Merge pull request zeux#634 from zeux/gltf-vnf

gltfpack: Introduce optional floating-point normal quantization

gltf/gltfpack.cpp

@@ -1257,6 +1257,10 @@ int main(int argc, char** argv)
 		{
 			settings.tex_float = true;
 		}
+		else if (strcmp(arg, "-vnf") == 0)
+		{
+			settings.nrm_float = true;
+		}
 		else if (strcmp(arg, "-at") == 0 && i + 1 < argc && isdigit(argv[i + 1][0]))
 		{
 			settings.trn_bits = clamp(atoi(argv[++i]), 1, 24);
@@ -1582,9 +1586,9 @@ int main(int argc, char** argv)
 		return 1;
 	}
 
-	if (settings.fallback && (settings.pos_float || settings.tex_float))
+	if (settings.fallback && (settings.pos_float || settings.tex_float || settings.nrm_float))
 	{
-		fprintf(stderr, "Option -cf can not be used together with -vpf or -tpf\n");
+		fprintf(stderr, "Option -cf can not be used together with -vpf, -vtf or -vnf\n");
 		return 1;
 	}
 

gltf/gltfpack.h

@@ -117,6 +117,7 @@ struct Settings
 	bool pos_normalized;
 	bool pos_float;
 	bool tex_float;
+	bool nrm_float;
 
 	int trn_bits;
 	int rot_bits;

gltf/stream.cpp

@@ -544,6 +544,10 @@ StreamFormat writeVertexStream(std::string& bin, const Stream& stream, const Qua
 		if (!settings.quantize)
 			return writeVertexStreamRaw(bin, stream, cgltf_type_vec3, 3);
 
+		// expand the encoded range to ensure it covers [0..1) interval
+		if (settings.nrm_float)
+			return writeVertexStreamFloat(bin, stream, cgltf_type_vec3, 3, settings, settings.nrm_bits, /* min_exp= */ 0);
+
 		bool oct = settings.compressmore && stream.target == 0;
 		int bits = settings.nrm_bits;