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( for those who do not want to read the whole post... just take a look in bold text smile.png )
 
After studying a bit about OpenGL and GLSL , I decided to put this knowledge into practice .
 
I found good tutorials to start such as opengl-tutorial.org and www.arcsynthesis.org/gltut/.
Also put my hands in OpenGL Superbible and almost finished reading it.
 
However each tutorial uses a different set of helper libraries (for loading images, event handling, managing windows , etc. )
 
I prefer to use the minimum libraries as possible, so did the whole treatment of windows and events handling using the native windows API.
 
In this case I was practically forced to use the ' glew ' because the OpenGL extensions are not provided by windows "gl.h" header ( I dont know if its the same thing in Mac or Linux).
 
Now I'm running into a problem trying to load images. While I'm working with BMP file format that's fine ( I wrote my own function to load BMP data ). However loading images from other formats ( PNG , TGA , JPG , etc ) is not so simple.
 
In this case I realize that running from third-party libraries will not work. So , I wonder what would be the most appropriate libraries to use with OpenGL ( 3.0 + ) .
 
I've seen setups using "SDL + OpenGL", "SFML + OpenGL" , "GLFW + OpenGL" or a mix of it all .
 
 
So, what would be a good 'toolbox' to a simple OpenGL project??
 
for example:
 
Window and Event handling : SDL, GLFW, SFML
Mathematics : GLM
Uploading Photos : DevIL
Charging Models : Assimp
 
ps: I did some research in this forum, but I don't find recent topics about it... the newest I found was dated from 2006... so I think that a new topic was necessary...
 
Thanks for any advice.
 
( and sry if my english is not good )

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For math, use GLM unless you're not using C++ or know you absolutely need something a different library uses. GLM seems as close to universally used as anything gets in OpenGL.

 
For Windows handling, I'd recommend SDL or SFML (not GLFW). Probably SDL if you're more C-like in your coding, and SFML if you're more OO.

 

For extensions, I'm using GLLoadgen since I prefer a c/h pair of files instead of an entire library and all that. It doesn't matter what you use though, they just use different init functions and then are the same.

 

For images, don't use DevIL. It's not maintained, so you'll run into trouble whenever you deviate from "normal" at all. You can use ResIL which branched off of it if you want basically the same thing. You can use libPNG like tons of people do. You can use stb_image if you prefer the simple c/h pair of files again. Once an image is a texture, you don't care how it got there though. So it doesn't really matter which image library you use as long as it works.

 

For models, I'd think that's more personal preference than anything. You can even load by hand pretty easily, although there's no reason to bother.

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So... may I consider using :   "SDL + OpenGL3.0 + glm" to a 'mid to big' project? I think SDL come with some image loading extensions.. right?

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I like FreeImage for loading images (DevIL is nice too but less features), and glew is basically must-have. glm seems nice but I don't have hands on experience. SDl is generally pretty decent and adds a lot of useful core functionality. On the other hand, I found that Assimp seemed to have a lot of bugs and both GLFW and SFML seem dicey to me.

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So... may I consider using :   "SDL + OpenGL3.0 + glm" to a 'mid to big' project? I think SDL come with some image loading extensions.. right?

Yes, SDL has an image library. I think SDL2 is still using libPNG 1.5.7 instead of 1.6.9, but if it works it works. And it will obviously have a wider feature set than libPNG.

 

Your choices should be absolutely fine. (I am assuming you'll be using SDL2 for SDL. While SDL 1.x is fine today, I have no idea how well it would be supported by the end of your project)

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why is the use of GLFW so discouraged? It's a light library that do only the bare minimum for window and input management, good for who don't want an entire framework like sfml. Or not?

 

For image loading I use SOIL, which is pretty good, light and simple in my opinion (and thinked to work with opengl).

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I used GLFW for a month. Ive found at least 3 annoying bugs and things that were done in a very unprofessional way. Like it didnt choose the proper window mode(WS_POPUPWINDOW / WS_POPUP) and my FPS dropped considerably. The input handling was also weird.

 

Its fine for a small project though.

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There is no reason not to use GLM, it's very good and it is made to go with OpenGL.

 

I've had no issues with GLFW3. In fact it is my favorite window and context creation library because it is very light weight and does exactly one thing, unlike a lot of the other libraries which try to do everything.

 

I've had better luck with the FreeImage library, but I would recommend you use it for creating your asset tools. For your actual texture assets you are probably going to be wanting to store things like mipmaps and compressed texture data, so you are better off using a custom texture file format and leaving FreeImage out of your game engine.

 

Same goes with Assimp. There is no reason to be loading your game models in your game engine from a format like Collada or any other format that requires parsing. Your game engine should be using a custom format that is ready to go.

