//
// Copyright 2018 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.
//
// FeaturesVk.h: Optional features for the Vulkan renderer.
//

#ifndef ANGLE_PLATFORM_FEATURESVK_H_
#define ANGLE_PLATFORM_FEATURESVK_H_

#include "platform/Feature.h"

namespace angle
{

struct FeaturesVk : FeatureSetBase
{
    FeaturesVk();
    ~FeaturesVk();

    // Line segment rasterization must follow OpenGL rules. This means using an algorithm similar
    // to Bresenham's. Vulkan uses a different algorithm. This feature enables the use of pixel
    // shader patching to implement OpenGL basic line rasterization rules. This feature will
    // normally always be enabled. Exposing it as an option enables performance testing.
    Feature basicGLLineRasterization = {
        "basic_gl_line_rasterization", FeatureCategory::VulkanFeatures,
        "Enable the use of pixel shader patching to implement OpenGL basic line "
        "rasterization rules",
        &members};

    // If the VK_EXT_line_rasterization extension is available we'll use it to get
    // Bresenham line rasterization.
    Feature bresenhamLineRasterization = {
        "bresenham_line_rasterization", FeatureCategory::VulkanFeatures,
        "Enable Bresenham line rasterization via VK_EXT_line_rasterization extension", &members};

    // If the VK_EXT_provoking_vertex extension is available, we'll use it to set
    // the provoking vertex mode
    Feature provokingVertex = {"provoking_vertex", FeatureCategory::VulkanFeatures,
                               "Enable provoking vertex mode via VK_EXT_provoking_vertex extension",
                               &members};

    // Flips the viewport to render upside-down. This has the effect to render the same way as
    // OpenGL. If this feature gets enabled, we enable the KHR_MAINTENANCE_1 extension to allow
    // negative viewports. We inverse rendering to the backbuffer by reversing the height of the
    // viewport and increasing Y by the height. So if the viewport was (0,0,width,height), it
    // becomes (0, height, width, -height). Unfortunately, when we start doing this, we also need
    // to adjust a lot of places since the rendering now happens upside-down. Affected places so
    // far:
    // -readPixels
    // -copyTexImage
    // -framebuffer blit
    // -generating mipmaps
    // -Point sprites tests
    // -texStorage
    Feature flipViewportY = {"flip_viewport_y", FeatureCategory::VulkanFeatures,
                             "Flips the viewport to render upside-down", &members};

    // Add an extra copy region when using vkCmdCopyBuffer as the Windows Intel driver seems
    // to have a bug where the last region is ignored.
    Feature extraCopyBufferRegion = {
        "extra_copy_buffer_region", FeatureCategory::VulkanWorkarounds,
        "Some drivers seem to have a bug where the last copy region in vkCmdCopyBuffer is ignored",
        &members};

    // This flag is added for the sole purpose of end2end tests, to test the correctness
    // of various algorithms when a fallback format is used, such as using a packed format to
    // emulate a depth- or stencil-only format.
    Feature forceFallbackFormat = {"force_fallback_format", FeatureCategory::VulkanWorkarounds,
                                   "Force a fallback format for angle_end2end_tests", &members};

    // On some NVIDIA drivers the point size range reported from the API is inconsistent with the
    // actual behavior. Clamp the point size to the value from the API to fix this.
    // Tracked in http://anglebug.com/2970.
    Feature clampPointSize = {
        "clamp_point_size", FeatureCategory::VulkanWorkarounds,
        "The point size range reported from the API is inconsistent with the actual behavior",
        &members, "http://anglebug.com/2970"};

    // On some android devices, the memory barrier between the compute shader that converts vertex
    // attributes and the vertex shader that reads from it is ineffective.  Only known workaround is
    // to perform a flush after the conversion.  http://anglebug.com/3016
    Feature flushAfterVertexConversion = {
        "flush_after_vertex_conversion", FeatureCategory::VulkanWorkarounds,
        "The memory barrier between the compute shader that converts vertex attributes and the "
        "vertex shader that reads from it is ineffective",
        &members, "http://anglebug.com/3016"};

    // Whether the VkDevice supports the VK_KHR_incremental_present extension, on which the
    // EGL_KHR_swap_buffers_with_damage extension can be layered.
    Feature supportsIncrementalPresent = {
        "supports_incremental_present", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_KHR_incremental_present extension", &members};

    // Whether texture copies on cube map targets should be done on GPU.  This is a workaround for
    // Intel drivers on windows that have an issue with creating single-layer views on cube map
    // textures.
    Feature forceCPUPathForCubeMapCopy = {
        "force_cpu_path_for_cube_map_copy", FeatureCategory::VulkanWorkarounds,
        "Some drivers have an issue with creating single-layer views on cube map textures",
        &members};

