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OpenGL working on Vertex Shader VS fixed pipeline thesis

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hi, I am looking for some ideas for my thesis. I was interested in learning shaders and showing its benefits and need some help since i am new to shader. I have found that shaders can be used to do per pixel phong lighting but is there anything else where i can use a shader and get performance increase. I have implemented some code and haven't found what i need yet. Hardware is X800PRO, using OpenGl and shader are being written in GLSL Here is what i have so far. First of all I found frame rates using ATITooltrays. i saw in some examples someone using a timer.h class that calculates the frame rate and when programs, atitool tray was slow by 10 frame. i will have to check if that is true for fixed pipeline or not.(Thought i would get advise first then go about doing the coding) I have a cube that i drew using glVertex3f and each side has different colors, which were set using glcolor3f. When i run the project with only 1 cube and tell the project to rotate the cube i get 1028 in full screen. Monitor is set at 1280x1024 resolution, 32bit and Vsync if off. 1 cube gives me 1030 and 100 cubes gives me 964 frames. With this shader attached void main(void) { gl_FrontColor = gl_Color; gl_Position = ftransform(); } gets me 1024 for 1 cube and 955 frame for 100 cubes. it's off by couple of frames but my thesis is to show that shaders are faster than fixed pipeline. if i attach a frag shader that is just void main(void) { gl_FragColor = gl_Color; } i take another 8-10 frames hit. i didn't change any of the openGL code, so the glcolor3f is in both shader and non shader code. Everytime a new cube is drawn it's front face has a different color thanthe previous one drawn.(it was a project for opengl to rotate cubes and get them to match colors on all sides) i can rotate cubes in x, y or in both direction. Doesn't affect the framerates I just need advise in which direction i should go. I haven't done much advance programming with shaders yet but i have to also keep in mind the time available(was hoping for multiple examples in my thesis and 1 advance one)

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Second i worked on introducing lights into the project. So now glcolor don't matter. One on front and one on back of cubes
Code is here

GLfloat position0[] = {0.0, 0.0, 15.0, 1.0};
GLfloat diffuse0[] = {1.0, 0.0, 0.0, 1.0};
GLfloat specular0[] = {1.0, 1.0, 1.0, 1.0};
GLfloat ambient0[] = {0.0, 1.0, 0.0, 1.0};

GLfloat position1[] = {0.0, 0.0, -15.0, 1.0};
GLfloat diffuse1[] = {0.0, 0.0, 1.0, 1.0};
GLfloat specular1[] = {0.0, 0.0, 1.0, 1.0};
GLfloat ambient1[] = {0.0, 0.0, 1.0, 1.0};

glEnable(GL_NORMALIZE);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glLightfv(GL_LIGHT0,GL_POSITION,position0);
glLightfv(GL_LIGHT0,GL_DIFFUSE,diffuse0);
glLightfv(GL_LIGHT0,GL_SPECULAR,specular0);
glLightfv(GL_LIGHT0,GL_AMBIENT,ambient0);

glEnable(GL_LIGHTING);
glEnable(GL_LIGHT1);

glLightfv(GL_LIGHT1,GL_POSITION,position1);
glLightfv(GL_LIGHT1,GL_DIFFUSE,diffuse1);
glLightfv(GL_LIGHT1,GL_SPECULAR,specular1);
glLightfv(GL_LIGHT1,GL_AMBIENT,ambient1);

I know that i have to take care all lighting calculations in my lightshader. but without the calculations the shader is about 200 frames faster than regular code. i read that i can have regular processor do some calculations and pass it to the shader. But i don't want to code all this and end by with a shader that has no performance gain(or something that i can show is better than before) than the fixed pipeline. I am using the OpenGl Shading Language by Randi J Rost as my resource on the lighting part.
So i am asking for advice. Is this example worth the trouble or should i find something else with textures?
BTW thank you for any help i really appreciate it.
Khaleel Ali

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Shaders can be more efficient if they reduce the number of passes required to render the scene.
In case of a pure FF vs. Shader I don't see how a shader could possibly be faster, especially since modern GPUs tend to translate FF calls to shader programs internally.
I'd rather focus on reducing passes and simply do things you cannot achieve with the FF pipeline efficiently - like post-processing effects, HDR rendering, many (point-) lights and such.
Also note that a framedrop by an amount of 8 to 10 in relation to a (artificial) frame rate >1000 is less than 1% in relative performance change (e.g. negligible).

