src/libANGLE/renderer/vulkan/vk_format_utils.cpp

//
// Copyright 2016 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// vk_format_utils:
//   Helper for Vulkan format code.

#include "libANGLE/renderer/vulkan/vk_format_utils.h"

#include "libANGLE/Texture.h"
#include "libANGLE/formatutils.h"
#include "libANGLE/renderer/load_functions_table.h"
#include "libANGLE/renderer/load_texture_border_functions_table.h"
#include "libANGLE/renderer/vulkan/ContextVk.h"
#include "libANGLE/renderer/vulkan/RendererVk.h"
#include "libANGLE/renderer/vulkan/vk_caps_utils.h"

namespace rx
{
namespace
{
void FillTextureFormatCaps(RendererVk *renderer,
                           angle::FormatID formatID,
                           gl::TextureCaps *outTextureCaps)
{
    const VkPhysicalDeviceLimits &physicalDeviceLimits =
        renderer->getPhysicalDeviceProperties().limits;
    bool hasColorAttachmentFeatureBit =
        renderer->hasImageFormatFeatureBits(formatID, VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT);
    bool hasDepthAttachmentFeatureBit = renderer->hasImageFormatFeatureBits(
        formatID, VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT);

    outTextureCaps->texturable =
        renderer->hasImageFormatFeatureBits(formatID, VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT);
    outTextureCaps->filterable = renderer->hasImageFormatFeatureBits(
        formatID, VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT);
    outTextureCaps->blendable =
        renderer->hasImageFormatFeatureBits(formatID, VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT);

    // For renderbuffer and texture attachments we require transfer and sampling for
    // GLES 2.0 CopyTexImage support. Sampling is also required for other features like
    // blits and EGLImages.
    outTextureCaps->textureAttachment =
        outTextureCaps->texturable &&
        (hasColorAttachmentFeatureBit || hasDepthAttachmentFeatureBit);
    outTextureCaps->renderbuffer = outTextureCaps->textureAttachment;

    if (outTextureCaps->renderbuffer)
    {
        if (hasColorAttachmentFeatureBit)
        {
            vk_gl::AddSampleCounts(physicalDeviceLimits.framebufferColorSampleCounts,
                                   &outTextureCaps->sampleCounts);
        }
        if (hasDepthAttachmentFeatureBit)
        {
            // Some drivers report different depth and stencil sample counts.  We'll AND those
            // counts together, limiting all depth and/or stencil formats to the lower number of
            // sample counts.
            vk_gl::AddSampleCounts((physicalDeviceLimits.framebufferDepthSampleCounts &
                                    physicalDeviceLimits.framebufferStencilSampleCounts),
                                   &outTextureCaps->sampleCounts);
        }
    }
}

bool HasFullBufferFormatSupport(RendererVk *renderer, angle::FormatID formatID)
{
    // Note: GL_EXT_texture_buffer support uses the same vkBufferFormat that is determined by
    // Format::initBufferFallback, which uses this function.  That relies on the fact that formats
    // required for GL_EXT_texture_buffer all have mandatory VERTEX_BUFFER feature support in
    // Vulkan.  If this function is changed to test for more features in such a way that makes any
    // of those formats use a fallback format, the implementation of GL_EXT_texture_buffer must be
    // modified not to use vkBufferFormat.
    return renderer->hasBufferFormatFeatureBits(formatID, VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT);
}

using SupportTest = bool (*)(RendererVk *renderer, angle::FormatID formatID);

template <class FormatInitInfo>
int FindSupportedFormat(RendererVk *renderer,
                        const FormatInitInfo *info,
                        size_t skip,
                        int numInfo,
                        SupportTest hasSupport)
{
    ASSERT(numInfo > 0);
    const int last = numInfo - 1;

    for (int i = static_cast<int>(skip); i < last; ++i)
    {
        ASSERT(info[i].format != angle::FormatID::NONE);
        if (hasSupport(renderer, info[i].format))
            return i;
    }

    if (skip > 0 && !hasSupport(renderer, info[last].format))
    {
        // We couldn't find a valid fallback, try again without skip
        return FindSupportedFormat(renderer, info, 0, numInfo, hasSupport);
    }