    // Whether the VkDevice supports the VK_ANDROID_external_memory_android_hardware_buffer
    // extension, on which the EGL_ANDROID_image_native_buffer extension can be layered.
    Feature supportsAndroidHardwareBuffer = {
        "supports_android_hardware_buffer", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_ANDROID_external_memory_android_hardware_buffer extension",
        &members};

    // Whether the VkDevice supports the VK_KHR_external_memory_fd extension, on which the
    // GL_EXT_memory_object_fd extension can be layered.
    Feature supportsExternalMemoryFd = {
        "supports_external_memory_fd", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_KHR_external_memory_fd extension", &members};

    // Whether the VkDevice supports the VK_FUCHSIA_external_memory
    // extension, on which the GL_ANGLE_memory_object_fuchsia extension can be layered.
    angle::Feature supportsExternalMemoryFuchsia = {
        "supports_external_memory_fuchsia", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_FUCHSIA_external_memory extension", &members};

    // Whether the VkDevice supports the VK_KHR_external_semaphore_fd extension, on which the
    // GL_EXT_semaphore_fd extension can be layered.
    Feature supportsExternalSemaphoreFd = {
        "supports_external_semaphore_fd", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_KHR_external_semaphore_fd extension", &members};

    // Whether the VkDevice supports the VK_FUCHSIA_external_semaphore
    // extension, on which the GL_ANGLE_semaphore_fuchsia extension can be layered.
    angle::Feature supportsExternalSemaphoreFuchsia = {
        "supports_external_semaphore_fuchsia", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_FUCHSIA_external_semaphore extension", &members};

    // Whether the VkDevice supports the VK_EXT_shader_stencil_export extension, which is used to
    // perform multisampled resolve of stencil buffer.  A multi-step workaround is used instead if
    // this extension is not available.
    Feature supportsShaderStencilExport = {
        "supports_shader_stencil_export", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_EXT_shader_stencil_export extension", &members};

    // Where VK_EXT_transform_feedback is not support, an emulation path is used.
    // http://anglebug.com/3205
    Feature emulateTransformFeedback = {
        "emulate_transform_feedback", FeatureCategory::VulkanFeatures,
        "Emulate transform feedback as the VK_EXT_transform_feedback is not present.", &members,
        "http://anglebug.com/3205"};

    // Where VK_EXT_transform_feedback is supported, it's preferred over an emulation path.
    // http://anglebug.com/3206
    Feature supportsTransformFeedbackExtension = {
        "supports_transform_feedback_extension", FeatureCategory::VulkanFeatures,
        "Transform feedback uses the VK_EXT_transform_feedback extension.", &members,
        "http://anglebug.com/3206"};

    // VK_PRESENT_MODE_FIFO_KHR causes random timeouts on Linux Intel. http://anglebug.com/3153
    Feature disableFifoPresentMode = {
        "disable_fifo_present_mode", FeatureCategory::VulkanWorkarounds,
        "VK_PRESENT_MODE_FIFO_KHR causes random timeouts", &members, "http://anglebug.com/3153"};

    // On Qualcomm, gaps in bound descriptor set indices causes the post-gap sets to misbehave.
    // For example, binding only descriptor set 3 results in zero being read from a uniform buffer
    // object within that set.  This flag results in empty descriptor sets being bound for any
    // unused descriptor set to work around this issue.  http://anglebug.com/2727
    Feature bindEmptyForUnusedDescriptorSets = {
        "bind_empty_for_unused_descriptor_sets", FeatureCategory::VulkanWorkarounds,
        "Gaps in bound descriptor set indices causes the post-gap sets to misbehave", &members,
        "http://anglebug.com/2727"};

    // OES_depth_texture is a commonly expected feature on Android. However it
    // requires that D16_UNORM support texture filtering
    // (e.g. VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT) and some devices
    // do not. Work-around this by setting saying D16_UNORM supports filtering
    // anyway.
    Feature forceD16TexFilter = {
        "force_D16_texture_filter", FeatureCategory::VulkanWorkarounds,
        "VK_FORMAT_D16_UNORM does not support VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT, "
        "which prevents OES_depth_texture from being supported.",
        &members, "http://anglebug.com/3452"};

    // On some android devices, vkCmdBlitImage with flipped coordinates blits incorrectly.  This
    // workaround makes sure this path is avoided.  http://anglebug.com/3498
    Feature disableFlippingBlitWithCommand = {
        "disable_flipping_blit_with_command", FeatureCategory::VulkanWorkarounds,
        "vkCmdBlitImage with flipped coordinates blits incorrectly.", &members,
        "http://anglebug.com/3498"};

