Panda3D
lightRampAttrib.cxx
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1 /**
2  * PANDA 3D SOFTWARE
3  * Copyright (c) Carnegie Mellon University. All rights reserved.
4  *
5  * All use of this software is subject to the terms of the revised BSD
6  * license. You should have received a copy of this license along
7  * with this source code in a file named "LICENSE."
8  *
9  * @file lightRampAttrib.cxx
10  * @author drose
11  * @date 2002-03-04
12  */
13 
14 #include "lightRampAttrib.h"
16 #include "dcast.h"
17 #include "bamReader.h"
18 #include "bamWriter.h"
19 #include "datagram.h"
20 #include "datagramIterator.h"
21 
22 TypeHandle LightRampAttrib::_type_handle;
23 int LightRampAttrib::_attrib_slot;
24 CPT(RenderAttrib) LightRampAttrib::_default;
25 
26 /**
27  * Constructs a new LightRampAttrib object. This is the standard OpenGL
28  * lighting ramp, which clamps the final light total to the 0-1 range.
29  */
30 CPT(RenderAttrib) LightRampAttrib::
31 make_default() {
32  if (_default == nullptr) {
33  LightRampAttrib *attrib = new LightRampAttrib();
34  _default = return_new(attrib);
35  }
36  return _default;
37 }
38 
39 /**
40  * Constructs a new LightRampAttrib object. This differs from the usual
41  * OpenGL lighting model in that it does not clamp the final lighting total to
42  * (0,1).
43  */
44 CPT(RenderAttrib) LightRampAttrib::
45 make_identity() {
46  LightRampAttrib *attrib = new LightRampAttrib();
47  attrib->_mode = LRT_identity;
48  return return_new(attrib);
49 }
50 
51 /**
52  * Constructs a new LightRampAttrib object. This causes the luminance of the
53  * diffuse lighting contribution to be quantized using a single threshold:
54  *
55  * @code
56  * if (original_luminance > threshold0) {
57  * luminance = level0;
58  * } else {
59  * luminance = 0.0;
60  * }
61  * @endcode
62  */
63 CPT(RenderAttrib) LightRampAttrib::
64 make_single_threshold(PN_stdfloat thresh0, PN_stdfloat val0) {
65  LightRampAttrib *attrib = new LightRampAttrib();
66  attrib->_mode = LRT_single_threshold;
67  attrib->_threshold[0] = thresh0;
68  attrib->_level[0] = val0;
69  return return_new(attrib);
70 }
71 
72 /**
73  * Constructs a new LightRampAttrib object. This causes the luminance of the
74  * diffuse lighting contribution to be quantized using two thresholds:
75  *
76  * @code
77  * if (original_luminance > threshold1) {
78  * luminance = level1;
79  * } else if (original_luminance > threshold0) {
80  * luminance = level0;
81  * } else {
82  * luminance = 0.0;
83  * }
84  * @endcode
85  */
86 CPT(RenderAttrib) LightRampAttrib::
87 make_double_threshold(PN_stdfloat thresh0, PN_stdfloat val0, PN_stdfloat thresh1, PN_stdfloat val1) {
88  LightRampAttrib *attrib = new LightRampAttrib();
89  attrib->_mode = LRT_double_threshold;
90  attrib->_threshold[0] = thresh0;
91  attrib->_level[0] = val0;
92  attrib->_threshold[1] = thresh1;
93  attrib->_level[1] = val1;
94  return return_new(attrib);
95 }
96 
97 /**
98  * Constructs a new LightRampAttrib object. This causes an HDR tone mapping
99  * operation to be applied.
100  *
101  * Normally, brightness values greater than 1 cannot be distinguished from
102  * each other, causing very brightly lit objects to wash out white and all
103  * detail to be erased. HDR tone mapping remaps brightness values in the
104  * range 0-infinity into the range (0,1), making it possible to distinguish
105  * detail in scenes whose brightness exceeds 1.
