1 files changed, 104 insertions, 0 deletions
diff --git a/texture.c b/texture.c
new file mode 100644
index 0000000..40539db
--- /dev/null
+++ b/texture.c
@@ -0,0 +1,104 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include <memdraw.h>
+#include <geometry.h>
+#include "libobj/obj.h"
+#include "graphics.h"
+#include "internal.h"
+
+/*
+ * uv-coords belong to the 4th quadrant (v grows bottom-up),
+ * hence the need to reverse the v coord.
+ */
+static Point
+uv2tp(Point2 uv, Memimage *i)
+{
+	assert(uv.x >= 0 && uv.x <= 1 && uv.y >= 0 && uv.y <= 1);
+	return Pt(uv.x*Dx(i->r), (1 - uv.y)*Dy(i->r));
+}
+
+static Color
+ul2col(ulong l)
+{
+	Color c;
+
+	c.a = (l     & 0xff)/255.0;
+	c.b = (l>>8  & 0xff)/255.0;
+	c.g = (l>>16 & 0xff)/255.0;
+	c.r = (l>>24 & 0xff)/255.0;
+	return c;
+}
+
+static Color
+cbuf2col(uchar b[4])
+{
+	Color c;
+
+	c.a = b[0] / 255.0;
+	c.b = b[1] / 255.0;
+	c.g = b[2] / 255.0;
+	c.r = b[3] / 255.0;
+	return c;
+}
+
+static Color
+_memreadpixel(Memimage *i, Point sp)
+{
+	uchar cbuf[4];
+
+	switch(i->chan){
+	case RGB24:
+		unloadmemimage(i, rectaddpt(UR, sp), cbuf+1, sizeof cbuf - 1);
+		cbuf[0] = 0xFF;
+		break;
+	case RGBA32:
+		unloadmemimage(i, rectaddpt(UR, sp), cbuf, sizeof cbuf);
+		break;
+	case XRGB32:
+		unloadmemimage(i, rectaddpt(UR, sp), cbuf, sizeof cbuf);
+		memmove(cbuf+1, cbuf, 3);
+		cbuf[0] = 0xFF;
+		break;
+	}
+
+	return cbuf2col(cbuf);
+}
+
+Color
+neartexsampler(Memimage *i, Point2 uv)
+{
+	return _memreadpixel(i, uv2tp(uv, i));
+}
+
+Color
+bilitexsampler(Memimage *i, Point2 uv)
+{
+	Rectangle r;
+	Color c1, c2;
+
+	r = rectaddpt(UR, uv2tp(uv, i));
+	if(r.min.x < i->r.min.x){
+		r.min.x++;
+		r.max.x++;
+	}if(r.min.y < i->r.min.y){
+		r.min.y++;
+		r.max.y++;
+	}if(r.max.x >= i->r.max.x){
+		r.min.x--;
+		r.max.x--;
+	}if(r.max.y >= i->r.max.y){
+		r.min.y--;
+		r.max.y--;
+	}
+	c1 = lerp3(_memreadpixel(i, r.min), _memreadpixel(i, Pt(r.max.x, r.min.y)), 0.5);
+	c2 = lerp3(_memreadpixel(i, Pt(r.min.x, r.max.y)), _memreadpixel(i, r.max), 0.5);
+	return lerp3(c1, c2, 0.5);
+}
+
+Color
+texture(Memimage *i, Point2 uv, Color(*sampler)(Memimage*,Point2))
+{
+	return sampler(i, uv);
+}