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OpenGL Forcing early Z, which extension to use?

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As far as my research has shown that there are two different extensions that can be used to force an early Z test in OpenGL 3.0. these are GL_ARB_conservative_depth and GL_ARB_shader_image_load_store. According to the spec they can be used to force early Z in glsl like so:

 

GL_ARB_conservative_depth:

layout(depth_unchanged) out float gl_FragDepth;

GL_ARB_shader_image_load_store:

layout(early_fragment_tests) in;

My question is do these have the exact same effect? if so can I use them interchangeably, if not which one should I use? 

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http://www.opengl.org/wiki/Image_Load_Store

Does not load like image_load_store has anything to do with early depth test. So no, you should use the conservative depth.

 

Yeah I know that the purpose of the extension is not specifically for early z tests but it can be used to enable them as I read here:

 

http://www.opengl.org/wiki/Early_Depth_Test#Explicit_specification

 

What I was hoping was that cards that didn't support GL_ARB_conservative_depth might support GL_ARB_shader_image_load_store to be used as a fallback or vice versa.

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I don't know. I just read that and nothing there suggests anything you are talking about. It is talking about how one thing affects the other. It says nothing about how textures (image load store) will effect depth testing. It does however say how depth testing will affect the image load store.

FYI from that page: "Thus the first restriction on early depth tests is that they cannot happen if the fragment shader writes gl_FragDepth?. If the fragment shader modifies the depth, then the depth test must wait until after the fragment shader executes."

 

In GL 2.0 (and it seems it has carried on to newer versions). If you don't write the depth in the shader, early z-cull and depth writing already takes place.

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FYI from that page: "Thus the first restriction on early depth tests is that they cannot happen if the fragment shader writes gl_FragDepth?. If the fragment shader modifies the depth, then the depth test must wait until after the fragment shader executes."

 

I'm sorry but you clearly didn't read that entire article, the use of that syntax for forcing early Z requires GL_ARB_shader_image_load_store:

 

More recent hardware can force early depth tests, using a special fragment shader layout qualifier:

layout(early_fragment_tests) in;

This will also perform early stencil tests.

 

...

 

This feature exists to ensure proper behavior when using Image Load Store or other incoherent memory writing.

 

Its mentioned in the spec too:

http://www.opengl.org/registry/specs/ARB/shader_image_load_store.txt

 

An explicit control is provided to allow fragment shaders to enable early

fragment tests. If the fragment shader specifies the
"early_fragment_tests" layout qualifier, the per-fragment tests described
in Section 3.X will be performed prior to fragment shader execution.
Otherwise, they will be performed after fragment shader execution.
Edited by ic0de

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In GL 2.0 (and it seems it has carried on to newer versions). If you don't write the depth in the shader, early z-cull and depth writing already takes place.

Yep.

 

I don't think OpenGL 2 even has the notion of early depth test at all (much like how it doesn't specify the exact algorithm for defining the shape of triangles). It was an optimization done by the hardware and as long as it gave the expected results it could do anything it wanted, so early depth tests worked by default simply because there was nothing against it. I imagine that disabling it if you modify the depth in a pixel shader has to do with caching (it invalidates the value in the cache).

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I don't think OpenGL 2 even has the notion of early depth test at all (much like how it doesn't specify the exact algorithm for defining the shape of triangles). It was an optimization done by the hardware and as long as it gave the expected results it could do anything it wanted, so early depth tests worked by default simply because there was nothing against it. I imagine that disabling it if you modify the depth in a pixel shader has to do with caching (it invalidates the value in the cache)..

 

Using blending will also disable this hardware optimization, for PowerVR at least.  They call this feature "Tile Based Deferred Rendering" in case anyone wants to look it up.  Those little machines can handle a lot until you turn on blending, and presumably pixel shader depth writes.  Once you do this they slow to a crawl.

 

I haven't gone to any trouble to see if the other embedded system manufacturers have similar schemes running under the hood. 

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Well as this article (which I didn't initially read) suggests, some cards support this and they use the word "explicitly" which implies that there is an "implicit" case.
ATI and NVIDIA are going to be supporting this early optimization. I don't know anything that suggests otherwise and have read some internal docs.

This extension also provides the capability to explicitly enable "early"
    per-fragment tests, where operations like depth and stencil testing are
    performed prior to fragment shader execution.  In unextended OpenGL,
    fragment shaders never have any side effects and implementations can
    sometimes perform per-fragment tests and discard some fragments prior to
    executing the fragment shader.

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If you investigate this page it further supports my claim:
http://gamedev.stackexchange.com/questions/16588/computing-gl-fragdepth

It has been existing for a long time. Also its not just early z-cull, its hierarchical early z-cull.  Look up hierarchical occlusion culling. Graphics cards support this on a per-triangle level, which would not be possible if the shader executed first.

