Followers 0

# DX11 DX11 - Deferred Shadows - Not working

## 5 posts in this topic

Hi guys  .

So for a long time I've been doing shadows per object pixel, not deferred, and, I had to switch to the deferred way. Which I am now attempting, direct lighting works fine for e.g. Directional lights, but, for the shadows, it's another story. They simply don't work, the reason is unclear for now, so, I've come here in order to ask for your help

I'm almost (Hence the almost) certain that the cpus work isn't the fault here, but if the gpus work seems fine, I'll post the cpus work.

So, the code!

For generating the shadow map I'm almost certain that it's fine as the same shader was used for the previous method and nothing has changed, but, I'll post it: ( I do realize that loads of optimizations may be done here, like outputting the depth into a one channel render target )

cbuffer ConstantObjectBuffer : register (b0)
{
matrix worldMatrix;
matrix viewMatrix;
matrix projectionMatrix;

float state;
float _instance;
float _alphamap;
};

struct VOut
{
float4 position : SV_POSITION;
float2 texcoord : TEXCOORD;
float4 depthPosition : TEXTURE0;
};

Texture2D t_alphamap : register(t0);
SamplerState ss;

VOut VShader(float4 position : POSITION, float2 texcoord : TEXCOORD, float3 instancePosition : INSTANCEPOS)
{
VOut output;

if (_instance == 1)
{
position.x += instancePosition.x;
position.y += instancePosition.y;
position.z += instancePosition.z;
}

position.w = 1.0f;
output.texcoord = texcoord;

output.position = mul(position, worldMatrix);
output.position = mul(output.position, viewMatrix);
output.position = mul(output.position, projectionMatrix);

// Store the position value in a second input value for depth value calculations.
output.depthPosition = output.position;

return output;
}

{
float4 color = float4(1,1,1,1);

float depth = (input.depthPosition.z / input.depthPosition.w);
color = float4(depth, depth, depth, 1);

if (_alphamap == 1)
{
color.a *= t_alphamap.Sample(ss, input.texcoord).a;
}

return color;
}


PS. The resource filled by this shader looks fine, the shadow map I mean.

// Get Normal Data
float4 normal = t_normals.Sample(ss, input.Tex); // Stored in view space
normal = mul(float4(normal.xyz, 0), texture_transform); // texture_transform == view^(-1)

// Get Position
float4 position = t_position.Sample(ss, input.Tex); // Stored in view space
position = mul(float4(position.xyz, 1), texture_transform);

normal.a = 1.0f;
position.w = 1.0f;

float4 lightViewPosition;
lightViewPosition = position;
lightViewPosition = mul(lightViewPosition, lightViewMatrix);
lightViewPosition = mul(lightViewPosition, lightProjectionMatrix);

float4 color = float4(0,0,0,1);

{
normal,
cameraPosition,
position,
lPosition-position,
lDirection,
lColor,
lightViewPosition,
1.0f // Specular Intensity
).rgb;
}
else
{
float diffusebrightness = saturate(dot(normal, lDirection));
color.rgb += lColor * diffusebrightness;
}

return color;


Helpers:

float4 GetShadowOcclusion(
float3 Normal,
float3 EyePos,
float3 WorldPosition,
float3 LightSurfaceDir,
float3 LightDirection,
float3 LightColor,
float4 LightViewPosition,
float SpecularIntensity
)
{
float bias;
float4 color = float4(0,0,0,1);
float2 projectTexCoord;
float depthValue;
float lightDepthValue;
float lightIntensity;

bias = 0.0001;
float occlusion = 0;

projectTexCoord.x =  LightViewPosition.x / LightViewPosition.w / 2.0f + 0.5f;
projectTexCoord.y = -LightViewPosition.y / LightViewPosition.w / 2.0f + 0.5f;

if((saturate(projectTexCoord.x) == projectTexCoord.x) && (saturate(projectTexCoord.y) == projectTexCoord.y))
{
color.a = 0.0f;

lightDepthValue = LightViewPosition.z / LightViewPosition.w;
lightDepthValue = lightDepthValue - bias;

lightIntensity = saturate(dot(Normal, LightSurfaceDir));

if(lightDepthValue < depthValue)
{
//float diffusebrightness = saturate(dot(normal, lDirection));
//color.rgb += lColor * diffusebrightness;

color.rgb += LightColor*lightIntensity;
occlusion = lightIntensity;
}
}

// Secular lighting occurs here, but it's irrelevant
}


I hope this will be enough to supply you with to approach this issue.

EDIT: I did not post any kind of result, so, where the shadows are not present are not being lit for some reason, it seems that the if(lightDepthValue < depthValue) is never fulfilled.

-MIGI0027

Edited by Migi0027
0

##### Share on other sites

People seem quiet, does everything look fine here?

If so, are you interested in the cpu side?

