- HOpenGL - Haskell.org

Texture Mapping??
by Hector Guilarte 11 Jul '10

11 Jul '10

Hello, I've been looking for a way to map a texture into a Quad primitive with HOpenGL with no luck. I've already done this in C++ and had no problem. I did the tutorial in http://www.haskell.org/~pairwise/HOpenGL/HOpenGL.html, downloaded the sources, compiled them and it worked great, but when I change the code to use a .rgb file created by me with the program they provide from a .png file of 256x256 pixels I don't have the same luck... My OpenGL version is 2.4.0.1... I'm really lost in mapping the file, so any kind of help would be greatly appretiated. I checked the textures in the examples of the red book, but they are "procedural" textures, and I need to map an image. One of the pictures I need to map is in http://dl.dropbox.com/u/1476919/Orange256.png Are six like that one and are for making a Rubik's Cube. After I finish it I'll upload it to hackage and let you all know. Thanks a lot, Hector Guilarte

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Re: [HOpenGL] Texture Mapping??
by Hector Guilarte 11 Jul '10

11 Jul '10

Hello Nik, Thank you very much, I gave it a look but for what I can see they draw the textures by placing them directly somewhere in 2D and specifying the pixels positions directly. My game is 3D and the moves are kind of complicated, so mapping the textures directly into each one of my quads would make my life a million times easier than using the approach from Raincat, I don't even think it's posible for me, it would be insane. Also it would be nice to be able to load the textures using nothing but OpenGL, so no extra libraries are needed. Greeting, Hector Guilarte On Sun, Jul 11, 2010 at 8:03 AM, <nik.nyby(a)gmail.com> wrote: > Hector, > I also had trouble finding documentation on this topic. I'm not sure > exactly where you are stuck, but have you tried using SDL-image > (http://hackage.haskell.org/package/SDL-image) to turn the PNG into an > IO Surface? That is how Raincat loads textures: > > http://github.com/styx/Raincat/blob/f458d076d9961b739d3010725ad7055b02282d2… > > I hope that helps, in some way. > > Nik > > On Sat, Jul 10, 2010 at 9:02 PM, Hector Guilarte <hectorg87(a)gmail.com> > wrote: > > Hello, > > I've been looking for a way to map a texture into a Quad primitive with > > HOpenGL with no luck. I've already done this in C++ and had no problem. I > > did the tutorial > > in http://www.haskell.org/~pairwise/HOpenGL/HOpenGL.html, downloaded the > > sources, compiled them and it worked great, but when I change the code to > > use a .rgb file created by me with the program they provide from a .png > file > > of 256x256 pixels I don't have the same luck... My OpenGL version > > is 2.4.0.1... > > I'm really lost in mapping the file, so any kind of help would be greatly > > appretiated. > > I checked the textures in the examples of the red book, but they are > > "procedural" textures, and I need to map an image. > > One of the pictures I need to map is in > > http://dl.dropbox.com/u/1476919/Orange256.png > > Are six like that one and are for making a Rubik's Cube. After I finish > it > > I'll upload it to hackage and let you all know. > > Thanks a lot, > > Hector Guilarte > > _______________________________________________ > > HOpenGL mailing list > > HOpenGL(a)haskell.org > > http://www.haskell.org/mailman/listinfo/hopengl > > > > >

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GLUT, the way to go?
by hopengl＠lonely-star.org 17 May '10

17 May '10

Hi, I am new to Haskell, but not new to OpenGL. I am reading the tutorials on the HOpenGL page and have a few questions. - First of all, all tutorials are using GLUT. Is that really the way to go with HOpenGL? They define (among other things) a onIdle and a onDraw function. That seems to me (at least for a game) not the way to go. onIdle updates the game logic, and onDraw draws the screen. As far as I can see, it does not make sense to update the game logic more than once between consecutive calls to onDraw. Same thing is true for class to onDraw between consecutive class to onIdle. Is this accounted for in the approach? - In addition there is the onInput function. The onInput, onIdle and onDraw functions communicate (in the tutorials) using variables declared with newIORef. I come from the OO language C++ and almost no experience with functional languages. But this puzzles me. Basically they define global variables for the exchange between the callback functions, correct?!? So, for every piece of information I want to pass between these functions, I have to declare a newIORef variable? In C/C++ I find GLUT not a very good approach and prefer plain OpenGL. Does it make sense to go with plain OpenGL in Haskell too? Are there any resources on how to do that? Thanks! Nathan

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Rendering to texture
by Alexander Göransson 27 Apr '10

27 Apr '10

Here's some C code i want to translate to haskell, but i can't find the proper bindings. I've been greping OpenGL and OpenGLRaw, but i can't find anything: // Let us create an FBO; to do this add the following at the end of initGL: glGenFramebuffers(1, &frameBuffer); // Bind the framebuffer such that following commands will affect it. glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer); // Then we will create a texture into which we will be rendering, directly after add: // Create a texture for the frame buffer, with specified filtering, // rgba-format and size glGenTextures(1, &texFrameBuffer); glBindTexture(GL_TEXTURE_2D, texFrameBuffer); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexImage2D(GL_TEXTURE_2D, 0, 4, 512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL); // Next we will attach the texture to the FBO: glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texFrameBuffer, 0); And this is the end of initGL: texture = ilutGLLoadImage("flake.ppm"); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture); glGenerateMipmap(GL_TEXTURE_2D); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 16); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); So far i have a modified version of my texture loader but i don't know if this is correct or what: whatIsThisIDontEven :: TextureSize2D -> IO TextureObject whatIsThisIDontEven size = do [texObj] <- genObjectNames 1 activeTexture $= TextureUnit 0 textureBinding Texture2D $= Just texObj generateMipmap Texture2D $= Enabled textureFilter Texture2D $= ((Nearest, Just Nearest), Nearest) texImage2D Nothing NoProxy 1 RGBA' size 0 (PixelData RGBA Float nullPtr) return texObj My problem is that glBindFramebuffer isn't available in the haskell bindings. At least i can't find it after extensive searching :( What to do? // Alexander

