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GiantsTools/Sdk/External/DirectXMath/Stereo3D/Stereo3DMatrixHelper.cpp
2021-01-23 15:40:09 -08:00

258 lines
10 KiB
C++

//-------------------------------------------------------------------------------------
// Stereo3DMatrixHelper.cpp -- SIMD C++ Math helper for Stereo 3D matricies
//
// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.
//-------------------------------------------------------------------------------------
#include "Stereo3DMatrixHelper.h"
using namespace DirectX;
namespace
{
inline bool StereoProjectionHelper
(
const STEREO_PARAMETERS& stereoParameters,
_Out_ float* fVirtualProjection,
_Out_ float* zNearWidth,
_Out_ float* zNearHeight,
float FovAngleY,
float AspectRatio,
float NearZ
)
{
// note that most people have difficulty fusing images into 3D
// if the separation equals even just the human average. by
// reducing the separation (interocular distance) by 1/2, we
// guarantee a larger subset of people will see full 3D
// the conservative setting should always be used. the only problem
// with the conservative setting is that the 3D effect will be less
// impressive on smaller screens (which makes sense, since your eye
// cannot be tricked as easily based on the smaller fov). to simulate
// the effect of a larger screen, use the liberal settings (debug only)
// Conservative Settings: * max acuity angle: 0.8f degrees * interoc distance: 1.25 inches
// Liberal Settings: * max acuity angle: 1.6f degrees * interoc distance: 2.5f inches
// maximum visual accuity angle allowed is 3.2 degrees for
// a physical scene, and 1.6 degrees for a virtual one.
// thus we cannot allow an object to appear any closer to
// the viewer than 1.6 degrees (divided by two for most
// half-angle calculations)
static const float fMaxStereoDistance = 780; // inches (should be between 10 and 20m)
static const float fMaxVisualAcuityAngle = 1.6f * (XM_PI / 180.0f); // radians
static const float fInterocularDistance = 1.25f; // inches
float fDisplayHeight = stereoParameters.fDisplaySizeInches / sqrtf(AspectRatio * AspectRatio + 1.0f);
float fDisplayWidth = fDisplayHeight * AspectRatio;
float fHalfInterocular = 0.5f * fInterocularDistance * stereoParameters.fStereoExaggerationFactor;
float fHalfPixelWidth = fDisplayWidth / stereoParameters.fPixelResolutionWidth * 0.5f;
float fHalfMaximumAcuityAngle = fMaxVisualAcuityAngle * 0.5f * stereoParameters.fStereoExaggerationFactor;
// float fHalfWidth = fDisplayWidth * 0.5f;
float fMaxSeparationAcuityAngle = atanf(fHalfInterocular / fMaxStereoDistance);
float fMaxSeparationDistance = fHalfPixelWidth / tanf(fMaxSeparationAcuityAngle);
float fRefinedMaxStereoDistance = fMaxStereoDistance - fMaxSeparationDistance;
float fFovHalfAngle = FovAngleY / 2.0f;
bool ComfortableResult = true;
if (fRefinedMaxStereoDistance < 0.0f || fMaxSeparationDistance > 0.1f * fMaxStereoDistance)
{
// Pixel resolution is too low to offer a comfortable stereo experience
ComfortableResult = false;
}
float fRefinedMaxSeparationAcuityAngle = atanf(fHalfInterocular / (fRefinedMaxStereoDistance));
float fPhysicalZNearDistance = fHalfInterocular / tanf(fHalfMaximumAcuityAngle);
// float fScalingFactor = fHalfMaximumAcuityAngle / atanf(fHalfInterocular / stereoParameters.fViewerDistanceInches);
float fNearZSeparation = tanf(fRefinedMaxSeparationAcuityAngle) * (fRefinedMaxStereoDistance - fPhysicalZNearDistance);
// float fNearZSeparation2 = fHalfInterocular * (fRefinedMaxStereoDistance - fPhysicalZNearDistance) / fRefinedMaxStereoDistance;
(*zNearHeight) = cosf(fFovHalfAngle) / sinf(fFovHalfAngle);
(*zNearWidth) = (*zNearHeight) / AspectRatio;
(*fVirtualProjection) = (fNearZSeparation * NearZ * (*zNearWidth * 4.0f)) / (2.0f * NearZ);
return ComfortableResult;
}
}
//------------------------------------------------------------------------------
void DirectX::StereoCreateDefaultParameters
(
STEREO_PARAMETERS& stereoParameters
)
{
// Default assumption is 1920x1200 resolution, a 22" LCD monitor, and a 2' viewing distance
stereoParameters.fViewerDistanceInches = 24.0f;
stereoParameters.fPixelResolutionWidth = 1920.0f;
stereoParameters.fPixelResolutionHeight = 1200.0f;
stereoParameters.fDisplaySizeInches = 22.0f;
stereoParameters.fStereoSeparationFactor = 1.0f;
stereoParameters.fStereoExaggerationFactor = 1.0f;
}
//------------------------------------------------------------------------------
XMMATRIX DirectX::StereoProjectionFovLH
(
_In_opt_ const STEREO_PARAMETERS* pStereoParameters,
STEREO_CHANNEL Channel,
float FovAngleY,
float AspectRatio,
