/// <summary>
/// Creates the configuration controls of this asset.
/// </summary>
public static void AddControls(HorizonBasedAmbientOcclusion asset, Window owner, ComboBox comboBoxResource)
{
GroupBox groupGeneral = CommonControls.Group("General", owner);
#region Quality
var quality = CommonControls.ComboBox("Quality", groupGeneral);
// Add textures name
quality.Items.Add("Low");
quality.Items.Add("Middle");
quality.Items.Add("High");
// Events
quality.ItemIndexChanged += delegate
{
switch (quality.ItemIndex)
{
case 0: asset.Quality = HorizonBasedAmbientOcclusion.QualityType.LowQuality; break;
case 1: asset.Quality = HorizonBasedAmbientOcclusion.QualityType.MiddleQuality; break;
case 2: asset.Quality = HorizonBasedAmbientOcclusion.QualityType.HighQuality; break;
}
};
quality.Draw += delegate
{
if (quality.ListBoxVisible)
return;
switch (asset.Quality)
{
case HorizonBasedAmbientOcclusion.QualityType.LowQuality : quality.ItemIndex = 0; break;
case HorizonBasedAmbientOcclusion.QualityType.MiddleQuality : quality.ItemIndex = 1; break;
case HorizonBasedAmbientOcclusion.QualityType.HighQuality : quality.ItemIndex = 2; break;
}
};
#endregion
var numberSteps = CommonControls.SliderNumericInt("Number Steps", groupGeneral, asset.NumberSteps, false, true, 0, 36, asset, "NumberSteps");
var numberDirections = CommonControls.SliderNumericInt("Number Directions", groupGeneral, asset.NumberDirections, false, true, 0, 36, asset, "NumberDirections");
var contrast = CommonControls.SliderNumericFloat("Contrast", groupGeneral, asset.Contrast, true, true, 0, 2, asset, "Contrast");
var lineAttenuation = CommonControls.SliderNumericFloat("LineAttenuation", groupGeneral, asset.LineAttenuation, false, false, 0, 2, asset, "LineAttenuation");
var radius = CommonControls.SliderNumericFloat("Radius", groupGeneral, asset.Radius, false, false, 0, 0.5f, asset, "Radius");
var angleBias = CommonControls.SliderNumericFloat("AngleBias", groupGeneral, asset.AngleBias, false, false, 0, 90, asset, "AngleBias");
groupGeneral.AdjustHeightFromChildren();
} // AddControls
} // GetParameters
#endregion
#region Render
/// <summary>
/// Generate ambient occlusion texture.
/// </summary>
internal RenderTarget Render(RenderTarget depthTexture, RenderTarget normalTexture, HorizonBasedAmbientOcclusion hbao, float fieldOfView, Size destinationSize, RenderTarget fullscreenDepthTexture)
{
try
{
// I decided to work with Color format for a number of reasons.
// First, this format is very used so chances are that I can reuse it latter in another shader.
// Second, GPUs tend to work faster in non-floating point render targets.
// Third, I can blur it with linear sampling.
// Last, I could need to return a color if I use directional occlusion.
// The main disadvantage is that I am wasting three channels (or just one in SSDO).
// A single 8 bit channel render target is not available in XNA 4.0 and I have two options for 16 bits render targets.
// First, the compressed 4 channels formats, the compression is visible and the results are not satisfactory.
// Last we have the half single format, it is a good option but I prefer to have linear sampling.
// Alternatively, I can pack several shadows result in only one texture and blurred fourth results at the same time.
// But I will do it only for shadows. I want to leave this shader simple. At least until a heavy optimization task needs to be performed.
RenderTarget ambientOcclusionTexture = RenderTarget.Fetch(depthTexture.Size, SurfaceFormat.Color, DepthFormat.None, RenderTarget.AntialiasingType.NoAntialiasing);
// Set shader atributes
SetNormalTexture(normalTexture);
SetDepthTexture(depthTexture);
// It works a the depth texture resolution. Use a downsampled version of the G-Buffer.
SetResolution(new Vector2(depthTexture.Width, depthTexture.Height));
SetInverseResolution(new Vector2(1 / (float)depthTexture.Width, 1 / (float)depthTexture.Height));
SetNumberSteps(hbao.NumberSteps);
SetNumberDirections(hbao.NumberDirections);
SetContrast(hbao.Contrast / (1.0f - (float)Math.Sin(hbao.AngleBias * (float)Math.PI / 180f)));
SetLineAttenuation(hbao.LineAttenuation);
SetRadius(hbao.Radius);
SetSquareRadius(hbao.Radius * hbao.Radius);
SetInverseRadius(1 / hbao.Radius);
SetHalfPixel(new Vector2(-0.5f / (ambientOcclusionTexture.Width / 2), 0.5f / (ambientOcclusionTexture.Height / 2)));
Vector2 focalLen = new Vector2
{
X = 1.0f / (float)Math.Tan(fieldOfView * (Math.PI / 180) * 0.5f) * (float)ambientOcclusionTexture.Height / (float)ambientOcclusionTexture.Width,
Y = 1.0f / (float)Math.Tan(fieldOfView * (Math.PI / 180) * 0.5f)
};
SetFocalLength(focalLen);
SetInverseFocalLength(new Vector2(1 / focalLen.X, 1 / focalLen.Y));
SetAngleBias(hbao.AngleBias * (float)Math.PI / 180f);
SetTanAngleBias((float)Math.Tan(hbao.AngleBias * (float)Math.PI / 180f));
switch (hbao.Quality)
{
case HorizonBasedAmbientOcclusion.QualityType.LowQuality: Resource.CurrentTechnique = Resource.Techniques["LowQuality"]; break;
case HorizonBasedAmbientOcclusion.QualityType.MiddleQuality: Resource.CurrentTechnique = Resource.Techniques["MiddleQuality"]; break;
case HorizonBasedAmbientOcclusion.QualityType.HighQuality: Resource.CurrentTechnique = Resource.Techniques["HighQuality"]; break;
}
// Set Render States.
EngineManager.Device.BlendState = BlendState.Opaque;
EngineManager.Device.DepthStencilState = DepthStencilState.None;
EngineManager.Device.RasterizerState = RasterizerState.CullCounterClockwise;
EngineManager.Device.SamplerStates[3] = SamplerState.PointWrap;
// Render
ambientOcclusionTexture.EnableRenderTarget();
ambientOcclusionTexture.Clear(Color.White);
Resource.CurrentTechnique.Passes[0].Apply();
RenderScreenPlane();
ambientOcclusionTexture.DisableRenderTarget();
// The blured texture has fullscreen size to improve the quality.
// This pass is a lot cheaper than the ambient occlusion pass so the performance penalty is acceptable.
RenderTarget bluredAmbientOcclusionTexture = RenderTarget.Fetch(destinationSize, ambientOcclusionTexture.SurfaceFormat,
DepthFormat.None, RenderTarget.AntialiasingType.NoAntialiasing);
BilateralBlurShader.Instance.Filter(ambientOcclusionTexture, bluredAmbientOcclusionTexture, depthTexture, 10, 10);
RenderTarget.Release(ambientOcclusionTexture);
return(bluredAmbientOcclusionTexture);
}
catch (Exception e)
{
throw new InvalidOperationException("Horizon Based Ambient Occlusion Shader: Unable to render.", e);
}
} // Render
