texture.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2026                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
 *                                                                           *
 * All rights reserved.                                                      *
 *                                                                           *
 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the Mozilla Public License Version 2.0 as published *
 * by the Mozilla Foundation; either version 2 of the License, or            *
 * (at your option) any later version.                                       *
 *                                                                           *
 * This program is distributed in the hope that it will be useful,           *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_BGFX_TEXTURE_H
#define VCL_BGFX_TEXTURE_H
 
#include <vclib/base.h>
#include <vclib/space/core.h>
 
#include <vclib/bgfx/context.h>
 
#include <bgfx/bgfx.h>
#include <bimg/bimg.h>
 
namespace vcl {
 
class Texture
{
    bgfx::TextureHandle mTextureHandle = BGFX_INVALID_HANDLE;
 
public:
    Texture() = default;
 
    Texture(const Texture& other) = delete;
 
    Texture(Texture&& other) noexcept { swap(other); }
 
    ~Texture()
    {
        if (bgfx::isValid(mTextureHandle))
            bgfx::destroy(mTextureHandle);
    }
 
    Texture& operator=(const Texture& other) = delete;
 
    Texture& operator=(Texture&& other) noexcept
    {
        swap(other);
        return *this;
    }
 
    void swap(Texture& other)
    {
        using std::swap;
        swap(mTextureHandle, other.mTextureHandle);
    }
 
    friend void swap(Texture& a, Texture& b) { a.swap(b); }
 
    bool isValid() const { return bgfx::isValid(mTextureHandle); }
 
    void set(const bimg::ImageContainer& image, bool hasMips, uint64_t flags)
    {
        const bool imageHasAlreadyMips = image.m_numMips > 1;
        const bool passDataDirectly =
            !hasMips || (hasMips && imageHasAlreadyMips);
 
        if (bgfx::isValid(mTextureHandle))
            bgfx::destroy(mTextureHandle);
 
        if (passDataDirectly) {
            const uint8_t* imageData = (uint8_t*) image.m_data;
 
            if (image.m_cubeMap) {
                mTextureHandle = bgfx::createTextureCube(
                    image.m_width,
                    hasMips,
                    image.m_numLayers,
                    bgfx::TextureFormat::Enum(image.m_format),
                    flags,
                    bgfxCopyMemory(imageData, image.m_size));
            }
            else {
                mTextureHandle = bgfx::createTexture2D(
                    image.m_width,
                    image.m_height,
                    hasMips,
                    image.m_numLayers,
                    bgfx::TextureFormat::Enum(image.m_format),
                    flags,
                    bgfxCopyMemory(imageData, image.m_size));
            }
        }
        else {
            // Image has not mips but we still want to allocate the related
            // memory. For this we need to actually create an empty texture and
            // update it manually to avoid undefined behavior.
 
            if (image.m_cubeMap) {
                mTextureHandle = bgfx::createTextureCube(
                    image.m_width,
                    hasMips,
                    image.m_numLayers,
                    bgfx::TextureFormat::Enum(image.m_format),
                    flags);
 
                for (uint8_t face = 0; face < 6; face++)
                    copyMip0ToTexture(image, face);
            }
            else {
                mTextureHandle = bgfx::createTexture2D(
                    image.m_width,
                    image.m_height,
                    hasMips,
                    image.m_numLayers,
                    bgfx::TextureFormat::Enum(image.m_format),
                    flags);
 
                copyMip0ToTexture(image);
            }
        }
    }
 
    void set(
        const void*               data,
        const vcl::Point2i&       size,
        bool                      hasMips = false,
        uint64_t                  flags = BGFX_TEXTURE_NONE | BGFX_SAMPLER_NONE,
        bgfx::TextureFormat::Enum format    = bgfx::TextureFormat::RGBA8,
        bool                      isCubemap = false,
        bgfx::ReleaseFn           releaseFn = nullptr)
    {
        uint32_t sz = bimg::imageGetSize(
            nullptr,
            size.x(),
            size.y(),
            1,
            isCubemap,
            hasMips,
            1,
            // there is correspondence between bimg and bgfx texture formats
            static_cast<bimg::TextureFormat::Enum>(toUnderlying(format)));
        set(bgfx::makeRef(data, sz, releaseFn),
            size,
            hasMips,
            1,
            format,
            isCubemap,
            flags);
    }
 
