currently using Quadratic Bezier Interpolation but have been told I should use Rational Quadratic Bezier Curve in order to get a ...
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Does the blending matrix change between calculating various curve segments in a uniform cubic B-splines approximation?
I would like to ask about uniform (periodic) cubic B-splines (approximation, no interpolation).
$$B=1/6\begin{bmatrix}-1&3&-3&1\\3&-6&3&0\\-3&0&3&0\\1&4&1&...
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Correct way to interpolate 1/z?
I have doubts on 1/z depth buffer interpolation. According to this website, the correct 1/z interpolation formula is
$\dfrac{1}{P.z} = \dfrac{1}{V0.z} * \lambda_0 + \dfrac{1}{V1.z} * \lambda_1 + \...
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Smooth triangular mesh interpolation
I am looking for an algorithm which would smoothly interpolate triangles of a mesh (computed by Delaunay triangulation) where each vertex has some value (elevation in my case). I need it for PDAL ...
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Interpolate vertex attributes with $z$ AFTER homogeneous divide
Usually, if we want to interpolate some vertex attributes, say $A_1$, $A_2$ and $A_3$, we have to first divide them by their corresponding $z$ in view space, then we interpolate them using barycentric ...
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Creating a gently moving 2D fog effect
I am trying to create a fog-like effect, similar to that found using perlin noise. I know where I can find information about that effect, but it's harder for me to tell if it's an efficient route for ...
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Interpolation in Graphics Pipeline
I am trying to program my own version of WEBGL graphics pipeline in python, however, I am confused as to where the color interpolation takes place in the pipeline. According to my research, it happens ...
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Find closest point on surface interpolated by 2d matrix of points
I have rectangular matrix of 3d points sampled from a parametric surface. In my program this matrix provides base points for bilinear interpolation of surface (In any (u,v) point it returns 3d point ...
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How to deal with light leaks?
I'm struggling with light leaking through meshes (especially thin ones) due to interpolation between probes located on the opposite sides of those.
First approach I took was mapping all static ...
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Irradiance field approximation with black probes
I'm posting here after some time searching the Internet and reading presentations and papers, to find out the best options to solve the problem I have.
I'm implementing irradiance field with ...
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Why my cosine interpolation of a cube's face doesn't work?
NB please : executable use cases are available at the end of this question. I begin this question by showing you the problems of my program, then I explain how the latter works, and finally I end up ...
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Sinc interpolation and Ideal reconstruction example
I am trying to apply sinc interpolation on this data set. The patches in the left image is a snapshot of AutoCAD 3d faces. Lux values are calculated for centre of each patch that are in 0.3m x 0.3m ...
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How to use Monotone cubic interpolation in 3D?
I wanted to use Monotone cubic interpolation, but the site only provide explanation for 2D case. How can I extend it to 3D?
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How to obtain generalized barycentric coordinates for n-sided polygon?
Quadrilateral linear basis functions(generalized barycentric coordinates) are defined as:
What are the steps to calculate the above functions?
Is it possible to obtain basis functions for a 5 sided ...
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Deriving formula for perspective correct interpolation
I am trying to derive the formula for perspective correct texture interpolation on my own while implementing my own software rasterizer (projecting an arbitrarily rotated triangle in camera space on ...
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139
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Interpolating HSV color with black
I'm interpolating RGB values by transforming them into HSV space and then back into RGB. I have trouble figuring out how to achieve ...
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computing derivatives of sampled data
I am trying to calculate the derivatives of a sampled data set by following an example in this book. The data is a set of 2d quads(green area in below) and their vertices(4 each). The data is in the ...
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ScratchAPixel : Understanding how to use Perlin's permutations hash table
Consider this course : https://www.scratchapixel.com/lessons/procedural-generation-virtual-worlds/procedural-patterns-noise-part-1/creating-simple-2D-noise . In sub-part Introducing the Concept of ...
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What is a common approach to smooth structures in textures?
I have a screen-aligned texture resulting from multiple rendering passes. It looks about this:
I want the edges to appear smoother than they do now (but still keep their characteristic shape). When ...
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Float point placement with anti aliasing
I have an image of size H,W, and I would like to draw a point on this image at x,...
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Vertex positions from particle position
I have a question about Nvidia Flex or any particle based simulation in general:
The particles are created by sampling the mesh, which can result in fewer particles than there are vertices in the ...
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Using GPU instead of CPU in Scala
I wrote a program that displays points expressed in 3D in a 2D canvas, using perspective projection. The aim is to display a cube. Each face of the cube is drawn by linearly interpolating the points ...
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Interpolating normals during animation
I'm doing linear tweening of a cyllinder to a cone of equal radius and height in OpenGL. I know parametric equations of both of them, so I derived vertex normals accordingly. Now, I know, that proper ...
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Make 3d objects from 3 projections in 3D Studio Max
In the early 3D Studio days before it got Max in its name it was possible to make a 3d object by defining its projections in xy, xz and yz plane. 3ds would then interpolate a 3d object from the ...
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What causes blobby edges with alpha testing?
I'm trying to understand what causes the blobby edges when using alpha testing to create transparency with 1-bit alpha channels. The edges appear pixelated, but with rounded corners and diagonal lines....
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Geometric interpretation of this bilinear interpolation equation?
Bilinear interpolation can be achieved by interpolating two values across the x axis, and then interpolating between the results across the y axis, like in the image below (from https://blog.demofox....
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Perlin Noise with Smooth function vs Lerp
I tried implementing Perlin Noise using the Wikipedia as my main resource. From what I can tell my implementation of the ...
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Texturing an "infinite" plane
I am rendering an infinite plane as described in the following answers:
https://stackoverflow.com/questions/12965161/rendering-infinitely-large-plane
https://stackoverflow.com/questions/7380250/how-...
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Bilinear Interpolation
I am trying to implement bilinear interpolation as described in the paper Spatial Tranformer Networks by Jaderberg et. al (see link to paper). They describe bilinear interpolation in Equation 5 as:
$$...
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Interpolating poisson disk samples in real time
If I have a regular sampling pattern there typically exist many reasonably fast ways to interpolate the results of the sampling procedure in between the sample locations. For example bilinear or ...
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How to calculate interpolation between multiple skeleton poses?
I found out that I should use spherical linear interpolation to blend two poses of a joint. I cannot find what to do if I have hundreds of poses to blend except applying the SLERP iteratively.
What ...
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