OpenSubdiv/opensubdiv/osd/bufferDescriptor.h

113 lines
3.7 KiB
C++

//
// Copyright 2015 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
// names, trademarks, service marks, or product names of the Licensor
// and its affiliates, except as required to comply with Section 4(c) of
// the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#ifndef OPENSUBDIV3_OSD_BUFFER_DESCRIPTOR_H
#define OPENSUBDIV3_OSD_BUFFER_DESCRIPTOR_H
#include "../version.h"
#include <string.h>
namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {
namespace Osd {
/// \brief BufferDescriptor is a struct which describes buffer elements in
/// interleaved data buffers. Almost all Osd Evaluator APIs take
/// BufferDescriptors along with device-specific buffer objects.
///
/// The offset of BufferDescriptor can also be used to express a
/// batching offset if the data buffer is combined across multiple
/// objects together.
///
/// * Note that each element has the same data type (float)
///
// example:
// n
// -----+----------------------------------------+-------------------------
// | vertex 0 |
// -----+----------------------------------------+-------------------------
// | X Y Z R G B A Xu Yu Zu Xv Yv Zv |
// -----+----------------------------------------+-------------------------
// <------------- stride = 13 -------------->
//
// - XYZ (offset = n+0, length = 3, stride = 13)
// - RGBA (offset = n+3, length = 4, stride = 13)
// - uTangent (offset = n+7, length = 3, stride = 13)
// - vTangent (offset = n+10, length = 3, stride = 13)
//
struct BufferDescriptor {
/// Default Constructor
BufferDescriptor() : offset(0), length(0), stride(0) { }
/// Constructor
BufferDescriptor(int o, int l, int s) : offset(o), length(l), stride(s) { }
/// Returns the relative offset within a stride
int GetLocalOffset() const {
return stride > 0 ? offset % stride : 0;
}
/// True if the descriptor values are internally consistent
bool IsValid() const {
return ((length > 0) &&
(length <= stride - GetLocalOffset()));
}
/// Resets the descriptor to default
void Reset() {
offset = length = stride = 0;
}
/// True if the descriptors are identical
bool operator == (BufferDescriptor const &other) const {
return (offset == other.offset &&
length == other.length &&
stride == other.stride);
}
/// True if the descriptors are not identical
bool operator != (BufferDescriptor const &other) const {
return !(this->operator==(other));
}
/// offset to desired element data
int offset;
/// number or length of the data
int length;
/// stride to the next element
int stride;
};
} // end namespace Osd
} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;
} // end namespace OpenSubdiv
#endif // OPENSUBDIV3_OSD_BUFFER_DESCRIPTOR_H