I believe the extension is explicitly able to perform the depth test by reading the depth buffer. Look up "discard".  You can discard any fragment in GL, to explicitly discard if (z < depthBuffer.z), you were not allowed direct access to the depth buffer. I don't know but am assuming that you are now allowed to read it. This may only be if you are using an FBO though........

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Using blending will also disable this hardware optimization, for PowerVR at least.  They call this feature "Tile Based Deferred Rendering" in case anyone wants to look it up.  Those little machines can handle a lot until you turn on blending, and presumably pixel shader depth writes.  Once you do this they slow to a crawl.

Is this tested? Have you tried enabling and then disabling depth test on enough blended fragments to test the performance is actually different? Seems strange this would happen since GL is a state machine.

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Using blending will also disable this hardware optimization, for PowerVR at least.  They call this feature "Tile Based Deferred Rendering" in case anyone wants to look it up.  Those little machines can handle a lot until you turn on blending, and presumably pixel shader depth writes.  Once you do this they slow to a crawl.

That would explain how they got OpenGL ES to work on that hardware in the first place.

 

I know what the algorithm does, it was used in the Dreamcast too, it's basically like an extremely simplified version of raytracing more or less. The more obvious issue, as you can imagine, is that such a thing doesn't even need the depth buffer at all, it processes all triangles and sorts them together (which is also how the Dreamcast got sort-independent alpha blending). I imagine the main reason Sega went with it back then is that it allowed for many more triangles at a much smaller fillrate.

 

I don't know how different is the current TBDR compared to the one from back then, but I presume that to get the same performance gains it must cheat a lot to work with OpenGL ES.

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Well as this article (which I didn't initially read) suggests, some cards support this and they use the word "explicitly" which implies that there is an "implicit" case.
ATI and NVIDIA are going to be supporting this early optimization. I don't know anything that suggests otherwise and have read some internal docs.

This extension also provides the capability to explicitly enable "early"
    per-fragment tests, where operations like depth and stencil testing are
    performed prior to fragment shader execution.  In unextended OpenGL,
    fragment shaders never have any side effects and implementations can
    sometimes perform per-fragment tests and discard some fragments prior to
    executing the fragment shader.

I think this extension is worded in a way that may be somewhat misleading, though at least they've put "early" in quotes. The same goes for the (wiki, by the way, so caveat emptor) page on opengl.org that you've dug up.

 

There is no "forcing early z" in OpenGL. OpenGL does not have any such thing as an "early z" at all, so you cannot enforce it. The specification is very clear about when the z test happens, and it is not "early", it is after the fragment shader has run. Still, implementations are allowed to do something different as long as the observable result is exactly identical, and most modern implementations in fact do something different.

 

If you search the OpenGL specification for "early", you find 3 occurrences of "linearly" and two occurrences of "clearly" (because Adobe Reader has no notion of searching for whole words), but "early" has no appearance at all. In particular, the additions to chapter 3 in above extension spec are funny because for example section 3.12.2 does not even exist in my copy of the specification (it stops at 3.11). They must be using a different copy smile.png

 

A better wording would be that you can give a strong hint to the implementation which effectively forces early z test on implementations that do an early z test (or, on most mainstream implementations).

 

The thing is, a modern implementation would of course always like to do the z test early, because this saves shader work. Insofar there is no need to "force" it. It's trying hard to do it anyway. However, the implementation must still guarantee that the result is the same, which it can only do with some very harsh constraints (for example if the shader does not modify z, so it is already known what the value will be long before the shader runs).

 

Now, by using a qualifier that tells the implementation so-and-so, you give a promise (for example "depth will not change" for "depth will always be greater"), or in the second example that you've given, you ask for a specific behaviour.

 

By doing so, you give a promise to the implementation that you know what you're doing, and that you guarantee that whatever you do will not cause the results to be wrong if it performs the early z optimization. You can of course break your promise or do something that will not work with the behaviour that you request, but this is very unwise -- that'd be welcome to the land of undefined behaviour.

 

Taking your word on that promise, the implementation will of course do the optimization (that's pretty much guaranteeed). In a way, you could maybe interprete this as "force on", but it really isn't. It's more "enabling" or "allowing" the implementation to do something outside the specification.

Edited by samoth

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This feature exists to ensure proper behavior when using Image Load Store or other incoherent memory writing.

To me, the part where it says, 'when using' seems fairly explicit. 

"...this ensures that image load/store operations will only happen on fragments that pass the depth test."  

I would say from what is written in that document that GL_ARB_conservative_depth is a filter for  GL_ARB_shader_image_load_store.

 

It states that GL_ARB_conservative_depth is meant to prevent operations on  GL_ARB_shader_image_load_store from being executed when the fragment fails the depth test.