HTH,
Pat.

PS: OGL Gurus - feel free to correct/enlighten me [smile]

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As mentioned, I doubt shaders will win doing the identical task as the FF pipeline, however they can allow you to do the same tasks in a more "clever" way, hopefully reducing overhead.

The 3D Labs shader gen program would be a good start if your trying to start out implementing lighting in shaders, however been warned they aren't the most efficient code at times.

http://developer.3dlabs.com/downloads/shadergen/


GOCP


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Generally it would be a good idea to record min, max, mean and standard deviation with your tests to provide a context for them. A histogram wouldn't be a bad idea either. I find loading performance data into a database such as MS Access to be extremely helpful. Particularly if you have to document your results.

I would be inclined to use glFinish, or a fence extension if available, to isolate just what you are measuring. Failing that I would want at least a baseline, i.e. how long does it take without what I'm testing. Also for something formal like a thesis I would be a bit more methodical. An example would be starting with one big polygon filling the screen.

You're basically building a model. You're trying to identify the parameters that are relevant to the model and how they should be used in the model. Two points don't tell you much and going from 1 to 100 cubes most likely changed a bunch of variables at once. All you do with two points is draw a straight line, but the actual curve may not be a straight line. Why not 100, 200, 500, 1000, 1500, 2000, 2500, 5000, 10000, 15000, etc. See what it really looks like.

The goal is to be able to plug some numbers into an equation and say how long it's going to take. It's no differant than research in physics, chemistry, biology, whatever. You develop a theory then run experiments to test it. Most often those experiments disprove your theory but often lead to refinement of the theory and to new theories.

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I thought the fixed functionality has been implemented in shaders since DX8 class hardware.

If you wrote a shader that implemented the same algorithms used in FF, and both your code and the FF code were running on the same hardware, how would there be an increase in speed?

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chances are, no.
The shader code which is used for the FFP emulation in the current generation of cards (R300 was when ATI dropped hardware FFP, GFFX was the last NV card to have FFP in hardware) is very optimised microcode, hand tuned by the guys who know the hardware.

Your shaders on the other hand are dealt with via a compiler, and while this compiler is good and getting better right now its not going to beat that code.

HOWEVER, the performance difference for well written shader code is going to be negligible, you'll start hitting other bottle necks long before optimisation makes a difference in 99.9% of cases.

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Quote:
Original post by darookie
Shaders can be more efficient if they reduce the number of passes required to render the scene.
In case of a pure FF vs. Shader I don't see how a shader could possibly be faster, especially since modern GPUs tend to translate FF calls to shader programs internally.
I'd rather focus on reducing passes and simply do things you cannot achieve with the FF pipeline efficiently - like post-processing effects, HDR rendering, many (point-) lights and such.
Also note that a framedrop by an amount of 8 to 10 in relation to a (artificial) frame rate >1000 is less than 1% in relative performance change (e.g. negligible).

HTH,
Pat.

PS: OGL Gurus - feel free to correct/enlighten me [smile]


Thank you all for the input i really really appreciate all your comments.
Here's what i was thinking(sorry finals and projects came at me at full force and had to drop thesis stuff for last month now i can start it up again).
I Read in one of the GLSL articles on gamedev that switching state(than using GL_color than has a cost since it switches the color state to a new color) in openGL has a cost. I was thinking maybe if i can avoid that and have my 6 colors in the shader. Then i would and pass in the variable++%6 to the shader and do the if testing and based on that i pick the color would improve performance. I am not sure if this will work or not. What do you guys think?

Also regarding the lights, any comments on that ?

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Quote:
Original post by GOCP
As mentioned, I doubt shaders will win doing the identical task as the FF pipeline, however they can allow you to do the same tasks in a more "clever" way, hopefully reducing overhead.

The 3D Labs shader gen program would be a good start if your trying to start out implementing lighting in shaders, however been warned they aren't the most efficient code at times.

http://developer.3dlabs.com/downloads/shadergen/


GOCP


Thanks for the reply. I am learning how to use ATI Render Monkey(figured since i have their card use their product). I didn't think it was useful until i saw that i can write shaders test them and see their affect without setting up the whole environment.
Then also Disney stopped by our college and i was asking them about their shaders useage and one of them told me that if they setup the environment it takes 40 mins or so just to see it. Shaders give them the result right away so we can see how it would look in their final renderer(which takes them 1 days or so to run).

