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//
// Copyright 2021 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.
//
// ProvokingVertexHelper.mm:
// Implements the class methods for ProvokingVertexHelper.
//
#include "libANGLE/renderer/metal/ProvokingVertexHelper.h"
#import <Foundation/Foundation.h>
#include "common/base/anglebase/numerics/checked_math.h"
#include "libANGLE/Display.h"
#include "libANGLE/renderer/metal/ContextMtl.h"
#include "libANGLE/renderer/metal/DisplayMtl.h"
#include "libANGLE/renderer/metal/mtl_common.h"
#include "libANGLE/renderer/metal/shaders/rewrite_indices_shared.h"
namespace rx
{
namespace
{
constexpr size_t kInitialIndexBufferSize = 0xFFFF; // Initial 64k pool.
}
static inline uint32_t primCountForIndexCount(const uint fixIndexBufferKey,
const GLsizei indexCount)
{
const uint fixIndexBufferMode =
(fixIndexBufferKey >> MtlFixIndexBufferKeyModeShift) & MtlFixIndexBufferKeyModeMask;
switch (fixIndexBufferMode)
{
case MtlFixIndexBufferKeyPoints:
return indexCount;
case MtlFixIndexBufferKeyLines:
return indexCount / 2;
case MtlFixIndexBufferKeyLineStrip:
// Prevent underflow with subtraction and avoid casting to a signed type
return std::max(indexCount - 1, 0);
case MtlFixIndexBufferKeyLineLoop:
return indexCount;
case MtlFixIndexBufferKeyTriangles:
return indexCount / 3;
case MtlFixIndexBufferKeyTriangleStrip:
// Prevent underflow with subtraction and avoid casting to a signed type
return std::max(indexCount - 2, 0);
case MtlFixIndexBufferKeyTriangleFan:
// Prevent underflow with subtraction and avoid casting to a signed type
return std::max(indexCount - 2, 0);
default:
ASSERT(false);
return 0;
}
}
static inline bool indexCountForPrimCount(const uint fixIndexBufferKey,
const uint32_t primCount,
uint32_t *outIndexCount)
{
const uint fixIndexBufferMode =
(fixIndexBufferKey >> MtlFixIndexBufferKeyModeShift) & MtlFixIndexBufferKeyModeMask;
uint32_t indicesPerPrimitive = 0;
switch (fixIndexBufferMode)
{
case MtlFixIndexBufferKeyPoints:
indicesPerPrimitive = 1;
break;
case MtlFixIndexBufferKeyLines:
case MtlFixIndexBufferKeyLineStrip:
case MtlFixIndexBufferKeyLineLoop:
indicesPerPrimitive = 2;
break;
case MtlFixIndexBufferKeyTriangles:
case MtlFixIndexBufferKeyTriangleStrip:
case MtlFixIndexBufferKeyTriangleFan:
indicesPerPrimitive = 3;
break;
default:
UNREACHABLE();
return false;
}
angle::CheckedNumeric<uint32_t> indexCount(primCount);
indexCount *= indicesPerPrimitive;
return indexCount.AssignIfValid(outIndexCount);
}
static inline gl::PrimitiveMode getNewPrimitiveMode(const uint fixIndexBufferKey)
{
const uint fixIndexBufferMode =
(fixIndexBufferKey >> MtlFixIndexBufferKeyModeShift) & MtlFixIndexBufferKeyModeMask;
switch (fixIndexBufferMode)
{
case MtlFixIndexBufferKeyPoints:
return gl::PrimitiveMode::Points;
case MtlFixIndexBufferKeyLines:
return gl::PrimitiveMode::Lines;
case MtlFixIndexBufferKeyLineStrip:
return gl::PrimitiveMode::Lines;
case MtlFixIndexBufferKeyLineLoop:
return gl::PrimitiveMode::Lines;
case MtlFixIndexBufferKeyTriangles:
return gl::PrimitiveMode::Triangles;
case MtlFixIndexBufferKeyTriangleStrip:
return gl::PrimitiveMode::Triangles;