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Sporadic idle function
by Robbie Carlton 13 Apr '10

13 Apr '10

Hey. First off: the hopengl bindings are amazing. I've already had a lot of fun with them. When I'm doing interactive stuff there is no problem. However, I've come across a problem with something which should be way simpler: I'm playing with a simple particle system in haskell using hopengl on mac os x. My idle callback function is only getting called sporadically, while the window has focus. If a different window has focus, the idle function is working fine, and everything is updating great. I can post the code, but there's a lot, and I'm wondering if this is a common problem that you guys have seen before. Thanks for reading Robbie

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Trouble getting buffer objects up and running!
by Alexander Göransson 07 Apr '10

07 Apr '10

Hello! I'm trying to port a C++ program that uses Vertex Buffer objects in OpenGL 3.0. As of now it seems like i can't get any further ;( Anyone who can help with as to what should be done next... I'm attaching the C++ source and shader files as well as my haskell source. regards // Alexander

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Hello World not using the fixed pipeline
by Alexander Göransson 03 Apr '10

03 Apr '10

After great effort, here it is! I had to run this on my laptop, so i had to go down to OpenGL 2.1 + GLSL 1.20. I tried to comment it so that semi-beginners could understand it. Please comment on any mistakes or dumb things i might have done :) // Alexander

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Segmentation Fault Running Panitz's Tutorial Code
by Scott 01 Apr '10

01 Apr '10

Hello! I have a problem when trying to run some code found on this tutorial page: http://public.beuth-hochschule.de/~panitz/hopengl/skript.html<http://public.beuth-hochschule.de/%7Epanitz/hopengl/skript.html> The demo is called "LightCube." The problem seems to have to do with the following line (which I've commented out in the provided source): depthFunc $= Just Less Uncommenting the line gives a Segmentation Fault when I run the executable generated by: ghc --make -package GLUT -o LightCube LightCube.hs Does anyone else have this problem? Here is the necessary code: * LightCube* import Graphics.Rendering.OpenGL import Graphics.UI.GLUT as GLUT import Cube main = do (progName,_) <- getArgsAndInitialize -- depthFunc $= Just Less createWindow progName lighting $= Enabled position (Light 0) $= Vertex4 1 0.4 0.8 1 light (Light 0) $= Enabled displayCallback $= display mainLoop display = do clear [ColorBuffer] rotate 40 (Vector3 1 1 (1::GLfloat)) cube 0.5 loadIdentity flush * Cube * module Cube where import Graphics.Rendering.OpenGL import Graphics.UI.GLUT as GLUT import PointsForRendering cube l = renderAs Quads corners where corners = [(l,0,l),(0,0,l),(0,l,l),(l,l,l) ,(l,l,l),(l,l,0),(l,0,0),(l,0,l) ,(0,0,0),(l,0,0),(l,0,l),(0,0,l) ,(l,l,0),(0,l,0),(0,0,0),(l,0,0) ,(0,l,l),(l,l,l),(l,l,0),(0,l,0) ,(0,l,l),(0,l,0),(0,0,0),(0,0,l) ] * PointsForRendering* module PointsForRendering where import Graphics.UI.GLUT import Graphics.Rendering.OpenGL renderInWindow displayFunction = do (progName,_) <- getArgsAndInitialize createWindow progName displayCallback $= displayFunction mainLoop displayPoints points primitiveShape = do renderAs primitiveShape points flush renderAs figure ps = renderPrimitive figure$makeVertexes ps makeVertexes = mapM_ (\(x,y,z)->vertex$Vertex3 x y z) mainFor primitiveShape = renderInWindow (displayMyPoints primitiveShape) displayMyPoints primitiveShape = do clear [ColorBuffer] currentColor $= Color4 1 1 0 1 displayPoints myPoints primitiveShape myPoints = [(0.2,-0.4,0::GLfloat) ,(0.46,-0.26,0) ,(0.6,0,0) ,(0.6,0.2,0) ,(0.46,0.46,0) ,(0.2,0.6,0) ,(0.0,0.6,0) ,(-0.26,0.46,0) ,(-0.4,0.2,0) ,(-0.4,0,0) ,(-0.26,-0.26,0) ,(0,-0.4,0) ]

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Christopher Perez wants to stay in touch on LinkedIn
by Christopher Perez 20 Mar '10

20 Mar '10

LinkedIn ------------ I'd like to add you to my professional network on LinkedIn. - Christopher Perez Confirm that you know Christopher Perez https://www.linkedin.com/e/isd/1162365063/iv9cjcaw/EML-invg_56/ ------ (c) 2010, LinkedIn Corporation

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GPipe: Binding textures to geometry
by Achim Schneider 09 Mar '10

09 Mar '10

I'm by no means an GL expert, but I think it should be possible to attach a texture index to vertices, so that only one fragment shader is needed instead of one for every texture. Currently, I'm duplicating the whole graphics pipeline for virtually every triangle, and it seems that is what's killing performance. Random minor nitpick: The matrix multiplications in the example are done on the CPU, not GPU. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited.

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