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Merge pull request #7904 from stenzek/do-the-atomic-shuffle

PixelShaderGen: Use subgroup reduction for bounding box
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stenzek committed Mar 29, 2019
2 parents 95c7b5c + d66d778 commit a50a34b94b3f1fc75f991dbd4f6415878be7de42
@@ -719,6 +719,29 @@ void ProgramShaderCache::CreateHeader()
break;
}

std::string shader_shuffle_string;
if (g_ogl_config.bSupportsShaderThreadShuffleNV)
{
shader_shuffle_string = R"(
#extension GL_NV_shader_thread_group : enable
#extension GL_NV_shader_thread_shuffle : enable
#define SUPPORTS_SUBGROUP_REDUCTION 1
// The xor shuffle below produces incorrect results if all threads in a warp are not active.
#define CAN_USE_SUBGROUP_REDUCTION (ballotThreadNV(true) == 0xFFFFFFFFu)
#define IS_HELPER_INVOCATION gl_HelperThreadNV
#define IS_FIRST_ACTIVE_INVOCATION (gl_ThreadInWarpNV == findLSB(ballotThreadNV(!gl_HelperThreadNV)))
#define SUBGROUP_REDUCTION(func, value) value = func(value, shuffleXorNV(value, 16, 32)); \
value = func(value, shuffleXorNV(value, 8, 32)); \
value = func(value, shuffleXorNV(value, 4, 32)); \
value = func(value, shuffleXorNV(value, 2, 32)); \
value = func(value, shuffleXorNV(value, 1, 32));
#define SUBGROUP_MIN(value) SUBGROUP_REDUCTION(min, value)
#define SUBGROUP_MAX(value) SUBGROUP_REDUCTION(max, value)
)";
}

s_glsl_header = StringFromFormat(
"%s\n"
"%s\n" // ubo
@@ -737,6 +760,7 @@ void ProgramShaderCache::CreateHeader()
"%s\n" // ES dual source blend
"%s\n" // shader image load store
"%s\n" // shader framebuffer fetch
"%s\n" // shader thread shuffle

// Precision defines for GLSL ES
"%s\n"
@@ -815,8 +839,9 @@ void ProgramShaderCache::CreateHeader()
((!is_glsles && v < Glsl430) || (is_glsles && v < GlslEs310)) ?
"#extension GL_ARB_shader_image_load_store : enable" :
"",
framebuffer_fetch_string.c_str(), is_glsles ? "precision highp float;" : "",
is_glsles ? "precision highp int;" : "", is_glsles ? "precision highp sampler2DArray;" : "",
framebuffer_fetch_string.c_str(), shader_shuffle_string.c_str(),
is_glsles ? "precision highp float;" : "", is_glsles ? "precision highp int;" : "",
is_glsles ? "precision highp sampler2DArray;" : "",
(is_glsles && g_ActiveConfig.backend_info.bSupportsPaletteConversion) ?
"precision highp usamplerBuffer;" :
"",
@@ -661,6 +661,9 @@ Renderer::Renderer(std::unique_ptr<GLContext> main_gl_context, float backbuffer_
if (g_ogl_config.max_samples < 1 || !g_ogl_config.bSupportsMSAA)
g_ogl_config.max_samples = 1;

g_ogl_config.bSupportsShaderThreadShuffleNV =
GLExtensions::Supports("GL_NV_shader_thread_shuffle");

// We require texel buffers, image load store, and compute shaders to enable GPU texture decoding.
// If the driver doesn't expose the extensions, but supports GL4.3/GLES3.1, it will still be
// enabled in the version check below.
@@ -70,6 +70,7 @@ struct VideoConfig
bool bSupportsBitfield;
bool bSupportsTextureSubImage;
EsFbFetchType SupportedFramebufferFetch;
bool bSupportsShaderThreadShuffleNV;

const char* gl_vendor;
const char* gl_renderer;
@@ -17,6 +17,7 @@
#include "ShaderLang.h"
#include "disassemble.h"