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Your choices should be absolutely fine. (I am assuming you'll be using SDL2 for SDL. While SDL 1.x is fine today, I have no idea how well it would be supported by the end of your project)

 

Yes, I am talking about SDL2... :)

 

Thanks everyone for the advices!! I will keep my toolbox as a 'SDL2 + OPENGL + GLM + GLEW' and lets see if I can do my job with only this tools...

 

Thanks a lot

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There is no reason not to use GLM, it's very good and it is made to go with OpenGL.


One good reason not to use GLM is that Eigen is much more versatile and suitable for more than simple graphics calculations :)

GLM doesn't have any of the advanced features that Eigen has and mixing different math libraries is messy as hell.

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There is no reason not to use GLM, it's very good and it is made to go with OpenGL.

 

I've had no issues with GLFW3. In fact it is my favorite window and context creation library because it is very light weight and does exactly one thing, unlike a lot of the other libraries which try to do everything.

 

I've had better luck with the FreeImage library, but I would recommend you use it for creating your asset tools. For your actual texture assets you are probably going to be wanting to store things like mipmaps and compressed texture data, so you are better off using a custom texture file format and leaving FreeImage out of your game engine.

 

Same goes with Assimp. There is no reason to be loading your game models in your game engine from a format like Collada or any other format that requires parsing. Your game engine should be using a custom format that is ready to go.

 

I disagree. GLFW has MANY bugs.. I ran into enough that I just gave up on it.

 

And as for assimp, I use assimp in my engine because my engine supports modding and I want modders to be able to load any file type that they want. Think of an engine like Unity. If it used a special format, no one would use it because it would be to complicated to convert EVERY model to the proprietary format.

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I disagree. GLFW has MANY bugs.. I ran into enough that I just gave up on it.

 

I hope you reported those bugs, so that they can be fixed. I haven't ran into any thus far.

 


And as for assimp, I use assimp in my engine because my engine supports modding and I want modders to be able to load any file type that they want. Think of an engine like Unity. If it used a special format, no one would use it because it would be to complicated to convert EVERY model to the proprietary format.

 

Unity is more than a game engine, it is a game engine and a advanced editor. There is absolutely no logical reason that the engine needs to be loading models from a number of different textual file formats. Have your assimp support built into the editor, so your modders can load assets to their heats content, and have that editor convert them to a binary representation specific to your engine, that way when someone actually distributes a game it can load the assets quickly. People don't like long loading times, and that is exactly what you will get if the engine has to parse every single model from a text or XML file.

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I hope you reported those bugs, so that they can be fixed. I haven't ran into any thus far.

I did report the ones I found. My fear, however, is that there are many that I HAVEN'T yet found.

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I hope you reported those bugs, so that they can be fixed. I haven't ran into any thus far.

I did report the ones I found. My fear, however, is that there are many that I HAVEN'T yet found.

 

 

With as many bugs as you are likely to encounter with OpenGL drivers, I wouldn't worry too much about them. Just report them when you encounter them, and hopefully they will be ironed out. GLFW is growing in popularity and it is becoming more streamlined.