float NearZ,
float FarZ,
STEREO_MODE StereoMode
)
{
assert(Channel == STEREO_CHANNEL_LEFT || Channel == STEREO_CHANNEL_RIGHT);
assert(StereoMode == STEREO_MODE_NORMAL || StereoMode == STEREO_MODE_INVERTED);
assert(!XMScalarNearEqual(FovAngleY, 0.0f, 0.00001f * 2.0f));
assert(!XMScalarNearEqual(AspectRatio, 0.0f, 0.00001f));
assert(!XMScalarNearEqual(FarZ, NearZ, 0.00001f));
STEREO_PARAMETERS DefaultParameters = {};
if (pStereoParameters == nullptr)
{
StereoCreateDefaultParameters(DefaultParameters);
pStereoParameters = &DefaultParameters;
}
assert(pStereoParameters->fStereoSeparationFactor >= 0.0f && pStereoParameters->fStereoSeparationFactor <= 1.0f);
assert(pStereoParameters->fStereoExaggerationFactor >= 1.0f && pStereoParameters->fStereoExaggerationFactor <= 2.0f);
float fVirtualProjection = 0.0f;
float zNearWidth = 0.0f;
float zNearHeight = 0.0f;
StereoProjectionHelper(*pStereoParameters, &fVirtualProjection, &zNearWidth, &zNearHeight, FovAngleY, AspectRatio, NearZ);
fVirtualProjection *= pStereoParameters->fStereoSeparationFactor; // incorporate developer defined bias
//
// By applying a translation, we are forcing our cameras to be parallel
//
float fInvertedAngle = atanf(fVirtualProjection / (2.0f * NearZ));
XMMATRIX proj = XMMatrixPerspectiveFovLH(FovAngleY, AspectRatio, NearZ, FarZ);
XMMATRIX patchedProjection;
if (Channel == STEREO_CHANNEL_LEFT)
{
if (StereoMode > STEREO_MODE_NORMAL)
{
XMMATRIX rots = XMMatrixRotationY(fInvertedAngle);
XMMATRIX trans = XMMatrixTranslation(-fVirtualProjection, 0, 0);
patchedProjection = XMMatrixMultiply(XMMatrixMultiply(rots, trans), proj);
}
else
{
XMMATRIX trans = XMMatrixTranslation(-fVirtualProjection, 0, 0);
patchedProjection = XMMatrixMultiply(trans, proj);
}
}
else
{
if (StereoMode > STEREO_MODE_NORMAL)
{
XMMATRIX rots = XMMatrixRotationY(-fInvertedAngle);
XMMATRIX trans = XMMatrixTranslation(fVirtualProjection, 0, 0);
patchedProjection = XMMatrixMultiply(XMMatrixMultiply(rots, trans), proj);
}
else
{
XMMATRIX trans = XMMatrixTranslation(fVirtualProjection, 0, 0);
patchedProjection = XMMatrixMultiply(trans, proj);
}
}
return patchedProjection;
}
//------------------------------------------------------------------------------
XMMATRIX DirectX::StereoProjectionFovRH
(
_In_opt_ const STEREO_PARAMETERS* pStereoParameters,
STEREO_CHANNEL Channel,
float FovAngleY,
float AspectRatio,
float NearZ,
float FarZ,
STEREO_MODE StereoMode
)
{
assert(Channel == STEREO_CHANNEL_LEFT || Channel == STEREO_CHANNEL_RIGHT);
assert(StereoMode == STEREO_MODE_NORMAL || StereoMode == STEREO_MODE_INVERTED);
assert(!XMScalarNearEqual(FovAngleY, 0.0f, 0.00001f * 2.0f));
assert(!XMScalarNearEqual(AspectRatio, 0.0f, 0.00001f));
assert(!XMScalarNearEqual(FarZ, NearZ, 0.00001f));
STEREO_PARAMETERS DefaultParameters = {};
if (pStereoParameters == nullptr)
{
StereoCreateDefaultParameters(DefaultParameters);
pStereoParameters = &DefaultParameters;
}
assert(pStereoParameters->fStereoSeparationFactor >= 0.0f && pStereoParameters->fStereoSeparationFactor <= 1.0f);
assert(pStereoParameters->fStereoExaggerationFactor >= 1.0f && pStereoParameters->fStereoExaggerationFactor <= 2.0f);
float fVirtualProjection = 0.0f;
float zNearWidth = 0.0f;
float zNearHeight = 0.0f;
StereoProjectionHelper(*pStereoParameters, &fVirtualProjection, &zNearWidth, &zNearHeight, FovAngleY, AspectRatio, NearZ);
fVirtualProjection *= pStereoParameters->fStereoSeparationFactor; // incorporate developer defined bias
//
// By applying a translation, we are forcing our cameras to be parallel
//
float fInvertedAngle = atanf(fVirtualProjection / (2.0f * NearZ));
XMMATRIX proj = XMMatrixPerspectiveFovRH(FovAngleY, AspectRatio, NearZ, FarZ);
//
// By applying a translation, we are forcing our cameras to be parallel
//
XMMATRIX patchedProjection;
if (Channel == STEREO_CHANNEL_LEFT)
{
if (StereoMode > STEREO_MODE_NORMAL)
{
XMMATRIX rots = XMMatrixRotationY(fInvertedAngle);
XMMATRIX trans = XMMatrixTranslation(-fVirtualProjection, 0, 0);
patchedProjection = XMMatrixMultiply(XMMatrixMultiply(rots, trans), proj);
}
else
{
XMMATRIX trans = XMMatrixTranslation(-fVirtualProjection, 0, 0);
patchedProjection = XMMatrixMultiply(trans, proj);
}
}
else
{
if (StereoMode > STEREO_MODE_NORMAL)
{
XMMATRIX rots = XMMatrixRotationY(-fInvertedAngle);
XMMATRIX trans = XMMatrixTranslation(fVirtualProjection, 0, 0);
patchedProjection = XMMatrixMultiply(XMMatrixMultiply(rots, trans), proj);
}
else
{
XMMATRIX trans = XMMatrixTranslation(fVirtualProjection, 0, 0);
patchedProjection = XMMatrixMultiply(trans, proj);
}
}
return patchedProjection;
}