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Quote:
Original post by khaleelali
Also regarding the lights, any comments on that ?

OpenGL (and Direct3D as well) provide a fixed number of lights that are supported by the hardware (using the FF pipeline). Usually this number is limited to something like 8 or so. Now imagine having a set of particles that illuminate the scene - say a swarm of fireflies or a number of candles in a room.
While the number of lights in a shader (per pass) is only limited by its max instruction count, the FF pipeline limit is fix.
Yet another good reason for shaders is faking global illumination. While the FF only supports the "ambient light" hack, shaders provide you with the flexibility of choosing from a number of different more sophisticated hacks.

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Quote:
Original post by darookie
Quote:
Original post by khaleelali
Also regarding the lights, any comments on that ?

OpenGL (and Direct3D as well) provide a fixed number of lights that are supported by the hardware (using the FF pipeline). Usually this number is limited to something like 8 or so. Now imagine having a set of particles that illuminate the scene - say a swarm of fireflies or a number of candles in a room.
While the number of lights in a shader (per pass) is only limited by its max instruction count, the FF pipeline limit is fix.
Yet another good reason for shaders is faking global illumination. While the FF only supports the "ambient light" hack, shaders provide you with the flexibility of choosing from a number of different more sophisticated hacks.


Sweet i will definately look into that. that's what i needed to get started with some ideas. thank you

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Quote:
Original post by darookie
Quote:
Original post by khaleelali
Also regarding the lights, any comments on that ?

OpenGL (and Direct3D as well) provide a fixed number of lights that are supported by the hardware (using the FF pipeline). Usually this number is limited to something like 8 or so. Now imagine having a set of particles that illuminate the scene - say a swarm of fireflies or a number of candles in a room.
While the number of lights in a shader (per pass) is only limited by its max instruction count, the FF pipeline limit is fix.
Yet another good reason for shaders is faking global illumination. While the FF only supports the "ambient light" hack, shaders provide you with the flexibility of choosing from a number of different more sophisticated hacks.


So how would I update my particle system so that each particle is a point source of light? Can I use cg for that? I only have a GeForce4 card... But how would I do this?

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Quote:
Original post by sjf
Quote:
Original post by darookie
Quote:
Original post by khaleelali
Also regarding the lights, any comments on that ?

OpenGL (and Direct3D as well) provide a fixed number of lights that are supported by the hardware (using the FF pipeline). Usually this number is limited to something like 8 or so. Now imagine having a set of particles that illuminate the scene - say a swarm of fireflies or a number of candles in a room.
While the number of lights in a shader (per pass) is only limited by its max instruction count, the FF pipeline limit is fix.
Yet another good reason for shaders is faking global illumination. While the FF only supports the "ambient light" hack, shaders provide you with the flexibility of choosing from a number of different more sophisticated hacks.


So how would I update my particle system so that each particle is a point source of light? Can I use cg for that? I only have a GeForce4 card... But how would I do this?



I have a GForce420 Go on my laptop and it doesn't support shaders. Nvidia's driver for gf4 doesn't support opengl 2.0, i tried running it get an error saying driver doesn't support it.
I could be wrong. you could go to www.nvidia.com and look up your card specs. If your card doesn't support shaders then you are limited to 8 lights in openGL since there is no light8 available.(you will get a compile time error)
As far as i know the way you would handle more than 8 lights in OpenGL is that you would write everything for lights in your shader code. OpenGL shading language is a book that tells you the code for it and i am using that. I have seen examples from that book all over the net. it is also called the orange book

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first,
thanks for all the replies.
So far i have found that with shaders i can show that
1. per pixel lighting is simpler, even though opengl fixed pipeline does allow us to do it, it's a hassle(the code i have seen so far are really really complicated compared to the shader version)
2. blurring is simpler to do in shader(almost same reason as 1).
3. I am not restricted to 8 lights(need to multi pass to enable more lights in fixed pipeline).

i am still looking for something with textures. Was thinking maybe i do something with multitexture etc. any ideas?