    ASSERT(info[last].format != angle::FormatID::NONE);
    ASSERT(hasSupport(renderer, info[last].format));
    return last;
}

bool HasNonFilterableTextureFormatSupport(RendererVk *renderer, angle::FormatID formatID)
{
    constexpr uint32_t kBitsColor =
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT | VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT;
    constexpr uint32_t kBitsDepth = VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT;

    return renderer->hasImageFormatFeatureBits(formatID, kBitsColor) ||
           renderer->hasImageFormatFeatureBits(formatID, kBitsDepth);
}
}  // anonymous namespace

namespace vk
{
// Format implementation.
Format::Format()
    : intendedFormatID(angle::FormatID::NONE),
      intendedGLFormat(GL_NONE),
      actualImageFormatID(angle::FormatID::NONE),
      actualBufferFormatID(angle::FormatID::NONE),
      actualCompressedBufferFormatID(angle::FormatID::NONE),
      imageInitializerFunction(nullptr),
      textureLoadFunctions(),
      vertexLoadFunction(nullptr),
      compressedVertexLoadFunction(nullptr),
      vertexLoadRequiresConversion(false),
      compressedVertexLoadRequiresConversion(false),
      vkBufferFormatIsPacked(false),
      vkFormatIsInt(false),
      vkFormatIsUnsigned(false)
{}

void Format::initImageFallback(RendererVk *renderer, const ImageFormatInitInfo *info, int numInfo)
{
    size_t skip                 = renderer->getFeatures().forceFallbackFormat.enabled ? 1 : 0;
    SupportTest testFunction    = HasFullTextureFormatSupport;
    const angle::Format &format = angle::Format::Get(info[0].format);
    if (format.isInt() || (format.isFloat() && format.redBits >= 32))
    {
        // Integer formats don't support filtering in GL, so don't test for it.
        // Filtering of 32-bit float textures is not supported on Android, and
        // it's enabled by the extension OES_texture_float_linear, which is
        // enabled automatically by examining format capabilities.
        testFunction = HasNonFilterableTextureFormatSupport;
    }
    if (format.isSnorm() || format.isBlock)
    {
        // Rendering to SNORM textures is not supported on Android, and it's
        // enabled by the extension EXT_render_snorm.
        // Compressed textures also need to perform this check.
        testFunction = HasNonRenderableTextureFormatSupport;
    }
    int i = FindSupportedFormat(renderer, info, skip, static_cast<uint32_t>(numInfo), testFunction);

    actualImageFormatID      = info[i].format;
    imageInitializerFunction = info[i].initializer;
}

void Format::initBufferFallback(RendererVk *renderer,
                                const BufferFormatInitInfo *info,
                                int numInfo,
                                int compressedStartIndex)
{
    {
        size_t skip = renderer->getFeatures().forceFallbackFormat.enabled ? 1 : 0;
        int i       = FindSupportedFormat(renderer, info, skip, compressedStartIndex,
                                    HasFullBufferFormatSupport);

        actualBufferFormatID         = info[i].format;
        vkBufferFormatIsPacked       = info[i].vkFormatIsPacked;
        vertexLoadFunction           = info[i].vertexLoadFunction;
        vertexLoadRequiresConversion = info[i].vertexLoadRequiresConversion;
    }

    if (renderer->getFeatures().compressVertexData.enabled && compressedStartIndex < numInfo)
    {
        int i = FindSupportedFormat(renderer, info, compressedStartIndex, numInfo,
                                    HasFullBufferFormatSupport);

        actualCompressedBufferFormatID         = info[i].format;
        vkCompressedBufferFormatIsPacked       = info[i].vkFormatIsPacked;
        compressedVertexLoadFunction           = info[i].vertexLoadFunction;
        compressedVertexLoadRequiresConversion = info[i].vertexLoadRequiresConversion;
    }
}

bool HasEmulatedImageChannels(const angle::Format &intendedFormat,
                              const angle::Format &actualFormat)
{
    return (intendedFormat.alphaBits == 0 && actualFormat.alphaBits > 0) ||
           (intendedFormat.blueBits == 0 && actualFormat.blueBits > 0) ||
           (intendedFormat.greenBits == 0 && actualFormat.greenBits > 0) ||
           (intendedFormat.depthBits == 0 && actualFormat.depthBits > 0) ||
           (intendedFormat.stencilBits == 0 && actualFormat.stencilBits > 0);
}

bool Format::hasEmulatedImageChannels() const
{
    return HasEmulatedImageChannels(intendedFormat(), actualImageFormat());
}

bool operator==(const Format &lhs, const Format &rhs)
{
    return &lhs == &rhs;
}

bool operator!=(const Format &lhs, const Format &rhs)
{
    return &lhs != &rhs;
}

