Tagged Questions

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

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2
votes
2answers
2k views

GLSL Motion blur on mobile.. possible at acceptable framerates?

I have been struggling to implement a simple linear motion blur effect on mobile (Android, OpenGLES 2.0) but it just seems to destroy my framerate. I'm rendering to texture (FBO) then applying a ...
7
votes
1answer
591 views

How wise is this multithreading architecture?

I'm rewriting a game engine I wrote in an attempt to parallelize as much as possible. I'm considering making properties which may be accessed from multiple threads all use accessors which use boost ...
0
votes
1answer
1k views

Create cylinder using OpenGL-ES [closed]

I want to draw cone using OpenGL ES I have gone through many links to draw cylinder but I don't have any idea or approach to draw the cylinder. I've seen the gluCylinder function for OpenGL, but no ...
0
votes
0answers
85 views

Make a layer over an image and adjust its co-ordinates by touch

I need to make a layer over an image and adjust the layer to fit to image and get its co-ordinates of the layer. I need to adjust the layer by touch and pinch. The sample image is as below. I need ...
3
votes
1answer
238 views

Rotate an image and get back to its original position - opengles glkit

I need to rotate an image in opengles GLkit and get it back to its original position in GLkit. rotation += 5; _modelViewMatrix = GLKMatrix4Rotate( _modelViewMatrix, GLKMathDegreesToRadians(5), 1, 0, ...
1
vote
1answer
238 views

opengles display human face in iphone and animate it?

I need to make a human 2D face to 3D face. I used this link to load an ".obj" file and map the textures. This example is only for cube and pyramid. I loaded a human face ".obj" file. This loads the ...
1
vote
1answer
443 views

OpenGL ES screen to world coordinate

I am currently attempting to convert my screen coordinates to world coordinates, to be able to interact with objects. I am using glm and unProject to try and achieve this, so far this is my code: ...
1
vote
1answer
128 views

Does iOS support BC4 compressed texture?

I've been designing a new OpenGL image algorithm using BC4 textures at its core. It works well accross Windows and Mac, my main targets up to now. But today, the customer added a new requirement : it ...
3
votes
2answers
1k views

Improving performance of a particle system (OpenGL ES)

I'm in the process of implementing a simple particle system for a 2D mobile game (using OpenGL ES 2.0). It's working, but it's pretty slow. I start getting frame rate battering after about 400 ...
1
vote
2answers
260 views

How to get a texture from current point of view in OpenGL 2.0 ES?

Probably the title is confusing, but I didn't know how to ask better, sorry about that. What I would like to do is get a bitmap texture that represents exactly what's rendered at one point in time and ...
2
votes
1answer
1k views

Trying to run sample AndEngine gles2 code in the simulator throws “java.lang.IllegalArgumentException: No EGLConfig found!”, how can I fix this?

I tried to run a small sample game code in the emulator but it crashed. My LogCat is given here. Can you help me resolve the issue. 02-23 15:18:50.543: D/AndEngine(636): MainActivity.onCreate ...
3
votes
2answers
2k views

Point Sprites vs Textured Quads in Open GLES 2.0

I'm wondering what would perform better, point sprites (GL_POINTS) or regular sprites (GL_TRIANGLES). Here's the scenario: I am developing a simple particle system to allow me to produce various ...
0
votes
1answer
871 views

Which version of AndEngine (gles1 or gles2) should I learn? [closed]

I m new to Game Development. I've chosen AndEngine, but there are 2 versions: gles1 and gles2. I tried sample code from both and found that gles2 code is not run on an emulator, but required an actual ...
3
votes
1answer
309 views

culling lines on the back of a globe

I am drawing a simple outline of the world using GL_LINE_STRIPs (in WebGL). I want to not draw those lines that are on the other side of the spinning globe. Using Nicol Bolas approach below I am ...
0
votes
0answers
791 views

Depth sorting 2D textures in a batch with OpenGL ES 2.0

I have a combo of texture atlases and sprite batches in an OpenGLES 2.0 2D game I'm developing which is working well, but I have a problem with depth sorting. I'm using atlases to reduce the number ...
-1
votes
1answer
642 views

2d triangle with OpenGL-Es on Android

hey I am trying to draw a triangle on opengl es . I just followed a tutorial to do it. eventhough everything seems to be fine it does not work. everytime I run my code it sends me back to main menu. ...
3
votes
1answer
351 views

