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• By stale
I'm continuing to learn more about terrain rendering, and so far I've managed to load in a heightmap and render it as a tessellated wireframe (following Frank Luna's DX11 book). However, I'm getting some really weird behavior where a large section of the wireframe is being rendered with a yellow color, even though my pixel shader is hard coded to output white.

The parts of the mesh that are discolored changes as well, as pictured below (mesh is being clipped by far plane).

Here is my pixel shader. As mentioned, I simply hard code it to output white:
float PS(DOUT pin) : SV_Target { return float4(1.0f, 1.0f, 1.0f, 1.0f); } I'm completely lost on what could be causing this, so any help in the right direction would be greatly appreciated. If I can help by providing more information please let me know.

• Hello,
i try to implement voxel cone tracing in my game engine.
I have read many publications about this, but some crucial portions are still not clear to me.
At first step i try to emplement the easiest "poor mans" method
a.  my test scene "Sponza Atrium" is voxelized completetly in a static voxel grid 128^3 ( structured buffer contains albedo)
b. i dont care about "conservative rasterization" and dont use any sparse voxel access structure
c. every voxel does have the same color for every side ( top, bottom, front .. )
d.  one directional light injects light to the voxels ( another stuctured buffer )
I will try to say what i think is correct ( please correct me )
GI lighting a given vertecie  in a ideal method
A.  we would shoot many ( e.g. 1000 ) rays in the half hemisphere which is oriented according to the normal of that vertecie
B.  we would take into account every occluder ( which is very much work load) and sample the color from the hit point.
C. according to the angle between ray and the vertecie normal we would weigth ( cosin ) the color and sum up all samples and devide by the count of rays
Voxel GI lighting
In priciple we want to do the same thing with our voxel structure.
Even if we would know where the correct hit points of the vertecie are we would have the task to calculate the weighted sum of many voxels.
Saving time for weighted summing up of colors of each voxel
To save the time for weighted summing up of colors of each voxel we build bricks or clusters.
Every 8 neigbour voxels make a "cluster voxel" of level 1, ( this is done recursively for many levels ).
The color of a side of a "cluster voxel" is the average of the colors of the four containing voxels sides with the same orientation.

After having done this we can sample the far away parts just by sampling the coresponding "cluster voxel with the coresponding level" and get the summed up color.
Actually this process is done be mip mapping a texture that contains the colors of the voxels which places the color of the neighbouring voxels also near by in the texture.
Cone tracing, howto ??
Here my understanding is confus ?? How is the voxel structure efficiently traced.
I simply cannot understand how the occlusion problem is fastly solved so that we know which single voxel or "cluster voxel" of which level we have to sample.
Supposed,  i am in a dark room that is filled with many boxes of different kind of sizes an i have a pocket lamp e.g. with a pyramid formed light cone
- i would see some single voxels near or far
- i would also see many different kind of boxes "clustered voxels" of different sizes which are partly occluded
How do i make a weighted sum of this ligting area ??
e.g. if i want to sample a "clustered voxel level 4" i have to take into account how much per cent of the area of this "clustered voxel" is occluded.
Please be patient with me, i really try to understand but maybe i need some more explanation than others
best regards evelyn

• Hi guys, when I do picking followed by ray-plane intersection the results are all wrong. I am pretty sure my ray-plane intersection is correct so I'll just show the picking part. Please take a look:

// get projection_matrix DirectX::XMFLOAT4X4 mat; DirectX::XMStoreFloat4x4(&mat, projection_matrix); float2 v; v.x = (((2.0f * (float)mouse_x) / (float)screen_width) - 1.0f) / mat._11; v.y = -(((2.0f * (float)mouse_y) / (float)screen_height) - 1.0f) / mat._22; // get inverse of view_matrix DirectX::XMMATRIX inv_view = DirectX::XMMatrixInverse(nullptr, view_matrix); DirectX::XMStoreFloat4x4(&mat, inv_view); // create ray origin (camera position) float3 ray_origin; ray_origin.x = mat._41; ray_origin.y = mat._42; ray_origin.z = mat._43; // create ray direction float3 ray_dir; ray_dir.x = v.x * mat._11 + v.y * mat._21 + mat._31; ray_dir.y = v.x * mat._12 + v.y * mat._22 + mat._32; ray_dir.z = v.x * mat._13 + v.y * mat._23 + mat._33;
That should give me a ray origin and direction in world space but when I do the ray-plane intersection the results are all wrong.
If I click on the bottom half of the screen ray_dir.z becomes negative (more so as I click lower). I don't understand how that can be, shouldn't it always be pointing down the z-axis ?
I had this working in the past but I can't find my old code

• Hi,
I finally managed to get the DX11 emulating Vulkan device working but everything is flipped vertically now because Vulkan has a different clipping space. What are the best practices out there to keep these implementation consistent? I tried using a vertically flipped viewport, and while it works on Nvidia 1050, the Vulkan debug layer is throwing error messages that this is not supported in the spec so it might not work on others. There is also the possibility to flip the clip scpace position Y coordinate before writing out with vertex shader, but that requires changing and recompiling every shader. I could also bake it into the camera projection matrices, though I want to avoid that because then I need to track down for the whole engine where I upload matrices... Any chance of an easy extension or something? If not, I will probably go with changing the vertex shaders.

