This change adds another layer of complexity and control to
the particle system. There are now two code chunks: the old
code that's run per-particle, and new code that's run for
the effect itself. This allows for effect lifetime to be set
by the script (eg, randomly), as well as the emission rate.
Rate can vary over time (see pulse.json), and particles can
be emitted in bursts by setting the effect's burst field
(see fireworks.json).
Additionally, the effect has its own frame of reference and
color, which becomes the default state for newly emitted
particles. This allows synchronizing state across particles
in various interesting ways (see color in fireworks.json).
Change-Id: Iec2f7a3427ce1d6411ed7ef5b3023cbef2e8a134
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/240498
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Change-Id: If99e1802c8187ebd98b67717d744c6695bb25900
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/238118
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Change-Id: If57fb79db8f8c5fd185fefaa202167c8082dd846
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/229921
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Change-Id: Ic81b3433b485ca9ce0e60bd10ec12706e673ee89
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/229917
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
This removes all of the fixed-function particle affector classes.
Instead, each particle effect just has two SkSL snippets, one for
spawn logic, and one for update logic. Each one gets an inout copy
of the particle struct. Ultimately, this makes the effects much
simpler and smaller, while also being far more flexible (you can
do whatever you want with any values you want). Finally, because
the interpreter is vectorized and a particular effect's scripts
are usually tuned to the specific behaviors desired, it's faster
on basically every effect I compared.
I re-created all of the old effects in the new system. Many just
use pure SkSL (no curves or anything). Some of the old curve and
path/text stuff was very handy, though - so those are now exposed
as external values in the interpreter. Basically, an effect can
have any number of named "bindings" that are a callable thing.
This can be a path, text (shortcut for making fancy paths), curve,
or color curve. The path ones return a float4 with position and
normal, the curves return one or four floats.
... and this transposes all of the particle data storage into
SoA form, so that it can use the much faster interpreter entry
point.
Change-Id: Iebe711c45994c4201041b12d171af976bc5e758e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/222057
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
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>
Bug: skia:
Change-Id: Ie6485a11bb57fecef470d727dcf3b4fe5dff0b90
Reviewed-on: https://skia-review.googlesource.com/c/195582
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Added explicit Linear segment type, merge math evaluation helpers for
scalar and color curves. Add logic to visitFields that cuts down on the
serialized size of simple curves, and makes the GUI easier to work with.
Remove the curve plot from the GUI. It was incorrect (wrong points at
cubic handle locations), not terribly helpful, and difficult to
maintain.
Bug: skia:
Change-Id: I190cb5d118b1f4b910984e4df50ee3351c8be895
Reviewed-on: https://skia-review.googlesource.com/c/195884
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
The other generator was never used (or useful). String-based serialization
of enums is quite helpful, though.
Bug: skia:
Change-Id: Ic9d58f8d20cfe7aba47722bd74f1e6f8f0f219e5
Reviewed-on: https://skia-review.googlesource.com/c/195368
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Add particle "frame" enum, to allow effects relative to local, world,
or velocity. Remove the "orient along velocity" and replace with a much
more general orientation affector (angle curve + frame). Add an angular
velocity affector to mirror the behavior of the linear velocity affector.
Bug: skia:
Change-Id: Ibbaaeb352c9547d00d81c7916d00148dd65ed2b9
Reviewed-on: https://skia-review.googlesource.com/c/195361
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Adjust reference frame for affector to be consistent (so angles are
counted clockwise from "up" in both local and world modes).
Bug: skia:
Change-Id: I643e1484bc0a58d1f1c0cfe35ac2ab37dc2ea409
Reviewed-on: https://skia-review.googlesource.com/c/194189
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
- Collapsed the per-particle data into a single struct, and
use that to communicate with drawables, too. Let the drawables
manage allocation of xforms, colors, etc. Helpful for non-atlas
drawables, and just to keep the effect code simpler.
- Having all of the params in a single struct allows us to move
the remaining animated behaviors into affectors (color/frame).
- Added SkColorCurve, which works like SkCurve for SkColor4f.
Use that to create a color affector (rather than simple
start/end colors in the effect params).
- Also put the stable random in SkParticleState. This is going
to be necessary if/when we change affectors to operate on all
particles (rather than one at a time). Still need to move t
value into the particle struct (or eval it from the lifetime
params on demand).
Change-Id: Icf39116acbfd5d6e8eb91e9affbd8898d106211d
Reviewed-on: https://skia-review.googlesource.com/c/193473
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Added a simpler circle drawable, moved drawing code out so that frame
calculation is handled by the drawable. Fixed all the sample effects,
including some size adjustments to better create the intended effect.
Bug: skia:
Change-Id: I60af9cd6262ff98352ca8ceaf6768aef9c7e164c
Reviewed-on: https://skia-review.googlesource.com/c/193029
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
- Converted all linear force stuff into a single affector,
used at either spawn or update time appropriately.
The new affector can either set or adjust velocity.
- Converted lifetime to a curve.
- Removed SkRangedFloat, initial velocity params, etc.
Looks like a large addition, but that's mostly down to the
JSON getting bigger. There's a net reduction in LoC.
Bug: skia:
Change-Id: Iac7417f15f96d0313efd08c4b26dc3250b80fa77
Reviewed-on: https://skia-review.googlesource.com/c/192102
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Effects now have a duration, and can be played looped
or one-shot. Added a second list of affectors that are
applied at spawn vs. update.
Effects grab and store the SkRandom at construction,
so it no longer needs to be passed to update().
Bug: skia:
Change-Id: Ib54d60466e162e4d4b70fa64c1215fc01680d47a
Reviewed-on: https://skia-review.googlesource.com/c/191722
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
This adds a new "Particles" slide to viewer, that allows
editing, loading, and saving particle effects. All of the
particle system code is in modules/particles.
There are many rough edges and some not-yet-finished changes
to generalize the model[1]. A rough overview:
- SkReflected.h implements a lightweight reflection system
for classes derived from SkReflected. Adding a new class
involves deriving from SkReflected, adding a macro to the
class declaration, and implementing visitFields(), which
simply calls a virtual on an SkFieldVisitor for each field.
Currently, emitters and affectors use this mechanism.
- SkParticleSerialization.h demonstrates two useful field
visitors - for serializing to and from JSON. The driver
code that uses those is directly in ParticlesSlide.
- SkParticleData.h and SkCurve.h define a variety of helper
types for talking about particles, both for parameterizing
individual values, and communicating about the state of a
particle among the effect, affectors, and emitters.
- SkParticleEffect.h defines the static data definition of
an effect (SkParticleEffectParams), as well as a running
instance of an effect (SkParticleEffect). The effect has
simple update() and draw() methods.
- ParticlesSlide.cpp adds a third field visitor to generate
GUIs for interactively editing the running effect.
---
1: The critical change I'd like to make is to remove all
special case behavior over time and at spawn (setting sprite
frames, size over time, color over time, etc...). Integration
is the only fixed function behavior. Everything else is driven
by two lists of affectors. One is applied at spawn time, using
the effect's lifetime to evaluate curves. This allows spawning
particles with different colors as the effect ages out, for
example. The second list is applied every frame to update
existing particles, and is driven by the particle's lifetime.
This allows particles to change color after being spawned, for
example.
With a small set of affectors using a single expressive curve
primitive (keyframed list of cubic curve segments), we can
have affectors that update color, size, velocity, position,
sprite frame, etc., and implement many complex behaviors.
Bug: skia:
Change-Id: Id9402bef22825d55d021c5a2f9e5e41791aabaf4
Reviewed-on: https://skia-review.googlesource.com/c/181404
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