case MtlFixIndexBufferKeyTriangleFan:
return gl::PrimitiveMode::Triangles;
default:
ASSERT(false);
return gl::PrimitiveMode::InvalidEnum;
}
}
ProvokingVertexHelper::ProvokingVertexHelper(ContextMtl *context) : mIndexBuffers(false)
{
mIndexBuffers.initialize(context, kInitialIndexBufferSize, mtl::kIndexBufferOffsetAlignment, 0);
}
void ProvokingVertexHelper::onDestroy(ContextMtl *context)
{
mIndexBuffers.destroy(context);
}
void ProvokingVertexHelper::releaseInFlightBuffers(ContextMtl *contextMtl)
{
mIndexBuffers.releaseInFlightBuffers(contextMtl);
}
static uint buildIndexBufferKey(gl::DrawElementsType elementType,
bool doPrimPrestart,
gl::PrimitiveMode primMode)
{
uint indexBufferKey = 0;
switch (elementType)
{
case gl::DrawElementsType::UnsignedShort:
indexBufferKey |= MtlFixIndexBufferKeyUint16 << MtlFixIndexBufferKeyInShift;
indexBufferKey |= MtlFixIndexBufferKeyUint16 << MtlFixIndexBufferKeyOutShift;
break;
case gl::DrawElementsType::UnsignedInt:
indexBufferKey |= MtlFixIndexBufferKeyUint32 << MtlFixIndexBufferKeyInShift;
indexBufferKey |= MtlFixIndexBufferKeyUint32 << MtlFixIndexBufferKeyOutShift;
break;
default:
ASSERT(false); // Index type should only be short or int.
break;
}
indexBufferKey |= (uint)primMode << MtlFixIndexBufferKeyModeShift;
indexBufferKey |= doPrimPrestart ? MtlFixIndexBufferKeyPrimRestart : 0;
// We only rewrite indices if we're switching the provoking vertex mode.
indexBufferKey |= MtlFixIndexBufferKeyProvokingVertexLast;
return indexBufferKey;
}
angle::Result ProvokingVertexHelper::prepareCommandEncoderForFunction(
ContextMtl *context,
mtl::ComputeCommandEncoder *encoder,
uint32_t indexBufferKey,
bool isForGenerateIndices)
{
auto &functionMap = isForGenerateIndices ? mGenIndexBufferFunctions : mFixIndexBufferFunctions;
NSString *functionName = isForGenerateIndices ? @"genIndexBuffer" : @"fixIndexBuffer";
angle::ObjCPtr<id<MTLFunction>> computeShader;
auto iter = functionMap.find(indexBufferKey);
if (iter != functionMap.end())
{
computeShader = iter->second;
}
else
{
id<MTLLibrary> provokingVertexLibrary = context->getDisplay()->getDefaultShadersLib();
auto fcValues = angle::adoptObjCPtr([[MTLFunctionConstantValues alloc] init]);
[fcValues setConstantValue:&indexBufferKey
type:MTLDataTypeUInt
withName:@"fixIndexBufferKey"];
ANGLE_TRY(CreateMslShader(context, provokingVertexLibrary, functionName, fcValues.get(),
&computeShader));
functionMap[indexBufferKey] = computeShader;
}
angle::ObjCPtr<id<MTLComputePipelineState>> pipelineState;
ANGLE_TRY(
context->getPipelineCache().getComputePipeline(context, computeShader, &pipelineState));
encoder->setComputePipelineState(pipelineState);
return angle::Result::Continue;
}
angle::Result ProvokingVertexHelper::preconditionIndexBuffer(ContextMtl *context,
mtl::BufferRef indexBuffer,
GLsizei glCount,
size_t indexOffset,
bool primitiveRestartEnabled,
gl::PrimitiveMode primitiveMode,
gl::DrawElementsType elementsType,
uint32_t &outIndexCount,
size_t &outIndexOffset,
gl::PrimitiveMode &outPrimitiveMode,
mtl::BufferRef &outNewBuffer)
{
// Get specialized program
// Upload index buffer
// dispatch per-primitive?
