1 // Copyright 2020 Google LLC.
2 // Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
3 #include "tools/fiddle/examples.h"
4
5 REG_FIDDLE_ANIMATED(Octopus_Generator_Animated, 256, 256, false, 0, 4) {
6 #include <random>
7
paintOctopus(float x,float y,int size_base,SkColor color,SkCanvas * canvas)8 void paintOctopus(float x, float y, int size_base, SkColor color, SkCanvas* canvas) {
9 // Set up the paint to draw the head and legs
10 SkPaint paint;
11 paint.setAntiAlias(true);
12 paint.setColor(color);
13 int radius = 3*size_base;
14 // Draw the big head
15 canvas->drawCircle(x, y, radius, paint);
16 // Draw 8 small legs
17 for (int leg = 0; leg < 8; ++leg) {
18 canvas->drawCircle(x - radius + (2*radius/7.5*leg),
19 y + radius - pow(abs(4-leg), 2), size_base/2 + 2, paint);
20 }
21 // Make the color a bit lighter for the eyes
22 paint.setColor(SkColorSetRGB(std::min(255u, SkColorGetR(color) + 20),
23 std::min(255u, SkColorGetG(color) + 20),
24 std::min(255u, SkColorGetB(color) + 20)));
25 // Draw the left and right eye
26 canvas->drawCircle(x-size_base, y+size_base, size_base/2, paint);
27 canvas->drawCircle(x+size_base, y+size_base, size_base/2, paint);
28 }
29
draw(SkCanvas * canvas)30 void draw(SkCanvas* canvas) {
31 // This is called many times, once per frame. To keep the octopods
32 // a consistent color, we depend on the RNG using the *same* seed
33 // for each of calls (i.e. don't reseed it based on time or something).
34 std::default_random_engine rng;
35 const auto randScalar = [&rng](float min, float max) -> float {
36 return std::uniform_real_distribution<float>(min, max)(rng);
37 };
38 const auto randInt = [&rng](int min, int max) -> int {
39 return std::uniform_int_distribution<int>(min, max)(rng);
40 };
41 const auto randOpaqueColor = [&rng]() -> SkColor {
42 return std::uniform_int_distribution<uint32_t>(0, 0xFFFFFF)(rng) | 0xFF000000;
43 };
44
45 // Don't make this too big or rendering will time out.
46 constexpr int numOctopods = 20;
47 for (int i = 0; i < numOctopods; ++i) {
48 float x = randScalar(0, 256);
49 float y = randScalar(0, 256);
50 int s = randInt(6, 12);
51 SkColor c = randOpaqueColor();
52 // To make the octopods "swim" we have them move around a circle
53 // of a random radius
54 float radius = randScalar(0, 40);
55 // frame is in range [0, 1.0], so this starts at some fraction of 2pi
56 // (e.g. 1/2 pi) and goes until that fraction + 2pi (e.g. 5/2 pi)
57 float angle = (randScalar(0, 1) + frame) * 6.28319;
58 x += radius * cos(angle);
59 y += radius * sin(angle);
60 paintOctopus(x, y, s, c, canvas);
61 }
62 }
63 } // END FIDDLE
64