X-Git-Url: https://eleni.mutantstargoat.com/git/?a=blobdiff_plain;f=src%2Fimage.cc;h=818b686744a658d17cf6da35d7c63ee2b3c3a999;hb=1e8963fc3f8191e328bbecd04cfbcba31d7d0bdf;hp=a99f75ade69ad7fc1c18e15e5560bffe74f36cd7;hpb=fd601d4218b63fdf92c5e4dfa32eac8adbda82fa;p=demo

diff --git a/src/image.cc b/src/image.cc
index a99f75a..818b686 100644
--- a/src/image.cc
+++ b/src/image.cc
@@ -121,21 +121,54 @@ bool Image::load(const char *fname)
 	return true;
 }
 
-Vec4 Image::lookup_nearest(float u, float v) const
+Vec4 Image::get_pixel(int x, int y) const
 {
-	int x = (int)(u * w) % w;
-	int y = (int)(v * h) % h;
-
 	if(is_float) {
-		return ((Vec4*)pixels)[y * w + x];
+		return ((Vec4 *)pixels)[y * w + x];
 	}
 
 	Vec4 color;
-	unsigned char *pptr = ((unsigned char*)pixels) + (y * w + x) * 4;
+	unsigned char *pptr = ((unsigned char *)pixels) + (y * w + x) * 4;
 	color.x = pptr[0] / 255.0;
 	color.y = pptr[1] / 255.0;
 	color.z = pptr[2] / 255.0;
 	color.w = pptr[3] / 255.0;
 
 	return color;
+}
+
+Vec4 Image::lookup_nearest(float u, float v) const
+{
+	int x = (int)(u * w) % w;
+	int y = (int)(v * h) % h;
+
+	return get_pixel(x, y);
+}
+
+Vec4 Image::lookup_linear(float u, float v, float du, float dv) const
+{
+	/* bottom left */
+	int x0 = (int)(u * w) % w;
+	int y0 = (int)(v * h) % h;
+	int x1 = (x0 + 1) % w;
+	int y1 = (y0 + 1) % h;
+
+	/* uv coordinates at the img corners */
+	float u0 = (float)x0 / (float)w;
+	float v0 = (float)y0 / (float)h;
+	float u1 = (float)(x0 + 1) / (float)w;
+	float v1 = (float)(y0 + 1) / (float)h;
+
+	float tu = (u - u0) / (u1 - u0);
+	float tv = (v - v0) / (v1 - v0);
+
+	Vec4 p00 = get_pixel(x0, y0);
+	Vec4 p01 = get_pixel(x0, y1);
+	Vec4 p11 = get_pixel(x1, y1);
+	Vec4 p10 = get_pixel(x1, y0);
+
+	Vec4 ptop = lerp(p01, p11, tu);
+	Vec4 pbot = lerp(p00, p10, tu);
+
+	return lerp(pbot, ptop, tv);
 }
\ No newline at end of file