com.bitfire.postprocessing.filters.Scattering.java Source code

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Here is the source code for com.bitfire.postprocessing.filters.Scattering.java

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/*******************************************************************************
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.bitfire.postprocessing.filters;

import com.badlogic.gdx.math.Vector2;
import com.bitfire.utils.ShaderLoader;

/** Scattering Light effect.
 * @see <a href="https://medium.com/community-play-3d/god-rays-whats-that-5a67f26aeac2">https://medium.com/community-play-3d/god-
 *      rays-whats-that-5a67f26aeac2</a>
 * @author Toni Sagrista **/
public final class Scattering extends Filter<Scattering> {
    // Number of light supported
    public static int N = 10;
    private Vector2 viewport;

    private float[] lightPositions;
    private float[] lightViewAngles;
    private int nLights;

    private float decay = 0.96815f;
    private float density = 0.926f;
    private float weight = 0.58767f;

    private int numSamples = 100;

    /// NUM_SAMPLES will describe the rays quality, you can play with
    int NUM_SAMPLES = 100;

    public enum Param implements Parameter {
        // @formatter:off
        Texture("u_texture0", 0), LightPositions("u_lightPositions", 2), LightViewAngles("u_lightViewAngles",
                1), Viewport("u_viewport", 2), NLights("u_nLights", 0), Decay("u_decay",
                        0), Density("u_density", 0), Weight("u_weight", 0), NumSamples("u_numSamples", 0);
        // @formatter:on

        private String mnemonic;
        private int elementSize;

        private Param(String mnemonic, int arrayElementSize) {
            this.mnemonic = mnemonic;
            this.elementSize = arrayElementSize;
        }

        @Override
        public String mnemonic() {
            return this.mnemonic;
        }

        @Override
        public int arrayElementSize() {
            return this.elementSize;
        }
    }

    public Scattering(int width, int height) {
        super(ShaderLoader.fromFile("screenspace", "lightscattering"));
        lightPositions = new float[N * 2];
        lightViewAngles = new float[N];
        viewport = new Vector2(width, height);
        rebind();
    }

    public void setViewportSize(float width, float height) {
        this.viewport.set(width, height);
        setParam(Param.Viewport, this.viewport);
    }

    public void setLightPositions(int nLights, float[] pos) {
        this.nLights = nLights;
        this.lightPositions = pos;
        setParam(Param.NLights, this.nLights);
        setParamv(Param.LightPositions, this.lightPositions, 0, N * 2);
    }

    public void setLightViewAngles(float[] ang) {
        this.lightViewAngles = ang;
        setParamv(Param.LightViewAngles, this.lightViewAngles, 0, N);
    }

    public float getDecay() {
        return decay;
    }

    public float getDensity() {
        return density;
    }

    public float getWeight() {
        return weight;
    }

    public int getNumSamples() {
        return numSamples;
    }

    public void setDecay(float decay) {
        this.decay = decay;
        setParam(Param.Decay, decay);
    }

    public void setDensity(float density) {
        this.density = density;
        setParam(Param.Density, density);
    }

    public void setWeight(float weight) {
        this.weight = weight;
        setParam(Param.Weight, weight);
    }

    public void setNumSamples(int numSamples) {
        this.numSamples = numSamples;
        setParam(Param.NumSamples, numSamples);
    }

    @Override
    public void rebind() {
        // Re-implement super to batch every parameter
        setParams(Param.Texture, u_texture0);
        setParams(Param.NLights, this.nLights);
        setParams(Param.Viewport, viewport);
        setParamsv(Param.LightPositions, lightPositions, 0, N * 2);
        setParamsv(Param.LightViewAngles, lightViewAngles, 0, N);
        setParams(Param.Decay, decay);
        setParams(Param.Density, density);
        setParams(Param.Weight, weight);
        setParams(Param.NumSamples, numSamples);
        endParams();
    }

    @Override
    protected void onBeforeRender() {
        inputTexture.bind(u_texture0);
    }
}