types.h

//
// Copyright 2020 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 PXR_IMAGING_HGI_TYPES_H
#define PXR_IMAGING_HGI_TYPES_H

#include "pxr/pxr.h"
#include "pxr/base/gf/vec3i.h"
#include "pxr/imaging/hgi/api.h"
#include <vector>
#include <limits>
#include <stdlib.h>


PXR_NAMESPACE_OPEN_SCOPE

enum HgiFormat : int
{
    HgiFormatInvalid = -1,

    // UNorm8 - a 1-byte value representing a float between 0 and 1.
    // float value = (unorm / 255.0f);
    HgiFormatUNorm8 = 0,
    HgiFormatUNorm8Vec2,
    /* HgiFormatUNorm8Vec3 */ // Unsupported Metal (MTLPixelFormat)
    HgiFormatUNorm8Vec4,

    // SNorm8 - a 1-byte value representing a float between -1 and 1.
    // float value = max(snorm / 127.0f, -1.0f);
    HgiFormatSNorm8,
    HgiFormatSNorm8Vec2,
    /* HgiFormatSNorm8Vec3 */ // Unsupported Metal (MTLPixelFormat)
    HgiFormatSNorm8Vec4,

    // Float16 - a 2-byte IEEE half-precision float.
    HgiFormatFloat16,
    HgiFormatFloat16Vec2,
    HgiFormatFloat16Vec3,
    HgiFormatFloat16Vec4,

    // Float32 - a 4-byte IEEE float.
    HgiFormatFloat32,
    HgiFormatFloat32Vec2,
    HgiFormatFloat32Vec3,
    HgiFormatFloat32Vec4,

    // Int16 - a 2-byte signed integer
    HgiFormatInt16,
    HgiFormatInt16Vec2,
    HgiFormatInt16Vec3,
    HgiFormatInt16Vec4,

    // UInt16 - a 2-byte unsigned integer
    HgiFormatUInt16,
    HgiFormatUInt16Vec2,
    HgiFormatUInt16Vec3,
    HgiFormatUInt16Vec4,

    // Int32 - a 4-byte signed integer
    HgiFormatInt32,
    HgiFormatInt32Vec2,
    HgiFormatInt32Vec3,
    HgiFormatInt32Vec4,

    // UNorm8 SRGB - a 1-byte value representing a float between 0 and 1.
    // Gamma compression/decompression happens during read/write.
    // Alpha component is linear.
    /* HgiFormatUNorm8srgb */     // Unsupported by OpenGL
    /* HgiFormatUNorm8Vec2srgb */ // Unsupported by OpenGL
    /* HgiFormatUNorm8Vec3srgb */ // Unsupported Metal (MTLPixelFormat)
    HgiFormatUNorm8Vec4srgb,

    // BPTC compressed. 3-component, 4x4 blocks, signed floating-point
    HgiFormatBC6FloatVec3,

    // BPTC compressed. 3-component, 4x4 blocks, unsigned floating-point
    HgiFormatBC6UFloatVec3,

    // BPTC compressed. 4-component, 4x4 blocks, unsigned byte.
    // Representing a float between 0 and 1.
    HgiFormatBC7UNorm8Vec4,

    // BPTC compressed. 4-component, 4x4 blocks, unsigned byte, sRGB.
    // Representing a float between 0 and 1.
    HgiFormatBC7UNorm8Vec4srgb,

    // S3TC/DXT compressed. 4-component, 4x4 blocks, unsigned byte
    // Representing a float between 0 and 1.
    HgiFormatBC1UNorm8Vec4,

    // S3TC/DXT compressed. 4-component, 4x4 blocks, unsigned byte
    // Representing a float between 0 and 1.
    HgiFormatBC3UNorm8Vec4,

    // Depth stencil format (Float32 can be used for just depth)
    HgiFormatFloat32UInt8,

    HgiFormatCount
};

struct HgiMipInfo
{
    size_t byteOffset;
    GfVec3i dimensions;
    size_t byteSizePerLayer;
};

HGI_API
size_t HgiGetComponentCount(HgiFormat f);

HGI_API
size_t HgiGetDataSizeOfFormat(
    HgiFormat f,
    size_t *blockWidth = nullptr,
    size_t *blockHeight = nullptr);

HGI_API
bool HgiIsCompressed(HgiFormat f);

HGI_API
size_t HgiGetDataSize(
    HgiFormat f,
    const GfVec3i &dimensions);

HGI_API
std::vector<HgiMipInfo>
HgiGetMipInfos(
    HgiFormat format,
    const GfVec3i& dimensions,
    size_t layerCount,
    size_t dataByteSize = std::numeric_limits<size_t>::max());

PXR_NAMESPACE_CLOSE_SCOPE

#endif