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• ### Similar Content

• By elect
Hi,
ok, so, we are having problems with our current mirror reflection implementation.
At the moment we are doing it very simple, so for the i-th frame, we calculate the reflection vectors given the viewPoint and some predefined points on the mirror surface (position and normal).
Then, using the least squared algorithm, we find the point that has the minimum distance from all these reflections vectors. This is going to be our virtual viewPoint (with the right orientation).
After that, we render offscreen to a texture by setting the OpenGL camera on the virtual viewPoint.
And finally we use the rendered texture on the mirror surface.
So far this has always been fine, but now we are having some more strong constraints on accuracy.
What are our best options given that:
- we have a dynamic scene, the mirror and parts of the scene can change continuously from frame to frame
- we have about 3k points (with normals) per mirror, calculated offline using some cad program (such as Catia)
- all the mirror are always perfectly spherical (with different radius vertically and horizontally) and they are always convex
- a scene can have up to 10 mirror
- it should be fast enough also for vr (Htc Vive) on fastest gpus (only desktops)

Looking around, some papers talk about calculating some caustic surface derivation offline, but I don't know if this suits my case
Also, another paper, used some acceleration structures to detect the intersection between the reflection vectors and the scene, and then adjust the corresponding texture coordinate. This looks the most accurate but also very heavy from a computational point of view.

Other than that, I couldn't find anything updated/exhaustive around, can you help me?

• Hello all,
I am currently working on a game engine for use with my game development that I would like to be as flexible as possible.  As such the exact requirements for how things should work can't be nailed down to a specific implementation and I am looking for, at least now, a default good average case scenario design.
Here is what I have implemented:
Deferred rendering using OpenGL Arbitrary number of lights and shadow mapping Each rendered object, as defined by a set of geometry, textures, animation data, and a model matrix is rendered with its own draw call Skeletal animations implemented on the GPU.   Model matrix transformation implemented on the GPU Frustum and octree culling for optimization Here are my questions and concerns:
Doing the skeletal animation on the GPU, currently, requires doing the skinning for each object multiple times per frame: once for the initial geometry rendering and once for the shadow map rendering for each light for which it is not culled.  This seems very inefficient.  Is there a way to do skeletal animation on the GPU only once across these render calls? Without doing the model matrix transformation on the CPU, I fail to see how I can easily batch objects with the same textures and shaders in a single draw call without passing a ton of matrix data to the GPU (an array of model matrices then an index for each vertex into that array for transformation purposes?) If I do the matrix transformations on the CPU, It seems I can't really do the skinning on the GPU as the pre-transformed vertexes will wreck havoc with the calculations, so this seems not viable unless I am missing something Overall it seems like simplest solution is to just do all of the vertex manipulation on the CPU and pass the pre-transformed data to the GPU, using vertex shaders that do basically nothing.  This doesn't seem the most efficient use of the graphics hardware, but could potentially reduce the number of draw calls needed.

Really, I am looking for some advice on how to proceed with this, how something like this is typically handled.  Are the multiple draw calls and skinning calculations not a huge deal?  I would LIKE to save as much of the CPU's time per frame so it can be tasked with other things, as to keep CPU resources open to the implementation of the engine.  However, that becomes a moot point if the GPU becomes a bottleneck.