0

##### Share on other sites
I'm not seeing anything obviously wrong. A couple suggestions though. Post a screenshot of the issue, run the DX debug device to make sure there are no DX errors or warnings, and change your shader to output these things to help debug: lightDepthValue, depthValue, depthValue - lightDepthValue. Also try rendering debug colors for shadow/non-shadow:

if(lightDepthValue < depthValue)
return float4(1, 0, 0, 1);
return float4(0, 1, 0, 1);

Hopefully one of those will reveal where the issue lies.
0

##### Share on other sites

Not really related to the issue, but you can render your depth map directly to a depth stencil target (no need to use render target). This way you can take advantage of the fast z-buffer fills and you don't need to use a pixel shader at all (unless you'll need alpha transparency).

In the shadowing code, most of the IFs are not necessary and won't add anything to the result. You can use clamping as shadow texture addressing mode.

I think also that your way of performing alpha testing is overly complicated.

the line "if (ShadowMap.Sample(ss, projectTexCoord).a == 0)color.a = 0.0f;" is unnecessary if you change the shadow pixel shader:

if (_alphamap == 1)
{
}

Cheers!

0

##### Share on other sites

Thanks for the input!

Yeah, it does seem that I've over complicated things, thanks for the points, I'll change them after I've fixed this issue  .

Telanor: Actually I tried most of what you mentioned, and the behavior was: it passed the if((saturate(projectTexCoord.x) == projectTexCoord.x) && (saturate(projectTexCoord.y) == projectTexCoord.y)) but not the if(lightDepthValue < depthValue). I'm going to try the other points.

-MIGI0027

0

##### Share on other sites

Finally, it's working

In the older version I used to have a global view + projection matrix (for shadows), but as that changed, I needed to replace some variables with others, so I replaced almost all of the occurrences but forgot one, therefore it broke, and replacing the last one did the magic.

Thanks guys!

Edited by Migi0027
0

## Create an account

Register a new account

Followers 0

• ### Similar Content

• Hi,
I started reading Introduction to 3D Game Programming with Direct3D 11.0 and have a little question about callback function. In author's example code d3dApp.cpp, he managed to assign a member function to WNDCLASS::lpfnWndProc
namespace {     // This is just used to forward Windows messages from a global window     // procedure to our member function window procedure because we cannot     // assign a member function to WNDCLASS::lpfnWndProc.     D3DApp* gd3dApp = 0; } LRESULT CALLBACK MainWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {     // Forward hwnd on because we can get messages (e.g., WM_CREATE)     // before CreateWindow returns, and thus before mhMainWnd is valid.     return gd3dApp->MsgProc(hwnd, msg, wParam, lParam); } in constructor D3DApp::D3DApp()
gd3dApp = this; and in bool D3DApp::InitMainWindow()
wc.lpfnWndProc = MainWndProc; Notice that D3DApp::MsgProc is a virtual function.
As far as I'm concerned, I would find it convenient to declare MsgProc member function as static. However, a static member can't be virtual. Is there any solution so that I can overcome the contradiction except author's method?

• I am working on a game (shameless plug: Cosmoteer) that is written in a custom game engine on top of Direct3D 11. (It's written in C# using SharpDX, though I think that's immaterial to the problem at hand.)
The problem I'm having is that a small but understandably-frustrated percentage of my players (about 1.5% of about 10K players/day) are getting frequent device hangs. Specifically, the call to IDXGISwapChain::Present() is failing with DXGI_ERROR_DEVICE_REMOVED, and calling GetDeviceRemovedReason() returns DXGI_ERROR_DEVICE_HUNG. I'm not ready to dismiss the errors as unsolveable driver issues because these players claim to not be having problems with any other games, and there are more complaints on my own forums about this issue than there are for games with orders of magnitude more players.
My first debugging step was, of course, to turn on the Direct3D debug layer and look for any errors/warnings in the output. Locally, the game runs 100% free of any errors or warnings. (And yes, I verified that I'm actually getting debug output by deliberately causing a warning.) I've also had several players run the game with the debug layer turned on, and they are also 100% free of errors/warnings, except for the actual hung device:
[MessageIdDeviceRemovalProcessAtFault] [Error] [Execution] : ID3D11Device::RemoveDevice: Device removal has been triggered for the following reason (DXGI_ERROR_DEVICE_HUNG: The Device took an unreasonable amount of time to execute its commands, or the hardware crashed/hung. As a result, the TDR (Timeout Detection and Recovery) mechanism has been triggered. The current Device Context was executing commands when the hang occurred. The application may want to respawn and fallback to less aggressive use of the display hardware). So something my game is doing is causing the device to hang and the TDR to be triggered for a small percentage of players. The latest update of my game measures the time spent in IDXGISwapChain::Present(), and indeed in every case of a hung device, it spends more than 2 seconds in Present() before returning the error. AFAIK my game isn't doing anything particularly "aggressive" with the display hardware, and logs report that average FPS for the few seconds before the hang is usually 60+.
So now I'm pretty stumped! I have zero clues about what specifically could be causing the hung device for these players, and I can only debug post-mortem since I can't reproduce the issue locally. Are there any additional ways to figure out what could be causing a hung device? Are there any common causes of this?
Here's my remarkably un-interesting Present() call:
SwapChain.Present(_vsyncIn ? 1 : 0, PresentFlags.None); I'd be happy to share any other code that might be relevant, though I don't myself know what that might be. (And if anyone is feeling especially generous with their time and wants to look at my full code, I can give you read access to my Git repo on Bitbucket.)
1. The errors happen on all OS'es my game supports (Windows 7, 8, 10, both 32-bit and 64-bit), GPU vendors (Intel, Nvidia, AMD), and driver versions. I've been unable to discern any patterns with the game hanging on specific hardware or drivers.
2. For the most part, the hang seems to happen at random. Some individual players report it crashes in somewhat consistent places (such as on startup or when doing a certain action in the game), but there is no consistency between players.
3. Many players have reported that turning on V-Sync significantly reduces (but does not eliminate) the errors.
4. I have assured that my code never makes calls to the immediate context or DXGI on multiple threads at the same time by wrapping literally every call to the immediate context and DXGI in a mutex region (C# lock statement). (My code *does* sometimes make calls to the immediate context off the main thread to create resources, but these calls are always synchronized with the main thread.) I also tried synchronizing all calls to the D3D device as well, even though that's supposed to be thread-safe. (Which did not solve *this* problem, but did, curiously, fix another crash a few players were having.)
5. The handful of places where my game accesses memory through pointers (it's written in C#, so it's pretty rare to use raw pointers) are done through a special SafePtr that guards against out-of-bounds access and checks to make sure the memory hasn't been deallocated/unmapped. So I'm 99% sure I'm not writing to memory I shouldn't be writing to.
6. None of my shaders use any loops.
Thanks for any clues or insights you can provide. I know there's not a lot to go on here, which is part of my problem. I'm coming to you all because I'm out of ideas for what do investigate next, and I'm hoping someone else here has ideas for possible causes I can investigate.
Thanks again!

