historical/toontown-classic.git/panda/include/depthOffsetAttrib.h

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/**
* PANDA 3D SOFTWARE
* Copyright (c) Carnegie Mellon University. All rights reserved.
*
* All use of this software is subject to the terms of the revised BSD
* license. You should have received a copy of this license along
* with this source code in a file named "LICENSE."
*
* @file depthOffsetAttrib.h
* @author drose
* @date 2002-03-14
*/
#ifndef DEPTHOFFSETATTRIB_H
#define DEPTHOFFSETATTRIB_H
#include "pandabase.h"
#include "renderAttrib.h"
#include "luse.h"
class FactoryParams;
/**
* This is a special kind of attribute that instructs the graphics driver to
* apply an offset or bias to the generated depth values for rendered
* polygons, before they are written to the depth buffer.
*
* This can be used to shift polygons forward slightly, to resolve depth
* conflicts. The cull traverser may optionally use this, for instance, to
* implement decals. However, driver support for this feature seems to be
* spotty, so use with caution.
*
* The bias is always an integer number, and each integer increment represents
* the smallest possible increment in Z that is sufficient to completely
* resolve two coplanar polygons. Positive numbers are closer towards the
* camera.
*
* Nested DepthOffsetAttrib values accumulate; that is, a DepthOffsetAttrib
* with a value of 1 beneath another DepthOffsetAttrib with a value of 2
* presents a net offset of 3. (A DepthOffsetAttrib will not, however,
* combine with any other DepthOffsetAttribs with a lower override parameter.)
* The net value should probably not exceed 16 or drop below 0 for maximum
* portability.
*
* Also, and only tangentially related, the DepthOffsetAttrib can be used to
* constrain the Z output value to a subset of the usual [0, 1] range (or
* reversing its direction) by specifying a new min_value and max_value.
*/
class EXPCL_PANDA_PGRAPH DepthOffsetAttrib : public RenderAttrib {
private:
INLINE DepthOffsetAttrib(int offset, PN_stdfloat min_value, PN_stdfloat max_value);
PUBLISHED:
static CPT(RenderAttrib) make(int offset = 1);
static CPT(RenderAttrib) make(int offset, PN_stdfloat min_value, PN_stdfloat max_value);
static CPT(RenderAttrib) make_default();
INLINE int get_offset() const;
INLINE PN_stdfloat get_min_value() const;
INLINE PN_stdfloat get_max_value() const;
PUBLISHED:
MAKE_PROPERTY(offset, get_offset);
MAKE_PROPERTY(min_value, get_min_value);
MAKE_PROPERTY(max_value, get_max_value);
public:
virtual void output(std::ostream &out) const;
protected:
virtual int compare_to_impl(const RenderAttrib *other) const;
virtual size_t get_hash_impl() const;
virtual CPT(RenderAttrib) compose_impl(const RenderAttrib *other) const;
virtual CPT(RenderAttrib) invert_compose_impl(const RenderAttrib *other) const;
private:
int _offset;
PN_stdfloat _min_value;
PN_stdfloat _max_value;
PUBLISHED:
static int get_class_slot() {
return _attrib_slot;
}
virtual int get_slot() const {
return get_class_slot();
}
MAKE_PROPERTY(class_slot, get_class_slot);
public:
static void register_with_read_factory();
virtual void write_datagram(BamWriter *manager, Datagram &dg);
protected:
static TypedWritable *make_from_bam(const FactoryParams &params);
void fillin(DatagramIterator &scan, BamReader *manager);
public:
static TypeHandle get_class_type() {
return _type_handle;
}
static void init_type() {
RenderAttrib::init_type();
register_type(_type_handle, "DepthOffsetAttrib",
RenderAttrib::get_class_type());
_attrib_slot = register_slot(_type_handle, 100,
new DepthOffsetAttrib(0, 0, 1));
}
virtual TypeHandle get_type() const {
return get_class_type();
}
virtual TypeHandle force_init_type() {init_type(); return get_class_type();}
private:
static TypeHandle _type_handle;
static int _attrib_slot;
};
#include "depthOffsetAttrib.I"
#endif