if you have any other ideas please let me know i would appreciate it.
Thank you

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      When sampling a texture in a shader, the texture sampler was traditionally specified as separate object that was bound to the pipeline at run time or set as part of the texture object itself. However, in most cases it is known beforehand what kind of sampler will be used in the shader. Next-generation APIs expose new type of sampler called static sampler that can be initialized directly in the pipeline state. Diligent Engine exposes this functionality: when creating a shader, textures can be assigned static samplers. If static sampler is assigned, it will always be used instead of the one initialized in the texture shader resource view. To initialize static samplers, prepare an array of StaticSamplerDesc structures and initialize StaticSamplers and NumStaticSamplers members. Static samplers are more efficient and it is highly recommended to use them whenever possible. On older APIs, static samplers are emulated via generic sampler objects.
      The following is an example of shader initialization:
      ShaderCreationAttribs Attrs; Attrs.Desc.Name = "MyPixelShader"; Attrs.FilePath = "MyShaderFile.fx"; Attrs.SearchDirectories = "shaders;shaders\\inc;"; Attrs.EntryPoint = "MyPixelShader"; Attrs.Desc.ShaderType = SHADER_TYPE_PIXEL; Attrs.SourceLanguage = SHADER_SOURCE_LANGUAGE_HLSL; BasicShaderSourceStreamFactory BasicSSSFactory(Attrs.SearchDirectories); Attrs.pShaderSourceStreamFactory = &BasicSSSFactory; ShaderVariableDesc ShaderVars[] = {     {"g_StaticTexture", SHADER_VARIABLE_TYPE_STATIC},     {"g_MutableTexture", SHADER_VARIABLE_TYPE_MUTABLE},     {"g_DynamicTexture", SHADER_VARIABLE_TYPE_DYNAMIC} }; Attrs.Desc.VariableDesc = ShaderVars; Attrs.Desc.NumVariables = _countof(ShaderVars); Attrs.Desc.DefaultVariableType = SHADER_VARIABLE_TYPE_STATIC; StaticSamplerDesc StaticSampler; StaticSampler.Desc.MinFilter = FILTER_TYPE_LINEAR; StaticSampler.Desc.MagFilter = FILTER_TYPE_LINEAR; StaticSampler.Desc.MipFilter = FILTER_TYPE_LINEAR; StaticSampler.TextureName = "g_MutableTexture"; Attrs.Desc.NumStaticSamplers = 1; Attrs.Desc.StaticSamplers = &StaticSampler; ShaderMacroHelper Macros; Macros.AddShaderMacro("USE_SHADOWS", 1); Macros.AddShaderMacro("NUM_SHADOW_SAMPLES", 4); Macros.Finalize(); Attrs.Macros = Macros; RefCntAutoPtr<IShader> pShader; m_pDevice->CreateShader( Attrs, &pShader );
      Creating the Pipeline State Object
      After all required shaders are created, the rest of the fields of the PipelineStateDesc structure provide depth-stencil, rasterizer, and blend state descriptions, the number and format of render targets, input layout format, etc. For instance, rasterizer state can be described as follows:
      PipelineStateDesc PSODesc; RasterizerStateDesc &RasterizerDesc = PSODesc.GraphicsPipeline.RasterizerDesc; RasterizerDesc.FillMode = FILL_MODE_SOLID; RasterizerDesc.CullMode = CULL_MODE_NONE; RasterizerDesc.FrontCounterClockwise = True; RasterizerDesc.ScissorEnable = True; RasterizerDesc.AntialiasedLineEnable = False; Depth-stencil and blend states are defined in a similar fashion.
      Another important thing that pipeline state object encompasses is the input layout description that defines how inputs to the vertex shader, which is the very first shader stage, should be read from the memory. Input layout may define several vertex streams that contain values of different formats and sizes:
      // Define input layout InputLayoutDesc &Layout = PSODesc.GraphicsPipeline.InputLayout; LayoutElement TextLayoutElems[] = {     LayoutElement( 0, 0, 3, VT_FLOAT32, False ),     LayoutElement( 1, 0, 4, VT_UINT8, True ),     LayoutElement( 2, 0, 2, VT_FLOAT32, False ), }; Layout.LayoutElements = TextLayoutElems; Layout.NumElements = _countof( TextLayoutElems ); Finally, pipeline state defines primitive topology type. When all required members are initialized, a pipeline state object can be created by IRenderDevice::CreatePipelineState() method:
      // Define shader and primitive topology PSODesc.GraphicsPipeline.PrimitiveTopologyType = PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE; PSODesc.GraphicsPipeline.pVS = pVertexShader; PSODesc.GraphicsPipeline.pPS = pPixelShader; PSODesc.Name = "My pipeline state"; m_pDev->CreatePipelineState(PSODesc, &m_pPSO); When PSO object is bound to the pipeline, the engine invokes all API-specific commands to set all states specified by the object. In case of Direct3D12 this maps directly to setting the D3D12 PSO object. In case of Direct3D11, this involves setting individual state objects (such as rasterizer and blend states), shaders, input layout etc. In case of OpenGL, this requires a number of fine-grain state tweaking calls. Diligent Engine keeps track of currently bound states and only calls functions to update these states that have actually changed.
