opengl-es

I am working on an OpenGL ES fluid simulation which uses texture maps to hold grid values. I need to iterate thru the grid that mimics the following loop: for (int r = 0; r < 128; r++) for (int c = 0; c < 128; c++) process grid element at (c,r) To iterate through the grid I am simply filling a quadrilateral which causes my fragment program to be invoked for each fragment. The texture coordinates (0,0), (1,0), (0,1), (1,1) are associated with the vertices (-1,-1), (+1,-1), (-1,+1), (+1,+1) and I render the quad (as a triangle strip) into a 128x128 texture map attached to a FBO as follows:

I want to take a .png image and use it as the background for my GLView. I've heard that glDrawTex* was the best way, but I've searched the internet and haven't found a single example of how to use it (at least not one that has worked for me). Any help? Although the OES_draw_texture extension is a good enough way to draw a background because it may sometimes be a little faster than using geometry, I'd recommend against using it too heavily on the basis that iPhones don't implement it under ES 2 and you don't want to box yourself into a corner. That being said, something like: int sourceRect[4]

I have a Sprite Kit game that is crashing when the game is over. This happening on the tvOS 9.1 and iOS 9.2. Before, I had it running on iOS 9.1 without crashing. It seems to be an OpenGL issue, but when I search the function in Xcode, it doesn't come up with anything. Unfortunately, the error is not consistent in appearing in the console. Here's the error: Jet: draw_indexed: indexType must be 'unsigned_int' or 'unsigned_short' Assertion failed: (indexType == jet_component_type_unsigned_int || indexType == jet_component_type_unsigned_short), function draw_indexed, file /BuildRoot/Library

This is a continuation of my previous problem and post, seen here . Thanks to the answer I received there I feel I was able to get a little closer to my goal, as well as further my learning of OpenGL, but shortly after figuring out the basics of working with stencil buffers, I've run into a problem. It seems that when I draw a sprite to the stencil buffer, it draws the entire square area, rather than just the pixels that aren't fully transparent as I had ignorantly hoped. I vaguely understand why it happens that way, but I am not sure where the solution lies. I have experimented with the

I'm making an application in C# Xamarin that uses a iPhoneOSGameView for rendering some video stream I receive from the network. The problem is that after around 10 seconds without any user interaction with the screen, the frame rate drops significantly. It seems that the iDevice is going into some sort of power saving mode. When I interact with the screen (e.g. I pull down the top bar menu (iOS menu)), the frame rate goes back up, just like the iDevice realized I was actually using the application now. Is there a setting/value I have to set in my application to prevent this type of CPU/GPU

I'm creating an openGL game and so far I have been using .pngs in the RGBA8888 format as texture sheets, but those are too memory hungry, and my app crashes frequently. I read in Apple's site that such format such be used just when too much quality is needed, and recommends to use RGBA4444 and RGBA5551 instead ( I already converted my textures to PVR but the quality loss is too great in most of the sprite sheets). I only need to use GL_UNSIGNED_SHORT_5_5_5_1 or GL_UNSIGNED_SHORT_4_4_4_4 in my glTexImage2D call inside my texture loader class in order to load my textures, but I need to convert