uint indexBufferKey = buildIndexBufferKey(elementsType, primitiveRestartEnabled, primitiveMode);
uint32_t primCount = primCountForIndexCount(indexBufferKey, glCount);
uint32_t newIndexCount = 0;
ANGLE_CHECK_GL_MATH(context, indexCountForPrimCount(indexBufferKey, primCount, &newIndexCount));
size_t indexSize = gl::GetDrawElementsTypeSize(elementsType);
size_t newOffset = 0;
mtl::BufferRef newBuffer;
angle::CheckedNumeric<size_t> checkedBufferSize(newIndexCount);
checkedBufferSize *= indexSize;
checkedBufferSize += indexOffset;
ANGLE_CHECK_GL_MATH(context, checkedBufferSize.IsValid());
ANGLE_TRY(mIndexBuffers.allocate(context, checkedBufferSize.ValueOrDie(), nullptr, &newBuffer,
&newOffset));
auto threadsPerThreadgroup = MTLSizeMake(MIN(primCount, 64u), 1, 1);
mtl::ComputeCommandEncoder *encoder =
context->getComputeCommandEncoderWithoutEndingRenderEncoder();
const bool isForGenerateIndices = false;
ANGLE_TRY(
prepareCommandEncoderForFunction(context, encoder, indexBufferKey, isForGenerateIndices));
encoder->setBuffer(indexBuffer, static_cast<uint32_t>(indexOffset), 0);
encoder->setBufferForWrite(
newBuffer, static_cast<uint32_t>(indexOffset) + static_cast<uint32_t>(newOffset), 1);
encoder->setData(static_cast<uint>(glCount), 2);
encoder->setData(primCount, 3);
encoder->dispatch(
MTLSizeMake((static_cast<NSUInteger>(primCount) + threadsPerThreadgroup.width - 1) /
threadsPerThreadgroup.width,
1, 1),
threadsPerThreadgroup);
outIndexCount = static_cast<uint32_t>(newIndexCount);
outIndexOffset = newOffset;
outPrimitiveMode = getNewPrimitiveMode(indexBufferKey);
outNewBuffer = newBuffer;
return angle::Result::Continue;
}
angle::Result ProvokingVertexHelper::generateIndexBuffer(ContextMtl *context,
size_t first,
GLsizei glCount,
gl::PrimitiveMode primitiveMode,
gl::DrawElementsType elementsType,
uint32_t &outIndexCount,
size_t &outIndexOffset,
gl::PrimitiveMode &outPrimitiveMode,
mtl::BufferRef &outNewBuffer)
{
// Get specialized program
// Upload index buffer
// dispatch per-primitive?
const bool primitiveRestartEnabled = false;
uint indexBufferKey = buildIndexBufferKey(elementsType, primitiveRestartEnabled, primitiveMode);
uint32_t primCount = primCountForIndexCount(indexBufferKey, glCount);
uint32_t newIndexCount = 0;
ANGLE_CHECK_GL_MATH(context, indexCountForPrimCount(indexBufferKey, primCount, &newIndexCount));
size_t indexSize = gl::GetDrawElementsTypeSize(elementsType);
size_t newIndexOffset = 0;
mtl::BufferRef newBuffer;
angle::CheckedNumeric<size_t> checkedBufferSize = newIndexCount;
checkedBufferSize *= indexSize;
ANGLE_CHECK_GL_MATH(context, checkedBufferSize.IsValid());
ANGLE_TRY(mIndexBuffers.allocate(context, checkedBufferSize.ValueOrDie(), nullptr, &newBuffer,
&newIndexOffset));
auto threadsPerThreadgroup = MTLSizeMake(MIN(primCount, 64u), 1, 1);
mtl::ComputeCommandEncoder *encoder =
context->getComputeCommandEncoderWithoutEndingRenderEncoder();
const bool isForGenerateIndices = true;
ANGLE_TRY(
prepareCommandEncoderForFunction(context, encoder, indexBufferKey, isForGenerateIndices));
encoder->setBufferForWrite(newBuffer, static_cast<uint>(newIndexOffset), 1);
encoder->setData(static_cast<uint>(glCount), 2);
encoder->setData(primCount, 3);
encoder->setData(static_cast<uint>(first), 4);
encoder->dispatch(
MTLSizeMake((static_cast<NSUInteger>(primCount) + threadsPerThreadgroup.width - 1) /
threadsPerThreadgroup.width,
1, 1),
threadsPerThreadgroup);
outIndexCount = static_cast<uint32_t>(newIndexCount);
outIndexOffset = newIndexOffset;
outPrimitiveMode = getNewPrimitiveMode(indexBufferKey);
outNewBuffer = newBuffer;
return angle::Result::Continue;
}
} // namespace rx