def generateTexTangentsAndBinormals(self): """If there are no texture tangents, this method will compute them. Texture coordinates must exist and it uses the first texture coordinate set.""" #The following is taken from: # http://www.terathon.com/code/tangent.html # It's pretty much a direct translation, using numpy arrays tris = self._vertex[self._vertex_index] uvs = self._texcoordset[0][self._texcoord_indexset[0]] x1 = tris[:, 1, 0] - tris[:, 0, 0] x2 = tris[:, 2, 0] - tris[:, 1, 0] y1 = tris[:, 1, 1] - tris[:, 0, 1] y2 = tris[:, 2, 1] - tris[:, 1, 1] z1 = tris[:, 1, 2] - tris[:, 0, 2] z2 = tris[:, 2, 2] - tris[:, 1, 2] s1 = uvs[:, 1, 0] - uvs[:, 0, 0] s2 = uvs[:, 2, 0] - uvs[:, 1, 0] t1 = uvs[:, 1, 1] - uvs[:, 0, 1] t2 = uvs[:, 2, 1] - uvs[:, 1, 1] r = 1.0 / (s1 * t2 - s2 * t1) sdirx = (t2 * x1 - t1 * x2) * r sdiry = (t2 * y1 - t1 * y2) * r sdirz = (t2 * z1 - t1 * z2) * r sdir = numpy.vstack((sdirx, sdiry, sdirz)).T tans1 = numpy.zeros(self._vertex.shape, dtype=self._vertex.dtype) tans1[self._vertex_index[:, 0]] += sdir tans1[self._vertex_index[:, 1]] += sdir tans1[self._vertex_index[:, 2]] += sdir norm = self._normal[self._normal_index] norm.shape = (-1, 3) tan1 = tans1[self._vertex_index] tan1.shape = (-1, 3) tangent = normalize_v3(tan1 - norm * dot_v3(norm, tan1)[:, numpy.newaxis]) self._textangentset = (tangent, ) self._textangent_indexset = (numpy.arange( len(self._vertex_index) * 3, dtype=self._vertex_index.dtype), ) self._textangent_indexset[0].shape = (len(self._vertex_index), 3) tdirx = (s1 * x2 - s2 * x1) * r tdiry = (s1 * y2 - s2 * y1) * r tdirz = (s1 * z2 - s2 * z1) * r tdir = numpy.vstack((tdirx, tdiry, tdirz)).T tans2 = numpy.zeros(self._vertex.shape, dtype=self._vertex.dtype) tans2[self._vertex_index[:, 0]] += tdir tans2[self._vertex_index[:, 1]] += tdir tans2[self._vertex_index[:, 2]] += tdir tan2 = tans2[self._vertex_index] tan2.shape = (-1, 3) tanw = dot_v3(numpy.cross(norm, tan1), tan2) tanw = numpy.sign(tanw) binorm = numpy.cross(norm, tangent).flatten() binorm.shape = (-1, 3) binorm = binorm * tanw[:, numpy.newaxis] self._texbinormalset = (binorm, ) self._texbinormal_indexset = (numpy.arange( len(self._vertex_index) * 3, dtype=self._vertex_index.dtype), ) self._texbinormal_indexset[0].shape = (len(self._vertex_index), 3)
def generateTexTangentsAndBinormals(self): """If there are no texture tangents, this method will compute them. Texture coordinates must exist and it uses the first texture coordinate set.""" # The following is taken from: # http://www.terathon.com/code/tangent.html # It's pretty much a direct translation, using numpy arrays tris = self._vertex[self._vertex_index] uvs = self._texcoordset[0][self._texcoord_indexset[0]] x1 = tris[:, 1, 0] - tris[:, 0, 0] x2 = tris[:, 2, 0] - tris[:, 1, 0] y1 = tris[:, 1, 1] - tris[:, 0, 1] y2 = tris[:, 2, 1] - tris[:, 1, 1] z1 = tris[:, 1, 2] - tris[:, 0, 2] z2 = tris[:, 2, 2] - tris[:, 1, 2] s1 = uvs[:, 1, 0] - uvs[:, 0, 0] s2 = uvs[:, 2, 0] - uvs[:, 1, 0] t1 = uvs[:, 1, 1] - uvs[:, 0, 1] t2 = uvs[:, 2, 1] - uvs[:, 1, 1] r = 1.0 / (s1 * t2 - s2 * t1) sdirx = (t2 * x1 - t1 * x2) * r sdiry = (t2 * y1 - t1 * y2) * r sdirz = (t2 * z1 - t1 * z2) * r sdir = numpy.vstack((sdirx, sdiry, sdirz)).T tans1 = numpy.zeros(self._vertex.shape, dtype=self._vertex.dtype) tans1[self._vertex_index[:, 0]] += sdir tans1[self._vertex_index[:, 1]] += sdir tans1[self._vertex_index[:, 2]] += sdir norm = self._normal[self._normal_index] norm.shape = (-1, 3) tan1 = tans1[self._vertex_index] tan1.shape = (-1, 3) tangent = normalize_v3(tan1 - norm * dot_v3(norm, tan1)[:, numpy.newaxis]) self._textangentset = (tangent,) self._textangent_indexset = (numpy.arange(len(self._vertex_index) * 3, dtype=self._vertex_index.dtype),) self._textangent_indexset[0].shape = (len(self._vertex_index), 3) tdirx = (s1 * x2 - s2 * x1) * r tdiry = (s1 * y2 - s2 * y1) * r tdirz = (s1 * z2 - s2 * z1) * r tdir = numpy.vstack((tdirx, tdiry, tdirz)).T tans2 = numpy.zeros(self._vertex.shape, dtype=self._vertex.dtype) tans2[self._vertex_index[:, 0]] += tdir tans2[self._vertex_index[:, 1]] += tdir tans2[self._vertex_index[:, 2]] += tdir tan2 = tans2[self._vertex_index] tan2.shape = (-1, 3) tanw = dot_v3(numpy.cross(norm, tan1), tan2) tanw = numpy.sign(tanw) binorm = numpy.cross(norm, tangent).flatten() binorm.shape = (-1, 3) binorm = binorm * tanw[:, numpy.newaxis] self._texbinormalset = (binorm,) self._texbinormal_indexset = (numpy.arange(len(self._vertex_index) * 3, dtype=self._vertex_index.dtype),) self._texbinormal_indexset[0].shape = (len(self._vertex_index), 3)