Fill texture with white color

How to paint texture with white color? Example what I mean: SpriteBatch.setColor changes tint only.
0
votes
1answer
157 views

Overlapping buttons with OpenGL and GLKit

I'm developing a game for iOS and I'm quite new to OpenGL. I'd like to ask some help please, hoping that it could be useful to other people too. At the moment I'm managing buttons simply by drawing ...
0
votes
1answer
846 views

All of my matrix functions not working? OpenGL ES 2.0

I am trying to make a projection matrix scaling the screen and making a coordination system. For some reason I don't think any of my matrix calling is working... the 3 function I am using are ...
3
votes
2answers
2k views

OpenGL GL_TRIANGLE_STRIP creating grid with degenerate triangles / for one draw call

I need to create a grid ready for GL_TRIANGLE_STRIP rendering with One drawcall - so i need to degenerate the triangles. I am almost there but missing last row/column and can't figure out why. My ...
4
votes
1answer
989 views

How to load a png file without alpha premultiplying in ios?

I am making a game in which I use the alpha value, in some cases for transparency, in others for occlusion, and for HDR in others. I'm loading the images like this (this is MonoTouch, but objective-c ...
2
votes
1answer
3k views

Android OpenGL ES RENDERMODE_WHEN_DIRTY implementation

I am trying to understand RENDERMODE_WHEN_DIRTY so that I could save battery life wherever possible.. I made this sample application so that GlSurfaceView is updated with random color only when the ...
3
votes
4answers
634 views

Benefits of upgrading from OpenGL ES 1.1 to 2.0 on iOS

I have an animated 3D iPhone game that I first wrote using OpenGL ES 1.1 in late 2009. After many updates to the rest of the game, the OpenGL ES 1.1 code still runs fine under iOS 6, but I'm ...
7
votes
1answer
2k views

OpenGL ES create stencil effect using texture

Environment This is the environment I am working in: OpenGL ES 2.0 iPhone Simulator & iPhone 4 iMac 27" using NVIDIA GeForce GTX 680MX 2048 MB Hope that helps. The Problem Been searching ...
6
votes
3answers
2k views

C++ and OpenGL ES: glDrawArrays calls are time consuming

Currently, I'm profiling my iOS. All the calls to glDrawArrays are expensive. For example, here is a screenshot of the rendering part of a particle system: As you can see, the glDrawArrays call ...
2
votes
1answer
2k views

Game Development at iOS, Android and PC with OpenGL ES

I'm beginning iOS apps development, and my aim is to make games to launch on App Store. But I want to know if it's possible to program a game on Xcode with OpenGL ES (C++ game logic), integrate it on ...
4
votes
3answers
584 views

OpenGL ES 2.0 - How to batch draw particles that have unique translations, rotations, scales, and alphas?

I've combined all of my vertex data for many particles into a single array. How would I batch draw all of those particles in a manner that preserves their unique translations? Any code examples ...
5
votes
3answers
443 views

OpenGL ES 1.1 - How to batch draw particles with different translations?

Assuming that I've combined all of my vertex data for many particles into a single array, how would I batch draw all of those particles in a manner that preserves their unique translations? Any code ...
1
vote
1answer
398 views

Keeping Track of Position OpenGL

I have a sphere in my 3D world located at the origin. I have models orbiting it and I need to keep track of each models' position (x, y, x coordinates) as well as update their bounding boxes for ...
1
vote
1answer
403 views

To stop Spite animation scrolling along the background in openGL ES

After using the endless road algorithm as described here, I also implemented the scrolling of walls along with it. I have the walk animation of the person which is stationed at the center of the ...
1
vote
1answer
481 views

Apply portion of texture atlas

I'm trying to write a shader that only maps a portion of a large texture to my sprite and I'm getting a strange behaviour with my current code. This is what I have right now: Texture atlas ...
1
vote
2answers
408 views

Quaternion Camera

Can someone help me figure out how to use a Quaternion with the PerspectiveCamera in libGDX or in general? I am trying to rotate my camera around a sphere that is being drawn at (0,0,0). I am not sure ...
1
vote
1answer
607 views

Using Quaternion in libGDX

Can someone give me an explanation about how to use the Quaternion class in libGDX to move my camera around a sphere or just set it up, manipulate it, and apply it general? I am trying to acheive ...
1
vote
1answer
210 views

How can I rotate a tile map (and all of it's individual tiles) around an arbitrary point? [duplicate]

I have a 3D tile map made up of individual billboards in OpenGL ES. Each tile is a two-triangle mesh with a 3D vector to determine position and another defining rotation. How can I rotate the entire ...
1
vote
2answers
904 views

How can I create a fast, real-time, fixed length glowing ray?

