bdcdf1a7c3
All curves (and path affectors) are driven by an SkParticleValue. The value can derive its value from the current defaults (age of particle or effect), or explicitly choose the other one, a random value, or any other particle value. Values can be range adjusted and support repeat, clamp, and mirror tiling. Also fixed some more issues related to resource path in the slide GUI. Bug: skia: Change-Id: I4755018d5b57ae2d5ec400d541055ca4fb542978 Reviewed-on: https://skia-review.googlesource.com/c/skia/+/196760 Reviewed-by: Brian Osman <brianosman@google.com> Commit-Queue: Brian Osman <brianosman@google.com>
140 lines
3.9 KiB
C++
140 lines
3.9 KiB
C++
/*
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* Copyright 2019 Google LLC
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkParticleData_DEFINED
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#define SkParticleData_DEFINED
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#include "SkColor.h"
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#include "SkPoint.h"
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#include "SkRandom.h"
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#include "SkReflected.h"
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#include "SkRSXform.h"
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/*
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* Various structs used to communicate particle information among emitters, affectors, etc.
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*/
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enum SkParticleFrame {
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kWorld_ParticleFrame, // "Up" is { 0, -1 }
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kLocal_ParticleFrame, // "Up" is particle's heading
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kVelocity_ParticleFrame, // "Up" is particle's direction of travel
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};
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static constexpr SkFieldVisitor::EnumStringMapping gParticleFrameMapping[] = {
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{ kWorld_ParticleFrame, "World" },
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{ kLocal_ParticleFrame, "Local" },
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{ kVelocity_ParticleFrame, "Velocity" },
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};
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struct SkParticlePose {
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SkPoint fPosition;
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SkVector fHeading;
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SkScalar fScale;
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SkRSXform asRSXform(SkPoint ofs) const {
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const float s = fHeading.fX * fScale;
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const float c = -fHeading.fY * fScale;
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return SkRSXform::Make(c, s,
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fPosition.fX + -c * ofs.fX + s * ofs.fY,
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fPosition.fY + -s * ofs.fX + -c * ofs.fY);
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}
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};
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struct SkParticleVelocity {
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SkVector fLinear;
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SkScalar fAngular;
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};
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struct SkParticleState {
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float fAge; // Normalized age [0, 1]
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float fInvLifetime; // 1 / Lifetime
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SkParticlePose fPose;
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SkParticleVelocity fVelocity;
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SkColor4f fColor;
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SkScalar fFrame; // Parameter to drawable for animated sprites, etc.
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SkRandom fRandom;
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SkVector getFrameHeading(SkParticleFrame frame) const {
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switch (frame) {
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case kLocal_ParticleFrame:
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return fPose.fHeading;
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case kVelocity_ParticleFrame: {
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SkVector heading = fVelocity.fLinear;
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if (!heading.normalize()) {
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heading.set(0, -1);
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}
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return heading;
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}
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case kWorld_ParticleFrame:
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default:
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return SkVector{ 0, -1 };
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}
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}
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};
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struct SkParticleUpdateParams {
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float fDeltaTime;
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float fEffectAge;
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int fAgeSource;
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};
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/**
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* SkParticleValue selects a specific value to be used when evaluating a curve, position on a path,
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* or any other affector that needs a scalar float input. An SkParticleValue starts with a source
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* value taken from the state of the effect or particle. That can be adjusted using a scale and
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* bias, and then reduced into the desired range (typically [0, 1]) via a chosen tile mode.
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*/
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struct SkParticleValue {
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enum Source {
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// Either the particle or effect age, depending on spawn or update
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kAge_Source,
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kRandom_Source,
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kParticleAge_Source,
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kEffectAge_Source,
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kPositionX_Source,
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kPositionY_Source,
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kHeadingX_Source,
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kHeadingY_Source,
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kScale_Source,
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kVelocityX_Source,
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kVelocityY_Source,
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kRotation_Source,
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kColorR_Source,
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kColorG_Source,
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kColorB_Source,
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kColorA_Source,
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kSpriteFrame_Source,
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};
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enum TileMode {
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kClamp_TileMode,
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kRepeat_TileMode,
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kMirror_TileMode,
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};
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void visitFields(SkFieldVisitor* v);
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float eval(const SkParticleUpdateParams& params, SkParticleState& ps) const;
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int fSource = kAge_Source;
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int fFrame = kWorld_ParticleFrame;
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int fTileMode = kRepeat_TileMode;
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// We map fLeft -> 0 and fRight -> 1. This is easier to work with and reason about.
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float fLeft = 0.0f;
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float fRight = 1.0f;
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// Cached from the above
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float fScale = 1.0f;
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float fBias = 0.0f;
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private:
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float getSourceValue(const SkParticleUpdateParams& params, SkParticleState& ps) const;
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};
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#endif // SkParticleData_DEFINED
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