    void set(
        const bgfx::Memory*       texture,
        const vcl::Point2i&       size,
        bool                      hasMips,
        uint                      nLayers,
        bgfx::TextureFormat::Enum format    = bgfx::TextureFormat::RGBA8,
        bool                      isCubemap = false,
        uint64_t                  flags = BGFX_TEXTURE_NONE | BGFX_SAMPLER_NONE)
    {
        if (bgfx::isValid(mTextureHandle))
            bgfx::destroy(mTextureHandle);
 
        if (isCubemap)
            mTextureHandle = bgfx::createTextureCube(
                size.x(), hasMips, nLayers, format, flags, texture);
        else
            mTextureHandle = bgfx::createTexture2D(
                size.x(), size.y(), hasMips, nLayers, format, flags, texture);
    }
 
    void bind(
        uint                stage,
        bgfx::UniformHandle samplerHandle,
        uint                samplerFlags = UINT32_MAX) const
    {
        if (bgfx::isValid(mTextureHandle) && bgfx::isValid(samplerHandle)) {
            bgfx::setTexture(
                stage, samplerHandle, mTextureHandle, samplerFlags);
        }
    }
 
    void bindForCompute(
        uint                      stage,
        uint                      mip,
        bgfx::Access::Enum        access,
        bgfx::TextureFormat::Enum format = bgfx::TextureFormat::Count) const
    {
        if (bgfx::isValid(mTextureHandle))
            bgfx::setImage(stage, mTextureHandle, mip, access, format);
    }
 
    static uint samplerFlagsFromTexture(const TextureDescriptor& tex)
    {
        using enum TextureDescriptor::MinificationFilter;
        using enum TextureDescriptor::WrapMode;
 
        uint flags = BGFX_SAMPLER_NONE;
 
        // set minification filter - bgfx default is linear
        if (tex.minFilter() == NEAREST ||
            tex.minFilter() == NEAREST_MIPMAP_LINEAR ||
            tex.minFilter() == NEAREST_MIPMAP_NEAREST)
            flags |= BGFX_SAMPLER_MIN_POINT;
 
        // set mipmap filter - bgfx default is linear
        if (tex.minFilter() == NEAREST_MIPMAP_NEAREST ||
            tex.minFilter() == LINEAR_MIPMAP_NEAREST)
            flags |= BGFX_SAMPLER_MIP_POINT;
 
        // set magnification filter - bgfx default is linear
        if (tex.magFilter() == TextureDescriptor::MagnificationFilter::NEAREST)
            flags |= BGFX_SAMPLER_MAG_POINT;
 
        // set wrap modes - bgfx default is repeat
        if (tex.wrapU() == CLAMP_TO_EDGE)
            flags |= BGFX_SAMPLER_U_CLAMP;
        else if (tex.wrapU() == MIRRORED_REPEAT)
            flags |= BGFX_SAMPLER_U_MIRROR;
 
        if (tex.wrapV() == CLAMP_TO_EDGE)
            flags |= BGFX_SAMPLER_V_CLAMP;
        else if (tex.wrapV() == MIRRORED_REPEAT)
            flags |= BGFX_SAMPLER_V_MIRROR;
 
        return flags;
    }
 
private:
    void copyMip0ToTexture(const bimg::ImageContainer& image, uint8_t face = 0)
    {
        bimg::ImageMip mip;
        bimg::imageGetRawData(image, face, 0, image.m_data, image.m_size, mip);
 
        if (image.m_cubeMap) {
            bgfx::updateTextureCube(
                mTextureHandle,
                0,
                face,
                0,
                0,
                0,
                mip.m_width,
                mip.m_height,
                bgfxCopyMemory(mip.m_data, mip.m_size));
        }
        else {
            bgfx::updateTexture2D(
                mTextureHandle,
                0,
                0,
                0,
                0,
                mip.m_width,
                mip.m_height,
                bgfxCopyMemory(mip.m_data, mip.m_size));
        }
    }
 
    static const bgfx::Memory* bgfxCopyMemory(
        const uint8_t* data,
        uint32_t       size)
    {
        auto [buffer, releaseFn] =
            Context::getAllocatedBufferAndReleaseFn<uint8_t>(size);
 
        std::copy(data, data + size, buffer);
 
        return bgfx::makeRef(buffer, size, releaseFn);
    }
};
 
} // namespace vcl
 
#endif // VCL_BGFX_TEXTURE_H