blob: 45e216edb271ce840a9ec61a6cb9c38040ebf1d3 [file] [log] [blame]
/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/utils/SkCamera.h"
static SkScalar SkScalarDotDiv(int count, const SkScalar a[], int step_a,
const SkScalar b[], int step_b,
SkScalar denom) {
SkScalar prod = 0;
for (int i = 0; i < count; i++) {
prod += a[0] * b[0];
a += step_a;
b += step_b;
}
return prod / denom;
}
///////////////////////////////////////////////////////////////////////////////
SkPatch3D::SkPatch3D() {
this->reset();
}
void SkPatch3D::reset() {
fOrigin = {0, 0, 0};
fU = {SK_Scalar1, 0, 0};
fV = {0, -SK_Scalar1, 0};
}
void SkPatch3D::transform(const SkM44& m, SkPatch3D* dst) const {
if (dst == nullptr) {
dst = (SkPatch3D*)this;
}
dst->fU = m * fU;
dst->fV = m * fV;
auto [x,y,z,_] = m.map(fOrigin.x, fOrigin.y, fOrigin.z, 1);
dst->fOrigin = {x, y, z};
}
SkScalar SkPatch3D::dotWith(SkScalar dx, SkScalar dy, SkScalar dz) const {
SkScalar cx = fU.y * fV.z - fU.z * fV.y;
SkScalar cy = fU.z * fV.x - fU.x * fV.y;
SkScalar cz = fU.x * fV.y - fU.y * fV.x;
return cx * dx + cy * dy + cz * dz;
}
///////////////////////////////////////////////////////////////////////////////
SkCamera3D::SkCamera3D() {
this->reset();
}
void SkCamera3D::reset() {
fLocation = {0, 0, -SkIntToScalar(576)}; // 8 inches backward
fAxis = {0, 0, SK_Scalar1}; // forward
fZenith = {0, -SK_Scalar1, 0}; // up
fObserver = {0, 0, fLocation.z};
fNeedToUpdate = true;
}
void SkCamera3D::update() {
fNeedToUpdate = true;
}
void SkCamera3D::doUpdate() const {
SkV3 axis, zenith, cross;
// construct a orthonormal basis of cross (x), zenith (y), and axis (z)
axis = fAxis.normalize();
zenith = fZenith - (axis * fZenith) * axis;
zenith = zenith.normalize();
cross = axis.cross(zenith);
{
SkMatrix* orien = &fOrientation;
auto [x, y, z] = fObserver;
// Looking along the view axis we have:
//
// /|\ zenith
// |
// |
// | * observer (projected on XY plane)
// |
// |____________\ cross
// /
//
// So this does a z-shear along the view axis based on the observer's x and y values,
// and scales in x and y relative to the negative of the observer's z value
// (the observer is in the negative z direction).
orien->set(SkMatrix::kMScaleX, x * axis.x - z * cross.x);
orien->set(SkMatrix::kMSkewX, x * axis.y - z * cross.y);
orien->set(SkMatrix::kMTransX, x * axis.z - z * cross.z);
orien->set(SkMatrix::kMSkewY, y * axis.x - z * zenith.x);
orien->set(SkMatrix::kMScaleY, y * axis.y - z * zenith.y);
orien->set(SkMatrix::kMTransY, y * axis.z - z * zenith.z);
orien->set(SkMatrix::kMPersp0, axis.x);
orien->set(SkMatrix::kMPersp1, axis.y);
orien->set(SkMatrix::kMPersp2, axis.z);
}
}
void SkCamera3D::patchToMatrix(const SkPatch3D& quilt, SkMatrix* matrix) const {
if (fNeedToUpdate) {
this->doUpdate();
fNeedToUpdate = false;
}
const SkScalar* mapPtr = (const SkScalar*)(const void*)&fOrientation;
const SkScalar* patchPtr;
SkV3 diff = quilt.fOrigin - fLocation;
SkScalar dot = diff.dot({mapPtr[6], mapPtr[7], mapPtr[8]});
// This multiplies fOrientation by the matrix [quilt.fU quilt.fV diff] -- U, V, and diff are
// column vectors in the matrix -- then divides by the length of the projection of diff onto
// the view axis (which is 'dot'). This transforms the patch (which transforms from local path
// space to world space) into view space (since fOrientation transforms from world space to
// view space).
//
// The divide by 'dot' isn't strictly necessary as the homogeneous divide would do much the
// same thing (it's just scaling the entire matrix by 1/dot). It looks like it's normalizing
// the matrix into some canonical space.
patchPtr = (const SkScalar*)&quilt;
matrix->set(SkMatrix::kMScaleX, SkScalarDotDiv(3, patchPtr, 1, mapPtr, 1, dot));
matrix->set(SkMatrix::kMSkewY, SkScalarDotDiv(3, patchPtr, 1, mapPtr+3, 1, dot));
matrix->set(SkMatrix::kMPersp0, SkScalarDotDiv(3, patchPtr, 1, mapPtr+6, 1, dot));
patchPtr += 3;
matrix->set(SkMatrix::kMSkewX, SkScalarDotDiv(3, patchPtr, 1, mapPtr, 1, dot));
matrix->set(SkMatrix::kMScaleY, SkScalarDotDiv(3, patchPtr, 1, mapPtr+3, 1, dot));
matrix->set(SkMatrix::kMPersp1, SkScalarDotDiv(3, patchPtr, 1, mapPtr+6, 1, dot));
patchPtr = (const SkScalar*)(const void*)&diff;
matrix->set(SkMatrix::kMTransX, SkScalarDotDiv(3, patchPtr, 1, mapPtr, 1, dot));
matrix->set(SkMatrix::kMTransY, SkScalarDotDiv(3, patchPtr, 1, mapPtr+3, 1, dot));
matrix->set(SkMatrix::kMPersp2, SK_Scalar1);
}
///////////////////////////////////////////////////////////////////////////////
Sk3DView::Sk3DView() {
fRec = &fInitialRec;
}
Sk3DView::~Sk3DView() {
Rec* rec = fRec;
while (rec != &fInitialRec) {
Rec* next = rec->fNext;
delete rec;
rec = next;
}
}
void Sk3DView::save() {
Rec* rec = new Rec;
rec->fNext = fRec;
rec->fMatrix = fRec->fMatrix;
fRec = rec;
}
void Sk3DView::restore() {
SkASSERT(fRec != &fInitialRec);
Rec* next = fRec->fNext;
delete fRec;
fRec = next;
}
#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
void Sk3DView::setCameraLocation(SkScalar x, SkScalar y, SkScalar z) {
// the camera location is passed in inches, set in pt
SkScalar lz = z * 72.0f;
fCamera.fLocation = {x * 72.0f, y * 72.0f, lz};
fCamera.fObserver = {0, 0, lz};
fCamera.update();
}
SkScalar Sk3DView::getCameraLocationX() const {
return fCamera.fLocation.x / 72.0f;
}
SkScalar Sk3DView::getCameraLocationY() const {
return fCamera.fLocation.y / 72.0f;
}
SkScalar Sk3DView::getCameraLocationZ() const {
return fCamera.fLocation.z / 72.0f;
}
#endif
void Sk3DView::translate(SkScalar x, SkScalar y, SkScalar z) {
fRec->fMatrix.preTranslate(x, y, z);
}
void Sk3DView::rotateX(SkScalar deg) {
fRec->fMatrix.preConcat(SkM44::Rotate({1, 0, 0}, deg * SK_ScalarPI / 180));
}
void Sk3DView::rotateY(SkScalar deg) {
fRec->fMatrix.preConcat(SkM44::Rotate({0,-1, 0}, deg * SK_ScalarPI / 180));
}
void Sk3DView::rotateZ(SkScalar deg) {
fRec->fMatrix.preConcat(SkM44::Rotate({0, 0, 1}, deg * SK_ScalarPI / 180));
}
SkScalar Sk3DView::dotWithNormal(SkScalar x, SkScalar y, SkScalar z) const {
SkPatch3D patch;
patch.transform(fRec->fMatrix);
return patch.dotWith(x, y, z);
}
void Sk3DView::getMatrix(SkMatrix* matrix) const {
if (matrix != nullptr) {
SkPatch3D patch;
patch.transform(fRec->fMatrix);
fCamera.patchToMatrix(patch, matrix);
}
}
#include "include/core/SkCanvas.h"
void Sk3DView::applyToCanvas(SkCanvas* canvas) const {
SkMatrix matrix;
this->getMatrix(&matrix);
canvas->concat(matrix);
}