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Check when shadow map is out of view and needs update
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@lilleyse
lilleyse committed Apr 11, 2016
1 parent 40a68bc commit 0582b1f
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Showing 2 changed files with 149 additions and 48 deletions.
6 changes: 5 additions & 1 deletion Source/Scene/Scene.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1241,7 +1241,7 @@ define([
// When moving the camera low LOD terrain tiles begin to load, whose bounding volumes
// throw off the near/far fitting for the shadow map. Only update shadowNear and shadowFar
// for reasonably sized bounding volumes.
if (!(distances.start < 0.0 && distances.stop > frameState.shadowFar)) {
if (!((distances.start < -100.0) && (distances.stop > 100.0) && (pass === Pass.GLOBE))){
shadowNear = Math.min(shadowNear, distances.start);
shadowFar = Math.max(shadowFar, distances.stop);
}
Expand Down Expand Up @@ -1791,6 +1791,10 @@ define([
var isPointLight = shadowMap.isPointLight;
var renderState = isPointLight ? shadowMap.pointRenderState : shadowMap.primitiveRenderState;

if (shadowMap.outOfView) {
return;
}

var shadowPassCommands = shadowMap.passCommands;
resetShadowCommands(shadowPassCommands);

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191 changes: 144 additions & 47 deletions Source/Scene/ShadowMap.js
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@ define([
'../Core/GeometryAttribute',
'../Core/GeometryAttributes',
'../Core/GeometryInstance',
'../Core/Intersect',
'../Core/Math',
'../Core/Matrix4',
'../Core/PixelFormat',
Expand Down Expand Up @@ -70,6 +71,7 @@ define([
GeometryAttribute,
GeometryAttributes,
GeometryInstance,
Intersect,
CesiumMath,
Matrix4,
PixelFormat,
Expand Down Expand Up @@ -145,6 +147,10 @@ define([
this.softShadows = defaultValue(options.softShadows, false);
this._exponentialShadows = false;

this._outOfView = false;
this._outOfViewPrevious = false;
this._needsUpdate = true;

this._terrainBias = {
polygonOffset : true,
polygonOffsetFactor : 1.1,
Expand Down Expand Up @@ -196,6 +202,7 @@ define([
this._shadowMapCamera = new ShadowMapCamera();
this._shadowMapCullingVolume = undefined;
this._sceneCamera = undefined;
this._boundingSphere = new BoundingSphere();

this._isPointLight = defaultValue(options.isPointLight, false);
this._radius = defaultValue(options.radius, 100.0);
Expand All @@ -210,6 +217,7 @@ define([
if (this._cascadesEnabled) {
// Cascaded shadows are always orthographic. The frustum dimensions are calculated on the fly.
this._lightCamera.frustum = new OrthographicFrustum();
this._shadowMapCamera.frustum = new OrthographicFrustum();
} else if (defined(this._lightCamera.frustum.fov)) {
// If the light camera uses a perspective frustum, then the light source is a spot light
this._isSpotLight = true;
Expand Down Expand Up @@ -248,7 +256,6 @@ define([
this._debugFreezeFrame = false;
this.debugVisualizeCascades = false;
this._debugLightFrustum = undefined;
this._debugLightFrustumMatrix = new Matrix4();
this._debugCameraFrustum = undefined;
this._debugCascadeFrustums = new Array(this._numberOfCascades);
this._debugShadowViewCommand = undefined;
Expand Down Expand Up @@ -314,6 +321,15 @@ define([
};

defineProperties(ShadowMap.prototype, {
/**
* Whether the shadow map is out of view of the scene camera.
*/
outOfView : {
get : function() {
return this._outOfView;
}
},