• Hello!
I would like to introduce Diligent Engine, a project that I've been recently working on. Diligent Engine is a light-weight cross-platform abstraction layer between the application and the platform-specific graphics API. Its main goal is to take advantages of the next-generation APIs such as Direct3D12 and Vulkan, but at the same time provide support for older platforms via Direct3D11, OpenGL and OpenGLES. Diligent Engine exposes common front-end for all supported platforms and provides interoperability with underlying native API. Shader source code converter allows shaders authored in HLSL to be translated to GLSL and used on all platforms. Diligent Engine supports integration with Unity and is designed to be used as a graphics subsystem in a standalone game engine, Unity native plugin or any other 3D application. It is distributed under Apache 2.0 license and is free to use. Full source code is available for download on GitHub.
Features:
True cross-platform Exact same client code for all supported platforms and rendering backends No #if defined(_WIN32) ... #elif defined(LINUX) ... #elif defined(ANDROID) ... No #if defined(D3D11) ... #elif defined(D3D12) ... #elif defined(OPENGL) ... Exact same HLSL shaders run on all platforms and all backends Modular design Components are clearly separated logically and physically and can be used as needed Only take what you need for your project (do not want to keep samples and tutorials in your codebase? Simply remove Samples submodule. Only need core functionality? Use only Core submodule) No 15000 lines-of-code files Clear object-based interface No global states Key graphics features: Automatic shader resource binding designed to leverage the next-generation rendering APIs Multithreaded command buffer generation 50,000 draw calls at 300 fps with D3D12 backend Descriptor, memory and resource state management Modern c++ features to make code fast and reliable The following platforms and low-level APIs are currently supported:
Windows Desktop: Direct3D11, Direct3D12, OpenGL Universal Windows: Direct3D11, Direct3D12 Linux: OpenGL Android: OpenGLES MacOS: OpenGL iOS: OpenGLES API Basics
Initialization
The engine can perform initialization of the API or attach to already existing D3D11/D3D12 device or OpenGL/GLES context. For instance, the following code shows how the engine can be initialized in D3D12 mode:
#include "RenderDeviceFactoryD3D12.h" using namespace Diligent; // ...  GetEngineFactoryD3D12Type GetEngineFactoryD3D12 = nullptr; // Load the dll and import GetEngineFactoryD3D12() function LoadGraphicsEngineD3D12(GetEngineFactoryD3D12); auto *pFactoryD3D11 = GetEngineFactoryD3D12(); EngineD3D12Attribs EngD3D12Attribs; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[0] = 1024; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[1] = 32; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[2] = 16; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[3] = 16; EngD3D12Attribs.NumCommandsToFlushCmdList = 64; RefCntAutoPtr<IRenderDevice> pRenderDevice; RefCntAutoPtr<IDeviceContext> pImmediateContext; SwapChainDesc SwapChainDesc; RefCntAutoPtr<ISwapChain> pSwapChain; pFactoryD3D11->CreateDeviceAndContextsD3D12( EngD3D12Attribs, &pRenderDevice, &pImmediateContext, 0 ); pFactoryD3D11->CreateSwapChainD3D12( pRenderDevice, pImmediateContext, SwapChainDesc, hWnd, &pSwapChain ); Creating Resources
Device resources are created by the render device. The two main resource types are buffers, which represent linear memory, and textures, which use memory layouts optimized for fast filtering. To create a buffer, you need to populate BufferDesc structure and call IRenderDevice::CreateBuffer(). The following code creates a uniform (constant) buffer:
BufferDesc BuffDesc; BufferDesc.Name = "Uniform buffer"; BuffDesc.BindFlags = BIND_UNIFORM_BUFFER; BuffDesc.Usage = USAGE_DYNAMIC; BuffDesc.uiSizeInBytes = sizeof(ShaderConstants); BuffDesc.CPUAccessFlags = CPU_ACCESS_WRITE; m_pDevice->CreateBuffer( BuffDesc, BufferData(), &m_pConstantBuffer ); Similar, to create a texture, populate TextureDesc structure and call IRenderDevice::CreateTexture() as in the following example:
TextureDesc TexDesc; TexDesc.Name = "My texture 2D"; TexDesc.Type = TEXTURE_TYPE_2D; TexDesc.Width = 1024; TexDesc.Height = 1024; TexDesc.Format = TEX_FORMAT_RGBA8_UNORM; TexDesc.Usage = USAGE_DEFAULT; TexDesc.BindFlags = BIND_SHADER_RESOURCE | BIND_RENDER_TARGET | BIND_UNORDERED_ACCESS; TexDesc.Name = "Sample 2D Texture"; m_pRenderDevice->CreateTexture( TexDesc, TextureData(), &m_pTestTex ); Initializing Pipeline State
Diligent Engine follows Direct3D12 style to configure the graphics/compute pipeline. One big Pipelines State Object (PSO) encompasses all required states (all shader stages, input layout description, depth stencil, rasterizer and blend state descriptions etc.)
To create a shader, populate ShaderCreationAttribs structure. An important member is ShaderCreationAttribs::SourceLanguage. The following are valid values for this member:
SHADER_SOURCE_LANGUAGE_DEFAULT  - The shader source format matches the underlying graphics API: HLSL for D3D11 or D3D12 mode, and GLSL for OpenGL and OpenGLES modes. SHADER_SOURCE_LANGUAGE_HLSL  - The shader source is in HLSL. For OpenGL and OpenGLES modes, the source code will be converted to GLSL. See shader converter for details. SHADER_SOURCE_LANGUAGE_GLSL  - The shader source is in GLSL. There is currently no GLSL to HLSL converter. To allow grouping of resources based on the frequency of expected change, Diligent Engine introduces classification of shader variables:
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. This post describes the resource binding model in Diligent Engine.
The following is an example of shader initialization:
To create a pipeline state object, define instance of PipelineStateDesc structure. The structure defines the pipeline specifics such as if the pipeline is a compute pipeline, number and format of render targets as well as depth-stencil format:
// This is a graphics pipeline PSODesc.IsComputePipeline = false; PSODesc.GraphicsPipeline.NumRenderTargets = 1; PSODesc.GraphicsPipeline.RTVFormats[0] = TEX_FORMAT_RGBA8_UNORM_SRGB; PSODesc.GraphicsPipeline.DSVFormat = TEX_FORMAT_D32_FLOAT; The structure also defines depth-stencil, rasterizer, blend state, input layout and other parameters. For instance, rasterizer state can be defined as in the code snippet below:
// Init rasterizer state RasterizerStateDesc &RasterizerDesc = PSODesc.GraphicsPipeline.RasterizerDesc; RasterizerDesc.FillMode = FILL_MODE_SOLID; RasterizerDesc.CullMode = CULL_MODE_NONE; RasterizerDesc.FrontCounterClockwise = True; RasterizerDesc.ScissorEnable = True; //RSDesc.MultisampleEnable = false; // do not allow msaa (fonts would be degraded) RasterizerDesc.AntialiasedLineEnable = False; When all fields are populated, call IRenderDevice::CreatePipelineState() to create the PSO:
Shader resource binding in Diligent Engine is based on grouping variables in 3 different groups (static, mutable and dynamic). Static variables 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. They are bound directly to the shader object:

