Any part of an object or graphic that light does not fully reflect off of, and thus can be seen through. Also applies to translucency effects.

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14
votes
7answers
2k views

What does the term “channel” mean when used in regards to computer graphics?

I was studying terminology for computer graphics, and this statement came up that confused me. The image can have alpha channels for transparency. I tried searching for the meaning of the term ...
10
votes
2answers
17k views

How Do I Do Alpha Transparency Properly In XNA 4.0?

Okay, I've read several articles, tutorials, and questions regarding this. Most point to the same technique which doesn't solve my problem. I need the ability to create semi-transparent sprites ...
9
votes
2answers
1k views

Why are some games using some dithering pattern instead of traditional alpha for transparency?

Recently, I have seen some 3D games (eg: GTA IV) to use some kind of ordered dithering to simulate transparency / alpha. The polygons are not transparent as usual, but instead render a dithering ...
8
votes
4answers
2k views

Shadow Mapping and Transparent Quads

Shadow mapping uses the depth buffer to calculate where shadows should be drawn. My problem is that I'd like some semi transparent textured quads to cast shadows - for example billboarded trees. As ...
8
votes
4answers
2k views

Order independent transparency in particle system

I'm writing a particle system and would like to find a trick to achieve proper alpha blending without sorting particles because: Each particle is a point sprite in a single mesh and I can't use ...
6
votes
1answer
7k views

How to render a texture partly transparent?

Good Morning StackOverflow, I'm having a bit of a problem right now as I can't seem to find a way to render part of a texture transparently with openGL. Here is my setting : I have a quad, ...
6
votes
1answer
418 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 ...
6
votes
3answers
3k views

How do I render a PNG with transparency in LibGDX?

I'm building a simple tic-tac-toe example with LibGDX. I have simple images: cross, circle and board, all pngs created with GIMP with a transparent background. How can I render them as a Texture with ...
5
votes
2answers
2k views

What is the order-less rendering technique that allows partial transparency?

I've seen somewhere rendering technique that allows order-less rendering of partially transparent sprites/objects. Though I can't remember what the technique is called, so I'm having trouble Googling ...
5
votes
2answers
285 views

Mobile 3D engine renders alpha as full-object transparency

I am running a iOS project using the isgl3d framework for showing pod files. I have a stylish car with 0.5 alpha windows, that I wish to render on a camera background, seeking some augmented reality ...
5
votes
1answer
411 views

Line at edge of transparent texture on XNA mesh

I have a mesh that is computer generated with a texture on top of it with transparancy on one side. The SamplerState is set to LinearWrap because I would like the texture to wrap. The problem I have ...
5
votes
1answer
195 views

How can glass breaking effect from Smash Hit be achieved? [duplicate]

I saw Smash Hit the other day and was amazed by the physics of the game, specially the shattered glass effect: I've read other posts about this subject but I still feel that they don't share enough ...
5
votes
3answers
1k views

Does Unity's “Transparent Bumped Specular” translate to “semi-shiny must be semi-transparent”?

Unity's documentation for the "Transparent Bumped Specular" shader/material-type is simply a concatenation of each of the descriptions for its Transparent and Specular Shaders (and also Bumped, but ...
4
votes
2answers
686 views

Jagged transparency when rendering translucent textures (OpenGL 3.2 + GLSL)

Like most others, I'll start off mentioning that I'm still a beginner when it comes to OpenGL and GLSL programming. So bear with me on any dumb mistakes you may spot in the code ahead. I'm basically ...
4
votes
1answer
446 views

How do games deal with Z-sorting partially transparent foliage textures?

I was busy implementing basic transparency in a prototype I'm working on when something occurred to me. In order for a given texture's transparency to work as expected, the (semi-)transparent texture ...
4
votes
2answers
1k views

Pygame set_colorkey transparency issues

I'm having a strange issue that I cannot seem to remedy. I am doing some prototyping with Pygame on a desktop running windows and a laptop running OS X. Both are running python v2.7.3 (installed via ...
4
votes
2answers
126 views

XNA Transparency depending on drawing order?