// FormatTable implementation.
FormatTable::FormatTable() {}

FormatTable::~FormatTable() {}

void FormatTable::initialize(RendererVk *renderer,
                             gl::TextureCapsMap *outTextureCapsMap,
                             std::vector<GLenum> *outCompressedTextureFormats)
{
    for (size_t formatIndex = 0; formatIndex < angle::kNumANGLEFormats; ++formatIndex)
    {
        Format &format                           = mFormatData[formatIndex];
        const auto intendedFormatID              = static_cast<angle::FormatID>(formatIndex);
        const angle::Format &intendedAngleFormat = angle::Format::Get(intendedFormatID);

        format.initialize(renderer, intendedAngleFormat);
        format.intendedFormatID = intendedFormatID;

        if (!format.valid())
        {
            continue;
        }

        gl::TextureCaps textureCaps;
        FillTextureFormatCaps(renderer, format.actualImageFormatID, &textureCaps);
        outTextureCapsMap->set(intendedFormatID, textureCaps);

        if (textureCaps.texturable)
        {
            format.textureLoadFunctions =
                GetLoadFunctionsMap(format.intendedGLFormat, format.actualImageFormatID);
            format.textureBorderLoadFunctions = GetLoadTextureBorderFunctionsMap(
                format.intendedGLFormat, format.actualImageFormatID);
        }

        if (intendedAngleFormat.isBlock)
        {
            outCompressedTextureFormats->push_back(format.intendedGLFormat);
        }
    }
}

size_t GetImageCopyBufferAlignment(angle::FormatID actualFormatID)
{
    // vkCmdCopyBufferToImage must have an offset that is a multiple of 4 as well as a multiple
    // of the texel size (if uncompressed) or pixel block size (if compressed).
    // https://www.khronos.org/registry/vulkan/specs/1.0/man/html/VkBufferImageCopy.html
    //
    // We need lcm(4, texelSize) (lcm = least common multiplier).  For compressed images,
    // |texelSize| would contain the block size.  Since 4 is constant, this can be calculated as:
    //
    //                      | texelSize             texelSize % 4 == 0
    //                      | 4 * texelSize         texelSize % 4 == 1
    // lcm(4, texelSize) = <
    //                      | 2 * texelSize         texelSize % 4 == 2
    //                      | 4 * texelSize         texelSize % 4 == 3
    //
    // This means:
    //
    // - texelSize % 2 != 0 gives a 4x multiplier
    // - else texelSize % 4 != 0 gives a 2x multiplier
    // - else there's no multiplier.
    //
    const angle::Format &actualFormat = angle::Format::Get(actualFormatID);

    ASSERT(actualFormat.pixelBytes != 0);
    const size_t texelSize  = actualFormat.pixelBytes;
    const size_t multiplier = texelSize % 2 != 0 ? 4 : texelSize % 4 != 0 ? 2 : 1;
    const size_t alignment  = multiplier * texelSize;

    return alignment;
}

size_t GetValidImageCopyBufferAlignment(angle::FormatID intendedFormatID,
                                        angle::FormatID actualFormatID)
{
    constexpr size_t kMinimumAlignment = 16;
    return (intendedFormatID == angle::FormatID::NONE)
               ? kMinimumAlignment
               : GetImageCopyBufferAlignment(actualFormatID);
}

VkImageUsageFlags GetMaximalImageUsageFlags(RendererVk *renderer, angle::FormatID formatID)
{
    constexpr VkFormatFeatureFlags kImageUsageFeatureBits =
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT | VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT |
        VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT | VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT |
        VK_FORMAT_FEATURE_TRANSFER_SRC_BIT | VK_FORMAT_FEATURE_TRANSFER_DST_BIT;
    VkFormatFeatureFlags featureBits =
        renderer->getImageFormatFeatureBits(formatID, kImageUsageFeatureBits);
    VkImageUsageFlags imageUsageFlags = 0;
    if (featureBits & VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT)
        imageUsageFlags |= VK_IMAGE_USAGE_SAMPLED_BIT;
    if (featureBits & VK_FORMAT_FEATURE_STORAGE_IMAGE_BIT)
        imageUsageFlags |= VK_IMAGE_USAGE_STORAGE_BIT;
    if (featureBits & VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT)
        imageUsageFlags |= VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
    if (featureBits & VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT)
        imageUsageFlags |= VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
    if (featureBits & VK_FORMAT_FEATURE_TRANSFER_SRC_BIT)
        imageUsageFlags |= VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
    if (featureBits & VK_FORMAT_FEATURE_TRANSFER_DST_BIT)
        imageUsageFlags |= VK_IMAGE_USAGE_TRANSFER_DST_BIT;
    imageUsageFlags |= VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT;
    return imageUsageFlags;
}
}  // namespace vk

bool HasFullTextureFormatSupport(RendererVk *renderer, angle::FormatID formatID)
{
    constexpr uint32_t kBitsColor = VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT |
                                    VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT |
                                    VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BIT;

