ref: 44cab0f62cdfaa2f208d07f52bd090d859a73c5a
parent: 12bb819509f967381e2e3619734a4a4f953cea6d
author: rodri <[email protected]>
date: Sun Nov 12 16:22:03 EST 2023
add some shaping function experiments.
--- a/main.c
+++ b/main.c
@@ -66,6 +66,23 @@
*b = t;
}
+double
+step(double edge, double n)
+{+ if(n < edge)
+ return 0;
+ return 1;
+}
+
+double
+smoothstep(double edge0, double edge1, double n)
+{+ double t;
+
+ t = fclamp((n-edge0)/(edge1-edge0), 0, 1);
+ return t*t * (3 - 2*t);
+}
+
void *
emalloc(ulong n)
{@@ -377,7 +394,35 @@
return sp->frag;
}
+/* some shaping functions from The Book of Shaders, Chapter 5 */
Memimage *
+sfshader(Sparams *sp)
+{+ Point2 uv;
+ double y, pct;
+ uchar cbuf[4];
+
+ uv = Pt2(sp->p.x,sp->p.y,1);
+ uv.x /= Dx(fb->r);
+ uv.y /= Dy(fb->r);
+ uv.y = 1 - uv.y; /* make [0 0] the bottom-left corner */
+
+// y = step(0.5, uv.x);
+ y = pow(uv.x, 5);
+// y = sin(uv.x);
+// y = smoothstep(0.1, 0.9, uv.x);
+ pct = smoothstep(y-0.02, y, uv.y) - smoothstep(y, y+0.02, uv.y);
+
+ cbuf[0] = 0xFF;
+ cbuf[1] = 0xFF*flerp(y, 0, pct);
+ cbuf[2] = 0xFF*flerp(y, 1, pct);
+ cbuf[3] = 0xFF*flerp(y, 0, pct);
+
+ memfillcolor(sp->frag, *(ulong*)cbuf);
+ return sp->frag;
+}
+
+Memimage *
modelshader(Sparams *sp)
{OBJObject *o;
@@ -491,24 +536,28 @@
t1 = nanosec();
fprint(2, "shader took %lludns\n", t1-t0);
}else{- t0 = nanosec();
- shade(fb, circleshader);
- t1 = nanosec();
- fprint(2, "shader took %lludns\n", t1-t0);
+// t0 = nanosec();
+// shade(fb, circleshader);
+// t1 = nanosec();
+// fprint(2, "shader took %lludns\n", t1-t0);
+//
+// bresenham(fb, Pt(40,40), Pt(300,300), red);
+// bresenham(fb, Pt(80,80), Pt(100,200), red);
+// bresenham(fb, Pt(80,80), Pt(200,100), red);
+//
+// filltriangle(fb, Pt(30,10), Pt(45, 45), Pt(5, 100), blue);
+// triangle(fb, Pt(30,10), Pt(45, 45), Pt(5, 100), red);
+// filltriangle(fb, Pt(300,120), Pt(200,350), Pt(50, 210), blue);
+// triangle(fb, Pt(300,120), Pt(200,350), Pt(50, 210), red);
+// filltriangle(fb, Pt(400,230), Pt(450,180), Pt(150, 320), blue);
+// triangle(fb, Pt(400,230), Pt(450,180), Pt(150, 320), red);
+//
+// t0 = nanosec();
+// shade(fb, triangleshader);
+// t1 = nanosec();
- bresenham(fb, Pt(40,40), Pt(300,300), red);
- bresenham(fb, Pt(80,80), Pt(100,200), red);
- bresenham(fb, Pt(80,80), Pt(200,100), red);
-
- filltriangle(fb, Pt(30,10), Pt(45, 45), Pt(5, 100), blue);
- triangle(fb, Pt(30,10), Pt(45, 45), Pt(5, 100), red);
- filltriangle(fb, Pt(300,120), Pt(200,350), Pt(50, 210), blue);
- triangle(fb, Pt(300,120), Pt(200,350), Pt(50, 210), red);
- filltriangle(fb, Pt(400,230), Pt(450,180), Pt(150, 320), blue);
- triangle(fb, Pt(400,230), Pt(450,180), Pt(150, 320), red);
-
t0 = nanosec();
- shade(fb, triangleshader);
+ shade(fb, sfshader);
t1 = nanosec();
fprint(2, "shader took %lludns\n", t1-t0);
}