Telanor

I found part of the problem was from me using the ViewProjection matrix from the wrong camera but now there seems to be an issue with the sampling coordinates for the projection depth map being wrong.



The projector camera is positioned approximately where the cursor is and is looking straight downwards. Ive changed the code from before slightly

float4 decalPos = mul(position, DecalViewProjection);
decalPos /= decalPos.w;
decalPos.xy = float2(decalPos.x, -decalPos.y) / 2.0f + 0.5f;

float shadowDepth = ProjectorDepthMap.Sample(pointSampler, decalPos.xy);

return float4(shadowDepth.rrr, 1);

That's what I figured but I wasn't able to get it to work. It just considers everything to be out of the shadow.

float4 position = //bunch of code to reconstruct world space position from log depth

float4 decalPos = mul(position, DecalViewProjection);

float shadowDepth = ProjectorDepthMap.Sample(pointSampler, decalTexCoord.xy);

if(shadowDepth < decalPos.z / decalPos.w)
	discard;

I'm trying to implement projective texturing but I'm having some trouble getting it to a usable state. Right now it works but it projects to infinity (or more specifically, to the far plane). I can't just pull back the far plane because it could result in the texture being cut off on steep surfaces, and wouldn't solve the problem of projecting through surfaces. I've tried to mimic a sort of spotlight shadow technique but wasn't able to get that to work since there are pretty much no tutorials on shadows for deferred shading pipelines. So, my question: How do you get a projective texture to stop at the first surface it hits?


Edit: I forgot to add tags. I'm using DX11 & sharpdx

Turns out we had to bake animations and ignore any bones that didn't have animations

I'm trying to calculate a view/projection/bounding frustum for the 6 directions of a point light and I'm having trouble with the views pointing along the Y axis. Our game uses a right-handed, Y-up system. For the other 4 directions I create the LookAt matrix using (0, 1, 0) as the up vector. Obviously that doesn't work when looking along the Y axis so for those I use an up vector of (-1, 0, 0) for -Y and (1, 0, 0) for +Y. The view matrix seems to come out correctly (and the projection matrix always stays the same), but the bounding frustum is definitely wrong.

This is the code I'm using:

camera.Projection = Matrix.PerspectiveFovRH((float)Math.PI / 2, ShadowMapSize / (float)ShadowMapSize, 1, 5);

for(var i = 0; i < 6; i++)
{
	var renderTargetView = shadowMap.GetRenderTargetView((TextureCubeFace)i);
	var up = DetermineLightUp((TextureCubeFace) i);
	var forward = DirectionToVector((TextureCubeFace) i);

	camera.View = Matrix.LookAtRH(Position, Position + forward, up);
	camera.BoundingFrustum = new BoundingFrustum(camera.View * camera.Projection);
}

private static Vector3 DirectionToVector(TextureCubeFace direction)
{
	switch (direction)
	{
		case TextureCubeFace.NegativeX:
			return -Vector3.UnitX;
		case TextureCubeFace.NegativeY:
			return -Vector3.UnitY;
		case TextureCubeFace.NegativeZ:
			return -Vector3.UnitZ;
		case TextureCubeFace.PositiveX:
			return Vector3.UnitX;
		case TextureCubeFace.PositiveY:
			return Vector3.UnitY;
		case TextureCubeFace.PositiveZ:
			return Vector3.UnitZ;
		default:
			throw new ArgumentOutOfRangeException("direction");
	}
}

private static Vector3 DetermineLightUp(TextureCubeFace direction)
{
	switch (direction)
	{
		case TextureCubeFace.NegativeY:
			return -Vector3.UnitX;
		case TextureCubeFace.PositiveY:
			return Vector3.UnitX;
		default:
			return Vector3.UnitY;
	}
}

I can post some example output if it'll help.

See here for instructions: http://blog.rthand.com/post/2010/10/25/Capture-DirectX-1011-debug-output-to-Visual-Studio.aspx

I think you need to add the application to the list before D3D11_CREATE_DEVICE_DEBUG has any effect

Ah, so the shadows are supposed to be added into the lighting buffer output apparently. Since I wasn't the one who set this up originally I hadn't really done much research into the compositing stage of shadows, so I just assumed it was normal to add them in during the final gbuffer pass. Thanks for the help guys.

I suggest you enable the directx debug runtimes and fix all the errors it reports. There are several of them

Your LightShader::RenderText method doesn't appear to draw the contents of the shared texture to screen. It looks like it sets up for it but never actually does the draw call.

How do you do that with a deferred renderer? Ambient and diffuse are precombined.

I had the wrong blend mode. Halos are fixed now. Can we use premultiplied alpha to get rid of the grass-on-grass darkness? Or does that not work?

Edit: Another question: will this work for glass and other transparent blocks without looking terrible?

-- Drawing your grass with additive blending and no depth testing, and a write mask of rgb=false, a=true (so that only the alpha channels are summed).

-- Drawing your grass with depth-testing and alpha-testing (no blending), and a write mask of rgb=true, a=false (so that only the color channels are written).

First pass state:

descBlendAlphaOnly.RenderTarget[0].IsBlendEnabled = true;
descBlendAlphaOnly.RenderTarget[0].RenderTargetWriteMask = ColorWriteMaskFlags.Alpha;
descBlendAlphaOnly.RenderTarget[0].SourceBlend = BlendOption.SourceAlpha;
descBlendAlphaOnly.RenderTarget[0].SourceAlphaBlend = BlendOption.SourceAlpha;
descBlendAlphaOnly.RenderTarget[0].DestinationBlend = BlendOption.One;
descBlendAlphaOnly.RenderTarget[0].DestinationAlphaBlend = BlendOption.One;

Second pass state:

descBlendColorOnly.RenderTarget[0].IsBlendEnabled = false;
descBlendColorOnly.RenderTarget[0].RenderTargetWriteMask = ColorWriteMaskFlags.Red | ColorWriteMaskFlags.Green | ColorWriteMaskFlags.Blue;

Are these correct?

This is the result I'm getting:


I have no alpha testing on the first pass and the 2nd pass uses this:

if(color.a == 0.0f)
	discard;

Is there a way to properly render layered transparent objects when you can't do depth sorting? Since the terrain is all built up into 2 vertex buffers per region (1 for solid blocks, 1 for transparent blocks), we can't do the typical depth sorting. Are there any alternatives?

This is what its coming out like right now:

Increasing the shadow bias fixed the remaining issue:



So it's pretty much working now. I'm getting just about every other problem possible though. Peter panning, jittering when moving, shadows disappearing when the object is behind the camera, and some weird issue where a triangle of shadow pops in on the right hand side (you can see it in the screenshot). The last two issues are particularly problematic though.

Edit: Switching to our old ESM shadow filtering (instead of PCF from the sample) mostly fixes issues 1, 2, and possibly 4. 3rd one is still something I'd really like to fix.

I can't get the reconstructed position to even come close to the position_ws_VS.  I found something else out, however, while reading MJPs blog about reconstructing linear depth.  The GetCorners function in SharpDX returns the corners in a different order than XNA.  So I switched the indexes around and now the first shader output seems a little closer to what it should be (at least I think so...).  It no longer rotates with the camera, but it's still moving with it:
 
http://www.youtube.com/watch?v=I0iOqgSWOmE