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
3k 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 ...
14
votes
2answers
5k 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 ...
12
votes
2answers
19k 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 ...
10
votes
4answers
3k 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 ...
10
votes
3answers
9k 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 ...
9
votes
3answers
4k 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 ...
8
votes
1answer
14k 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, ...
7
votes
1answer
164 views

Depth Peeling implementation problem: How to render the next layer? (OpenGL)

I try to implement order-independet transparency sticking to the pseudo code in the linked paper (page 4). I can't figure out how they are able to do this in OpenGL. I am rendering the scene two ...
6
votes
1answer
865 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
1answer
171 views

How to detect collision only in non-transparent texture?

I am developing a game using libgdx. I am trying to detect the collision between bee and tube. I am using the following code to detect the collision. if(player.getBounds().overlaps(boundsBot)){ } ...
5
votes
2answers
3k 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
334 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
2k 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 ...
5
votes
1answer
448 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
1k 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
2answers
1k 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 ...
5
votes
2answers
2k 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
1answer
1k 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
3k 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
1answer
140 views

How do I check for collision between transparent textures?

I am creating a 2D game using OpenGL. For sprites, I use textured quads (actually two triangles). The texures contain transparent pixels, since objects are not always perfectly rectangular. How do I ...
4
votes
2answers
180 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
956 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
3k 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 ...
3
votes
1answer
4k 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
4k 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
7k 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 ...
3
votes
2answers
81 views

How to render transparent meshes without sorting? [duplicate]

Let's assume we have some arbitrary triangle manifold meshes which are transparent. How real guys effectively render it? Is it possible todo it without sorting faces back to front (e.g. via bsp) and ...
3
votes
1answer
3k 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
3answers
2k 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
2answers
377 views

Color key or transparent images?

Ive seen a lot of people make sprite sheets magenta instead of transparent and then they make the magenta transparent using code. What is best (Performance) to use transparent images or use a color ...
3
votes
1answer
540 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
2answers
4k 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
1k 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 ...
3
votes
3answers
2k 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
1answer
838 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
2answers
50 views

How can I render all objects behind a plane with a specific transparency value?

I have a game where there a multiple floor levels between the player switches. The floor is not present everywhere, so you can look through it. When 'working' (playing, building stuff, etc.) on a ...
3
votes
1answer
1k 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 ...
3
votes
1answer
518 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 ...
3
votes
1answer
535 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
2answers
61 views

Why is my alpha transparency not working correctly in Unity?

In Unity I have never seen a bug quite as weird as this one. As usual, I import my texture with a transparent background and then check the alpha is transparency box and apply it, and everything ...
3
votes
0answers
50 views

Optimal batching for 2D objects with transparency

I have a collection of 2d objects with transparency. Each object has a depth value to determine draw order and a material. I'm trying to batch them in an optimal way to minimize draw calls. Assume ...
3
votes
0answers
81 views

Unusual black squares in transparency effect after wake from sleep

I've encountered unusual black squares in semi transparent textures for a while now, usually in processes that were resumed after the computer woke from sleep. For example I've seen the effect in the ...
3
votes
0answers
1k 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
2answers
486 views

How do I use transparent textures in panda3d?

I need to map a partially transparent texture on a flat quad with panda3d. With the quad as a canvas I'd like to create something like sprites positioned in the 3d coordinate system. I wanted to ...
2
votes
1answer
595 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
783 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
2answers
2k 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
467 views

How do I procedurally create a directional light cone with an HTML canvas?

To create a directional light effect, I want to draw this kind of transparency mask on an HTML canvas (using context2d): I also want to be able to generate such a mask dynamically. I've tried using ...
2
votes
2answers
502 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
135 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 ...