skia2/docs/examples/pong.cpp
Hal Canary 8800042f69 docs/examples: REG_FIDDLE_ANIMATED
I also added the `get_examples.py` script which pulls down new fiddles.

Change-Id: I953e461685a4d118ac4e425453e47d665a485aa2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/264570
Commit-Queue: Hal Canary <halcanary@skia.org>
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
2020-01-15 19:02:25 +00:00

34 lines
1.1 KiB
C++

// Copyright 2020 Google LLC.
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
#include "tools/fiddle/examples.h"
REG_FIDDLE_ANIMATED(pong, 256, 256, false, 0, 10) {
static SkScalar PingPong(double t, SkScalar period, SkScalar phase,
SkScalar ends, SkScalar mid) {
double value = ::fmod(t + phase, period);
double half = period / 2.0;
double diff = ::fabs(value - half);
return SkDoubleToScalar(ends + (1.0 - diff / half) * (mid - ends));
}
void draw(SkCanvas* canvas) {
canvas->clear(SK_ColorBLACK);
float ballX = PingPong(frame * duration, 2.5f, 0.0f, 0.0f, 1.0f);
float ballY = PingPong(frame * duration, 2.0f, 0.4f, 0.0f, 1.0f);
SkPaint p;
p.setColor(SK_ColorWHITE);
p.setAntiAlias(true);
float bX = ballX * 472 + 20;
float bY = ballY * 200 + 28;
if (canvas->getGrContext()) {
canvas->drawRect(SkRect::MakeXYWH(236, bY - 15, 10, 30), p);
bX -= 256;
} else {
canvas->drawRect(SkRect::MakeXYWH(10, bY - 15, 10, 30), p);
}
canvas->drawCircle(bX, bY, 5, p);
}
} // END FIDDLE