Similar to the disintegrate skill in Diablo 3. It should not light other objects in scene. Just glowing and animated. Like in this video http://www.youtube.com/watch?v=D_c4x6aQAG8. Should I use ...
1
vote
1answer
306 views

2D map/plane with nodes overlayed that supports panning, scaling and clicking on nodes

I'm trying my hand at Android development and seem to be running into an invisible ceiling in trying to get what I want accomplished. Basically I'm trying to create an app that renders a 2D surface ...
0
votes
1answer
399 views

Android, apply a pixelshader on a canvas

Can an opengl pixelshader be applied on a Canvas? I want to render a bitmap on a canvas, then apply a pixelshader to get, for example, a blur effect. Is this possible? I don't want to simulate the ...
5
votes
1answer
815 views

exporting bind and keyframe bone poses from blender to use in OpenGL

EDIT: I decided to reformulate the question in much simpler terms to see if someone can give me a hand with this. Basically, I'm exporting meshes, skeletons and actions from blender into an engine ...
0
votes
3answers
308 views

Simple iOS glDrawElements - BAD_ACCESS

You can copy paste this into the default OpenGl template created in Xcode. Why am I not seeing anything :-) It is strange as the glDrawArrays(GL_TRIANGLES, 0, 3); is working fine, but with ...
3
votes
2answers
1k views

The purpose of using invert and transpose

In openGl ES and the World of 3D - why use the invers matrix? The thing is that I dont have any intuition to, why it is used, therefore please correct me: As fare as I understand, it is used in ...
3
votes
1answer
1k views

How do I generate mipmap .png and model .obj files for LibGDX?

I'm playing a bit with LibGDX (OpenGL ES 2.0 wrapper for Android). I found some sample code which used prepared files to load models and mipmap textures for them, e.g., at ...
2
votes
1answer
510 views

Bad FPS for smaller size (OpenGL ES with SDL)

If you saw my other question, well, there is still a little problem: Click here to watch on youtube Basically, the frame rate is very bad on the actual device, where for some reason the animation is ...
0
votes
1answer
503 views

OpenGLES GLSL Shader attributes always bound to 0

So I have a very simple vertex shader as follows #version 120 attribute vec3 position; attribute vec3 inColor; uniform mat4 mvp; varying vec3 fragColor; void main(void){ fragColor = inColor; ...
2
votes
2answers
192 views

how to render small texture on another texture?

can anybody help me to render small texture on another texture. i.e I have one background image, when user touches on the screen it should draw small(circle or any object) on it. can anybody suggest ...
4
votes
2answers
2k views

How to send multiple MVP matrices to a vertex shader in OpenGL ES 2.0

I'm working my way through optimizing the rendering of sprites in a 2D game using OpenGL ES and I've hit the limit of my knowledge when it comes to GLSL and vertex shaders. I have two large float ...
3
votes
1answer
1k views

Z Order in 2D with orthographic projection and texture atlas

I am working with a 2D game in OpenGL ES and have a question about z-order together with a texture atlas. I am using an orthographic projection because I want pixel-perfect rendering of 2D sprites, ...
7
votes
4answers
10k views

What is the purpose of glScissor?

I know that it is more efficient than stencil test, but am I right assuming that the same functionality could be achieved using projection transformations with viewport?
2
votes
1answer
501 views

cocos2d/OpenGL multitexturing problem

I've got a simple shader to test multitextureing the problem is both samplers are using same image as their reference. the shader code is basically just this : vec4 mid = ...
7
votes
4answers
3k views

Sprite Animation in Android with OpenGL ES

How to do a sprite animation in android using OpenGL ES? What i have done : Now I am able to draw a rectangle and apply my texture(Spritesheet) to it What I need to know : Now the rectangle shows ...
2
votes
0answers
131 views

Is there a way to export 3D objects with animation from Blender or any other app into OpenGL ES 1.1 code?

The problem is that all the examples I've found are obsolete or iOS/Android specific and not "pure" OpenGL ES 1.1. If anyone can provide me with a good example/tutorial/book it would be very much ...