m_pPSO->CreateShaderResourceBinding(&m_pSRB); Dynamic and mutable resources are then bound through SRB object:
m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "tex2DDiffuse")->Set(pDiffuseTexSRV); m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); The difference between mutable and dynamic resources is that mutable ones can only be set once for every instance of a shader resource binding. Dynamic resources can be set multiple times. It is important to properly set the variable type as this may affect performance. Static variables are generally most efficient, followed by mutable. Dynamic variables are most expensive from performance point of view. This post explains shader resource binding in more details.
Setting the Pipeline State and Invoking Draw Command
Before any draw command can be invoked, all required vertex and index buffers as well as the pipeline state should be bound to the device context:
// Clear render target const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); // 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); m_pContext->SetPipelineState(m_pPSO); Also, all shader resources must be committed to the device context:
m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); When all required states and resources are bound, IDeviceContext::Draw() can be used to execute draw command or IDeviceContext::DispatchCompute() can be used to execute compute command. Note that for a draw command, graphics pipeline must be bound, and for dispatch command, compute pipeline must be bound. Draw() 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); Tutorials and Samples
The GitHub repository contains a number of tutorials and sample applications that demonstrate the API usage.

AntTweakBar sample demonstrates how to use AntTweakBar library to create simple user interface.

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 textures, using compute shaders and unordered access views, etc.

The repository includes Asteroids performance benchmark based on this demo developed by Intel. It renders 50,000 unique textured asteroids and lets compare performance of D3D11 and D3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures.

Integration with Unity
Diligent Engine supports integration with Unity through Unity low-level native plugin interface. The engine relies on Native API Interoperability to attach to the graphics API initialized by Unity. After Diligent Engine device and context are created, they can be used us usual to create resources and issue rendering commands. GhostCubePlugin shows an example how Diligent Engine can be used to render a ghost cube only visible as a reflection in a mirror.

