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- /*
- * Copyright 2019 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #include "src/gpu/ccpr/GrOctoBounds.h"
- #include <algorithm>
- bool GrOctoBounds::clip(const SkIRect& clipRect) {
- // Intersect dev bounds with the clip rect.
- float l = std::max(fBounds.left(), (float)clipRect.left());
- float t = std::max(fBounds.top(), (float)clipRect.top());
- float r = std::min(fBounds.right(), (float)clipRect.right());
- float b = std::min(fBounds.bottom(), (float)clipRect.bottom());
- float l45 = fBounds45.left();
- float t45 = fBounds45.top();
- float r45 = fBounds45.right();
- float b45 = fBounds45.bottom();
- // Check if either the bounds or 45-degree bounds are empty. We write this check as the NOT of
- // non-empty rects, so we will return false if any values are NaN.
- if (!(l < r && t < b && l45 < r45 && t45 < b45)) {
- return false;
- }
- // Tighten dev bounds around the new (octagonal) intersection that results after clipping. This
- // may be tighter now even than the clipped bounds, depending on the diagonals. Shader code that
- // emits octagons expects both bounding boxes to circumcribe the inner octagon, and will fail if
- // they do not.
- if (l45 > Get_x45(r,b)) {
- // Slide the bottom upward until it crosses the l45 diagonal at x=r.
- // y = x + (y0 - x0)
- // Substitute: l45 = x0 - y0
- // y = x - l45
- b = SkScalarPin(r - l45, t, b);
- } else if (r45 < Get_x45(r,b)) {
- // Slide the right side leftward until it crosses the r45 diagonal at y=b.
- // x = y + (x0 - y0)
- // Substitute: r45 = x0 - y0
- // x = y + r45
- r = SkScalarPin(b + r45, l, r);
- }
- if (l45 > Get_x45(l,t)) {
- // Slide the left side rightward until it crosses the l45 diagonal at y=t.
- // x = y + (x0 - y0)
- // Substitute: l45 = x0 - y0
- // x = y + l45
- l = SkScalarPin(t + l45, l, r);
- } else if (r45 < Get_x45(l,t)) {
- // Slide the top downward until it crosses the r45 diagonal at x=l.
- // y = x + (y0 - x0)
- // Substitute: r45 = x0 - y0
- // y = x - r45
- t = SkScalarPin(l - r45, t, b);
- }
- if (t45 > Get_y45(l,b)) {
- // Slide the left side rightward until it crosses the t45 diagonal at y=b.
- // x = -y + (x0 + y0)
- // Substitute: t45 = x0 + y0
- // x = -y + t45
- l = SkScalarPin(t45 - b, l, r);
- } else if (b45 < Get_y45(l,b)) {
- // Slide the bottom upward until it crosses the b45 diagonal at x=l.
- // y = -x + (y0 + x0)
- // Substitute: b45 = x0 + y0
- // y = -x + b45
- b = SkScalarPin(b45 - l, t, b);
- }
- if (t45 > Get_y45(r,t)) {
- // Slide the top downward until it crosses the t45 diagonal at x=r.
- // y = -x + (y0 + x0)
- // Substitute: t45 = x0 + y0
- // y = -x + t45
- t = SkScalarPin(t45 - r, t, b);
- } else if (b45 < Get_y45(r,t)) {
- // Slide the right side leftward until it crosses the b45 diagonal at y=t.
- // x = -y + (x0 + y0)
- // Substitute: b45 = x0 + y0
- // x = -y + b45
- r = SkScalarPin(b45 - t, l, r);
- }
- // Tighten the 45-degree bounding box. Since the dev bounds are now fully tightened, we only
- // have to clamp the diagonals to outer corners.
- // NOTE: This will not cause l,t,r,b to need more insetting. We only ever change a diagonal by
- // pinning it to a FAR corner, which, by definition, is still outside the other corners.
- l45 = SkScalarPin(Get_x45(l,b), l45, r45);
- t45 = SkScalarPin(Get_y45(l,t), t45, b45);
- r45 = SkScalarPin(Get_x45(r,t), l45, r45);
- b45 = SkScalarPin(Get_y45(r,b), t45, b45);
- // Make one final check for empty or NaN bounds. If the dev bounds were clipped completely
- // outside one of the diagonals, they will have been pinned to empty. It's also possible that
- // some Infs crept in and turned into NaNs.
- if (!(l < r && t < b && l45 < r45 && t45 < b45)) {
- return false;
- }
- fBounds.setLTRB(l, t, r, b);
- fBounds45.setLTRB(l45, t45, r45, b45);
- #ifdef SK_DEBUG
- // Verify dev bounds are inside the clip rect.
- SkASSERT(l >= (float)clipRect.left());
- SkASSERT(t >= (float)clipRect.top());
- SkASSERT(r <= (float)clipRect.right());
- SkASSERT(b <= (float)clipRect.bottom());
- this->validateBoundsAreTight();
- #endif
- return true;
- }
- #if defined(SK_DEBUG) || defined(GR_TEST_UTILS)
- void GrOctoBounds::validateBoundsAreTight() const {
- this->validateBoundsAreTight([](bool cond, const char* file, int line, const char* code) {
- SkASSERTF(cond, "%s(%d): assertion failure: \"assert(%s)\"", file, line, code);
- });
- }
- void GrOctoBounds::validateBoundsAreTight(const std::function<void(
- bool cond, const char* file, int line, const char* code)>& validateFn) const {
- constexpr static float epsilon = 1e-3f;
- float l=fBounds.left(), l45=fBounds45.left();
- float t=fBounds.top(), t45=fBounds45.top();
- float r=fBounds.right(), r45=fBounds45.right();
- float b=fBounds.bottom(), b45=fBounds45.bottom();
- #define VALIDATE(CODE) validateFn(CODE, __FILE__, __LINE__, #CODE)
- // Verify diagonals are inside far corners of the dev bounds.
- VALIDATE(l45 >= Get_x45(l,b) - epsilon);
- VALIDATE(t45 >= Get_y45(l,t) - epsilon);
- VALIDATE(r45 <= Get_x45(r,t) + epsilon);
- VALIDATE(b45 <= Get_y45(r,b) + epsilon);
- // Verify verticals and horizontals are inside far corners of the 45-degree dev bounds.
- VALIDATE(l >= Get_x(l45,t45) - epsilon);
- VALIDATE(t >= Get_y(r45,t45) - epsilon);
- VALIDATE(r <= Get_x(r45,b45) + epsilon);
- VALIDATE(b <= Get_y(l45,b45) + epsilon);
- // Verify diagonals are outside middle corners of the dev bounds.
- VALIDATE(l45 <= Get_x45(r,b) + epsilon);
- VALIDATE(l45 <= Get_x45(l,t) + epsilon);
- VALIDATE(t45 <= Get_y45(l,b) + epsilon);
- VALIDATE(t45 <= Get_y45(r,t) + epsilon);
- VALIDATE(r45 >= Get_x45(l,t) - epsilon);
- VALIDATE(r45 >= Get_x45(r,b) - epsilon);
- VALIDATE(b45 >= Get_y45(r,t) - epsilon);
- VALIDATE(b45 >= Get_y45(l,b) - epsilon);
- // Verify verticals and horizontals are outside middle corners of the 45-degree dev bounds.
- VALIDATE(l <= Get_x(l45,b45) + epsilon);
- VALIDATE(l <= Get_x(r45,t45) + epsilon);
- VALIDATE(t <= Get_y(r45,b45) + epsilon);
- VALIDATE(t <= Get_y(l45,t45) + epsilon);
- VALIDATE(r >= Get_x(r45,t45) - epsilon);
- VALIDATE(r >= Get_x(l45,b45) - epsilon);
- VALIDATE(b >= Get_y(l45,t45) - epsilon);
- VALIDATE(b >= Get_y(r45,b45) - epsilon);
- #undef VALIDATE
- }
- #endif
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