    // In OpenGL ES, all renderable formats except 32-bit floating-point support blending.
    // 32-bit floating-point case validation is handled by ANGLE's frontend.
    uint32_t kBitsColorFull = kBitsColor;
    switch (formatID)
    {
        case angle::FormatID::R32_FLOAT:
        case angle::FormatID::R32G32_FLOAT:
        case angle::FormatID::R32G32B32A32_FLOAT:
            break;
        default:
            kBitsColorFull |= VK_FORMAT_FEATURE_COLOR_ATTACHMENT_BLEND_BIT;
            break;
    }

    constexpr uint32_t kBitsDepth = VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT;

    return renderer->hasImageFormatFeatureBits(formatID, kBitsColorFull) ||
           renderer->hasImageFormatFeatureBits(formatID, kBitsDepth);
}

bool HasNonRenderableTextureFormatSupport(RendererVk *renderer, angle::FormatID formatID)
{
    constexpr uint32_t kBitsColor =
        VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT | VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT;
    constexpr uint32_t kBitsDepth = VK_FORMAT_FEATURE_DEPTH_STENCIL_ATTACHMENT_BIT;

    return renderer->hasImageFormatFeatureBits(formatID, kBitsColor) ||
           renderer->hasImageFormatFeatureBits(formatID, kBitsDepth);
}

size_t GetVertexInputAlignment(const vk::Format &format, bool compressed)
{
    const angle::Format &bufferFormat = format.actualBufferFormat(compressed);
    size_t pixelBytes                 = bufferFormat.pixelBytes;
    return format.vkBufferFormatIsPacked ? pixelBytes : (pixelBytes / bufferFormat.channelCount);
}

GLenum GetSwizzleStateComponent(const gl::SwizzleState &swizzleState, GLenum component)
{
    switch (component)
    {
        case GL_RED:
            return swizzleState.swizzleRed;
        case GL_GREEN:
            return swizzleState.swizzleGreen;
        case GL_BLUE:
            return swizzleState.swizzleBlue;
        case GL_ALPHA:
            return swizzleState.swizzleAlpha;
        default:
            return component;
    }
}

gl::SwizzleState ApplySwizzle(const gl::SwizzleState &formatSwizzle,
                              const gl::SwizzleState &toApply)
{
    gl::SwizzleState result;

    result.swizzleRed   = GetSwizzleStateComponent(formatSwizzle, toApply.swizzleRed);
    result.swizzleGreen = GetSwizzleStateComponent(formatSwizzle, toApply.swizzleGreen);
    result.swizzleBlue  = GetSwizzleStateComponent(formatSwizzle, toApply.swizzleBlue);
    result.swizzleAlpha = GetSwizzleStateComponent(formatSwizzle, toApply.swizzleAlpha);

    return result;
}

gl::SwizzleState GetFormatSwizzle(const ContextVk *contextVk,
                                  const angle::Format &angleFormat,
                                  const bool sized)
{
    gl::SwizzleState internalSwizzle;

    if (angleFormat.isLUMA())
    {
        GLenum swizzleRGB, swizzleA;
        if (angleFormat.luminanceBits > 0)
        {
            swizzleRGB = GL_RED;
            swizzleA   = (angleFormat.alphaBits > 0 ? GL_GREEN : GL_ONE);
        }
        else
        {
            swizzleRGB = GL_ZERO;
            swizzleA   = GL_RED;
        }
        internalSwizzle.swizzleRed   = swizzleRGB;
        internalSwizzle.swizzleGreen = swizzleRGB;
        internalSwizzle.swizzleBlue  = swizzleRGB;
        internalSwizzle.swizzleAlpha = swizzleA;
    }
    else
    {
        if (angleFormat.hasDepthOrStencilBits())
        {
            // In OES_depth_texture/ARB_depth_texture, depth
            // textures are treated as luminance.
            // If the internalformat was not sized, use OES_depth_texture behavior
            bool hasGB = (angleFormat.depthBits > 0) && !sized;

            internalSwizzle.swizzleRed   = GL_RED;
            internalSwizzle.swizzleGreen = hasGB ? GL_RED : GL_ZERO;
            internalSwizzle.swizzleBlue  = hasGB ? GL_RED : GL_ZERO;
            internalSwizzle.swizzleAlpha = GL_ONE;
        }
        else
        {
            // Color bits are all zero for blocked formats
            if (!angleFormat.isBlock)
            {
                // Set any missing channel to default in case the emulated format has that channel.
                internalSwizzle.swizzleRed   = angleFormat.redBits > 0 ? GL_RED : GL_ZERO;
                internalSwizzle.swizzleGreen = angleFormat.greenBits > 0 ? GL_GREEN : GL_ZERO;
                internalSwizzle.swizzleBlue  = angleFormat.blueBits > 0 ? GL_BLUE : GL_ZERO;
                internalSwizzle.swizzleAlpha = angleFormat.alphaBits > 0 ? GL_ALPHA : GL_ONE;
            }
        }
    }

    return internalSwizzle;
}
}  // namespace rx