diff options
| -rw-r--r-- | main.c | 81 |
1 files changed, 65 insertions, 16 deletions
@@ -66,6 +66,23 @@ swap(int *a, int *b) *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) { @@ -377,6 +394,34 @@ circleshader(Sparams *sp) 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) { @@ -491,24 +536,28 @@ render(void) 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); - - 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, 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(); t0 = nanosec(); - shade(fb, triangleshader); + shade(fb, sfshader); t1 = nanosec(); fprint(2, "shader took %lludns\n", t1-t0); } |