• By thmfrnk
Hello,
I am working on a Deferred Shading Engine, which actually uses MSAA for Antialising. Apart from the big G-Buffer ressources its working fine. But the intention of my engine is not only realtime-rendering as also render Screenshots as well as Videos. In that case I've enough time to do everything to get the best results. While using 8x MSAA, some scenes might still flicker.. especially on vegetations. Unfortunately 8x seems to be the maximum on DX11 Hardware, so there is no way to get better results, even if don't prefer realtime.
So finally I am looking for a solution, which might offer an unlimited Sample count. The first thing I thought about was to find a way to manually manipulate MSAA Sample locations, in order to be able to render multiple frames with different patterns and combining them. I found out that NVIDIA did something equal with TXAA. However, I only found a solution to use NVAPI, in order to change sample locations. https://mynameismjp.wordpress.com/2015/09/13/programmable-sample-points/
While I am working on .NET and SlimDX I've no idea how hard it would to implement the NVIDIA API and if its possible to use it together with SlimDX. And this approach would be also limited to NV.
Does anyone have an idea or maybe a better approach I could use?
Thanks, Thomas

• For vector operations which mathematically result in a single scalar f (such as XMVector3Length or XMPlaneDotCoord), which of the following extractions from an XMVECTOR is preferred:
1. The very explicit store operation
const XMVECTOR v = ...; float f; XMStoreFloat(&f, v); 2. A shorter but less explicit version (note that const can now be used explicitly)
const XMVECTOR v = ...; const float f = XMVectorGetX(v);

• Hi guys,
this is a exam question regarding alpha blending, however there is no official solution, so i am wondering  whether my solution is right or not... thanks in advance...

my idea:
BS1:
since BS1 with BlendEnable set as false, just write value into back buffer.
-A : (0.4, 0.4, 0.0, 0.5)
-B : (0.2, 0.4, 0.8, 0.5)

BS2:

backbuffer.RGB: = (0.4, 0.0, 0.0) * 1 + (0.0, 0.0, 0.0) * (1-0.5)      = ( 0.4, 0.0, 0.0)
backbuffer.Alpha = 1*1 + 0*0   =1

A.RGB = (0.4, 0.4, 0.0)* 0.5 + (0.4, 0.0, 0.0)* ( 1-0.5)   = (0.4,0.2,0.0)
A.Alpha=0.5*1+1*(1-0.5) = 1

B.RGB = (0.2, 0.4, 0.8) * 0.5 + (0.4, 0.2, 0.0) * (1-0.5)  = (0.3, 0.3, 0.4)
B.Alpha = 0.5 * 1 + 1*(1-0.5)  = 1

==========================
BS3:

backbuffer.RGB = (0.4, 0.0, 0.0) + (0.0, 0.0, 0.0)  = (0.4, 0.0, 0.0)
backbuffer.Alpha = 0

A.RGB = (0.4, 0.4, 0.0) + (0.4, 0.0, 0.0) = (0.8, 0.4, 0.0)
A.Alpha = 0

B.RGB = (0.2, 0.4, 0.8) + (0.8, 0.4, 0.0) = (1.0, 0.8, 0.8)
B.Alpha = 0

• 11
• 11
• 14
• 19
• 14