I am drawing two 3D objects, both of them can fade from opaque to transparent independently, and they can intersect between them (so you cannot say when one of them is before the other one). Look at ...
4
votes
1answer
397 views

How do you display non-cutout transparent 2D textures with a depth buffer? (OpenGL)

I've been able to get my 2D renderer to display transparent cutout textures by testing the alpha of a fragment and discarding if it is less than 1 (or any fraction really). The problem is I want to ...
3
votes
1answer
2k views

Why do my sprites have a dark shadow/line/frame surrounding the texture?

I'm starting OpenGL with Apple's GLKit hand I'm having some trouble to get my sprites displayed properly. The Problem is that they all are surrounded with thin dark lines. The screen shot below shows ...
3
votes
4answers
2k views

IOS OpenGl transparency performance issue

I have built a game in Unity that uses OpenGL ES 1.1 for IOS. I have a nice constant frame rate of 30 until i place a semi transparent texture over the top on my entire scene. I expect the drop in ...
3
votes
1answer
381 views

OpenGL - Z- Buffer translucency

So lately I wanted to use the Z buffer in opengl to order my 2D sprites in my program. Now I didn;t relaize that if you use the Z buffer then you cant blend these sprites. And some of these sprites ...
3
votes
3answers
1k views

Alpha blending without depth writing

A recurring problem I get is this one: given two different billboard sets with alpha textures intended to create particle special effects (such as point lights and smoke puffs), rendering them ...
3
votes
1answer
2k views

What is the AlphaToCoverage blend state useful for?

Alright, just finished most of my early UI stuff and I wanted the windows to have some transparency. So I expanded my application to initialize and bind blend states so that my UI shader could ...
3
votes
1answer
214 views

Make some black pixels transparent in Love2D

Is it possible to put a black opaque rectangle over my game screen and then change transparency on some pixels? For example I have black rectangle on screen represented by 1 1111111111111111111111 ...
3
votes
3answers
1k views

How can I render a semi transparent model with OpenGL correctly?

I'm using OpenGL ES 2 and I want to render a simple model with some level of transparency. I'm just starting out with shaders, and I wrote a simple diffuse shader for the model without any issues but ...
3
votes
2answers
2k views

Android: Loading bitmaps without premultiplied alpha (OpenGL ES 2.0)

Is this possible? To load textures in non-premultiplied format (Straight alpha?)? My game has 1 or 2 images which have semi-transparent pixels and I need to be able to fade them in and out but this ...
3
votes
1answer
427 views

Change opacity of a texture in XNA 4.0

I have created a terrain using VertexPositionNormalTexture in XNA 4.0, but now I would like to allow the user changing the opacity of the terrain (from 0%, totally opaque, to 100%, totally ...
3
votes
1answer
422 views

What are some effective methods for implementing downsampled transparency?

It seems that some games have managed to implement downsampled transparency, and presumably gained a significant performance boost. (Examples: Uncharted 2, Crysis 2) A while back I attempted to ...
3
votes
0answers
742 views

How to make the background of an OpenGL object transparent? [closed]

It sounds so simple but i didn't get it to work. The Background of my FrameLayout where i add the GLSurfaceView in is colored blue but there is only black. So here is my method to initiate the ...
2
votes
1answer
2k views

Collision detection with non-rectangular images

I'm creating a game and I need to detect collisions between a character and some parts of the environment. Since my character's frames are taken from a sprite sheet with a transparent background, I'm ...
2
votes
1answer
4k views

How do I make magenta in my PNG transparent in HTML5/Canvas/JS?

I'm putting together a simple hex map to use within an HTML5 / Canvas / JS game and before I get round to sorting any custom graphics, I was wondering if anybody knew how to make the pink/magenta ...
2
votes
1answer
197 views

When should I use color keying vs PNG transparency?