#include "Common/CommonFuncs.h"
#include "Common/FileUtil.h"
#include "Common/Logging/Log.h"
#include "Common/MsgHandler.h"
@@ -99,6 +100,18 @@ static const char COMPUTE_SHADER_HEADER[] = R"(
#define frac fract
#define lerp mix
)";
static const char SUBGROUP_HELPER_HEADER[] = R"(
#extension GL_KHR_shader_subgroup_basic : enable
#extension GL_KHR_shader_subgroup_arithmetic : enable
#extension GL_KHR_shader_subgroup_ballot : enable
#define SUPPORTS_SUBGROUP_REDUCTION 1
#define CAN_USE_SUBGROUP_REDUCTION true
#define IS_HELPER_INVOCATION gl_HelperInvocation
#define IS_FIRST_ACTIVE_INVOCATION (gl_SubgroupInvocationID == subgroupBallotFindLSB(subgroupBallot(true)))
#define SUBGROUP_MIN(value) value = subgroupMin(value)
#define SUBGROUP_MAX(value) value = subgroupMax(value)
)";

bool CompileShaderToSPV(SPIRVCodeVector* out_code, EShLanguage stage, const char* stage_filename,
const char* source_code, size_t source_code_length, const char* header,
@@ -120,13 +133,20 @@ bool CompileShaderToSPV(SPIRVCodeVector* out_code, EShLanguage stage, const char
int pass_source_code_length = static_cast<int>(source_code_length);
if (header_length > 0)
{
full_source_code.reserve(header_length + source_code_length);
constexpr size_t subgroup_helper_header_length = ArraySize(SUBGROUP_HELPER_HEADER) - 1;
full_source_code.reserve(header_length + subgroup_helper_header_length + source_code_length);
full_source_code.append(header, header_length);
if (g_vulkan_context->SupportsShaderSubgroupOperations())
full_source_code.append(SUBGROUP_HELPER_HEADER, subgroup_helper_header_length);
full_source_code.append(source_code, source_code_length);
pass_source_code = full_source_code.c_str();
pass_source_code_length = static_cast<int>(full_source_code.length());
}

// Sub-group operations require Vulkan 1.1 and SPIR-V 1.3.
if (g_vulkan_context->SupportsShaderSubgroupOperations())
shader->setEnvTarget(glslang::EShTargetSpv, glslang::EShTargetSpv_1_3);

shader->setStringsWithLengths(&pass_source_code, &pass_source_code_length, 1);

auto DumpBadShader = [&](const char* msg) {
@@ -384,6 +384,7 @@ std::unique_ptr<VulkanContext> VulkanContext::Create(VkInstance instance, VkPhys

// Initialize DriverDetails so that we can check for bugs to disable features if needed.
context->InitDriverDetails();
context->PopulateShaderSubgroupSupport();

// Enable debug reports if the "Host GPU" log category is enabled.
if (enable_debug_reports)
@@ -864,4 +865,31 @@ void VulkanContext::InitDriverDetails()
static_cast<double>(m_device_properties.driverVersion),
DriverDetails::Family::UNKNOWN);
}

void VulkanContext::PopulateShaderSubgroupSupport()
{
// If this function isn't available, we don't support Vulkan 1.1.
if (!vkGetPhysicalDeviceProperties2)
return;

VkPhysicalDeviceProperties2 device_properties_2 = {};
device_properties_2.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_PROPERTIES_2;

VkPhysicalDeviceSubgroupProperties subgroup_properties = {};
subgroup_properties.sType = VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SUBGROUP_PROPERTIES;
device_properties_2.pNext = &subgroup_properties;

vkGetPhysicalDeviceProperties2(m_physical_device, &device_properties_2);

m_shader_subgroup_size = subgroup_properties.subgroupSize;

// We require basic ops (for gl_SubgroupInvocationID), ballot (for subgroupBallot,
// subgroupBallotFindLSB), and arithmetic (for subgroupMin/subgroupMax).
constexpr VkSubgroupFeatureFlags required_operations = VK_SUBGROUP_FEATURE_BASIC_BIT |
VK_SUBGROUP_FEATURE_ARITHMETIC_BIT |
VK_SUBGROUP_FEATURE_BALLOT_BIT;
m_supports_shader_subgroup_operations =
(subgroup_properties.supportedOperations & required_operations) == required_operations &&
subgroup_properties.supportedStages & VK_SHADER_STAGE_FRAGMENT_BIT;
}
} // namespace Vulkan
@@ -80,6 +80,8 @@ class VulkanContext
{
return m_device_features.occlusionQueryPrecise == VK_TRUE;
}
u32 GetShaderSubgroupSize() const { return m_shader_subgroup_size; }
bool SupportsShaderSubgroupOperations() const { return m_supports_shader_subgroup_operations; }