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      Setting the Pipeline State and Committing Shader Resources
      Before any draw or compute command can be invoked, the pipeline state needs to be bound to the context:
      m_pContext->SetPipelineState(m_pPSO); Under the hood, the engine sets the internal PSO object in the command list or calls all the required native API functions to properly configure all pipeline stages.
      The next step is to bind all required shader resources to the GPU pipeline, which is accomplished by IDeviceContext::CommitShaderResources() method:
      m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); The method takes a pointer to the shader resource binding object and makes all resources the object holds available for the shaders. In the case of D3D12, this only requires setting appropriate descriptor tables in the command list. For older APIs, this typically requires setting all resources individually.
      Next-generation APIs require the application to track the state of every resource and explicitly inform the system about all state transitions. For instance, if a texture was used as render target before, while the next draw command is going to use it as shader resource, a transition barrier needs to be executed. Diligent Engine does the heavy lifting of state tracking.  When CommitShaderResources() method is called with COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES flag, the engine commits and transitions resources to correct states at the same time. Note that transitioning resources does introduce some overhead. The engine tracks state of every resource and it will not issue the barrier if the state is already correct. But checking resource state is an overhead that can sometimes be avoided. The engine provides IDeviceContext::TransitionShaderResources() method that only transitions resources:
      m_pContext->TransitionShaderResources(m_pPSO, m_pSRB); In some scenarios it is more efficient to transition resources once and then only commit them.
      Invoking Draw Command
      The final step is to set states that are not part of the PSO, such as render targets, vertex and index buffers. Diligent Engine uses Direct3D11-syle API that is translated to other native API calls under the hood:
      ITextureView *pRTVs[] = {m_pRTV}; m_pContext->SetRenderTargets(_countof( pRTVs ), pRTVs, m_pDSV); // Clear render target and depth buffer const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); m_pContext->ClearDepthStencil(nullptr, CLEAR_DEPTH_FLAG, 1.f); // Set vertex and index buffers IBuffer *buffer[] = {m_pVertexBuffer}; Uint32 offsets[] = {0}; Uint32 strides[] = {sizeof(MyVertex)}; m_pContext->SetVertexBuffers(0, 1, buffer, strides, offsets, SET_VERTEX_BUFFERS_FLAG_RESET); m_pContext->SetIndexBuffer(m_pIndexBuffer, 0); Different native APIs use various set of function to execute draw commands depending on command details (if the command is indexed, instanced or both, what offsets in the source buffers are used etc.). For instance, there are 5 draw commands in Direct3D11 and more than 9 commands in OpenGL with something like glDrawElementsInstancedBaseVertexBaseInstance not uncommon. Diligent Engine hides all details with single IDeviceContext::Draw() method that takes takes DrawAttribs structure as an argument. The structure members define all attributes required to perform the command (primitive topology, number of vertices or indices, if draw call is indexed or not, if draw call is instanced or not, if draw call is indirect or not, etc.). For example:
      DrawAttribs attrs; attrs.IsIndexed = true; attrs.IndexType = VT_UINT16; attrs.NumIndices = 36; attrs.Topology = PRIMITIVE_TOPOLOGY_TRIANGLE_LIST; pContext->Draw(attrs); For compute commands, there is IDeviceContext::DispatchCompute() method that takes DispatchComputeAttribs structure that defines compute grid dimension.
      Source Code
      Full engine source code is available on GitHub and is free to use. The repository contains two samples, asteroids performance benchmark and example Unity project that uses Diligent Engine in native plugin.
      AntTweakBar sample is Diligent Engine’s “Hello World” example.

       
      Atmospheric scattering sample is a more advanced example. It demonstrates how Diligent Engine can be used to implement various rendering tasks: loading textures from files, using complex shaders, rendering to multiple render targets, using compute shaders and unordered access views, etc.

      Asteroids performance benchmark is based on this demo developed by Intel. It renders 50,000 unique textured asteroids and allows comparing performance of Direct3D11 and Direct3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures.

      Finally, there is an example project that shows how Diligent Engine can be integrated with Unity.

      Future Work
      The engine is under active development. It currently supports Windows desktop, Universal Windows and Android platforms. Direct3D11, Direct3D12, OpenGL/GLES backends are now feature complete. Vulkan backend is coming next, and support for more platforms is planned.
    • By reenigne
      For those that don't know me. I am the individual who's two videos are listed here under setup for https://wiki.libsdl.org/Tutorials
      I also run grhmedia.com where I host the projects and code for the tutorials I have online.
      Recently, I received a notice from youtube they will be implementing their new policy in protecting video content as of which I won't be monetized till I meat there required number of viewers and views each month.

      Frankly, I'm pretty sick of youtube. I put up a video and someone else learns from it and puts up another video and because of the way youtube does their placement they end up with more views.
      Even guys that clearly post false information such as one individual who said GLEW 2.0 was broken because he didn't know how to compile it. He in short didn't know how to modify the script he used because he didn't understand make files and how the requirements of the compiler and library changes needed some different flags.

      At the end of the month when they implement this I will take down the content and host on my own server purely and it will be a paid system and or patreon. 

      I get my videos may be a bit dry, I generally figure people are there to learn how to do something and I rather not waste their time. 
      I used to also help people for free even those coming from the other videos. That won't be the case any more. I used to just take anyone emails and work with them my email is posted on the site.

      I don't expect to get the required number of subscribers in that time or increased views. Even if I did well it wouldn't take care of each reoccurring month.
      I figure this is simpler and I don't plan on putting some sort of exorbitant fee for a monthly subscription or the like.
      I was thinking on the lines of a few dollars 1,2, and 3 and the larger subscription gets you assistance with the content in the tutorials if needed that month.
      Maybe another fee if it is related but not directly in the content. 
      The fees would serve to cut down on the number of people who ask for help and maybe encourage some of the people to actually pay attention to what is said rather than do their own thing. That actually turns out to be 90% of the issues. I spent 6 hours helping one individual last week I must have asked him 20 times did you do exactly like I said in the video even pointed directly to the section. When he finally sent me a copy of the what he entered I knew then and there he had not. I circled it and I pointed out that wasn't what I said to do in the video. I didn't tell him what was wrong and how I knew that way he would go back and actually follow what it said to do. He then reported it worked. Yea, no kidding following directions works. But hey isn't alone and well its part of the learning process.