/**
* The camera representing the shadow volume.
*
Expand Down Expand Up @@ -609,6 +625,8 @@ define([
} else {
createFramebufferColor(shadowMap, context);
}

clearFramebuffer(shadowMap, context);
}

function checkFramebuffer(shadowMap, context) {
Expand All @@ -629,6 +647,14 @@ define([
}
}

function clearFramebuffer(shadowMap, context, pass) {
pass = defaultValue(pass, 0);
if ((shadowMap._isPointLight && shadowMap._usesCubeMap) || (pass === 0)) {
shadowMap._clearCommand.framebuffer = shadowMap._passFramebuffers[pass];
shadowMap._clearCommand.execute(context, shadowMap._clearPassState);
}
}

ShadowMap.prototype.setSize = function(size) {
this._shadowMapSize = size;
var numberOfPasses = this._numberOfPasses;
Expand Down Expand Up @@ -932,24 +958,20 @@ define([
}
}
} else if (shadowMap._isPointLight) {
var translation = shadowMap._shadowMapCamera.positionWC;
var rotation = Quaternion.IDENTITY;
var uniformScale = shadowMap._radius * 2.0;
var scale = Cartesian3.fromElements(uniformScale, uniformScale, uniformScale, scratchScale);
var modelMatrix = Matrix4.fromTranslationQuaternionRotationScale(translation, rotation, scale, scratchMatrix);
if (!defined(shadowMap._debugLightFrustum) || !Matrix4.equals(modelMatrix, shadowMap._debugLightFrustumMatrix)) {
// Recreate debug point light if the radius or position changes
if (!defined(shadowMap._debugLightFrustum) || shadowMap._needsUpdate) {
var translation = shadowMap._shadowMapCamera.positionWC;
var rotation = Quaternion.IDENTITY;
var uniformScale = shadowMap._radius * 2.0;
var scale = Cartesian3.fromElements(uniformScale, uniformScale, uniformScale, scratchScale);
var modelMatrix = Matrix4.fromTranslationQuaternionRotationScale(translation, rotation, scale, scratchMatrix);

shadowMap._debugLightFrustum = shadowMap._debugLightFrustum && shadowMap._debugLightFrustum.destroy();
shadowMap._debugLightFrustum = createDebugPointLight(modelMatrix, Color.YELLOW);
Matrix4.clone(modelMatrix, shadowMap._debugLightFrustumMatrix);
}
shadowMap._debugLightFrustum.update(frameState);
} else {
var matrix = shadowMap._shadowMapCamera.getViewProjection();
if (!defined(shadowMap._debugLightFrustum) || !Matrix4.equals(matrix, shadowMap._debugLightFrustumMatrix)) {
// Recreate debug frustum if the light camera changes
if (!defined(shadowMap._debugLightFrustum) || shadowMap._needsUpdate) {
shadowMap._debugLightFrustum = createDebugFrustum(shadowMap._shadowMapCamera, Color.YELLOW);
Matrix4.clone(matrix, shadowMap._debugLightFrustumMatrix);
}
shadowMap._debugLightFrustum.update(frameState);
}
Expand Down Expand Up @@ -1129,7 +1151,7 @@ define([

// TODO : This is just an estimate, should take scene geometry into account
// 2. Set bounding box back to include objects in the light's view
max.z += 100.0; // Note: in light space, a positive number is behind the camera
max.z += 1000.0; // Note: in light space, a positive number is behind the camera

// 3. Adjust light view matrix so that it is centered on the bounding volume
var translation = scratchTranslation;
Expand Down Expand Up @@ -1211,16 +1233,90 @@ define([
}
}

var scratchCartesian1 = new Cartesian3();
var scratchCartesian2 = new Cartesian3();
var scratchBoundingSphere = new BoundingSphere();
var scratchCenter = scratchBoundingSphere.center;

function checkVisibility(shadowMap, frameState) {
var camera = frameState.camera;
var lightCamera = shadowMap._lightCamera;
var sceneCamera = shadowMap._sceneCamera;
var shadowMapCamera = shadowMap._shadowMapCamera;

var boundingSphere = scratchBoundingSphere;

