standalone version release.

1 files changed, 135 insertions, 0 deletions

diff --git a/render.c b/render.c
new file mode 100644
index 0000000..d8b7088
--- /dev/null
+++ b/render.c
@@ -0,0 +1,135 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+#include <memdraw.h>
+#include <geometry.h>
+#include <graphics.h>
+
+//static Memimage*
+//imagetomemimage(Image *src)
+//{
+//	Memimage *dst;
+//	uchar *buf;
+//	uint buflen;
+//
+//	buflen = Dx(src->r)*Dy(src->r);
+//	buflen *= (chantodepth(src->chan)+7)/8;
+//	buf = malloc(buflen);
+//	if(buf == nil)
+//		sysfatal("malloc: %r");
+//	dst = allocmemimage(src->r, src->chan);
+//	if(dst == nil)
+//		sysfatal("allocmemimage: %r");
+//	if(src->repl){
+//		dst->flags |= Frepl;
+//		dst->clipr = Rect(-1e6, -1e6, 1e6, 1e6);
+//	}
+//	unloadimage(src, src->r, buf, buflen);
+//	loadmemimage(dst, src->r, buf, buflen);
+//	free(buf);
+//	return dst;
+//}
+
+static Point2
+flatten(Camera *c, Point3 p)
+{
+	Point2 p2;
+	Matrix S = {
+		Dx(c->viewport->r)/2, 0, 0,
+		0, Dy(c->viewport->r)/2, 0,
+		0, 0, 1,
+	}, T = {
+		1, 0, 1,
+		0, 1, 1,
+		0, 0, 1,
+	};
+
+	p2 = Pt2(p.x, p.y, p.w);
+	if(p2.w != 0)
+		p2 = divpt2(p2, p2.w);
+	mulm(S, T);
+	p2 = xform(p2, S);
+	return p2;
+}
+
+/* requires p to be in NDC */
+int
+isclipping(Point3 p)
+{
+	if(p.x > p.w || p.x < -p.w ||
+	   p.y > p.w || p.y < -p.w ||
+	   p.z > p.w || p.z < 0)
+		return 1;
+	return 0;
+}
+
+Point
+toviewport(Camera *c, Point3 p)
+{
+	Point2 p2;
+	RFrame rf = {
+		c->viewport->r.min.x, c->viewport->r.max.y, 1,
+		1, 0, 0,
+		0, -1, 0
+	};
+
+	p2 = invrframexform(flatten(c, p), rf);
+	return Pt(p2.x, p2.y);
+}
+
+Point2
+fromviewport(Camera *c, Point p)
+{
+	RFrame rf = {
+		c->viewport->r.min.x, c->viewport->r.max.y, 1,
+		1, 0, 0,
+		0, -1, 0
+	};
+
+	return rframexform(Pt2(p.x,p.y,1), rf);
+}
+
+void
+perspective(Matrix3 m, double fov, double a, double n, double f)
+{
+	double cotan;
+
+	cotan = 1/tan(fov/2*DEG);
+	identity3(m);
+	m[0][0] =  cotan/a;
+	m[1][1] =  cotan;
+	m[2][2] = -(f+n)/(f-n);
+	m[2][3] = -2*f*n/(f-n);
+	m[3][2] = -1;
+}
+
+void
+orthographic(Matrix3 m, double l, double r, double b, double t, double n, double f)
+{
+	identity3(m);
+	m[0][0] =  2/(r - l);
+	m[1][1] =  2/(t - b);
+	m[2][2] = -2/(f - n);
+	m[0][3] = -(r + l)/(r - l);
+	m[1][3] = -(t + b)/(t - b);
+	m[2][3] = -(f + n)/(f - n);
+}
+
+void
+line3(Camera *c, Point3 p0, Point3 p1, int end0, int end1, Image *src)
+{
+	p0 = WORLD2NDC(c, p0);
+	p1 = WORLD2NDC(c, p1);
+	if(isclipping(p0) || isclipping(p1))
+		return;
+	line(c->viewport, toviewport(c, p0), toviewport(c, p1), end0, end1, 0, src, ZP);
+}
+
+Point
+string3(Camera *c, Point3 p, Image *src, Font *f, char *s)
+{
+	p = WORLD2NDC(c, p);
+	if(isclipping(p))
+		return Pt(-1,-1);
+	return string(c->viewport, toviewport(c, p), src, ZP, f, s);
+}