# Questions tagged [interpolation]

The practice of estimating a result (usually numeric) based on a set of known results.

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### How does interpolation actually work to smooth out an object's movement?

I've asked a few similar questions over the past 8 months or so with no real joy, so I am going make the question more general. I have an Android game which is OpenGL ES 2.0. within it I have the ...
590 views

### Smooth decelerate, interpolation?

I have two points A and B. I want to perform a smooth deceleration from A stopping at B over time t. The only thing I managed to do so far was a lerp, which isn't right of course because it's ...
10k views

### How do I generalise Bresenham's line algorithm to floating-point endpoints?

I'm trying to combine two things. I'm writing a game and I need to determine the grid squares lying on a line with the floating-point endpoints. Moreover I need it to include all the grid squares it ...
1k views

### How to synchronize the ball in a network pong game?

I’m developing a multiplayer network pong game, my first game ever. The current state is, I’ve running the physic engine with the same configurations on the server and the clients. The own paddle ...
500 views

### Handling early/late/dropped packets for interpolation in a 3D multiplayer game

I'm working on a multiplayer game that for the purposes of this question, is most similar to Team Fortress. Each network data packet will contain the 3D position of the target moving object. (this ...
917 views

### Convert vector interpolation to quaternion interpolation? (Catmull-Rom)

I have some existing code which does catmull-rom interpolation on two vectors (facing and up). I'm converting this to use quaternions instead (to replace the two vectors). Is there a general way to ...
919 views

### How to make other semantics behave like SV_Position?

I'm having a lot of trouble with shadow mapping, and I believe I've found the problem. When passing vectors from the vertex shader to the pixel shader, does the hardware automatically change any of ...
461 views

### Issue with multiplayer interpolation

In a fast-paced multiplayer game I'm working on, there is an issue with the interpolation algorithm. This interpolation is for a moving object not controlled by the local computer. The server sends ...
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### Fixed timestep and interpolation question

I'm following Glenn Fiedlers excellent Fix Your Timestep! tutorial to step my 2D game. The problem I'm facing is in the interpolation phase in the end. My game has a Tween-function which lets me ...
2k views

### Frameskipping in Android gameloop causing choppy sprites (Open GL ES 2.0)

I have written a simple 2d platform game for Android and am wondering how one deals with frame-skipping? Are there any alternatives? Let me explain further. So, my game loop allows for the ...
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### Interpolation using a sprite's previous frame and current frame

Overview I'm currently using a method which has been pointed out to me is extrapolation rather than interolation. As a result, I'm also now looking into the possibility of using another method which ...
863 views

### Extrapolation breaks collision detection

Before applying extrapolation to my sprite's movement, my collision worked perfectly. However, after applying extrapolation to my sprite's movement (to smooth things out), the collision no longer ...
110 views

### Problems with my interpolation inplementation

When I interpolate my sprite's movement (code below), I'm curious as to whether the part where I actually apply the interpolation to the sprite's current X position (in my render call) is correct. ...
3k views

### How can I make a spline out of three points that define a circular arc?

I was looking at the descriptions of various curve techniques here and noticed the mention of circular arcs. I want to implement something like this, but I'm not quite sure what the correct formula to ...
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### 2D Animation Blending [closed]

I have been researching on 2D Animation Blending technique similar to what Unity 4.3 has. I know how Animation blending in 3D works but I have no idea how it works in 2D. How does 2D Animation ...
63 views

### Constantly interpolated splines

Trying to implement a movement through a curve - I'm trying to find a type of curve/spline that interpolates constantly. What I mean: when I interpolate from t=0 to t=0.1, I want it be the same ...
2k views

### How do I avoid interpolation artefacts when scaling up a heightmap?

I am using a bicubic interpolation algorithm in order to upscale a height map, and I am noticing some artifacts around the pixels boundaries. However, these artifacts don't seem to appear when I use a ...
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### Dealing with interpolation and object creation/destruction

I've implemented a game loop similar to that in Glenn Fiedler's Fix Your Timestep! article. I have an update step running at 50Hz and a render step running at 60Hz (monitor refresh rate). To keep ...
2k views

### Bilinear filtering: Selecting pixels to interpolate between

When looking for implementations of bilinear filtering online, all the ones I can find seem to just pick the current pixel, and the three pixels to the bottom and right side of the current pixel. ...
902 views

### Update and Render logic with interpolation

I am working with C and SDL2 and just wanted some insight as to how to properly apply interpolation to the rendering. EDIT - some clarification, update() ...
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### Smooth interpolation with variable time steps

My game engine just went through a small overhaul that changed its fixed time step loops into variable time steps ones. Though everything has already been adapted steadily to the new environment, ...
1k views

### Why is interpolation passed into the rendering routine when the position and speed are related to the update routine?