SDL (and other toolkits) can use color keying to make a certain color in an image transparent. Alternatively, you could load a PNG image that supports transparency. When should I use which?
2
votes
3answers
201 views

Order of render with transparency opengl

I tried to render using different render configurations (GL_BLEND_FUNC()) but I couldn't get the back object to render in certain angles. The first screenshot here shows one angle where the back ...
2
votes
1answer
861 views

XNA 4.0 - Transparent 3D model

I have a little problem with my 3D model (.fbx) rendered in XNA, look at screenshot. Screenshot: It should be a lego brick, which was modelated in Blender, then exported to .fbx and added to XNA ...
2
votes
2answers
1k views

Alpha in model XNA

OK been googling nonstop for ages... My problem is, i need transparent models in my game. After a lot of annoying fiddling around with my code, i changed the blendstate to alphablend. This allowed ...
2
votes
1answer
295 views

Alpha Blending: use the pixel with the smallest alpha

I'm writing a transparency shader where I need any intersecting textures to, wherever they overlap, take the texture pixel with the smallest alpha value and render only that, discarding the other ...
2
votes
2answers
197 views

fast java2d translucency

I'm trying to draw a bunch of translucent circles on a Swing JComponent. This isn't exactly fast, and I was wondering if there is a way to speed it up. My custom JComponent has the following ...
2
votes
1answer
262 views

Odd blending result (semi-transparent 2d quad over 3D scene)

I'm working on a GUI library for my game, and I'm having problems with my blending. I have a 3D scene, which I render with glDrawArrays. In the fragment shader the alpha color is hardcoded 1.0f ...
2
votes
0answers
77 views

Transparency behaviour on PowerVR

I'm doing some graphics optimizing tests, especially on PowerVR transparency. Now I made a scene where there are two groups of simple objects. One group has the shape in geometry using diffuse shader ...
1
vote
3answers
185 views

Rendering order

In this thread Rendering a model with transparent or translucent uv map applied doesn't work , I asked about what was wrong with my model that the transparency wasn't working. I've got an answer ...
1
vote
2answers
2k views

How can I make a tile appear on top of another without completely blocking the tile below?

Making a small RPG with libdgx just for learning about how to draw tiled maps and move around in them. I've got the tiles drawn and OrthographicCamera stuff figured out so I can see my world. My ...
1
vote
1answer
1k views

Early Z culling - Ogre

For Ogre experienced people, but also experts in the field: Early Z culling is sometimes quite desirable, and that's what I tried to do in Ogre by using a two pass material. The first one is writing ...
1
vote
1answer
594 views

Keyframing or programmatically changing attachment transparency in Spine

I've just recently been getting to grips with Spine and Unity 2D, porting some of my assets from different sources (SWFs, SVGs, GIFs, Canvas animations). Whilst I'm able to reproduce a lot of what I ...
1
vote
2answers
4k views

Transparent parts of texture are opaque black instead

I render a sprite twice, one on top of the other. The sprites have transparent parts, so I should be able to see the bottom sprite under the top sprite. The transparent parts are black (the clear ...
1
vote
1answer
75 views

How can I fix this transparency problem when my data is viewed from a certain angle?

using Microsoft.DirectX.Direct3D; using Microsoft.DirectX; I render a 3D data by setting device.RenderState.AlphaBlendEnable = true Now my top view looks like below, the outer surface layer ...
1
vote
1answer
591 views

Broken alpha of two-sided OpenGL mesh

How do I get rid of this alpha transparency artifacting with classic fixed function OpenGL? I tried all kinds of settings but I'm not sure why it's good in the upper half of the mask but not in the ...
1
vote
1answer
1k views

OpenGL ES Shader help (Blending)

Earlier I required assistance getting to grips with how to retain the alpha channel of a transparent texture in my colourised texture shader program. Whilst playing with that first version of my ...
1
vote
1answer
644 views

Rendering a image with some transparency has removed all black pixels and makes full texture transparent

I am writing a program where with Directx11 I am rendering a texture to a flat rectangle something along the line a of 2D engine. Now parts of this image need to be transparent, to this effect I ...
1
vote
5answers
333 views

Drawing transparent and opaque 3D objects. How do I preventing z-fighting?

I am using a transparent weighted average algorithm to draw my transparent objects. The transparent object is drawn with the following notable render states (the rest are default XNA values): ...
1
vote
1answer
191 views

Drawing Transparency in XNA 4.0

Using C# (VS2010) with XNA 4.0, I have a terrain layer (RenderTarget2D) in a 2D side-scroller. My visual system tracks updates to redraw individual tiles, but I am having trouble finding a way to ...