Questions tagged [alpha-blending]

Alpha blending is the process of combining a translucent foreground color with a background color, thereby producing a new blended color.

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5k views

“Normal” Blend Mode with OpenGL Trouble

I've been having a lot of trouble trying to get a OpenGL blend function to work as I'd expect it to with like what I'd expect (or from any sensible image editing program). As an example, I'll use ...
6
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1answer
3k views

Self occluding object and alpha blending

Look at the object I've rendered with my app: It's the same screen twice, above the original and below I've drawn (by hand :P) the shape of the mesh of one of plant's leaves. You can clearly see ...
6
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1answer
1k views

Sprite with alpha Blending in 3D world

I'm working on a game in a 3D world with elements 2D only (Like Don't starve game) for Android and IOS. Currently, I've managed "Sprite" without alpha blending, I've just put a condition in the pixel ...
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2answers
651 views

Colour intersection of two alpha-blended sprites

In XNA, is it possible to merge two alpha blended sprites so they look like one contiguous shape, eliminating the merge of colour at the overlap? At the moment when I try, the intersection is quite ...
3
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1answer
2k views

Alpha Blending performance on IOS

I've got few questions without responses about my game development, can you help me? Here is the questions: In my game when a large object appear on the screen, the GPU go to his limits, my framerate ...
3
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1answer
136 views

Why does my PixelShader ignore color but respond to alpha changes?

I started teaching myself some DirectX a short time ago and found something I'm confused about. For some reason, I can only get the color of the model I'm drawing to vary between black and white, ...
3
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2answers
1k views

Possible to create transparency shader which doesn't stack alpha values

The image above best demonstrates what I'm trying to achieve. It's a transparent shader for objects, but wherever the objects with this shader intersect they don't add together but simply merge with ...
3
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2answers
1k views

Blending semi-transparent images while not stacking their alphas

In libgdx/OpenGL ES I want to render multiple semitransparent textures while keeping the alpha still semi transparent. For example If I render a 0.5 alpha circle on top of another 0.5 alpha circle, ...
3
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2answers
1k views

Batching and Z-order with Alpha blending in a 3D world

I'm working on a game in a 3D world with 2D sprites only (like Don't Starve game). (OpenGL ES2 with C++) Currently, I'm ordering elements back to front before drawing them without batch (so 1 element ...
3
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1answer
790 views

Linear filter problem with diagonal lines on adjecent tiles

I am quite new at using OpenGL/GLSL. Basically, the project I am working on is my first 'real' experience with it. I do not know whether this is relevant, but I use libgdx for my project. Currently, ...
3
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1answer
614 views

DirectX11 Equivalent of OpenGL code

I am currently porting parts of my engine over to D3D11 from OpenGL and was trying to figure out how I would accomplish the following blending functions in D3D11. ...
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0answers
33 views

Blending Lights Into An Image Pulled From Memory (2d)

The circumstances to why I am forced to do things this way are a bit weird, without going into them, I have the following situation: I have a pointer that points to image data arranged in the form ...
3
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0answers
2k views

Overlap transparent particles without blending? (Unity)

I'm trying to create a continuous output of light from an object (like the exhaust of a space ship), and I thought I'd use particles to achieve this. But I'm running into a problem with alpha blending....
3
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0answers
406 views

Enabling OpenGL lighting seems to disable blending

I have the following code to set up for some 2D drawing using OpenTK. I originally wrote it without any lighting considerations, but later added the lighting block. This version of the code uses ...
3
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0answers
354 views

Smoothly fitting texture tiles using alpha gradient on edges

I'm trying to draw a background texture with tiles that I'll rotate and mirror to create a maze. Here is a sample tile: As you can see, I use an alpha gradient on the borders. If I'd use a sharp ...
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1answer
994 views

What is this alpha blending result?

I'm having an exam soon and got a problem with one alpha blending exercise: ...
2
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1answer
2k views

iOS Sprite Kit - Blend Mode Effect

This question builds upon the following question: How can I achieve a good fire effect with alpha blending and particles? I want to achieve the visual effect of using ...
2
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1answer
119 views

When do I need straight alpha?

I am writing some alpha-blending code, and I realized that premultiplied alpha is enough for most cases. So I thought about using only premultiplied alpha on my engine code to simplify the structure....
2
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1answer
195 views

Write colors with alphablending but don't write into the alpha channel

I am using XNA 4.0, hence DX9 and HLSL. I have a RenderTarget2D "MAIN" that I want to add semi-transparent objects "TRANS" to. I want them to blend with MAIN using the TRANS's alpha and inverseAlpha ...
2
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1answer
80 views

Can I use a BlendState object to emulate a draw call's blending color?

I'm working on a lighting system for a tile-based game. What I want to do is draw my tiles to the screen, then draw a single Texture2D object (my light map) over top of them. However, doing it in ...
2
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1answer
575 views

XNA/MonoGame/SharpDX: Pixel shader with sprite sheet

I've searched around for two days now on the internet but cannot find a solution. I've also read up on Pixel Shaders on MSDN with no luck. I'm trying to apply a simple pixel shader to a sprite batch ...
2
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1answer
377 views

Use different values for Depth Test and Depth Write in OpenGL

Is there a way to use something similar to PolygonOffset to make a depth test more permissive (move fragment depth towards eye) but still write the original depth value to the depth buffer? The only ...
2
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1answer
59 views

Additive Blending and Gamma Correction

Should one do additive blending (aka lightmapping) in linear space? I tried doing it in linear space, and it became, well, linear and bland, losing that cool HDR-style bloomy effect. Is there some ...
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1answer
481 views

How can i make fade in/out of the alpha color of a material from black to none black?

