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OpenGL Check out what I've made so far :)

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This is my first game in openGL, mind you its not 3D. Its a suped up version of the original asteroids game (like there arn't enough of those out there already) here are the keys: Arrow keys - move control - fire blasters space - fire rockets. here are some things you should be aware of: -i dont know if it will work with anything other than windows xp -there's no sound -you cannot die -there is a limited supply of asteroids, once you destroy them all, you cant do anything else but fly around. Let me know what you think, If the link does not work, try back another time, i might have shut off my server for the night (I'm running it off my personal computer) http://69.193.101.122/Asteroids_1.1.zip (includes sprite files) http://69.193.101.122/Asteroids_1.1.exe UPDATED: http://69.193.101.122/Asteroids_1.2.zip (includes sprite files) http://69.193.101.122/Asteroids_1.2.exe [Edited by - Gavinl on March 10, 2005 9:32:41 AM]

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Gavinl that is very nice! The particle effects from the rockets being fired are great. But I do have some quirks.

1. Movement is a bit 'uncomfortable'
2. The rockets delay too long before being fired. I can shoot turn 360 and it still wouldn't have fired.

Other than that great work! I am on my old P3 733 with a 64mb Nvidia Geforce 2 and it plays smoothly without any problems. I just now realized you had blasters and those look great as well! Very spiffy. I'd definitly like to see some more versions as they come along, ones with sound, more weapons [grin], collisions, heck, maybe even powerups! Well done. First game eh?!

- Drew

[Edited by - Drew_Benton on March 10, 2005 12:09:04 PM]

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Yeah this is my first game in openGL, I did a lot of game programming in macromedia flash for a number of years so I know how to make games feel real, (for the most part).
I still gotta learn how to do sound effects and music too. And I'm having a little problem adding a Heads up Display on the screen to indicate your score, how much health you have, and how much ammo you have, etc.
I'll have to experiment a bit more later. I'm going to be adding collisions between the spaceship and the asteroids sometime soon also, but I have some midterms to study for so I have to put that on hold for a little bit.

Thanks for letting me know your quirks, I'll fix those as soon as I have some time, and update it on my server.

-Gavin

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Ok well I just made the turning speed a bit faster, and decreased the delay between the rocket being ejected and when it was propelled.

You can get the complete zip from here:
http://69.193.101.122/Asteroids_1.1.zip

or just the .exe without the texture files
http://69.193.101.122/Asteroids_1.1.exe

-Gavin

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gj man that game is awsome. One thing u should look into is that after playing the game for a hwile it starts laggin for like 2 sec at a time. It gets worse and worse til it stops working. I was playing this for a long time lol cause its fun flying around :d. good game hope to see some new version of this game in the future

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Very cool man. Wish I could do something like this. How long have you been programming?

Only thing I found annoying was acceleration when you turn. Makes the controls feel unprecise. Maybe make it constant instead?

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Awesome! The game worked fine for me with no errors. The particle effects were very nice. The only problem, as stated before, is the turning is pretty imprecise. Beside that, great job!

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Ok, I like the improvments on the rockets firing [smile]. Now I would like to suggest scaling them down some so they are not as bit as the vessel. I also feel that the accelerating while turning is what I first called "uncomfortable".

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Just updated it a bit more,

-Rockets are a bit smaller now
-Asteroids collide with each other (I tried to obey the laws of conservation of momentum and Energy as best as I could)
-I'm leaving collision between the spaceship and asteroids out for a while, just so It doesn't get in the way while i'm testing other aspects of the game.

http://69.193.101.122/Asteroids_1.2.zip (includes sprite files)
http://69.193.101.122/Asteroids_1.2.exe



And back I go to the library to study, God I hate triple Integrals! Stupid calculus!

-Gavin

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Sure

Since the asteroids are all circular, I checked when the distance between the centers of 2 asteroids were less than the sum of the radii of the two.
I then used the spring force equation: F=kx, where k was a constant, and x is
(sum of the 2 radii - distance_between_asteroids)
then i just applied the force to the asteroid in the opposite direction of the collision, It seems to work fairly ok, but it probably would change if the FPS was smaller on a slower computer. I remember trying to do proper calculations using Kinetic energy and momentum, but I could never figure out which direction the 2 circular objects would bounce off each other, I could easily do it in one dimension, 2 was a bit harder, But the way I did it seemed fairly realistic.

-Gavin

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Thanks, that's the way i'm trying to do it too(i've been working on an asteriods game too), but it's not quite working out as nice as yours. I've undoubtitly miscalculated something. : )
Levi

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That's very nice! ;)
I liked the rocket particle effect, it looks very sweet...
althought, like most noticed the turning of the ship is very unconvienent, so you should consider changing that...
also, i dont like the fact that i can only see such a small distance around ship, could you add zoom buttons or smting like that
anyway, very nice, keep up the work!
Good Luck,
looking forward to see a new version :)


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Quote:
Original post by Gavinl
Can you guys tell me exactly whats wrong with the turning, and how would you like it to be?


it seems that it is "accelerating", it's not just turning at constant speed, turning has acceleration...

your ship should turn at constant speed, with no acceleration...

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Quote:
Original post by Jnz86
it seems that it is "accelerating", it's not just turning at constant speed, turning has acceleration...
your ship should turn at constant speed, with no acceleration...


Agreed. Like I could start turning then stop and it'd keep on going. I wanted to see less accel, and that was done in vers. 1.2 I believe. Now you might also want to increase the 'friction' - air resistance - when you stop accelerating so it doesn't fly as far.

Gavinl, feel free to make it how you see fit. I think the thing is that you have accurately modeled physics for your game, so we are not used to something so realistic. Usually there is no or hardly any acceleration in those old school asteroid games, etc...

Nevertheless, keep the updates coming! If you could, you know what would be nice? Make all of the variables data driven that allow changes to be made, so we can find a 'best solution' when playing around with it. I think that could help get us a feel for it as well. Just an idea though for later, right now it's probabalyl a bad idea to do that at this stage.

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Yes i was planning on doing that soon, like having an external text file with all the data for the different objects, like mass, drag coefficient, engine force, etc for the ships, rockets, and asteroids.

And I'll get rid of the acceleration, and you're right, I tried to make it as realistic as I could, I noticed that when you turn a car around a corner, the car doesn't instantly stop turning when it reaches its new angle, but it has to slow down.

I guess the problem with being a physics major is you want everything to be realistic :P


PS: look for guided rockets and space mines, in the next update, hopefully.

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I have to stop working on it for a while, school work is getting in the way, its the end of the semister so all the lab reports are starting to be due, and exams are coming up that i gotta study for, I'm afraid I wont be able to work on it much until probably end of april :(
Sorry, You guys are going to have to wait until then.

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      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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