• Hello,
in my game engine i want to implement my own bone weight painting tool, so to say a virtual brush painting tool for a mesh.
I have already implemented my own "dual quaternion skinning" animation system with "morphs" (=blend shapes)  and "bone driven"  "corrective morphs" (= morph is dependent from a bending or twisting bone)
But now i have no idea which is the best method to implement a brush painting system.
Just some proposals
a.  i would build a kind of additional "vertecie structure", that can help me to find the surrounding (neighbours) vertecie indexes from a given "central vertecie" index
b.  the structure should also give information about the distance from the neighbour vertecsies to the given "central vertecie" index
c.  calculate the strength of the adding color to the "central vertecie" an the neighbour vertecies by a formula with linear or quadratic distance fall off
d.  the central vertecie would be detected as that vertecie that is hit by a orthogonal projection from my cursor (=brush) in world space an the mesh
but my problem is that there could be several  vertecies that can be hit simultaniously. e.g. i want to paint the inward side of the left leg. the right leg will also be hit.
I think the given problem is quite typical an there are standard approaches that i dont know.
Any help or tutorial are welcome
P.S. I am working with SharpDX, DirectX11

# DX11 DX11 Rendering an Object the fastest way

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Hi guys,

my engine has come to a stage where instancing will be required, so what i do right now is somewhat like this:

void RenderFunc(..)
{
renderAllLights

RenderDiffuse

If instancing: // This one knows if I'm rendering an instance
RenderFunc(instance);
}


Now the thing is that I'm using one render function to render all meshes, is that a bad idea? My full render function looks like this:

void C3DEngineObject::RenderMesh(UMesh &mesh, bool recursive)
{
#define Passes      mesh.passes  Passes is just a class containing information for the passes

ObjectBuffer.AmbientColor = Passes.GlobalMaterial.AmbientColor;

/////////PREPARE ALPHA SETTINGS////////////
ObjectBuffer.Alpha = 1.0f;

ObjectBuffer.Alpha = Passes.getAlpha();
if (Passes.Lighting)
{
ObjectBuffer.Alpha += Lights.Directional.size();
BlendStateManager.AlphaPass(devcon);
}

float alphaUp = 1.0f/ObjectBuffer.Alpha;
ObjectBuffer.Alpha = 1.0f/ObjectBuffer.Alpha;

#define AlphaStepUp ObjectBuffer.Alpha += alphaUp

if (!recursive) // Don't send the buffers if recursive
mesh.SendBuffers(devcon, dev, Camera, ObjectBuffer, Bufferphase);

/////////RENDER LIGHTING/////////////////

if (Passes.Lighting)
{
//////////////////////////////////////////////////
////      For each directional light          ////
//////////////////////////////////////////////////

FOREACH (Lights.Directional.safe_size())
{

// INJECT!
Lights.Directional[i].Inject(FrameBuffer);

//Shaders[7].SendRegBuffer(FrameBuffer, 1, 0, devcon);

// Step up one alpha
AlphaStepUp;
}
}

/////////RENDER THE MESH/////////////////

for (int p = 1; p <= Passes.options; p++) // Get all the passes
{
if (Passes.getAt(p) == true) // Is this pass enabled?
{
int relative = Passes.getRelative(p); // If so, find the mat id.
Material* active = getMaterial(relative, Passes); // Find the mat of the id

active->ApplyMaterial(dev, devcon);

active->ShaderRef->UpdateObject(ObjectBuffer, devcon); // Send the object and world buffers

if (relative == BUMPMAP_SHADER) // Is this bump mapping?
{
MatrixBuffer.world = ObjectBuffer.Final;
}

if (relative == TEXTURE_SHADER) // Texturing?
{
}

if (mesh.Instanced && !recursive) // Is this mesh instanced
{
FOREACH (mesh.InstancedData.size()) // For all instances
{
mesh.SendInstancedData(ObjectBuffer, Camera, i, Bufferphase); // Send the location, rotation and scaling of this instance.