// Helpers for getting constants
VkDeviceSize GetUniformBufferAlignment() const
@@ -112,6 +114,7 @@ class VulkanContext
bool SelectDeviceFeatures();
bool CreateDevice(VkSurfaceKHR surface, bool enable_validation_layer);
void InitDriverDetails();
void PopulateShaderSubgroupSupport();

VkInstance m_instance = VK_NULL_HANDLE;
VkPhysicalDevice m_physical_device = VK_NULL_HANDLE;
@@ -128,6 +131,9 @@ class VulkanContext
VkPhysicalDeviceFeatures m_device_features = {};
VkPhysicalDeviceProperties m_device_properties = {};
VkPhysicalDeviceMemoryProperties m_device_memory_properties = {};

u32 m_shader_subgroup_size = 1;
bool m_supports_shader_subgroup_operations = false;
};

extern std::unique_ptr<VulkanContext> g_vulkan_context;
@@ -59,6 +59,7 @@ VULKAN_INSTANCE_ENTRY_POINT(vkCreateMacOSSurfaceMVK, false)
VULKAN_INSTANCE_ENTRY_POINT(vkCreateDebugReportCallbackEXT, false)
VULKAN_INSTANCE_ENTRY_POINT(vkDestroyDebugReportCallbackEXT, false)
VULKAN_INSTANCE_ENTRY_POINT(vkDebugReportMessageEXT, false)
VULKAN_INSTANCE_ENTRY_POINT(vkGetPhysicalDeviceProperties2, false)

#endif // VULKAN_INSTANCE_ENTRY_POINT

@@ -459,6 +459,17 @@ SSBO_BINDING(0) buffer BBox {
};
#endif
void UpdateBoundingBoxBuffer(float2 min_pos, float2 max_pos) {
if (bbox_left > int(min_pos.x))
atomicMin(bbox_left, int(min_pos.x));
if (bbox_right < int(max_pos.x))
atomicMax(bbox_right, int(max_pos.x));
if (bbox_top > int(min_pos.y))
atomicMin(bbox_top, int(min_pos.y));
if (bbox_bottom < int(max_pos.y))
atomicMax(bbox_bottom, int(max_pos.y));
}
void UpdateBoundingBox(float2 rawpos) {
// The pixel center in the GameCube GPU is 7/12, not 0.5 (see VertexShaderGen.cpp)
// Adjust for this by unapplying the offset we added in the vertex shader.
@@ -471,18 +482,25 @@ void UpdateBoundingBox(float2 rawpos) {
#endif
// The bounding box register is exclusive of the right coordinate, hence the +1.
int2 pos = iround(rawpos * cefbscale + offset);
int2 pos_offset = pos + int2(1, 1);
if (bbox_left > pos.x)
atomicMin(bbox_left, pos.x);
if (bbox_right < pos_offset.x)
atomicMax(bbox_right, pos_offset.x);
if (bbox_top > pos.y)
atomicMin(bbox_top, pos.y);
if (bbox_bottom < pos_offset.y)
atomicMax(bbox_bottom, pos_offset.y);
int2 min_pos = iround(rawpos * cefbscale + offset);
int2 max_pos = min_pos + int2(1, 1);
#ifdef SUPPORTS_SUBGROUP_REDUCTION
if (CAN_USE_SUBGROUP_REDUCTION) {
min_pos = IS_HELPER_INVOCATION ? int2(2147483647, 2147483647) : min_pos;
max_pos = IS_HELPER_INVOCATION ? int2(-2147483648, -2147483648) : max_pos;
SUBGROUP_MIN(min_pos);
SUBGROUP_MAX(max_pos);
if (IS_FIRST_ACTIVE_INVOCATION)
UpdateBoundingBoxBuffer(min_pos, max_pos);
} else {
UpdateBoundingBoxBuffer(min_pos, max_pos);
}
#else
UpdateBoundingBoxBuffer(min_pos, max_pos);
#endif
}
)");
}
}
@@ -1332,7 +1350,7 @@ static void WriteAlphaTest(ShaderCode& out, const pixel_shader_uid_data* uid_dat
if (!uid_data->alpha_test_use_zcomploc_hack)
{
out.Write("\t\tdiscard;\n");
if (ApiType != APIType::D3D)
if (ApiType == APIType::D3D)
out.Write("\t\treturn;\n");
}

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