      So the point of this isn't to be a gripe session. I'm just looking for a bit of feed back. Do you think the fees are unreasonable?
      Should I keep the youtube channel and do just the fees with patreon or do you think locking the content to my site and require a subscription is an idea.

      I'm just looking at the fact it is unrealistic to think youtube/google will actually get stuff right or that youtube viewers will actually bother to start looking for more accurate videos. 
    • By Balma Alparisi
      i got error 1282 in my code.
      sf::ContextSettings settings; settings.majorVersion = 4; settings.minorVersion = 5; settings.attributeFlags = settings.Core; sf::Window window; window.create(sf::VideoMode(1600, 900), "Texture Unit Rectangle", sf::Style::Close, settings); window.setActive(true); window.setVerticalSyncEnabled(true); glewInit(); GLuint shaderProgram = createShaderProgram("FX/Rectangle.vss", "FX/Rectangle.fss"); float vertex[] = { -0.5f,0.5f,0.0f, 0.0f,0.0f, -0.5f,-0.5f,0.0f, 0.0f,1.0f, 0.5f,0.5f,0.0f, 1.0f,0.0f, 0.5,-0.5f,0.0f, 1.0f,1.0f, }; GLuint indices[] = { 0,1,2, 1,2,3, }; GLuint vao; glGenVertexArrays(1, &vao); glBindVertexArray(vao); GLuint vbo; glGenBuffers(1, &vbo); glBindBuffer(GL_ARRAY_BUFFER, vbo); glBufferData(GL_ARRAY_BUFFER, sizeof(vertex), vertex, GL_STATIC_DRAW); GLuint ebo; glGenBuffers(1, &ebo); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,GL_STATIC_DRAW); glVertexAttribPointer(0, 3, GL_FLOAT, false, sizeof(float) * 5, (void*)0); glEnableVertexAttribArray(0); glVertexAttribPointer(1, 2, GL_FLOAT, false, sizeof(float) * 5, (void*)(sizeof(float) * 3)); glEnableVertexAttribArray(1); GLuint texture[2]; glGenTextures(2, texture); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); sf::Image* imageOne = new sf::Image; bool isImageOneLoaded = imageOne->loadFromFile("Texture/container.jpg"); if (isImageOneLoaded) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageOne->getSize().x, imageOne->getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageOne->getPixelsPtr()); glGenerateMipmap(GL_TEXTURE_2D); } delete imageOne; glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture[1]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); sf::Image* imageTwo = new sf::Image; bool isImageTwoLoaded = imageTwo->loadFromFile("Texture/awesomeface.png"); if (isImageTwoLoaded) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageTwo->getSize().x, imageTwo->getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageTwo->getPixelsPtr()); glGenerateMipmap(GL_TEXTURE_2D); } delete imageTwo; glUniform1i(glGetUniformLocation(shaderProgram, "inTextureOne"), 0); glUniform1i(glGetUniformLocation(shaderProgram, "inTextureTwo"), 1); GLenum error = glGetError(); std::cout << error << std::endl; sf::Event event; bool isRunning = true; while (isRunning) { while (window.pollEvent(event)) { if (event.type == event.Closed) { isRunning = false; } } glClear(GL_COLOR_BUFFER_BIT); if (isImageOneLoaded && isImageTwoLoaded) { glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture[0]); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture[1]); glUseProgram(shaderProgram); } glBindVertexArray(vao); glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr); glBindVertexArray(0); window.display(); } glDeleteVertexArrays(1, &vao); glDeleteBuffers(1, &vbo); glDeleteBuffers(1, &ebo); glDeleteProgram(shaderProgram); glDeleteTextures(2,texture); return 0; } and this is the vertex shader
      #version 450 core layout(location=0) in vec3 inPos; layout(location=1) in vec2 inTexCoord; out vec2 TexCoord; void main() { gl_Position=vec4(inPos,1.0); TexCoord=inTexCoord; } and the fragment shader
      #version 450 core in vec2 TexCoord; uniform sampler2D inTextureOne; uniform sampler2D inTextureTwo; out vec4 FragmentColor; void main() { FragmentColor=mix(texture(inTextureOne,TexCoord),texture(inTextureTwo,TexCoord),0.2); } I was expecting awesomeface.png on top of container.jpg

    • By khawk
      We've just released all of the source code for the NeHe OpenGL lessons on our Github page at https://github.com/gamedev-net/nehe-opengl. code - 43 total platforms, configurations, and languages are included.
      Now operated by GameDev.net, NeHe is located at http://nehe.gamedev.net where it has been a valuable resource for developers wanting to learn OpenGL and graphics programming.

      View full story
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