      Binding Shader Resources
      Direct3D11 and OpenGL utilize fine-grain resource binding models, where an application binds individual buffers and textures to certain shader or program resource binding slots. Direct3D12 uses a very different approach, where resource descriptors are grouped into tables, and an application can bind all resources in the table at once by setting the table in the command list. Resource binding model in Diligent Engine is designed to leverage this new method. It introduces a new object called shader resource binding that encapsulates all resource bindings required for all shaders in a certain pipeline state. It also introduces the classification of shader variables based on the frequency of expected change that helps the engine group them into tables under the hood:
      Static variables (SHADER_VARIABLE_TYPE_STATIC) are variables that are expected to be set only once. They may not be changed once a resource is bound to the variable. Such variables are intended to hold global constants such as camera attributes or global light attributes constant buffers. Mutable variables (SHADER_VARIABLE_TYPE_MUTABLE) define resources that are expected to change on a per-material frequency. Examples may include diffuse textures, normal maps etc. Dynamic variables (SHADER_VARIABLE_TYPE_DYNAMIC) are expected to change frequently and randomly. Shader variable type must be specified during shader creation by populating an array of ShaderVariableDesc structures and initializing ShaderCreationAttribs::Desc::VariableDesc and ShaderCreationAttribs::Desc::NumVariables members (see example of shader creation above).
      Static variables cannot be changed once a resource is bound to the variable. They are bound directly to the shader object. For instance, a shadow map texture is not expected to change after it is created, so it can be bound directly to the shader:
      PixelShader->GetShaderVariable( "g_tex2DShadowMap" )->Set( pShadowMapSRV ); Mutable and dynamic variables are bound via a new Shader Resource Binding object (SRB) that is created by the pipeline state (IPipelineState::CreateShaderResourceBinding()):
      m_pPSO->CreateShaderResourceBinding(&m_pSRB); Note that an SRB is only compatible with the pipeline state it was created from. SRB object inherits all static bindings from shaders in the pipeline, but is not allowed to change them.
      Mutable resources can only be set once for every instance of a shader resource binding. Such resources are intended to define specific material properties. For instance, a diffuse texture for a specific material is not expected to change once the material is defined and can be set right after the SRB object has been created:
      m_pSRB->GetVariable(SHADER_TYPE_PIXEL, "tex2DDiffuse")->Set(pDiffuseTexSRV); In some cases it is necessary to bind a new resource to a variable every time a draw command is invoked. Such variables should be labeled as dynamic, which will allow setting them multiple times through the same SRB object:
      m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); Under the hood, the engine pre-allocates descriptor tables for static and mutable resources when an SRB objcet is created. Space for dynamic resources is dynamically allocated at run time. Static and mutable resources are thus more efficient and should be used whenever possible.
      As you can see, Diligent Engine does not expose low-level details of how resources are bound to shader variables. One reason for this is that these details are very different for various APIs. The other reason is that using low-level binding methods is extremely error-prone: it is very easy to forget to bind some resource, or bind incorrect resource such as bind a buffer to the variable that is in fact a texture, especially during shader development when everything changes fast. Diligent Engine instead relies on shader reflection system to automatically query the list of all shader variables. Grouping variables based on three types mentioned above allows the engine to create optimized layout and take heavy lifting of matching resources to API-specific resource location, register or descriptor in the table.
      This post gives more details about the resource binding model in Diligent Engine.
      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.
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