Subset of the OpenGL 3D graphics API designed for embedded devices such as mobile phones.

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9
votes
2answers
5k views

How do I use depth testing and texture transparency together in my 2.5D world?

Note: I've already found an answer (which I will post after this question) - I was just wondering if I was doing it right, or if there is a better way. I'm making a "2.5D" isometric game using OpenGL ...
6
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 ...
5
votes
1answer
1k views

Game Code Design for Rendering

I first created a game on the iPhone and I'm now porting it to Android. I wrote most of the code in C++, but when it came to porting it wasn't so easy. The Android's way is to have two threads, one ...
1
vote
2answers
836 views

Disabling depth write trashes the frame buffer on some GPUs

I sometimes disable depth buffer writing via glDepthMask(GL_FALSE) during the alpha rendering of a frame. That works perfectly fine on some GPUs (like the Motorola Droid's PowerVR), but on the HTC EVO ...
5
votes
3answers
8k views

Android - Efficient way to draw tiles in OpenGL ES

I am trying to write efficient code to render a tile based map in android. I load for each tile the corresponding bitmap (just one time) and then create the according tiles. I have designed a class to ...
3
votes
3answers
7k views

OpenGL ES 2.0: Vertex and Fragment Shader for 2D with Transparency

Could I knindly ask for correct examples of OpenGL ES 2.0 Vertex and Fragment shader for displaying 2D textured sprites with transparency? I have fairly simple shaders that display textured polygon ...
0
votes
1answer
1k views

Formula for replicating glTexGen in OpenGL ES 2.0 GLSL

I also posted this on the main StackExchange, but this seems like a better place, but for give me for the double post if it shows up twice. I have been trying for several hours to implement a GLSL ...
2
votes
1answer
3k views

Computing a normal matrix in conjunction with gluLookAt

I have a hand-rolled camera class that converts yaw, pitch, and roll angles into a forward, side, and up vector suitable for calling gluLookAt. Using this camera class I can modify the model-view ...
2
votes
2answers
961 views

OpenGL ES 2.0: Picking Individual Polygon Sprites from within VBO

Say, I send 10 polygon pairs (one polygon pair == one 2d sprite == one rectangle == two triangles) into OpenGL ES 2.0 VBO. The 10 polygon pairs represent one animated 2D object consisting of 10 ...
8
votes
1answer
16k views

GLSL: How Do I cast a float into an int?

In a GLSL fragment shader I am trying to cast a float into an int. The compiler has other ideas. It complains thusly: ERROR: 0:60: '=' : cannot convert from 'mediump float' to 'highp int' I am ...
6
votes
2answers
3k views

OpenGL ES 2.0: Using VBOs?

OpenGL VBOs (vertex buffer objects) have been developed to improve performance of OpenGL (OpenGL ES 2.0 in my case). The logic is that with the help of VBOs, the data does not need to be copied from ...
0
votes
1answer
3k views

How to calculate vertex normals for a mesh in Java in OpenGL ES?

Can some one point me to Java code ( in Java not C or C++) that calculates all the normals for all the vertices of a mesh for OpenGL ES application. I need this for lighting. Lets say I have a cube ...
2
votes
4answers
2k views

Setting up OpenGL camera with off-center perspective

I'm using OpenGL ES (in iOS) and am struggling with setting up a viewport with an off-center distance point. Consider a game where you have a character in the left hand side of the screen, and some ...
2
votes
1answer
271 views

Creating an alphabet with numbers in 3d using opengl-es

How should I create an alphabet with numbers in 3d in opengl-es? I'm trying to create them with the existing primitives, but it's not looking good. Do we have any alternate way to get these things ...
2
votes
2answers
3k views

OpenGL-ES: clearing the alpha of the FrameBufferObject

This question is a follow-up to Texture artifacts on iPad How does one "clear the alpha of the render texture frameBufferObject"? I've searched around here, StackOverflow and various search engines ...
3
votes
3answers
681 views

What tool should I use for drawing 2D OpenGL shapes?

I'm working on a very simple OpenGL ES 2.0 game, and I'm not sure what tool to use to create the vertex data I need. My first thought was adobe illustrator, but I can't seem to find any info on how to ...
3
votes
2answers
1k views

How to create per-vertex normals when reusing vertex data?

I am displaying a cube using a vertex buffer object (gl.ELEMENT_ARRAY_BUFFER). This allows me to specify vertex indicies, rather than having duplicate vertexes. In the case of displaying a simple ...
3
votes
2answers
533 views

Texture artifacts on iPad

I'm porting an iPhone game to the iPad. When I move textures "quickly" (5.0 pixels every update at a rate of 60 Hz) I start to see little "artifacts" or remnants of where the texture used to be. I'm ...
1
vote
1answer
577 views

OpenGL ES Loading

I want to know what is the norm of loading rendering code. Take a button. When the application is loaded, a texture is loaded which has the image of the button on it. When the button is tapped, it ...
7
votes
2answers
1k views

Missing features from WebGL and OpenGL ES

I've started using WebGL and am pleased with how easy it is to leverage my OpenGL (and by extension OpenGL ES) experience. However, my understanding is as follows: OpenGL ES is a subset of OpenGL ...
12
votes
5answers
7k views

Complete Math Library for use in OpenGL ES 2.0 Game? [closed]

Are you aware of a complete (or almost complete) cross platform math library for use in OpenGL ES 2.0 games? The library should contain: Matrix2x2, Matrix 3x3, Matrix4x4 classes Quaternions ...
2
votes
1answer
3k views

Using gluLookAt to move camera in 2D iPhone game?

