2398d8aa8a
- fixed 1-section long walls being impossible to fix after their body has been destroyed - better looking blur (small lights aren't "skewed")
98 lines
3.4 KiB
C#
98 lines
3.4 KiB
C#
using Microsoft.Xna.Framework;
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using Microsoft.Xna.Framework.Graphics;
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace Barotrauma
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{
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class BlurEffect
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{
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public readonly Effect Effect;
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public BlurEffect(Effect effect, float dx, float dy)
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{
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Effect = effect;
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SetParameters(dx, dy);
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}
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/// <summary>
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/// Computes sample weightings and texture coordinate offsets
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/// for one pass of a separable gaussian blur filter.
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/// </summary>
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public void SetParameters(float dx, float dy)
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{
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EffectParameter weightsParameter = Effect.Parameters["SampleWeights"];
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EffectParameter offsetsParameter = Effect.Parameters["SampleOffsets"];
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// Look up how many samples our gaussian blur effect supports.
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int sampleCount = weightsParameter.Elements.Count;
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// Create temporary arrays for computing our filter settings.
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float[] sampleWeights = new float[sampleCount];
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Vector2[] sampleOffsets = new Vector2[sampleCount];
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sampleWeights[0] = ComputeGaussian(0);
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sampleOffsets[0] = new Vector2(0);
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float totalWeights = sampleWeights[0];
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// Add pairs of additional sample taps, positioned
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// along a line in both directions from the center.
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for (int i = 0; i < sampleCount / 2; i++)
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{
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// Store weights for the positive and negative taps.
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float weight = ComputeGaussian(i + 1);
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sampleWeights[i * 2 + 1] = weight;
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sampleWeights[i * 2 + 2] = weight;
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totalWeights += weight * 2;
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// To get the maximum amount of blurring from a limited number of
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// pixel shader samples, we take advantage of the bilinear filtering
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// hardware inside the texture fetch unit. If we position our texture
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// coordinates exactly halfway between two texels, the filtering unit
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// will average them for us, giving two samples for the price of one.
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// This allows us to step in units of two texels per sample, rather
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// than just one at a time. The 1.5 offset kicks things off by
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// positioning us nicely in between two texels.
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float sampleOffset = i * 2 + 1.5f;
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Vector2 delta = new Vector2(dx, dy) * sampleOffset;
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// Store texture coordinate offsets for the positive and negative taps.
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sampleOffsets[i * 2 + 1] = delta;
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sampleOffsets[i * 2 + 2] = -delta;
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}
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// Normalize the list of sample weightings, so they will always sum to one.
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for (int i = 0; i < sampleWeights.Length; i++)
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{
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sampleWeights[i] /= totalWeights;
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}
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weightsParameter.SetValue(sampleWeights);
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offsetsParameter.SetValue(sampleOffsets);
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}
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/// <summary>
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/// Evaluates a single point on the gaussian falloff curve.
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/// Used for setting up the blur filter weightings.
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/// </summary>
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float ComputeGaussian(float n)
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{
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float theta = 2.0f;
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return (float)((1.0 / Math.Sqrt(2 * Math.PI * theta)) *
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Math.Exp(-(n * n) / (2 * theta * theta)));
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}
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}
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}
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