opengl-es

I'm attempting to use the ANGLE_instanced_arrays extension in WebGL to render multiple instances of an object with different mat3 transformation matrices. This is the code related to the buffer for my matrices: //setup this.shaderProgram.transformAttribute = gl.getAttribLocation(this.shaderProgram, "transform"); ext.vertexAttribDivisorANGLE(this.shaderProgram.transformAttribute, 1); this.transformBuffer = gl.createBuffer(); //each render gl.enableVertexAttribArray(this.shaderProgram.transformAttribute); gl.bindBuffer(gl.ARRAY_BUFFER, this.transformBuffer); gl.bufferData(gl.ARRAY_BUFFER, new

I want to convert mouse's current X and Y coordinates into the 3D space I have drawn in the viewport. I need to do this on the OpenGL ES platform. I found following possible solutions implemented in OpenGL, but none fits what I am looking for. I found NeHe's tutorial on doing exactly this, but in traditional OpenGL way. It uses gluUnProject. http://nehe.gamedev.net/data/articles/article.asp?article=13 Although gluUnProject is not available in OpenGL ES, its implementation seems simple enough to port back. But before calling it, we need to call glReadPixels with GL_DEPTH_COMPONENT and that is

My goal is to display a simple 3D model and apply a texture on it. I've downloaded the GLEssentials ios sample project to learn how to develop this (i'm new in ios OpenGL-ES API) But the example model is a .model file, which I never heard about and which never appear in model bank websites . What is this kind of file? is the sample code compatible with other common model types (.obj, .c2d, .3ds)? is it a good idea to start from this project? Ricardo RendonCepeda Have a look at this question: How to convert Blender blend (or obj) file to Qualcom Vuforia .h file In my answer, I describe a script

In opengl, is it bad practice or not recommended to modify the vertex array after I have drawn it? It's not bad practice if you modify the vertex array when you draw it as ordinary vertex array. It's bad practice to modify the vertex array if you use vertex buffer objects in your draw method. That's because you have to reupload it to your VRAM once it is edited. 来源： https://stackoverflow.com/questions/4703550/android-opengl-modify-vertex-array-after-draw-call

Could someone please explain how you render background images on an OpenGL ES view? From the basics of setting up the OpenGL environment. I'm a newbie to OpenGL here. I'm seeing a few questions/ answers on stackoverflow about creating background images, but I'm trying to modify existing code at the moment (Apple's GLPaint in particular), and I'm not sure what is needed and what is not. Having tried the solutions, with no success, I thought I should take a step back and actually try and understand what is going on. Mindlessly hacking hasn't gotten me far =( Are there any simple apps that show

I have a strange problem with openGL ES. I’m working on a paint app for iphone [taking reference from GLPaint app] .In my code I'm using an imageView which contain outline image on which I am puting [CAEAGLLayer] paintView for filling colors. I am filling colors in outline image by drawings lines onscreen based on where the user touches. I'm using the "renderLineFromPoint" function to draw a line between two points using "touchesMoved" for getting starting point and ending point. - (void) renderLineFromPoint:(CGPoint)start toPoint:(CGPoint)end{ // Drawings a line onscreen based on where the