<!//  ShadowCore.slh//  libraries/render-utils/src////  Created by Olivier Prat on 11/13/17.//  Copyright 2017 High Fidelity, Inc.////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html!><@if not SHADOW_CORE_SLH@><@def SHADOW_CORE_SLH@> <@include Shadows_shared.slh@> UNIFORM_BUFFER(RENDER_UTILS_BUFFER_SHADOW_PARAMS, shadowTransformBuffer) {    ShadowParameters shadow;}; int getShadowCascadeCount() {    return shadow.cascadeCount;} float getShadowCascadeInvBlendWidth() {    return shadow.invCascadeBlendWidth;} float evalShadowFalloff(float depth) {    return clamp((shadow.maxDistance-depth) * shadow.invFalloffDistance, 0.0, 1.0);} mat4 getShadowReprojection(int cascadeIndex) {    return shadow.cascades[cascadeIndex].reprojection;} float getShadowScale() {    return shadow.invMapSize;} float getShadowFixedBias(int cascadeIndex) {    return shadow.cascades[cascadeIndex].fixedBias;} float getShadowSlopeBias(int cascadeIndex) {    return shadow.cascades[cascadeIndex].slopeBias;}  // Compute the texture coordinates from world coordinatesvec4 evalShadowTexcoord(int cascadeIndex, vec4 position) {    vec4 shadowCoord = getShadowReprojection(cascadeIndex) * position;    return vec4(shadowCoord.xyz, 1.0);} bool isShadowCascadeProjectedOnPixel(vec4 cascadeTexCoords) {    bvec2 greaterThanZero = greaterThan(cascadeTexCoords.xy, vec2(0));    bvec2 lessThanOne = lessThan(cascadeTexCoords.xy, vec2(1));    return all(greaterThanZero) && all(lessThanOne);} int getFirstShadowCascadeOnPixel(int startCascadeIndex, vec4 worldPosition, out vec4 cascadeShadowCoords) {    int cascadeIndex;    startCascadeIndex = min(startCascadeIndex, getShadowCascadeCount()-1);    for (cascadeIndex=startCascadeIndex ; cascadeIndex<getShadowCascadeCount() ; cascadeIndex++) {        cascadeShadowCoords = evalShadowTexcoord(cascadeIndex, worldPosition);        if (isShadowCascadeProjectedOnPixel(cascadeShadowCoords)) {            return cascadeIndex;        }    }    return cascadeIndex;} float evalShadowCascadeWeight(vec4 cascadeTexCoords) {    // Inspired by DirectX CascadeShadowMaps11 example    vec2 distanceToOne = vec2(1.0) - cascadeTexCoords.xy;    float blend1 = min( cascadeTexCoords.x, cascadeTexCoords.y );    float blend2 = min( distanceToOne.x, distanceToOne.y );    float blend = min( blend1, blend2 );    return clamp(blend * getShadowCascadeInvBlendWidth(), 0.0, 1.0);} float evalCascadeMix(float firstCascadeWeight, float secondCascadeWeight) {    return ((1.0-firstCascadeWeight) * secondCascadeWeight) / (firstCascadeWeight + secondCascadeWeight);} float determineShadowCascadesOnPixel(vec4 worldPosition, float viewDepth, out vec4 cascadeShadowCoords[2], out ivec2 cascadeIndices) {    cascadeIndices.x = getFirstShadowCascadeOnPixel(0, worldPosition, cascadeShadowCoords[0]);    cascadeIndices.y = cascadeIndices.x+1;    float firstCascadeWeight = evalShadowCascadeWeight(cascadeShadowCoords[0]);    if (firstCascadeWeight<1.0 && cascadeIndices.x < (getShadowCascadeCount()-1)) {        cascadeIndices.y = getFirstShadowCascadeOnPixel(cascadeIndices.y, worldPosition, cascadeShadowCoords[1]);         float secondCascadeWeight = evalShadowCascadeWeight(cascadeShadowCoords[1]);        // Returns the mix amount between first and second cascade.        return evalCascadeMix(firstCascadeWeight, secondCascadeWeight);    } else {        return 0.0;    }} <@endif@>