 

I don't see anything that says they can be interchangeable replacements or substitutes for one another.

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ic0de, I think the summary is openGL may or may not allow this, but the hardware for great graphics cards (AMD/NVIDIA ...Intel should as well), requires heavy optimization to make powerful cards. They will take care of it whether openGL does or not.

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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
    • By TheChubu
      The Khronos™ Group, an open consortium of leading hardware and software companies, announces from the SIGGRAPH 2017 Conference the immediate public availability of the OpenGL® 4.6 specification. OpenGL 4.6 integrates the functionality of numerous ARB and EXT extensions created by Khronos members AMD, Intel, and NVIDIA into core, including the capability to ingest SPIR-V™ shaders.
      SPIR-V is a Khronos-defined standard intermediate language for parallel compute and graphics, which enables content creators to simplify their shader authoring and management pipelines while providing significant source shading language flexibility. OpenGL 4.6 adds support for ingesting SPIR-V shaders to the core specification, guaranteeing that SPIR-V shaders will be widely supported by OpenGL implementations.
      OpenGL 4.6 adds the functionality of these ARB extensions to OpenGL’s core specification:
      GL_ARB_gl_spirv and GL_ARB_spirv_extensions to standardize SPIR-V support for OpenGL GL_ARB_indirect_parameters and GL_ARB_shader_draw_parameters for reducing the CPU overhead associated with rendering batches of geometry GL_ARB_pipeline_statistics_query and GL_ARB_transform_feedback_overflow_querystandardize OpenGL support for features available in Direct3D GL_ARB_texture_filter_anisotropic (based on GL_EXT_texture_filter_anisotropic) brings previously IP encumbered functionality into OpenGL to improve the visual quality of textured scenes GL_ARB_polygon_offset_clamp (based on GL_EXT_polygon_offset_clamp) suppresses a common visual artifact known as a “light leak” associated with rendering shadows GL_ARB_shader_atomic_counter_ops and GL_ARB_shader_group_vote add shader intrinsics supported by all desktop vendors to improve functionality and performance GL_KHR_no_error reduces driver overhead by allowing the application to indicate that it expects error-free operation so errors need not be generated In addition to the above features being added to OpenGL 4.6, the following are being released as extensions:
      GL_KHR_parallel_shader_compile allows applications to launch multiple shader compile threads to improve shader compile throughput WGL_ARB_create_context_no_error and GXL_ARB_create_context_no_error allow no error contexts to be created with WGL or GLX that support the GL_KHR_no_error extension “I’m proud to announce OpenGL 4.6 as the most feature-rich version of OpenGL yet. We've brought together the most popular, widely-supported extensions into a new core specification to give OpenGL developers and end users an improved baseline feature set. This includes resolving previous intellectual property roadblocks to bringing anisotropic texture filtering and polygon offset clamping into the core specification to enable widespread implementation and usage,” said Piers Daniell, chair of the OpenGL Working Group at Khronos. “The OpenGL working group will continue to respond to market needs and work with GPU vendors to ensure OpenGL remains a viable and evolving graphics API for all its customers and users across many vital industries.“
      The OpenGL 4.6 specification can be found at https://khronos.org/registry/OpenGL/index_gl.php. The GLSL to SPIR-V compiler glslang has been updated with GLSL 4.60 support, and can be found at https://github.com/KhronosGroup/glslang.
      Sophisticated graphics applications will also benefit from a set of newly released extensions for both OpenGL and OpenGL ES to enable interoperability with Vulkan and Direct3D. These extensions are named:
      GL_EXT_memory_object GL_EXT_memory_object_fd GL_EXT_memory_object_win32 GL_EXT_semaphore GL_EXT_semaphore_fd GL_EXT_semaphore_win32 GL_EXT_win32_keyed_mutex They can be found at: https://khronos.org/registry/OpenGL/index_gl.php
      Industry Support for OpenGL 4.6
      “With OpenGL 4.6 our customers have an improved set of core features available on our full range of OpenGL 4.x capable GPUs. These features provide improved rendering quality, performance and functionality. As the graphics industry’s most popular API, we fully support OpenGL and will continue to work closely with the Khronos Group on the development of new OpenGL specifications and extensions for our customers. NVIDIA has released beta OpenGL 4.6 drivers today at https://developer.nvidia.com/opengl-driver so developers can use these new features right away,” said Bob Pette, vice president, Professional Graphics at NVIDIA.
      "OpenGL 4.6 will be the first OpenGL release where conformant open source implementations based on the Mesa project will be deliverable in a reasonable timeframe after release. The open sourcing of the OpenGL conformance test suite and ongoing work between Khronos and X.org will also allow for non-vendor led open source implementations to achieve conformance in the near future," said David Airlie, senior principal engineer at Red Hat, and developer on Mesa/X.org projects.

      View full story
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