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// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "third_party/blink/renderer/modules/xr/xr_cpu_depth_information.h"
#include <algorithm>
#include <cmath>
#include <cstdlib>
#include "base/numerics/byte_conversions.h"
#include "base/numerics/checked_math.h"
#include "base/numerics/ostream_operators.h"
#include "device/vr/public/mojom/xr_session.mojom-blink.h"
#include "third_party/blink/renderer/core/dom/dom_exception.h"
#include "third_party/blink/renderer/core/typed_arrays/dom_typed_array.h"
#include "third_party/blink/renderer/platform/bindings/exception_state.h"
#include "ui/gfx/geometry/point3_f.h"
namespace {
constexpr char kOutOfBoundsAccess[] =
"Attempted to access data that is out-of-bounds.";
constexpr char kArrayBufferDetached[] =
"Attempted to access data from a detached data buffer.";
constexpr size_t GetBytesPerElement(
device::mojom::XRDepthDataFormat data_format) {
switch (data_format) {
case device::mojom::XRDepthDataFormat::kLuminanceAlpha:
case device::mojom::XRDepthDataFormat::kUnsignedShort:
return 2;
case device::mojom::XRDepthDataFormat::kFloat32:
return 4;
}
}
// We have to use the type names below, this enables us to ensure that we are
// using them properly in a switch statement.
static_assert(
GetBytesPerElement(device::mojom::XRDepthDataFormat::kLuminanceAlpha) ==
sizeof(uint16_t));
static_assert(
GetBytesPerElement(device::mojom::XRDepthDataFormat::kUnsignedShort) ==
sizeof(uint16_t));
static_assert(GetBytesPerElement(device::mojom::XRDepthDataFormat::kFloat32) ==
sizeof(float));
} // namespace
namespace blink {
XRCPUDepthInformation::XRCPUDepthInformation(
const XRView* view,
const device::mojom::blink::XRViewGeometryPtr& view_geometry,
const gfx::Size& size,
const gfx::Transform& norm_texture_from_norm_view,
float raw_value_to_meters,
device::mojom::XRDepthDataFormat data_format,
DOMArrayBuffer* data)
: XRDepthInformation(view,
view_geometry,
size,
norm_texture_from_norm_view,
raw_value_to_meters),
data_(data),
data_format_(data_format),
bytes_per_element_(GetBytesPerElement(data_format)) {
DVLOG(3) << __func__;
CHECK_EQ(base::CheckMul(bytes_per_element_, size_.width(), size_.height())
.ValueOrDie(),
data_->ByteLength());
}
DOMArrayBuffer* XRCPUDepthInformation::data(
ExceptionState& exception_state) const {
if (!ValidateFrame(exception_state)) {
return nullptr;
}
return data_.Get();
}
float XRCPUDepthInformation::getDepthInMeters(
float x,
float y,
ExceptionState& exception_state) const {
DVLOG(3) << __func__ << ": x=" << x << ", y=" << y;
// Check if `data_` is detached:
if(data_->IsDetached()) {
exception_state.ThrowDOMException(DOMExceptionCode::kInvalidStateError,
kArrayBufferDetached);
return 0.0;
}
if (!ValidateFrame(exception_state)) {
return 0.0;
}
if (x > 1.0 || x < 0.0) {
exception_state.ThrowRangeError(kOutOfBoundsAccess);
return 0.0;
}
if (y > 1.0 || y < 0.0) {
exception_state.ThrowRangeError(kOutOfBoundsAccess);
return 0.0;
}
gfx::PointF norm_view_coordinates(x, y);
gfx::PointF norm_depth_coordinates =
norm_depth_buffer_from_norm_view_.MapPoint(norm_view_coordinates);
gfx::PointF depth_coordinates =
gfx::ScalePoint(norm_depth_coordinates, size_.width(), size_.height());
uint32_t column = std::clamp<uint32_t>(
static_cast<uint32_t>(depth_coordinates.x()), 0, size_.width() - 1);
uint32_t row = std::clamp<uint32_t>(
static_cast<uint32_t>(depth_coordinates.y()), 0, size_.height() - 1);
auto checked_index =
base::CheckAdd(column, base::CheckMul(row, size_.width()));
size_t index = checked_index.ValueOrDie();
// Convert from data's native units to meters when accessing:
float result = GetItem(index) * raw_value_to_meters_;
DVLOG(3) << __func__ << ": x=" << x << ", y=" << y << ", column=" << column
<< ", row=" << row << ", index=" << index << ", result=" << result;
return result;
}
float XRCPUDepthInformation::GetItem(size_t index) const {
DVLOG(3) << __func__ << ": index=" << index;
CHECK(!data_->IsDetached());
// This generates a non-fixed span of size `bytes_per_element_`. We will need
// to use the templated version of `first` below once we know the type to
// generate a fixed span, which we unfortunately cannot do at this time.
const auto offset = index * bytes_per_element_;
auto value = data_->ByteSpan().subspan(offset).first(bytes_per_element_);
switch (data_format_) {
case device::mojom::XRDepthDataFormat::kUnsignedShort:
case device::mojom::XRDepthDataFormat::kLuminanceAlpha: {
// This should also be guaranteed by that static_asserts above.
CHECK_EQ(bytes_per_element_, sizeof(uint16_t));
return base::U16FromNativeEndian(value.first<sizeof(uint16_t)>());
}
case device::mojom::XRDepthDataFormat::kFloat32: {
// This should also be guaranteed by that static_asserts above.
CHECK_EQ(bytes_per_element_, sizeof(float));
return base::FloatFromNativeEndian(value.first<sizeof(float)>());
}
}
}
void XRCPUDepthInformation::Trace(Visitor* visitor) const {
visitor->Trace(data_);
XRDepthInformation::Trace(visitor);
}
} // namespace blink
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