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smoother lod fading

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This commit is contained in:
David Rose
2008-12-17 00:08:37 +00:00
parent 55a789293a
commit 02352ab5e6
3 changed files with 101 additions and 66 deletions
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panda/src/pgraph/fadeLodNode.cxx
+94 -64
View File
@@ -114,7 +114,7 @@ cull_callback(CullTraverser *trav, CullTraverserData &data) {
// This is the first time we have rendered this instance of this
// LOD node in a while.
ldata = new FadeLODNodeData;
ldata->_fade_mode = false;
ldata->_fade_mode = FadeLODNodeData::FM_solid;
ldata->_fade_out = -1;
ldata->_fade_in = compute_child(trav, data);
camera->set_aux_scene_data(this_np, ldata);
@@ -123,13 +123,22 @@ cull_callback(CullTraverser *trav, CullTraverserData &data) {
// We had rendered this LOD node last frame (or not too long ago,
// at least).
if (!ldata->_fade_mode) {
if (ldata->_fade_mode == FadeLODNodeData::FM_solid) {
// We were drawing just one solid child last frame; check whether
// it's time to begin a transition.
int index = compute_child(trav, data);
if (index != ldata->_fade_in) {
// Start a transition.
ldata->_fade_mode = true;
if (index >= 0 && ldata->_fade_in >= 0 &&
get_out(index) > get_out(ldata->_fade_in)) {
// We are fading from a more-detailed model to a
// less-detailed model.
ldata->_fade_mode = FadeLODNodeData::FM_less_detail;
} else {
// We are fading from a less-detailed model to a
// more-detailed model.
ldata->_fade_mode = FadeLODNodeData::FM_more_detail;
}
// We start the fade as of the last frame we actually rendered;
// that way, if the object happened to be offscreen for a large
@@ -141,74 +150,90 @@ cull_callback(CullTraverser *trav, CullTraverserData &data) {
}
}
if (ldata->_fade_mode) {
if (ldata->_fade_mode != FadeLODNodeData::FM_solid) {
// Play the transition.
float elapsed = now - ldata->_fade_start;
float half_fade_time = _fade_time * 0.5f;
if (elapsed < half_fade_time) {
// FIRST HALF OF FADE
// Fade the new LOD in with z writing off
// Keep drawing the old LOD opaque with z writing on
if (ldata->_fade_out >= 0 && ldata->_fade_out < get_num_children()) {
PandaNode *child = get_child(ldata->_fade_out);
if (child != (PandaNode *)NULL) {
CullTraverserData next_data_out(data, child);
next_data_out._state =
next_data_out._state->compose(get_fade_1_old_state());
trav->traverse(next_data_out);
}
}
if (ldata->_fade_in >= 0 && ldata->_fade_in < get_num_children()) {
PandaNode *child = get_child(ldata->_fade_in);
if (child != (PandaNode *)NULL) {
CullTraverserData next_data_in(data, child);
float in_alpha = elapsed / half_fade_time;
next_data_in._state =
next_data_in._state->compose(get_fade_1_new_state(in_alpha));
trav->traverse(next_data_in);
}
}
} else if (elapsed < _fade_time) {
// SECOND HALF OF FADE:
// Fade out the old LOD with z write off and
// draw the opaque new LOD with z write on
if (ldata->_fade_in >= 0 && ldata->_fade_in < get_num_children()) {
PandaNode *child = get_child(ldata->_fade_in);
if (child != (PandaNode *)NULL) {
CullTraverserData next_data_in(data, child);
next_data_in._state =
next_data_in._state->compose(get_fade_2_new_state());
trav->traverse(next_data_in);
}
}
if (ldata->_fade_out >= 0 && ldata->_fade_out < get_num_children()) {
PandaNode *child = get_child(ldata->_fade_out);
if (child != (PandaNode *)NULL) {
CullTraverserData next_data_out(data, child);
float out_alpha = 1.0f - (elapsed - half_fade_time) / half_fade_time;
next_data_out._state =
next_data_out._state->compose(get_fade_2_old_state(out_alpha));
trav->traverse(next_data_out);
}
}
} else {
if (elapsed >= _fade_time) {
// Transition complete.