RenderMesh(mesh, true); // Call this function, with recursive true so the origional matrixes wont be re-sent (removing the instance loc,rot and scaling).
}
}

// Render the mesh in diffuse mode
active->Render(devcon, Bufferphase);

// Step up one alpha
AlphaStepUp;
}
}

if (recursive)
return;

BlendStateManager.RestoreBlendState(devcon);
}



PS. The mesh.passes is just a class with contains the passes(e.g. Texture, shadows, Lighting).

Now if you look at my code, in each pass it checks if it is bump mapping or texturing, but is this a slow method, how could it be improved? Or even better, how can it be improved in the concept of instancing?

Also if you have time, it could be nice if you could post a good way of handling mesh rendering, or an efficient method, as I'm just following my minds advice, and not a professional persons advice.

Also, how much time does it take to check if a bool is true?

Thank You

Edited by Migi0027

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It seems to me like you are looking for improvements without a strong need in mind, which will make it very hard to find a solution that you are looking for.  Ultimately, you will find that normally the CPU side manipulations account for a fairly small amount of work in the grand scheme of things unless you are using lots and lots of small objects.  However, even in that case, the GPU work being done can often take up more time than the CPU side - meaning that any optimization on the CPU side won't make any difference to the end result framerate.

For your specific question about testing a bool - it is pretty much one of the fastest operations that exist, so you don't need to worry about changing that.  You should invest some time in learning how to use profiling tools (free or otherwise) and also tools like PIX/Graphics Debugger to learn more about the performance of your engine/app.  That will allow you to pinpoint the bottlenecks and make effective use of your optimization time.

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Thanks Jason Z, though I already knew of the profiling tools, I never really put any effort into it, but they(tools) actually impress me!

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Well most of the lost performance is from the direct draw calls, is there any way to make them faster?

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Most of the loss of performance is /not/ the draw calls, but a Game Engine's utilization of them...

From an architectural point of view, the code hint that you may not be implementing standard "Separation of Concerns" patterns, (ensuring that methods/classes don't do more than one thing, but rather responsible for doing a specialized purpose).

In other words, at this stage, I believe everyone would agree that getting your engine do to what you want is more important than the performance.

For example, you are using a "renderfunc"  and "rendermesh" function names: Okay, I know this sounds a little out of left field for being, nitpicky, but bear with me ... Rather than, RenderScene, -> RenderEachLayout  -> RenderBufferSet -> RenderBufferPartitions ->  or some other rendering step in the context of your Game Engine's OWN Pipeline.

In a game engine, there is /massive/ importance on the efficient management of the associations between Modeling entities, specifically:

1. Scenes to Layouts

2. Layouts To Buffers

3. Buffers to Buffer Partitions, Shaders, etc

4. Model to: (Mesh, Behaviors, Textures, Shaders, etc)

5. Many Textures to Many Models and Meshes

6. Many Meshes to Many Models

7. and the list goes on and on and on and on.

The GPU operations are /fast/ ....  Managing memory, garbage collection, managing collections in memory that are hundreds of megabytes, etc, is one of the biggest game performance hits.  This is where a lot of your optimizations will need to occur.  As horrible as it sounds, use place holder shaders, textures, etc at first, (greyscale gradients, etc), to ensure your Game Engine's Framework is working right.

In other words, pick a game engine feature, set of features that you want, program towards them, and find out if those features are running slow or not, then performance tune them.

Stage 1 Features:

1. Rendering Multiple Instances of the Same Model definition.  (sidewalk squares)

2. Rendering Multiple Instances of the Same Model, but with different Shaders,  (stars, the same car but different color, etc)

3. Rendering Multiple Types of Models, (Tree, Sidewalk Square, etc)

4. Pre-Defined animations for a subset of models, (rotations, movement/translation in a circle pattern, movement along a Bezier, whatever).

5. User Driven Movement,

6. etc.

There are a /lot/ of design patterns that can be used to organize the complexity of the code, so that the application will scale appropriately with the features you want.

You may think that implementing facades, multiton, or factory design patterns are a /lot/ of overhead for a small program, but in actuality this is not the case as compilers optimize and inline what needs to be.

Still, the point that I am trying to make, the use of Design Patterns, and the avoidance of Anti-Patterns in a game engine is what is going to always be what will determine your game engine's performance story.

Then, there are fancy shmancy GPU render operations... See, the funny thing about fancy shmancy GPU operations is that /only if/ your architecture is "sound" in the first place, can you implement GPU operations on a priority basis, (maybe ensure that that that fancy shmancy model never attempts to get rendered more than once a frame, or maybe once every two frames, (there is a LOT of overrendering in games).

Architectural techniques and optimizations are probably where you want to start off first when facing performance problems, and regardless, you will be able to do more with your engine anyway.

Edited by e.s.