    // On platform with Intel or AMD GPU, a window resizing would not trigger the vulkan driver to
    // return VK_ERROR_OUT_OF_DATE on swapchain present.  Work-around by query current window extent
    // every frame to detect a window resizing.
    // http://anglebug.com/3623, http://anglebug.com/3624, http://anglebug.com/3625
    Feature perFrameWindowSizeQuery = {
        "per_frame_window_size_query", FeatureCategory::VulkanWorkarounds,
        "Vulkan swapchain is not returning VK_ERROR_OUT_OF_DATE when window resizing", &members,
        "http://anglebug.com/3623, http://anglebug.com/3624, http://anglebug.com/3625"};

    // Seamful cube map emulation misbehaves on the AMD windows driver, so it's disallowed.
    Feature disallowSeamfulCubeMapEmulation = {
        "disallow_seamful_cube_map_emulation", FeatureCategory::VulkanWorkarounds,
        "Seamful cube map emulation misbehaves on some drivers, so it's disallowed", &members,
        "http://anglebug.com/3243"};

    // Qualcomm and SwiftShader shader compiler doesn't support sampler arrays as parameters, so
    // revert to old RewriteStructSamplers behavior, which produces fewer.
    Feature forceOldRewriteStructSamplers = {
        "force_old_rewrite_struct_samplers", FeatureCategory::VulkanWorkarounds,
        "Some shader compilers don't support sampler arrays as parameters, so revert to old "
        "RewriteStructSamplers behavior, which produces fewer.",
        &members, "http://anglebug.com/2703"};

    // Vulkan considers vertex attribute accesses to count up to the last multiple of the stride.
    // This additional access supports AMD's robust buffer access implementation.
    // AMDVLK in particular will return incorrect values when the vertex access extends into the
    // range that would be the stride padding and the buffer is too small.
    // This workaround limits GL_MAX_VERTEX_ATTRIB_STRIDE to a reasonable value and pads out
    // every buffer allocation size to be large enough to support a maximum vertex stride.
    // http://anglebug.com/4428
    Feature padBuffersToMaxVertexAttribStride = {
        "pad_buffers_to_max_vertex_attrib_stride", FeatureCategory::VulkanWorkarounds,
        "Vulkan considers vertex attribute accesses to count up to the last multiple of the "
        "stride. This additional access supports AMD's robust buffer access implementation. "
        "AMDVLK in particular will return incorrect values when the vertex access extends into "
        "the range that would be the stride padding and the buffer is too small. "
        "This workaround limits GL_MAX_VERTEX_ATTRIB_STRIDE to a maximum value and "
        "pads up every buffer allocation size to be a multiple of the maximum stride.",
        &members, "http://anglebug.com/4428"};

    // Whether the VkDevice supports the VK_EXT_swapchain_colorspace extension
    // http://anglebug.com/2514
    Feature supportsSwapchainColorspace = {
        "supports_swapchain_colorspace", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_EXT_swapchain_colorspace extension", &members,
        "http://anglebug.com/2514"};

    // Whether the VkDevice supports the VK_EXT_external_memory_host extension, on which the
    // ANGLE_iosurface_client_buffer extension can be layered.
    Feature supportsExternalMemoryHost = {
        "supports_external_memory_host", FeatureCategory::VulkanFeatures,
        "VkDevice supports the VK_EXT_external_memory_host extension", &members};

    // Whether to fill new buffers and textures with nonzero data to sanitize robust resource
    // initialization and flush out assumptions about zero init.
    Feature allocateNonZeroMemory = {
        "allocate_non_zero_memory", FeatureCategory::VulkanFeatures,
        "Fill new allocations with non-zero values to flush out errors.", &members,
        "http://anglebug.com/4384"};

    // Android needs to pre-rotate surfaces that are not oriented per the native device's
    // orientation (e.g. a landscape application on a Pixel phone).  This feature works for
    // full-screen applications. http://anglebug.com/3502
    Feature enablePreRotateSurfaces = {"enable_pre_rotation_surfaces",
                                       FeatureCategory::VulkanFeatures,
                                       "Enable Android pre-rotation for landscape applications",
                                       &members, "http://anglebug.com/3502"};
};

inline FeaturesVk::FeaturesVk()  = default;
inline FeaturesVk::~FeaturesVk() = default;

}  // namespace angle

#endif  // ANGLE_PLATFORM_FEATURESVK_H_
