// There are two types of nodes for which we want to "render"
// 1) Leaves that are in the LOD
// 2) Non-leaves are more complicated though... usually you don't want to render them, but if their children
// wouldn't be rendered, then you do want to render them. But sometimes they have some children that ARE
// in the LOD, and others that are not. In this case we want to render the parent, and none of the children.
//
// Since, if we know the camera position and orientation, we can know which of the corners is the "furthest"
// corner. We can use we can use this corner as our "voxel position" to do our distance calculations off of.
// By doing this, we don't need to test each child voxel's position vs the LOD boundary
bool OctreeElement::calculateShouldRender(const ViewFrustum* viewFrustum, float voxelScaleSize, int boundaryLevelAdjust) const {
bool shouldRender = false;
if (hasContent()) {
float furthestDistance = furthestDistanceToCamera(*viewFrustum);
float childBoundary = boundaryDistanceForRenderLevel(getLevel() + 1 + boundaryLevelAdjust, voxelScaleSize);
bool inChildBoundary = (furthestDistance <= childBoundary);
if (hasDetailedContent() && inChildBoundary) {
shouldRender = true;
} else {
float boundary = childBoundary * 2.0f; // the boundary is always twice the distance of the child boundary
bool inBoundary = (furthestDistance <= boundary);
shouldRender = inBoundary && !inChildBoundary;
}
}
return shouldRender;
}
float calculateRenderAccuracy(const glm::vec3& position,
const AABox& bounds,
float octreeSizeScale,
int boundaryLevelAdjust) {
float largestDimension = bounds.getLargestDimension();
const float maxScale = (float)TREE_SCALE;
float visibleDistanceAtMaxScale = boundaryDistanceForRenderLevel(boundaryLevelAdjust, octreeSizeScale) / OCTREE_TO_MESH_RATIO;
static std::once_flag once;
static QMap<float, float> shouldRenderTable;
std::call_once(once, [&] {
float SMALLEST_SCALE_IN_TABLE = 0.001f; // 1mm is plenty small
float scale = maxScale;
float factor = 1.0f;
while (scale > SMALLEST_SCALE_IN_TABLE) {
scale /= 2.0f;
factor /= 2.0f;
shouldRenderTable[scale] = factor;
}
});
float closestScale = maxScale;
float visibleDistanceAtClosestScale = visibleDistanceAtMaxScale;
QMap<float, float>::const_iterator lowerBound = shouldRenderTable.lowerBound(largestDimension);
if (lowerBound != shouldRenderTable.constEnd()) {
closestScale = lowerBound.key();
visibleDistanceAtClosestScale = visibleDistanceAtMaxScale * lowerBound.value();
}
if (closestScale < largestDimension) {
visibleDistanceAtClosestScale *= 2.0f;
}
// FIXME - for now, it's either visible or not visible. We want to adjust this to eventually return
// a floating point for objects that have small angular size to indicate that they may be rendered
// with lower preciscion
float distanceToCamera = glm::length(bounds.calcCenter() - position);
return (distanceToCamera <= visibleDistanceAtClosestScale) ? 1.0f : 0.0f;
}
bool LODManager::shouldRender(const RenderArgs* args, const AABox& bounds) {
const float maxScale = (float)TREE_SCALE;
const float octreeToMeshRatio = 4.0f; // must be this many times closer to a mesh than a voxel to see it.
float octreeSizeScale = args->_sizeScale;
int boundaryLevelAdjust = args->_boundaryLevelAdjust;
float visibleDistanceAtMaxScale = boundaryDistanceForRenderLevel(boundaryLevelAdjust, octreeSizeScale) / octreeToMeshRatio;
float distanceToCamera = glm::length(bounds.calcCenter() - args->_viewFrustum->getPosition());
float largestDimension = bounds.getLargestDimension();
static bool shouldRenderTableNeedsBuilding = true;
static QMap<float, float> shouldRenderTable;
if (shouldRenderTableNeedsBuilding) {
float SMALLEST_SCALE_IN_TABLE = 0.001f; // 1mm is plenty small
float scale = maxScale;
float factor = 1.0f;
while (scale > SMALLEST_SCALE_IN_TABLE) {
scale /= 2.0f;
factor /= 2.0f;
shouldRenderTable[scale] = factor;
}
shouldRenderTableNeedsBuilding = false;
}
float closestScale = maxScale;
float visibleDistanceAtClosestScale = visibleDistanceAtMaxScale;
QMap<float, float>::const_iterator lowerBound = shouldRenderTable.lowerBound(largestDimension);
if (lowerBound != shouldRenderTable.constEnd()) {
closestScale = lowerBound.key();
visibleDistanceAtClosestScale = visibleDistanceAtMaxScale * lowerBound.value();
}
if (closestScale < largestDimension) {
visibleDistanceAtClosestScale *= 2.0f;
}
return distanceToCamera <= visibleDistanceAtClosestScale;
};
// TODO: This is essentially the same logic used to render octree cells, but since models are more detailed then octree cells
// I've added a voxelToModelRatio that adjusts how much closer to a model you have to be to see it.
bool LODManager::shouldRenderMesh(float largestDimension, float distanceToCamera) {
const float octreeToMeshRatio = 4.0f; // must be this many times closer to a mesh than a voxel to see it.
float octreeSizeScale = getOctreeSizeScale();
int boundaryLevelAdjust = getBoundaryLevelAdjust();
float maxScale = (float)TREE_SCALE;
float visibleDistanceAtMaxScale = boundaryDistanceForRenderLevel(boundaryLevelAdjust, octreeSizeScale) / octreeToMeshRatio;
if (_shouldRenderTableNeedsRebuilding) {
_shouldRenderTable.clear();
float SMALLEST_SCALE_IN_TABLE = 0.001f; // 1mm is plenty small
float scale = maxScale;
float visibleDistanceAtScale = visibleDistanceAtMaxScale;
while (scale > SMALLEST_SCALE_IN_TABLE) {
scale /= 2.0f;
visibleDistanceAtScale /= 2.0f;
_shouldRenderTable[scale] = visibleDistanceAtScale;
}
_shouldRenderTableNeedsRebuilding = false;
}
float closestScale = maxScale;
float visibleDistanceAtClosestScale = visibleDistanceAtMaxScale;
QMap<float, float>::const_iterator lowerBound = _shouldRenderTable.lowerBound(largestDimension);
if (lowerBound != _shouldRenderTable.constEnd()) {
closestScale = lowerBound.key();
visibleDistanceAtClosestScale = lowerBound.value();
}
if (closestScale < largestDimension) {
visibleDistanceAtClosestScale *= 2.0f;
}
return (distanceToCamera <= visibleDistanceAtClosestScale);
}
float getAccuracyAngle(float octreeSizeScale, int boundaryLevelAdjust) {
const float maxScale = (float)TREE_SCALE;
float visibleDistanceAtMaxScale = boundaryDistanceForRenderLevel(boundaryLevelAdjust, octreeSizeScale) / OCTREE_TO_MESH_RATIO;
return atan(maxScale / visibleDistanceAtMaxScale);
}