• By Yxjmir
I'm trying to load data from a .gltf file into a struct to use to load a .bin file. I don't think there is a problem with how the vertex positions are loaded, but with the indices. This is what I get when drawing with glDrawArrays(GL_LINES, ...):

Also, using glDrawElements gives a similar result. Since it looks like its drawing triangles using the wrong vertices for each face, I'm assuming it needs an index buffer/element buffer. (I'm not sure why there is a line going through part of it, it doesn't look like it belongs to a side, re-exported it without texture coordinates checked, and its not there)
I'm using jsoncpp to load the GLTF file, its format is based on JSON. Here is the gltf struct I'm using, and how I parse the file:
glBindVertexArray(g_pGame->m_VAO);
glDrawElements(GL_LINES, g_pGame->m_indices.size(), GL_UNSIGNED_BYTE, (void*)0); // Only shows with GL_UNSIGNED_BYTE
glDrawArrays(GL_LINES, 0, g_pGame->m_vertexCount);
So, I'm asking what type should I use for the indices? it doesn't seem to be unsigned short, which is what I selected with the Khronos Group Exporter for blender. Also, am I reading part or all of the .bin file wrong?
Test.gltf
Test.bin

• That means how do I use base DirectX or OpenGL api's to make a physics based destruction simulation?
Will it be just smart rendering or something else is required?

# OpenGL Sub-surface scattering hack ( comments wanted! )

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I was fiddling around in FX Composer last night and came up with a pretty nice-looking fake sub-surface scattering effect, as follows: http://img131.imageshack.us/img131/1489/sss1je8.jpg http://img131.imageshack.us/img131/2131/sss2tt2.jpg http://img131.imageshack.us/img131/3440/sss3gu5.jpg http://img141.imageshack.us/img141/3603/sss4nu5.jpg I'll post my full algorithm/code when I get back from work later today. In a nutshell, I have a simple half-lambert base diffuse term, nothing special. The sub-surface scattering effect is divided up into three parts: 1) A dot product between the inverse surface normal and the light, clamped from 0 to 1, and finally distance attenuated; 2) Another half-lambert term between the inverse normal and view, also distance attenuated; 3) Scaling of subsurface color by red, green and blue extinction coefficients. The final shot demonstrates the effects of tweaking these to produce a blue scatter color. In addition, I have the 1 - N dot V squared rim lighting term put forth in the Dawn demo by nVidia (but this time scaled by the clamped dot product between light and normal, to avoid that weird backlighting) and a basic Blinn-Phong specular added on top. Since those pictures were taken I've done some basic work on extending my algorithm to account for colored lighting and non-uniform material thickness, although it doesn't look quite as nice as it does in those earlier screens. So, my questions are: 1) Anyone know of a good way to make this handle the non-uniform thickness more gracefully (I'll post some pictures later for review) 2) Any additonal suggestions for improving this to look more skin-like as a whole? Feedback of any sort is appreciated, though. I originally wrote this to replace some shaders in Oblivion and possibly even Doom 3, and as such lack the ability to use depth buffers, spherical harmonics or any of that stuff, unless any and all information can be passed in through textures and shader constants ONLY. This is also targeted at SM3.0, although it works just fine in SM2.0 and the OpenGL equivalents (this has been ported to ARB assembly without incident)

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Alright, that took decidedly longer than expected to post-- that's what you get for being busy, I guess :(

Anyways, here's a shot with the translucency map and a few tweaks:
http://img143.imageshack.us/img143/2391/sssab9.jpg

I obviously fixed the eyebrow and hair thing, but it looks less... soft. Any suggestions? Should I even bother posting the code?

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For being so simple, these screenies look quite impressive. I'd certainly love to see that fx/fxproj to play with it :)

I only miss a little rougness (pores) and some more oilyness (specular) to be convinced that this is skin. But again, for being a quite simple approximation, this already looks awesome.

To address the thickness problem, maybe xNormal can help? That tool supports among many other things producing a thickness map. Having thickness from every point of view as shader input, the wrong lighting visible on the ear in the last shot should disappear.
One could also overlay two thickness maps, to account for bones (this would need another model for the skull to be created, but I guess that wouldn't be too hard to derive from the original mesh - it doesn't have to be perfect). This would make the head in the last shot look less like an obsidian statue and more like a flesh and bone thing (well, if red was used for scattering).

