opengl-es

glBindTexture Problem with OpenGL ES on iPhone

I'm new to OpenGL, and am having a curious problem with my textures - looking for a nudge in the right direction. I have an app which uses a Render to texture technique for accomplishing a certain effect - it's working marvelously. I draw to an offscreen buffer every time I need to, and am able to use this as a texture in my render loo...

How do I define and standardize units in my 3D app?

I'm starting to design my object graph for an OpenGL ES 1.1 app on Android. What's advisable when it comes to actually drawing my triangles and controlling their size? Should I store all the vertices in units relative to each other and then multiply them by a value I pass during a draw(GL10 gl)? Would this approach have any impact whe...

Use OpenGL ES to create an iPhone painting tool?

Is it feasible to use OpenGL ES to create an iPhone raster graphics editor like SketchBook Mobile(http://usa.autodesk.com/adsk/servlet/pc/item?siteID=123112&id=13872203)? Any related reference(tutorial, sample) you can recommend? Why I try to use OpenGL ES? Because it's hardware accelerated and cross-platform. Thanks in advance! ...

mixing OpenGL and Interface Builder/ UI Controls - bad idea? Why? (iPhone)

I've heard that OpenGL ES and standard iPhone UI controls don't play well together, but I'm wondering if anyone knows why, and what the effects are? I'm writing an OpenGL based game, and the view is loaded from a nib file with ui controls, and it seems to work ok, but the game is really simple at this point... does using ui controls cau...

Should I use OpenGL for chess with animations?

At the moment I am experimenting with SurfaceView for my chess game with animations. I am getting only about 8 FPS in the emulator. I draw a chess board and 32 chess pieces and rotate everything (to see how smooth it is), I am using antialiasing. On the Droid I'm getting about 20FPS, so it's not very smooth. Is it possible to implement a...

How do I determine what is touched in 3D space from the screen?

How do I use gl.gluUnproject in my OpenGL ES 1.1 android app to determine what is selected when the user touches the screen? My understanding is that the touch event results in a line and I have to find the first "thing" it intersects with. Are there any tutorials on how to do this? ...

iPhone GLGravity example using quaternions

Hello, GLGravity iPhone example showing how to use accelerometer and OpenGL suffers from Gimbal Lock problem. I'm wondering is there any code available using quaternion rotation instead of Euler angles? Any help will be greatly appreciated, I'm struggling with this from a long time without having a success ... ...

Learning Quartz and/or openGL for iPhone resources?

I am interested in learning how to program game graphics for iPhone OS (3.x and beyond...). Can anyone recommend (based on personal experience) good books/websites that deal specifically with Quartz/OpenGL ES programming. Thanks. ...

Loading textures in an Android OpenGL ES App.

I was wondering if anyone could advise on a good pattern for loading textures in an Android Java & OpenGL ES app. My first concern is determining how many texture names to allocate and how I can efficiently go about doing this prior to rendering my vertices. My second concern is in loading the textures, I have to infer the texture to b...

Drawing a texture with an alpha channel doesn't work -- draws black

I am modifying GLPaint to use a different background, so in this case it is white. Anyway the existing stamp they are using assumes the background is black, so I made a new background with an alpha channel. When I draw on the canvas it is still black, what gives? When I actually draw, I just bind the texture and it works. Something is wr...

OpenGLES mix and match blending options complicated question

So I have a background line drawing, black and white. I want to be able to draw over this, keeping the black lines in there, and drawing only where it is white. I can do this by using glBlendFunc(GL_DST_COLOR, GL_ONE_MINUS_SRC_ALPHA); And the black stays black and white gets whatever color I want. However in the white areas, I want to...

Why does UIImageView "darken"/saturate PNG images, and can I stop it?

I have a PNG file in a UIImageView, and next to that I have an EAGLView which displays the continuation of that same image (long story) as a texture, carved from the same original PNG. The point is, that these images, which should match up flawlessly, actually have somewhat differing color saturation. Normally I'd blame my handling of t...

OpenGLES Add User Interactions

http://www.switchonthecode.com/tutorials/getting-started-with-opengl-es-for-the-iphone From the above link they created tutorial by No Nib File. But i need to add User interactions like , adding Progress View. Please help me. i am new to iphone OpenGLES. Thanks In Advance. ...

BlackBerry - SVG (JSR 226) or OpenGL ES (JSR 239) charting library

Does anyone know of a library to display charts and graphs natively on blackberry devices ? There are quite a few javascript (Flot...) charting libraries but I'd rather use something similar to Coreplot on iPhone if it is possible. I didn't find anything on top of SVG (JSR 226) or open GL ES (JSR 239) so any help is appreciated. Ideally...

How to merge two FBOs?

OK so I have 4 buffers, 3 FBOs and a render buffer. Let me explain. I have a view FBO, which will store the scene before I render it to the render buffer. I have a background buffer, which contains the background of the scene. I have a user buffer, which the user manipulates. When the user makes some action I draw to the user buffer,...

OpenGL ES clarifying question regarding FBOs -- sorry can't find this info anywhere else?

If I instantiate an FBO without binding a rendering buffer or a texture to it, what happens when I draw to it, nothing? Do I need to associate a rendering target (renderbuffer or texture) to have an FBO do anything? What I'm trying to do is precache some buffers and then merge them later, but that doesn't seem to work at all. Ideally I...

iPhone Human Interface Guidelines question

iPhone Human Interface Guidelines -- Do they apply for OpenGL games? GL games typically have custom buttons, custom lists, etc. Take the Quake player list for example, if ported, it wouldnt be a typical UI list object. Does this mean the reviewer in question would reject anything that wasn't using standard UI? Or, is there an excepti...

Attempted to render a circle in opengl es 1.1, renders as oval

Hi all, I attempted to render a circle in opengl es 1.1 as a test before building a larger program, but it renders as an oval. Here is the code I use to generate and render my vertices: static const int numVerts = 40; static GLfloat myFirstCircle[82]; myFirstCircle[0] = 0.0f; myFirstCircle[1] = 0.0f; for (int i = 2; i < (numVerts+1...

Problem enabling OpenGL ES depth test on iPhone. What steps are necessary?

I remember running into this problem when I started using OpenGL in OS X. Eventually I solved it, but I think that was just by using glut and c++ instead of Objective-C... The lines of code I have in init for the ES1Renderer are as follows: glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); Then in the render method, I have this: glCl...

iPad GLSL. From within a fragment shader how do I get the surface - not vertex - normal

Is it possible to access the surface normal - the normal associated with the plane of a fragment - from within a fragment shader? Or perhaps this can be done in the vertex shader? Is all knowledge of the associated geometry lost when we go down the shader pipeline or is there some clever way of recovering that information in either the ...