• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
lipsryme

Few issues with Bloom / Eye adapation / Vol.Scattering

3 posts in this topic

I'm having a few issues here that are concerning bloom, eye adaption and volumetric scattering.

Both can be seen in the video below.

 

1. Having implemented eye adaption, how do you handle the volumetric scattering effect of e.g. the sun. Because whenever you look at it the exposure is going down and therefore also the glow of the sun and it's scattering effect. Sure the original pixels to blur are still the same but the effect suffers from the reduced exposure and bloom.

 

2. I'm having issues with bloom on tiny but very bright specular parts that shape the glowing pixel to basically a rather huge spherical glow.

Another issue here is that there's some parts that produce a NdotL product that is higher than zero even if they are opposite to the light direction.

 

 

http://www.youtube.com/watch?v=XHlPI_BuJhg&feature=youtu.be

0

Share this post


Link to post
Share on other sites

[quote name='lipsryme' timestamp='1357904924' post='5020274']
2. I'm having issues with bloom on tiny but very bright specular parts that shape the glowing pixel to basically a rather huge spherical glow.
[/quote]

I think you need to tweak it until it looks good :) Have you tried to reduce the blur radius ?

 

[quote name='lipsryme' timestamp='1357904924' post='5020274']
Another issue here is that there's some parts that produce a NdotL product that is higher than zero even if they are opposite to the light direction.
[/quote]

You always need to consider, that rendered normals will bend, even if the poly-surface normal will not. This often happens when using normal maps, the surface is visible (surface normal points towards the camera), but the texture/vertex normal will bend it into the screen towards the light source.

 

In this case a shadow map would be helpful to avoid it.

0

Share this post


Link to post
Share on other sites

I've tried to reduce the radius but it still shapes to the glowing ball in the end when the bright pixels are small enough.

1

Share this post


Link to post
Share on other sites

Using shadows helps a little for the parts that should be occluded but I still need some help on the two problems above.

 

I'm using the following seperable gaussian blur function for the bloom (which is exactly like being used in MJPs recent samples):

 

cbuffer cbBlurProperties : register(b0)
{
	float2 _ScreenSize;
	float _BloomBlurSigma;
	float _padding;
};




// Calculates the gaussian blur weight for a given distance and sigmas
float CalcGaussianWeight(int sampleDist, float sigma)
{
	float g = 1.0f / sqrt(2.0f * 3.14159 * sigma * sigma);
	return (g * exp(-(sampleDist * sampleDist) / (2 * sigma * sigma)));
}

// Performs a gaussian blur in one direction
float4 Blur(in float2 UV, float2 texScale, float sigma)
{
    float4 color = 0;
    for (int i = -3; i < 3; i++)
    {
		float weight = CalcGaussianWeight(i, sigma);
        float2 texCoord = UV;
		texCoord += (i / _ScreenSize) * texScale;
		float4 sample = TargetTexture.Sample(TargetTextureSampler, texCoord);
		color += sample * weight;
    }

    return color;
}


float4 PS(VSO input) : SV_TARGET0
{
	return Blur(input.UV, float2(1, 0), _BloomBlurSigma);
}	

 

I've tried different sigmas from 0.5 to 1.5 but at glancing angles the few pixels at the edge always lit up to extreme values and get expanded during the blur to the glowing ball (as seen in the video).

 

Do you think the problem might be my BRDF ?

Here's the one I'm using for the the head:


float3 N = Normal;
	float3 L = normalize(LightDir);
	float3 V = ViewDir;
	float3 H = V + L;
	float3 H_norm = normalize(H);




	float4 Ls = float4(0, 0, 0, 1);
	float4 Lr = float4(0, 0, 0, 1);
	
	// Incident radiance
	float3 Li = ToLinear(_LightColor.rgb) * _LightIntensity;

	// Calculate cos(theta)
	float NdotL = saturate(dot(N, L));

	// Compute Fresnel Term (F) using Schlick's approximation
	float base = 1.0f - saturate(dot(L, H_norm));
	float exponential = pow(base, 5.0);
	float3 F = 0.028f + (1.0f - 0.028f) * exponential;


	// Add ambient light
	Lr.rgb += ambient;

	// Add diffuse light
	Lr.rgb += NdotL * Li * shadowFactor;
	Lr.rgb *= DiffuseAlbedo;
	Lr.rgb *= (1.0f - F);


	// Kelemen/Szirmay-Kalos (D) using a precomputed beckmann distribution
	float NdotH = saturate(dot(N, H_norm));
	float PH = pow(abs(2.0f * BeckmannTarget.SampleLevel(LinearSampler, float2(NdotH, SpecularPower), 0).r), 10.0f);
	float ksk = max(PH / dot(H, H), 0.0f);
	float D = ksk;

	// Cook-Torrance approximation (G) by Kelemen and Szirmay-Kalos
	float NdotV = saturate(dot(N, V)) + 0.00001f;
	float LdotH = saturate(dot(L, H_norm)); + 0.00001f;
	float G = 1.0f / (LdotH * LdotH);

	float3 nominator = F * G * D;
	float denominator = 4.0f;

	Ls.rgb += nominator / denominator;
	Ls.rgb *= NdotL * Li * shadowFactor; // multiply by cosine factor and incoming radiance

	return Lr + Ls;
1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0