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Code isn't a problem, here's all the relevant shader stuff
string description = "Subsurface Scattering Hack";//------------------------------------float4x4 worldViewProj : WorldViewProjection;float4x4 world   : World;float4x4 worldInverseTranspose : WorldInverseTranspose;float4x4 viewInverse : ViewInverse;float4 LightPosition1 : POSITION<	string Object = "PointLight";	string UIName =  "Light 1";	string Space = "World";> 	= {1403.0f, 1441.0f, 1690.0f, 0.0f};float3 specColor<	string UIWidget = "color";	string UIName = "Specular Color";> = {0.9f, 0.9f, 1.0f};float3 lightColor<	string UIWidget = "color";	string UIName = "Light Color";> = {1.0f, 1.0f, 1.0f};float materialThickness<	string UIWidget = "Slider";	float UIMin = 0.0f;	float UIMax = 1.0f;	float UIStep = 0.01f;	string UIName = "Material Thickness Factor";> 	= 0.6f;float rimScalar<	string UIWidget = "Slider";	float UIMin = 0.0f;	float UIMax = 1.0f;	float UIStep = 0.01f;	string UIName = "Rim Light Strength";> 	= 1.0f;float extinctionCoefficientRed<	string UIWidget = "Slider";	float UIMin = 0.0f;	float UIMax = 1.0f;	float UIStep = 0.01f;	string UIName = "Extinction Coefficient, Red";> 	= 0.80f;float extinctionCoefficientBlue<	string UIWidget = "Slider";	float UIMin = 0.0f;	float UIMax = 1.0f;	float UIStep = 0.01f;	string UIName = "Extinction Coefficient, Blue";> 	= 0.12f;float extinctionCoefficientGreen<	string UIWidget = "Slider";	float UIMin = 0.0f;	float UIMax = 1.0f;	float UIStep = 0.01f;	string UIName = "Extinction Coefficient, Green";> 	= 0.20f;float specularPower<	string UIWidget = "Slider";	float UIMin = 0.0f;	float UIMax = 100.0f;	float UIStep = 0.50f;	string UIName = "Blinn Specular Power";> = 1.0f;texture diffuseTex;texture thicknessTex;texture normalTex;sampler normalSampler = sampler_state{	texture		= <normalTex>;	MinFilter	=	point;	MagFilter	=	point;	MipFilter	=	point;	AddressU	=	CLAMP;	AddressV	=	CLAMP;};sampler2D diffuseSampler = sampler_state{	Texture		=	<diffuseTex>;	MinFilter	=	Linear;	MagFilter	=	Linear;	MipFilter	=	Linear;	AddressU	=	WRAP;	AddressV	=	WRAP;};sampler2D thicknessSampler = sampler_state{	Texture		=	<diffuseTex>;	MinFilter	=	Linear;	MagFilter	=	Linear;	MipFilter	=	Linear;	AddressU	=	WRAP;	AddressV	=	WRAP;};struct VSOut{	float4 position			:	POSITION;	float2 texCoord			:	TEXCOORD0;	float3 worldNormal		:	TEXCOORD1;	float3 eyeVec     		:	TEXCOORD2;	float3 lightVec			:	TEXCOORD3;	float3 worldTangent		: 	TEXCOORD4;	float3 worldBinormal		: 	TEXCOORD5;	float3 vertPos			:	TEXCOORD6;};struct AppData {   	float4 position	:	POSITION;	float2 UV	:	TEXCOORD0;	float3 normal	:	NORMAL;	float3 tangent	: 	TANGENT;	float3 binormal	: 	BINORMAL;};VSOut SkinVS(AppData IN, uniform float4 lightPosition){	VSOut OUT;	OUT.worldNormal = normalize(mul(IN.normal, worldInverseTranspose).xyz);	OUT.worldTangent = normalize(mul(IN.tangent, worldInverseTranspose).xyz);	OUT.worldBinormal = normalize(mul(IN.binormal, worldInverseTranspose).xyz);	 	float3 worldSpacePos = mul(IN.position, world);	OUT.lightVec = lightPosition - worldSpacePos;	OUT.texCoord = IN.UV;	OUT.eyeVec = viewInverse[3].xyz - worldSpacePos;	OUT.position = mul(IN.position, worldViewProj);	OUT.vertPos = worldSpacePos;	return OUT;};float halfLambert(float3 vec1, float3 vec2){	float product = dot(vec1, vec2);	product *= 0.5;	product += 0.5;	return product;}float blinnPhongSpecular(float3 normalVec, float3 lightVec, float specPower){	float3 halfAngle = normalize(normalVec + lightVec);	return pow(saturate(dot(normalVec, halfAngle)), specPower);}float4 SkinPS(VSOut IN) : COLOR0{	float attenuation = (1.0f/distance(LightPosition1, IN.vertPos));	attenuation *= 10.0f;	float3 eyeVec 	= normalize(IN.eyeVec);	float3 lightVec = normalize(IN.lightVec.xyz);	float3 worldNormal = normalize(IN.worldNormal);	//float3 nMap = tex2D(normalSampler, IN.texCoord);	//worldNormal.x = dot(nMap.x, IN.worldTangent);	//worldNormal.y = dot(nMap.y, IN.worldBinormal);	//worldNormal.z = dot(nMap.z, IN.worldNormal);	float4 dotLN	= halfLambert(lightVec, worldNormal) * attenuation;	float3 indirectLightComponent = (float3)(materialThickness * max(0, dot(-worldNormal, lightVec)));	indirectLightComponent += materialThickness * halfLambert(-eyeVec, lightVec);	indirectLightComponent *= attenuation;	indirectLightComponent.r *= extinctionCoefficientRed;	indirectLightComponent.g *= extinctionCoefficientGreen;	indirectLightComponent.b *= extinctionCoefficientBlue;	indirectLightComponent.rgb *= tex2D(thicknessSampler, IN.texCoord).r;	float3 rim = (float3)(1.0f - max(0.0f, dot(worldNormal, eyeVec)));	rim *= rim;	dotLN *= tex2D(diffuseSampler, IN.texCoord);	float4 finalCol = dotLN + float4(indirectLightComponent, 1.0f);	rim *= max(0.0f, dot(worldNormal, lightVec)) * specColor;	finalCol.rgb += (rim * rimScalar * attenuation * finalCol.a);	finalCol.rgb += (blinnPhongSpecular(worldNormal, lightVec, specularPower) * attenuation * specColor * finalCol.a * 0.05f);	finalCol.rgb *= lightColor;	return float4(finalCol);};technique subSurfaceScattering{    pass p0     {				VertexShader		= compile vs_2_0 SkinVS(LightPosition1);		PixelShader			= compile ps_2_0 SkinPS();		ZEnable 			= true;		ZWriteEnable 		= true;		AlphaBlendEnable	= false;		SrcBlend 			= SrcAlpha;		DestBlend 			= InvSrcAlpha;		CullMode 			= CW; //None, CW, or CCW    }}