This is script is attached to a black plane. I have a plane and i added to it a material and the plane is in black. When running the game the alpha color of the plane material is changing slowly. The ...
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1answer
79 views

Pack four alpha maps into one

I have read an article about texture splatting that says: Because the alphamap only has to be in a single channel of a texture, we can pack up to four alphamaps into a single texture – one in red,...
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1answer
1k views

Unity3D setting blend mode in shader using vertex data

I'm porting a game from iOS / Obj-C / OpenGL ES 2.0 to Unity. I have a procedural mesh script that generates a batch of quads that need to blend together to create a game board. Some of the quads ...
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1answer
3k views

Libgdx drawing semi-transparent circle on pixmap

I am currently working on an android game using libgdx and would like to add a joystick to its interface. For this I use the built-in touchpad class. Untill now I have used external images for ...
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2answers
2k views

How AlphaBlend Blendstate works in XNA 4 when accumulighting light into a RenderTarget?

I am using a Deferred Rendering engine from Catalin Zima's tutorial: His lighting shader returns the color of the light in the rgb channels and the specular component in the alpha channel. Here is ...
1
vote
1answer
431 views

How to set a global alpha-blending value in Direct3D 9?

Is it possible to set an alpha value globally in Direct3D 9, which modulates the pixel alpha values of every subsequent draw? I would like to let a whole scene fade in/out. I know that for example <...
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1answer
207 views

How to blend the surface with HTML5 canvas?

I can simply blend the surface in GameMaker using these codes: ...
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1answer
89 views

Alpha blending sometimes gives the wrong color?

I've got a method for alpha blending: ...
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2answers
555 views

libgdx texture edge blending problem

I have two completely white bitmaps here: They're there, trust me. When I put one on top of the other and scale them down with TextureFilter.Linear I get this: ...
1
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1answer
343 views

Alpha blending, transparence and z-ordering

I'm making some tests with alpha blending in a projet and I don't understand something. In my tests I've done something like that and everything look good: Draw blue box first (depth test: true, ...
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vote
1answer
249 views

Show only some parts of a point cloud. OpenGl4

I am developing an opengl 4.0 app which is showing a point cloud. In the other hand, I have an array "pos" where I have some x,y,z positions: ...
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0answers
28 views

Fallback for R32F alpha blending

I'm rendering an aggregation of value into an R32F format texture, using alpha blending to accomplish the sum operation. R32F alpha blending is not supported on all hardware. What kind of fallback ...
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0answers
60 views

Controllable color blending?

I'm relatively new to color blending in DirectX, and I'm hoping there is a relatively simple answer to this question. I am targeting Direct10.1. What I am trying to achieve is colour blending of two ...
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vote
1answer
700 views

Change the alpha blending color of scaled textures

It looks like semitransparent pixels are blended with while color when textures are drawn scaled. It is very noticeable and looks ugly when textures are drawn on dark background. ...
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0answers
94 views

Alpha blending is too smooth

I got the exercise to create a color map from a heightfield and given normals with alpha blending. Therefore I have to blend 4 textures (deep-flat, deep-steep, high-flat, high-steep) depending on the ...
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0answers
606 views

DirectX 11 GenerateMips only works with premultiplied alpha?

The GenerateMips method in the ID3D11DeviceContext allows generation of mipmaps at runtime, which is fine for fully opaque textures. However, when this method is used with transparent textures that do ...
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0answers
127 views

How can I eliminate these white outlines on my sprites in libgdx?

I'm recently started working on a game in libgdx, and I've run into the problem that my sprites tend to get a thin, whitish outline around them. This is especially a problem for me since I'm working ...
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1answer
402 views

How to setup a particular blend state where the alpha channel is additive?

I would like to set a blend state to be "additive" and do the following: ...
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0answers
141 views

Weird blending behavior on PowerVR SGX544MP2

On PowerVR SGX544MP2, sometimes blending behaves in a very strange way for me. Instead of blending with the actual color from the previous draw calls, it tries to blend with black: (sorry about the ...
1
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1answer
74 views

Only affect pixels in buffer with alpha 0

I'm working on a transition effect where I have a texture and simply draw that as a pattern to my buffer. Here is a demo, use "e" to start the effect again. This looks fine but it won't work if the ...
0
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1answer
185 views

How to get rid of the white border/background on my png image?

I am making a game using pyGame; it is basically a space invader game, with a tank. As we can see, this tank image I have has white borders / a white background, which I really want to get rid of. I ...
0
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1answer
2k views

Simplest way to render image over top of another with another image used as mask in OpenGL?

The effect I'm looking for is to have a single large background image that is always visible (at full alpha) and then show a second image (what I call a light map or specular map) that is partially ...
0
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1answer
1k views

C++ Additive Blending Algorithm 2d Game

I was wondering if anyone could shed any light on whats going wrong with my additive blending here, I think I'm nearly there, currently my outcome is black squares. I have tried using both the formula'...
0
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1answer
343 views

Artefacts when drawing textures

I am working on a level-based android game. The level is constructed of many blocks, all drawn with the same texture. Until now I didn't have any problems with drawing the different textures next to ...
0
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1answer
39 views

Unity Shader Blend like ugui Outline

Unity UGUI Outline it create fourfold vertexs, So I wirte shader to optimization ( vertex only create once ), And I want to Keep one pass . (one drawcall) There ...
0
votes
1answer
281 views

HLSL Manual Alpha Blending

I'm trying to do alpha blending manually because I only want to apply alpha blending on certain pixels. Underlying is the texture I'm writing to. This is what I got so far, but it doesn't give the ...
0
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1answer
430 views

DX11: Alpha blending not working with textured quads

A bit novice on directx11. I am rendering some textured quads out of PNG files (with alpha transparency) and get some inconsistency with my alpha blending. I have a background changing color ...