skia2/include/private/SkShadowParams.h

49 lines
1.6 KiB
C

/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkShadowParams_DEFINED
#define SkShadowParams_DEFINED
/** \struct SkShadowParams
This struct holds information needed for drawing shadows.
fShadowRadius - radius of the shadow blur
fBiasingConstant - A constant used in variance shadow mapping to directly
0.0 - 1.0 reduce light bleeding. Essentially sets all shadows
~.25 below a certain brightness equal to no light, and does
a linear step on the rest. Essentially makes shadows
darker and more rounded at higher values.
fMinVariance - Too low of a variance (near the outer edges of blurry
~512, 1024 shadows) will lead to ugly sharp shadow brightness
distortions. This enforces a minimum amount of variance
in the calculation to smooth out the outside edges of
blurry shadows. However, too high of a value for this will
cause all shadows to be lighter by visibly different
amounts varying on depth.
fType - Decides which algorithm to use to draw shadows.
*/
struct SkShadowParams {
SkScalar fShadowRadius;
SkScalar fBiasingConstant;
SkScalar fMinVariance;
enum ShadowType {
kNoBlur_ShadowType,
kVariance_ShadowType,
kLast_ShadowType = kVariance_ShadowType
};
static const int kShadowTypeCount = kLast_ShadowType + 1;
ShadowType fType;
};
#endif