// Check whether the shadow map is in view and needs to be updated
if (shadowMap._cascadesEnabled) {
// If the nearest shadow receiver is further than the shadow map's maximum distance then the shadow map is out of view.
if (sceneCamera.frustum.near > shadowMap._maximumDistance) {
shadowMap._outOfView = true;
shadowMap._needsUpdate = false;
return;
}

// If the light source is below the horizon then the shadow map is out of view
var surfaceNormal = frameState.mapProjection.ellipsoid.geodeticSurfaceNormal(sceneCamera.positionWC, scratchCartesian1);
var lightDirection = Cartesian3.negate(shadowMapCamera.directionWC, scratchCartesian2);
var dot = Cartesian3.dot(surfaceNormal, lightDirection);
if (dot < 0.1) {
shadowMap._outOfView = true;
shadowMap._needsUpdate = false;
return;
}

// If the scene camera or light direction changes, then the shadow map needs to update
var sceneCameraChanged = !Matrix4.equals(sceneCamera.viewMatrix, camera.viewMatrix);
var directionChanged = !Cartesian3.equals(shadowMapCamera.directionWC, lightCamera.directionWC);
shadowMap._needsUpdate = sceneCameraChanged || directionChanged;

// By default cascaded shadows are always in view
shadowMap._outOfView = false;
} else if (shadowMap._isPointLight) {
// Sphere-frustum intersection test
boundingSphere.center = shadowMapCamera.positionWC;
boundingSphere.radius = shadowMap._radius;
shadowMap._outOfView = frameState.cullingVolume.computeVisibility(boundingSphere) === Intersect.OUTSIDE;
shadowMap._needsUpdate = !shadowMap._outOfView && !shadowMap._boundingSphere.equals(boundingSphere);
BoundingSphere.clone(boundingSphere, shadowMap._boundingSphere);
} else {
// Simplify frustum-frustum intersection test as a sphere-frustum test
var frustumRadius = shadowMapCamera.frustum.far / 2.0;
var frustumCenter = Cartesian3.add(shadowMapCamera.positionWC, Cartesian3.multiplyByScalar(shadowMapCamera.directionWC, frustumRadius, scratchCenter), scratchCenter);
boundingSphere.center = frustumCenter;
boundingSphere.radius = frustumRadius;
shadowMap._outOfView = frameState.cullingVolume.computeVisibility(boundingSphere) === Intersect.OUTSIDE;
shadowMap._needsUpdate = !shadowMap._outOfView && !shadowMap._boundingSphere.equals(boundingSphere);
BoundingSphere.clone(boundingSphere, shadowMap._boundingSphere);
}
}

function updateCameras(shadowMap, frameState) {
if (shadowMap.debugFreezeFrame) {
return;
var camera = frameState.camera; // The actual camera in the scene
var lightCamera = shadowMap._lightCamera; // The external camera representing the light source
var sceneCamera = shadowMap._sceneCamera; // Clone of camera, with clamped near and far planes
var shadowMapCamera = shadowMap._shadowMapCamera; // Camera representing the shadow volume, initially cloned from lightCamera

if (defined(sceneCamera)) {
// Skip check on the first frame
checkVisibility(shadowMap, frameState);
}

var camera = frameState.camera;
// Clear the shadow texture when a cascaded shadow map goes out of view (e.g. when the sun dips below the horizon).
// This prevents objects that still read from the shadow map from reading old values.
if (shadowMap._cascadesEnabled && !shadowMap._outOfViewPrevious && shadowMap._outOfView) {
clearFramebuffer(shadowMap, frameState.context);
}
shadowMap._outOfViewPrevious = shadowMap._outOfView;