ldata->_fade_mode = false;
ldata->_fade_mode = FadeLODNodeData::FM_solid;
} else {
float half_fade_time = _fade_time * 0.5f;
int in_child = ldata->_fade_in;
int out_child = ldata->_fade_out;
if (ldata->_fade_mode == FadeLODNodeData::FM_less_detail) {
// If we're fading from a more-detailed model to a
// less-detailed model, reverse the fade effect for best
// visual quality.
elapsed = _fade_time - elapsed;
int t = in_child;
in_child = out_child;
out_child = t;
}
nassertr(elapsed >= 0.0f && elapsed <= _fade_time, false);
if (elapsed < half_fade_time) {
// FIRST HALF OF FADE
// Fade the new LOD in with z writing off
// Keep drawing the old LOD opaque with z writing on
if (out_child >= 0 && out_child < get_num_children()) {
PandaNode *child = get_child(out_child);
if (child != (PandaNode *)NULL) {
CullTraverserData next_data_out(data, child);
next_data_out._state =
next_data_out._state->compose(get_fade_1_old_state());
trav->traverse(next_data_out);
}
}
if (in_child >= 0 && in_child < get_num_children()) {
PandaNode *child = get_child(in_child);
if (child != (PandaNode *)NULL) {
CullTraverserData next_data_in(data, child);
float in_alpha = elapsed / half_fade_time;
next_data_in._state =
next_data_in._state->compose(get_fade_1_new_state(in_alpha));
trav->traverse(next_data_in);
}
}
} else {
// SECOND HALF OF FADE:
// Fade out the old LOD with z write off and
// draw the opaque new LOD with z write on
if (in_child >= 0 && in_child < get_num_children()) {
PandaNode *child = get_child(in_child);
if (child != (PandaNode *)NULL) {
CullTraverserData next_data_in(data, child);
next_data_in._state =
next_data_in._state->compose(get_fade_2_new_state());
trav->traverse(next_data_in);
}
}
if (out_child >= 0 && out_child < get_num_children()) {
PandaNode *child = get_child(out_child);
if (child != (PandaNode *)NULL) {
CullTraverserData next_data_out(data, child);
float out_alpha = 1.0f - (elapsed - half_fade_time) / half_fade_time;
next_data_out._state =
next_data_out._state->compose(get_fade_2_old_state(out_alpha));
trav->traverse(next_data_out);
}
}
}
}
}
}
if (!ldata->_fade_mode) {
if (ldata->_fade_mode == FadeLODNodeData::FM_solid) {
// This is the normal case: we're not in the middle of a
// transition; we're just drawing one child of the LOD.
int index = ldata->_fade_in;
@@ -261,7 +286,13 @@ set_fade_bin(const string &name, int draw_order) {
////////////////////////////////////////////////////////////////////
CPT(RenderState) FadeLODNode::
get_fade_1_old_state() {
return RenderState::make_empty();
static CPT(RenderState) state = (const RenderState *)NULL;
if (state == (const RenderState *)NULL) {
state = RenderState::make
(DepthOffsetAttrib::make());
}
return state;
}
////////////////////////////////////////////////////////////////////
@@ -275,7 +306,6 @@ get_fade_1_new_state(float in_alpha) {
if (_fade_1_new_state == (const RenderState *)NULL) {
_fade_1_new_state = RenderState::make
(TransparencyAttrib::make(TransparencyAttrib::M_alpha),
DepthWriteAttrib::make(DepthWriteAttrib::M_off),
CullBinAttrib::make(_fade_bin_name, _fade_bin_draw_order),
DepthOffsetAttrib::make());
}
panda/src/pgraph/fadeLodNodeData.cxx
+1 -1
View File
@@ -25,7 +25,7 @@ TypeHandle FadeLODNodeData::_type_handle;
void FadeLODNodeData::
output(ostream &out) const {
AuxSceneData::output(out);
if (_fade_mode) {
if (_fade_mode != FM_solid) {
out << " fading " << _fade_out << " to " << _fade_in << " since "
<< _fade_start;
} else {
panda/src/pgraph/fadeLodNodeData.h
+6 -1
View File
@@ -26,7 +26,12 @@
////////////////////////////////////////////////////////////////////
class EXPCL_PANDA_PGRAPH FadeLODNodeData : public AuxSceneData {
public:
bool _fade_mode;
enum FadeMode {
FM_solid,
FM_more_detail,
FM_less_detail,
};
FadeMode _fade_mode;
float _fade_start;
int _fade_out;
int _fade_in;