三角波 - 0b5vr

三角波

asin使う

code:glsl

// (1/TAU)Hz, DC=0, Amp=PI/2, Delta is always abs(1)

#define tri(x) (asin(sin(x)))

// 1Hz, DC=0, Amp=1

#define tri(x) (asin(sin(TAU*x))/HALF_PI)

absとfract使う

code:glsl

// Cheaper. 1Hz, DC=0, Amp=1

#define tri(x) (1.-4.*abs(fract(x)-0.5))

// Same as above but the wave starts from 0.0

#define tri(x) (1.-4.*abs(fract(x+0.25)-0.5))

https://gyazo.com/3c1cf442cf013ba7e2d5ae4bbed53f63

clamp使う

code:glsl

// 0.25Hz, DC=0, Amp=1, Delta is always abs(1)

float tri(float x) {

x = mod(x, 4.0) - 2.0;

return x - 2.0 * clamp(x, -1.0, 1.0);

}

https://gyazo.com/186e23fcd8a57bc3a32c124ae25eca0d