// Clone light camera into the shadow map camera
var shadowMapCamera = shadowMap._shadowMapCamera;
shadowMapCamera.clone(shadowMap._lightCamera);
if (shadowMap._cascadesEnabled) {
Cartesian3.clone(lightCamera.directionWC, shadowMapCamera.directionWC);
} else if (shadowMap._isPointLight) {
Cartesian3.clone(lightCamera.positionWC, shadowMapCamera.positionWC);
} else {
shadowMapCamera.clone(lightCamera);
}

// Get the light direction in eye coordinates
var lightDirection = shadowMap._lightDirectionEC;
Expand All @@ -1237,50 +1333,54 @@ define([
var far;
if (shadowMap._fitNearFar) {
// shadowFar can be very large, so limit to shadowMap._maximumDistance
near = frameState.shadowNear;
far = Math.max(Math.min(frameState.shadowFar, shadowMap._maximumDistance), near + 0.01);
near = Math.min(frameState.shadowNear, shadowMap._maximumDistance);
far = Math.min(frameState.shadowFar, shadowMap._maximumDistance);
} else {
near = camera.frustum.near;
far = shadowMap._maximumDistance;
}

shadowMap._sceneCamera = Camera.clone(camera, shadowMap._sceneCamera);
shadowMap._sceneCamera = Camera.clone(camera, sceneCamera);
shadowMap._sceneCamera.frustum.near = near;
shadowMap._sceneCamera.frustum.far = far;
shadowMap._distance = far - near;
}

ShadowMap.prototype.update = function(frameState) {
var lightMoved = !Cartesian3.equals(this._lightCamera.positionWC, this._shadowMapCamera.positionWC);

updateFramebuffer(this, frameState.context);
updateCameras(this, frameState);

if (this._isPointLight && lightMoved) {
computeOmnidirectional(this);
}
if (this._needsUpdate) {
updateFramebuffer(this, frameState.context);

if (this._cascadesEnabled) {
fitShadowMapToScene(this, frameState);
if (this._isPointLight) {
computeOmnidirectional(this);
}

if (this._cascadesEnabled) {
fitShadowMapToScene(this, frameState);

if (this._numberOfCascades > 1) {
computeCascades(this);
if (this._numberOfCascades > 1) {
computeCascades(this);
}
}
}

if (!this._isPointLight) {
// Compute the culling volume
var position = this._shadowMapCamera.positionWC;
var direction = this._shadowMapCamera.directionWC;
var up = this._shadowMapCamera.upWC;
this._shadowMapCullingVolume = this._shadowMapCamera.frustum.computeCullingVolume(position, direction, up);
if (!this._isPointLight) {
// Compute the culling volume
var position = this._shadowMapCamera.positionWC;
var direction = this._shadowMapCamera.directionWC;
var up = this._shadowMapCamera.upWC;
this._shadowMapCullingVolume = this._shadowMapCamera.frustum.computeCullingVolume(position, direction, up);

if (this._numberOfPasses === 1) {
// Since there is only one pass, use the shadow map camera as the pass camera.
this._passCameras[0].clone(this._shadowMapCamera);
}
}
}

if (this._numberOfPasses === 1) {
// Since there is only one pass, use the shadow map camera as the pass camera.
this._passCameras[0].clone(this._shadowMapCamera);

// Transforms from eye space to shadow texture space
// Transforms from eye space to shadow texture space.
// Always requires an update since the scene camera constantly changes.
var inverseView = this._sceneCamera.inverseViewMatrix;
Matrix4.multiply(this._shadowMapCamera.getViewProjection(), inverseView, this._shadowMapMatrix);
}
Expand All @@ -1291,10 +1391,7 @@ define([
};

ShadowMap.prototype.updatePass = function(context, pass) {
if ((this._isPointLight && this._usesCubeMap) || (pass === 0)) {
this._clearCommand.framebuffer = this._passFramebuffers[pass];
this._clearCommand.execute(context, this._clearPassState);
}
clearFramebuffer(this, context, pass);
};

var scratchTexelStepSize = new Cartesian2();
Expand Down

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