I've read this in several well known articles, including this one: http://www.koonsolo.com/news/dewitters-gameloop/ Under the Interpolation and Prediction subheading is the description of the ...
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### Algorithm for smoothing a network object's movement

We are building multiplayer game where there's no central server managing the game. Each player is responsible for sending out its state to all connected players. In addition, all clients run ...
2k views

### Multiplayer object interpolation

Currently I'm participating in a multiplayer game project as a network developer. Unfortunately, however, I'm facing an interpolation problem which makes game objects look like they are 'jumping/...
12k views

### Computing pixel's screen position in a vertex shader: right or wrong?

I am building a deferred rendering engine and I have a question. The article I took the sample code from suggested computing screen position of the pixel as follows: ...
352 views

### Easing equations with moving end points

Usually easing equations have 4 parameters: time duration begin point end point For example: ...
1k views

### How can I convert between float3 and float2 in HLSL?

I want to offload some 3D calculations to the GPU without raising my requirements to DX10. Specifically, I am generating densities in 64x64x64 3D blocks, which fit nicely into 512x512 2D textures. I ...
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### Method for interpolation between 3+ quaternions?

I'm currently using spherical linear interpolation (slerp) to interpolate between two quaterions with a weighted value. But, I'm having a difficult time coming up with a method to interpolate between ...
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### "retro"-look in 3d-XNA-game

In my XNA-4.0-game (which somehow is a bit like MineCraft), I have got some big cubes with small textures (16x16px) on it. By default, XNA just scales them up smooth so there aren't any hard borders. ...
3k views

### Multiplayer Network Game - Interpolation and Frame Rate

Consider the following scenario: Let's say, for sake of example and simplicity, that you have an authoritative game server that sends state to its clients every 45ms. The clients are interpolating ...
591 views

### Lerp an object based on timers

I'm trying to make a target lerp between two objects based on a timer. At the moment, I have the following code: ...
3k views

### Interpolating a player between two 2D points?

I would like a player to be able to move in a direction smoothly, whilst sticking to a fixed grid. Much like in Pokemon, how the player can move, but when the key is pressed and released quickly, they ...
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### Networked Physics - Interpolation Causes Physics Engine to Explode

A major issue I am encountering right now is that my physics engine (BEPU) and my network interpolation are conflicting with each other. The player is a physics object, and so the physics engine ...
48k views

### How to avoid texture bleeding in a texture atlas?

In my game there is a Minecraft-like terrain made out of cubes. I generate a vertex buffer from the voxel data and use a texture atlas for looks of different blocks: The problem is that the texture ...
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### Input and packets handling when using render interpolation

I'm implementing valve's networking model for my simple top down game but I have some design problems and I just can't think of good solutions. The one of the main ideas that there is a render time ...
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### Interpolating between two networked states?

I have many entities on the client side that are simulated (their velocities are added to their positions on a per frame basis) and I let them dead reckon themselves. They send updates about where ...
5k views

### Narrow-phase collision detection algorithms

There are three phases of collision detection. Broadphase: It loops between all objecs that can interact, false positives are allowed, if it would speed up the loop. Narrowphase: Determines whether ...
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### GLSL custom interpolation filter

I'm currently building a fragment shader which is using several textures to render the final pixel color. The textures are not really textures, they are in fact "input data" to be used in the formula ...
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### UV texture mapping with perspective correct interpolation

I am working on a software rasterizer for educational purposes and I am having issues with the texturing. The problem is, only one face of the cube gets correctly textured. The rest are stretched ...
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### Depth interpolation for z-buffer, with scanline

I have to write my own software 3d rasterizer, and so far I am able to project my 3d model made of triangles into 2d space: I rotate, translate and project my points to get a 2d space representation ...
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### Server-side Input

Currently in my game, the client is nothing but a renderer. When input state is changed, the client sends a packet to the server and moves the player as if it were processing the input, but the ...
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### What algorithm is mostly used to interpolate animations?

Because DCC tools supports very many options, we resample the animation curve splines, but I think it still need to be interpolated. I think there's some de facto standard for this animation ...
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### Interpolate and collisions

Lets take the simple example of a ball bouncing off a wall. The physics is separated from the display. The physics is set to run at say 20 frames per second and the display is running faster than this ...
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### How do I interpolate air drag with a variable time step?

So I have a little game which works with small steps, however those steps vary in time, so for example I sometimes have 10 Steps/second and then I have 20 Steps/second. This changes automatically ...
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### Interpolation gives the appearance of collisions

I'm implementing a simple 2D platformer with a constant speed update of the game logic, but with the rendering done as fast as the machine can handle. I interpolate positions between actual game ...
774 views

### Frame Interpolation issues for skeletal animation

I'm trying to animate in-between keyframes for skeletal animation but having some issues. Each joint is represented by a quaternion and there is no translation component. When I try to slerp between ...
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### How do you blend multiple colors in HSV (polar) color-space?

In RGB color space, you can do a weighted multiple-color blend by just doing: Start with R = G = B = 0. Then we perform a blend at index i using a set of colors C, and a set of normalized weights w ...
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### Effort of impementing interpolation in networked Asteroids

Questions: When we draw with interpolation, where should the collision detection code be? Is it worth implementing interpolation in the following situation? This is for Scrolling Asteroids. I have my ...