using UnityEngine; namespace Unity.UIWidgets.ui { static class ShadowUtils { public const bool kUseFastShadow = false; const float kAmbientHeightFactor = 1.0f / 128.0f; const float kAmbientGeomFactor = 64.0f; const float kBlurSigmaScale = 0.57735f; const float kMaxAmbientRadius = 300 * kAmbientHeightFactor * kAmbientGeomFactor; static float divideAndPin(float numer, float denom, float min, float max) { return (numer / denom).clamp(min, max); } static float ambientBlurRadius(float height) { return Mathf.Min(height * kAmbientHeightFactor * kAmbientGeomFactor, kMaxAmbientRadius); } static float ambientRecipAlpha(float height) { return 1.0f + Mathf.Max(height * kAmbientHeightFactor, 0.0f); } static float spotBlurRadius(float occluderZ, float lightZ, float lightRadius) { return lightRadius * divideAndPin(occluderZ, lightZ - occluderZ, 0.0f, 0.95f); } static void getSpotParams(float occluderZ, float lightX, float lightY, float lightZ, float lightRadius, ref float blurRadius, ref float scale, ref Vector2 translate) { float zRatio = divideAndPin(occluderZ, lightZ - occluderZ, 0.0f, 0.95f); blurRadius = lightRadius * zRatio; scale = divideAndPin(lightZ, lightZ - occluderZ, 1.0f, 1.95f); translate = new Vector2(-zRatio * lightX, -zRatio * lightY); } static float convertRadiusToSigma(float radius) { return radius > 0 ? kBlurSigmaScale * radius + 0.5f : 0.0f; } public static void computeTonalColors(uiColor inAmbientColor, uiColor inSpotColor, ref uiColor? outAmbientColor, ref uiColor? outSpotColor) { outAmbientColor = uiColor.fromARGB(inAmbientColor.alpha, 0, 0, 0); outSpotColor = inSpotColor; } static readonly Matrix3 _toHomogeneous = Matrix3.I(); static bool getSpotShadowTransform(Vector3 lightPos, float lightRadius, Matrix3 ctm, Vector3 zPlaneParams, Rect pathBounds, Matrix3 shadowTransform, ref float radius) { float heightFunc(float x, float y) { return zPlaneParams.x * x + zPlaneParams.y * y + zPlaneParams.z; } float occluderHeight = heightFunc(pathBounds.center.dx, pathBounds.center.dy); if (!ctm.hasPerspective()) { float scale = 0.0f; Vector2 translate = new Vector2(); getSpotParams(occluderHeight, lightPos.x, lightPos.y, lightPos.z, lightRadius, ref radius, ref scale, ref translate); shadowTransform.setScaleTranslate(scale, scale, translate.x, translate.y); shadowTransform.preConcat(ctm); } else { if (pathBounds.width.valueNearlyZero() || pathBounds.height.valueNearlyZero()) { return false; } Offset[] pts = ctm.mapRectToQuad(pathBounds); if (!MathUtils.isConvexPolygon(pts, 4)) { return false; } Vector3[] pts3D = new Vector3[4]; float z = heightFunc(pathBounds.left, pathBounds.top); pts3D[0] = new Vector3(pts[0].dx, pts[0].dy, z); z = heightFunc(pathBounds.right, pathBounds.top); pts3D[1] = new Vector3(pts[1].dx, pts[1].dy, z); z = heightFunc(pathBounds.right, pathBounds.bottom); pts3D[2] = new Vector3(pts[2].dx, pts[2].dy, z); z = heightFunc(pathBounds.left, pathBounds.bottom); pts3D[3] = new Vector3(pts[3].dx, pts[3].dy, z); for (int i = 0; i < 4; i++) { float dz = lightPos.z - pts3D[i].z; if (dz.valueNearlyZero()) { return false; } float zRatio = pts3D[i].z / dz; pts3D[i].x -= (lightPos.x - pts3D[i].x) * zRatio; pts3D[i].y -= (lightPos.y - pts3D[i].y) * zRatio; pts3D[i].z = 1f; } Vector3 h0 = Vector3.Cross(Vector3.Cross(pts3D[1], pts3D[0]), Vector3.Cross(pts3D[2], pts3D[3])); Vector3 h1 = Vector3.Cross(Vector3.Cross(pts3D[0], pts3D[3]), Vector3.Cross(pts3D[1], pts3D[2])); Vector3 h2 = Vector3.Cross(Vector3.Cross(pts3D[0], pts3D[2]), Vector3.Cross(pts3D[1], pts3D[3])); if (h2.z.valueNearlyZero()) { return false; } Vector3 v = pts3D[3] - pts3D[0]; Vector3 w = h0 - pts3D[0]; float perpDot = v.x * w.y - v.y * w.x; if (perpDot > 0) { h0 = -h0; } v = pts3D[1] - pts3D[0]; perpDot = v.x * w.y - v.y * w.x; if (perpDot < 0) { h1 = -h1; } shadowTransform.setAll(h0.x / h2.z, h1.x / h2.z, h2.x / h2.z, h0.y / h2.z, h1.y / h2.z, h2.y / h2.z, h0.z / h2.z, h1.z / h2.z, 1); float xScale = 2.0f / (pathBounds.right - pathBounds.left); float yScale = 2.0f / (pathBounds.bottom - pathBounds.top); _toHomogeneous.setAll(xScale, 0, -xScale * pathBounds.left - 1, 0, yScale, -yScale * pathBounds.top - 1, 0, 0, 1); shadowTransform.preConcat(_toHomogeneous); radius = spotBlurRadius(occluderHeight, lightPos.z, lightRadius); } return true; } static readonly Path _devSpacePath = new Path(); public static void drawShadow(Canvas canvas, Path path, Vector3 zPlaneParams, Vector3 devLightPos, float lightRadius, uiColor ambientColor, uiColor spotColor, int flags) { if (kUseFastShadow) { drawShadowFast(canvas, path, zPlaneParams, devLightPos, lightRadius, ambientColor, spotColor, flags); } else { drawShadowFull(canvas, path, zPlaneParams, devLightPos, lightRadius, ambientColor, spotColor, flags); } } //cached variables static readonly Paint _shadowPaint = new Paint(); static readonly Matrix3 _shadowMatrix = Matrix3.I(); static void drawShadowFull(Canvas canvas, Path path, Vector3 zPlaneParams, Vector3 devLightPos, float lightRadius, uiColor ambientColor, uiColor spotColor, int flags) { Matrix3 viewMatrix = canvas.getTotalMatrix(); //ambient light _devSpacePath.resetAll(); _devSpacePath.addPath(path, viewMatrix); float devSpaceOutset = ambientBlurRadius(zPlaneParams.z); float oneOverA = ambientRecipAlpha(zPlaneParams.z); float blurRadius = 0.5f * devSpaceOutset * oneOverA; float strokeWidth = 0.5f * (devSpaceOutset - blurRadius); //Paint paint = new Paint {color = ambientColor, strokeWidth = strokeWidth, style = PaintingStyle.fill}; _shadowPaint.color = new Color(ambientColor.value); _shadowPaint.strokeWidth = strokeWidth; _shadowPaint.style = PaintingStyle.fill; canvas.save(); _shadowMatrix.reset(); canvas.setMatrix(_shadowMatrix); float sigma = convertRadiusToSigma(blurRadius); _shadowPaint.maskFilter = MaskFilter.blur(BlurStyle.normal, sigma); canvas.drawPath(_devSpacePath, _shadowPaint); canvas.restore(); //spot light //Matrix3 shadowMatrix = Matrix3.I(); float radius = 0.0f; if (!getSpotShadowTransform(devLightPos, lightRadius, viewMatrix, zPlaneParams, path.getBounds(), _shadowMatrix, ref radius)) { return; } canvas.save(); canvas.setMatrix(_shadowMatrix); _shadowPaint.color = new Color(spotColor.value); _shadowPaint.strokeWidth = 0; _shadowPaint.style = PaintingStyle.fill; float sigma2 = convertRadiusToSigma(radius); _shadowPaint.maskFilter = MaskFilter.blur(BlurStyle.normal, sigma2); canvas.drawPath(path, _shadowPaint); canvas.restore(); _shadowPaint.maskFilter = null; } static void drawShadowFast(Canvas canvas, Path path, Vector3 zPlaneParams, Vector3 devLightPos, float lightRadius, uiColor ambientColor, uiColor spotColor, int flags) { Matrix3 viewMatrix = canvas.getTotalMatrix(); //ambient light float devSpaceOutset = ambientBlurRadius(zPlaneParams.z); float oneOverA = ambientRecipAlpha(zPlaneParams.z); float blurRadius = 0.5f * devSpaceOutset * oneOverA; float strokeWidth = 0.5f * (devSpaceOutset - blurRadius); //Paint paint = new Paint {color = ambientColor, strokeWidth = strokeWidth, style = PaintingStyle.fill}; _shadowPaint.color = new Color(ambientColor.value); _shadowPaint.strokeWidth = strokeWidth; _shadowPaint.style = PaintingStyle.fill; canvas.drawPath(path, _shadowPaint); //spot light float radius = 0.0f; if (!getSpotShadowTransform(devLightPos, lightRadius, viewMatrix, zPlaneParams, path.getBounds(), _shadowMatrix, ref radius)) { return; } canvas.save(); canvas.setMatrix(_shadowMatrix); //Paint paint2 = new Paint {color = spotColor}; _shadowPaint.color = new Color(spotColor.value); _shadowPaint.strokeWidth = 0; _shadowPaint.style = PaintingStyle.fill; canvas.drawPath(path, _shadowPaint); canvas.restore(); } } }