I'm trying to use gluLookAt to move the camera in my iPhone game, but every time I've tried to use gluLookAt my screen just goes "blank" ( grey in this case ) I'm trying to render a simple triangle ...
5
votes
2answers
3k views

In OpenGL Can I Discover the Depth Range of a Depth Buffer?

I am doing a GL multi-pass rendering app for iOS. The first pass renders to a depthbuffer texture. The second pass uses the values in the depth buffer to control the application of a fragment shader. ...
6
votes
2answers
613 views

OpenGL or OpenGL ES

What should I learn? OpenGL 4.1 or OpenGL ES 2.0? I will be developing desktop applications using Qt but I may start developing mobile applications in a few months, too. I don't know anything about ...
4
votes
2answers
471 views

What is the ballpark GL framerate for iPad and iPhone 4?

Does anyone the GL frame rate for iPad and iPhone 4 under the follow conditions: Unlit Non supersampled GLSL texture mapped with two textures. Single quad, 4 vertices Thanks, Doug
3
votes
1answer
2k views

Why does glGetUniformLocation report some of my uniform locations as -1?

I have been writing GLSL shaders for over a year but this is the first time I have run into this problem. I am on the iOS platform - if that matters. In a vertex shader I have this: uniform mediump ...
-3
votes
2answers
6k views

Make Pong on android using OpenGL-ES

I am trying to make a simple pong game using opengl-es. I have checked out some of the tutorials/samples, but most of them are pre-dated to 2009. I am familiar with game programming, and consider ...
9
votes
5answers
3k views

OpenGL's matrix stack vs Hand multiplying

Which is more efficient using OpenGL's transformation stack or applying the transformations by hand. I've often heard that you should minimize the number of state transitions in your graphics ...
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 ...
2
votes
2answers
3k views

how disable texture after drawing an object?

i try to make a textured object then draw other without (only colored). i had tried to play with glEnable/Disable(GL10.GL_TEXTURE_2D) , ...
2
votes
1answer
2k views

Drawing polygons with a repeating texture on iOS

I want to draw a terrain for a 2d game, and this terrain is defined by some rotated rectangles and circles, I want to draw my terrain as if it was a repeating texture clipped by those forms. I already ...
7
votes
3answers
8k views

Maya 3D model to iOS OpenGL ES

I need to display, rotate, and zoom a 3D model in OpenGL ES (iPhone/iPad). The 3D graphic artists are using Maya (on OS/X). What export format should I be looking at to use their 3D models in the ...
4
votes
1answer
2k views

Rendering 2d sprites into a 3d world?

In opengl how do I render 2d sprites in opengl given that I have a png of the sprite? See images as an example of the effect I'd like to achieve. Also I would like to overlay weapons on the screen ...
3
votes
2answers
1k views

how to apply a texture to a 3d scene background?

i don't really know the exact term for that (i thought it was hdr but no...). i want to put a texture as a background in opengl-es , and when we rotate the view , the background rotate too ...
4
votes
1answer
372 views

Spriting engine on mobile platforms, OpenGLES

I'm writing a basic spriting engine for a blackberry app, and I want to know the best way to draw tons of sprites using the glDrawArrays() command. We have several sprites that move around the ...
13
votes
2answers
15k views

OpenGL ES 2.0: Setting up 2D Projection

This article describes in general, how to draw sharp OpenGL 2D graphics, using fixed function pipeline. http://basic4gl.wikispaces.com/2D+Drawing+in+OpenGL Because OpenGL ES 2.0 has some ES 1.x ...
6
votes
4answers
2k views

iPhone 3d Model format: .h file, .obj, or some other?

I'm beginning to write an iPhone game using OpenGL-ES and I've come across a problem with deciding what format my 3D models should be in. I've read (link escapes me at the moment) that some ...
2
votes
1answer
874 views

Post processing texture sizes

I'm trying to write some code to do post processing in OpenGL ES2 on the iPhone. All is fine an dandy, except I am having trouble working out how to scale the texture rendered in the rendering step, ...
3
votes
1answer
717 views

iPhone/OpenGL-ES partially texture mapping an object

I only have a basic understanding of OpenGL, so I'm probably showing my ignorance here. I'm looking for a great iPhone/OpenGL-ES example of applying a texture (preferably from a texture atlas, but ...
6
votes
3answers
586 views

Is Frustum Culling by itself enough for Consoles and Mobiles?

Software occlusion culling is often expensive, especially for smaller and older devices. Is frustum culling alone adequate on systems that can optimally display 10k triangles at most? If not, are ...
4
votes
5answers
2k views

How can I improve the “smoothness” of a 2D side-scrolling iPhone game?

I'm working on a relatively simple 2D side-scrolling iPhone game. The controls are tilt-based. I use OpenGL ES 1.1 for the graphics. The game state is updated at a rate of 30 Hz... And the drawing ...
5
votes
1answer
1k views

How do you activate multisampling in OpenGL ES on the iPhone?

I'm experimenting w/ improving the "resolution" of an OpenGL ES based app. Apple mentions here (developer.apple.com) that OpenGL ES in iOS 4 supports multisampling... and this can improve the ...
1
vote
1answer
913 views

How can I take advantage of the iPhone 4's higher resolution screen?

I've recently tested an OpenGL ES based 2D game on the iPhone 4. I've done almost all of the development and testing so far on my 3G device. The game works fine (except for a few multitasking ...
7
votes
4answers
5k views

Updating OpenGL ES 1.1 based iPhone game to use Open GL ES 2.0

I'm fairly new to anything OpenGL in general. I've made an OpenGL ES 1.1 based 2D iPhone game by working from sample code. I'm under the impression that OpenGL ES 2.0 is substantially different from ...
18
votes
3answers
10k views

What is the difference between OpenGL ES and OpenGL?

Android uses OpenGL ES, what is the difference between it and OpenGL?