That's regular HLSL, could be converted to Cg, GLSL or whatever other shading language you prefer. I just use the Dawn lambert skin fxproj and apply that skin shader to the face. I made the thickness map myself, as you can see it's pretty hack-y, so I'll leave you be on that. Diffuse map comes with FX Composer.

Thanks for the tips! :) I'm working on a normal map thing as we speak, although the ones supplied with the Dawn demo just look kind of funny when I apply them-- perhaps they're in the wrong space or something.

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Thanks for the shader code, InvalidPointer. Unluckily, it'll take some work this weekend to get it to work, since FX Composer doesn't like something, it crashes right away :(

I've been thinking about thickness and all for a while, there seems to be no easy way to get it perfect everywhere. Even a thickness map won't do, because no matter how you turn it, the ears will always be shaded wrong. There's of course the option to calculate per-pixel thicknes like in nVidia's "Luna" demo, but then we're not talking about a fast and efficient implementation any more (render several passes, blur, etc...). Also, the algorithm again is only an approximation. Mostly it doesn't matter much, but for example looking at the oral cavity from the side, it will produce a false "thick" result, when in fact it's mostly "empty" air with two thin layers of cheeks.

So, I was wondering if shadow mapping the skull wouldn't be helpful, and still cheap enough (a single z-only render of a possibly much simplified model).
The idea is to scale the head model down a bit, and remove/flatten ears and nose and render that into the shadow map. It probably doesn't even have to be perfectly anatomically accurate.
So that will leave you with an "outer part" where there is skin and flesh (and rim light scattering), and an "inner part" where bones absorb all of the back light (regardless of thickness), so only scattering from incidential light and half-lambert lighting account to the colour.

Thickness should not be something to worry about much then. Around the border, anything N dot V isn't a terribly bad approximation, since the normals will point more "sidewards" the thinner the cross-section.
Now, in the "deeper" regions it does not work so well, but we have these masked out with the shadow map. Also, the disturbing artefacts when the ear is rim-lit although it obviously couldn't be (as the head is in the way) are gone.

Quote: