//! returns level of detail for tile (-1 if not visible)
int tileLevelOfDetail(int row, int col, const matrix4x4 &world, const render::Camera &camera) {
matrix4x4 quadFront(
0, span.x, span.x, 0,
0, 0, span.y, span.y,
0, 0, 0, 0,
1, 1, 1, 1
);
matrix4x4 quadBack(
0, span.x, span.x, 0,
0, 0, span.y, span.y,
span.z, span.z, span.z, span.z,
1, 1, 1, 1
);
matrix4x4 transform = camera.transform() * world;
quadFront = transform * quadFront;
quadBack = transform * quadBack;
projectQuad(quadFront);
projectQuad(quadBack);
bool invisible = !(quadVisible(quadFront) || quadVisible(quadBack));
if (invisible) {
return -1;
}
// determine a bounding box around all the corners
matrix4x1 bounding;
matrix4x4 *faces[] = { &quadFront, &quadBack };
int p = 0;
for (int j = 0; j < 2; j++) {
for (int i = 0; i < 4; i++, ++p) {
matrix4x1 col = (*faces[j]).column(i);
if (!p || col.x < bounding._0) bounding._0 = col.x;
if (!p || col.y < bounding._1) bounding._1 = col.y;
if (!p || col.x > bounding._2) bounding._2 = col.x;
if (!p || col.y > bounding._3) bounding._3 = col.y;
}
}
// determine LOD by area
float longDimension = std::max((bounding._3 - bounding._1), (bounding._2 - bounding._0)) / 2.0f;
int lod = 0;
if (longDimension > 0.75f) {
lod = 0;
}
else if (longDimension > 0.5f) {
lod = 1;
}
else if (longDimension > 0.25f) {
lod = 2;
}
else {
lod = 3;
}
return lod;
}
static inline IntRect computeUnoccludedContentRect(const IntRect& contentRect, const TransformationMatrix& contentSpaceTransform, const IntRect& scissorRect, const Region& occlusion)
{
if (!contentSpaceTransform.isInvertible())
return contentRect;
FloatRect transformedRect = contentSpaceTransform.mapRect(FloatRect(contentRect));
// Take the enclosingIntRect at each step, as we want to contain any unoccluded partial pixels in the resulting IntRect.
IntRect shrunkRect = rectSubtractRegion(intersection(enclosingIntRect(transformedRect), scissorRect), occlusion);
bool clamped; // FIXME: projectQuad returns invalid results when a point gets clamped. To be fixed in bug https://bugs.webkit.org/show_bug.cgi?id=80806.
IntRect unoccludedRect = enclosingIntRect(projectQuad(contentSpaceTransform.inverse(), FloatQuad(FloatRect(shrunkRect)), clamped).boundingBox());
if (clamped)
return contentRect;
// The rect back in content space is a bounding box and may extend outside of the original contentRect, so clamp it to the contentRectBounds.
return intersection(unoccludedRect, contentRect);
}