106  *
107  * However, the monitor has finite contrast. Normally, all of that contrast
108  * is used to represent brightnesses in the range 0-1. The HDR0 tone mapping
109  * operator 'steals' one quarter of that contrast to represent brightnesses in
110  * the range 1-infinity.
111  *
112  * @code
113  * FINAL_RGB = (RGB^3 + RGB^2 + RGB) / (RGB^3 + RGB^2 + RGB + 1)
114  * @endcode
115  */
116 CPT(RenderAttrib) LightRampAttrib::
117 make_hdr0() {
118  LightRampAttrib *attrib = new LightRampAttrib();
119  attrib->_mode = LRT_hdr0;
120  return return_new(attrib);
121 }
122 
123 /**
124  * Constructs a new LightRampAttrib object. This causes an HDR tone mapping
125  * operation to be applied.
126  *
127  * Normally, brightness values greater than 1 cannot be distinguished from
128  * each other, causing very brightly lit objects to wash out white and all
129  * detail to be erased. HDR tone mapping remaps brightness values in the
130  * range 0-infinity into the range (0,1), making it possible to distinguish
131  * detail in scenes whose brightness exceeds 1.
132  *
133  * However, the monitor has finite contrast. Normally, all of that contrast
134  * is used to represent brightnesses in the range 0-1. The HDR1 tone mapping
135  * operator 'steals' one third of that contrast to represent brightnesses in
136  * the range 1-infinity.
137  *
138  * @code
139  * FINAL_RGB = (RGB^2 + RGB) / (RGB^2 + RGB + 1)
140  * @endcode
141  */
142 CPT(RenderAttrib) LightRampAttrib::
143 make_hdr1() {
144  LightRampAttrib *attrib = new LightRampAttrib();
145  attrib->_mode = LRT_hdr1;
146  return return_new(attrib);
147 }
148 
149 /**
150  * Constructs a new LightRampAttrib object. This causes an HDR tone mapping
151  * operation to be applied.
152  *
153  * Normally, brightness values greater than 1 cannot be distinguished from
154  * each other, causing very brightly lit objects to wash out white and all
155  * detail to be erased. HDR tone mapping remaps brightness values in the
156  * range 0-infinity into the range (0,1), making it possible to distinguish
157  * detail in scenes whose brightness exceeds 1.
158  *
159  * However, the monitor has finite contrast. Normally, all of that contrast
160  * is used to represent brightnesses in the range 0-1. The HDR2 tone mapping
161  * operator 'steals' one half of that contrast to represent brightnesses in
162  * the range 1-infinity.
163  *
164  * @code
165  * FINAL_RGB = (RGB) / (RGB + 1)
166  * @endcode
167  */
168 CPT(RenderAttrib) LightRampAttrib::
169 make_hdr2() {
170  LightRampAttrib *attrib = new LightRampAttrib();
171  attrib->_mode = LRT_hdr2;
172  return return_new(attrib);
173 }
174 
175 /**
176  *
177  */
178 void LightRampAttrib::
179 output(std::ostream &out) const {
180  out << get_type() << ":";
181  switch (_mode) {
182  case LRT_default:
183  out << "default()";
184  break;
185  case LRT_identity:
186  out << "identity()";
187  break;
188  case LRT_single_threshold:
189  out << "single_threshold(" << _level[0] << "," << _level[1] << "," << _threshold[0] << ")";
190  break;
191  case LRT_double_threshold:
192  out << "double_threshold(" << _level[0] << "," << _level[1] << "," << _threshold[0] << "," << _threshold[1] << ")";
193  break;
194  case LRT_hdr0:
195  out << "hdr0()";
196  break;
197  case LRT_hdr1:
198  out << "hdr1()";
199  break;
200  case LRT_hdr2:
201  out << "hdr2()";
202  break;
203  }
204 }
205 
206 /**
207  * Intended to be overridden by derived LightRampAttrib types to return a
208  * unique number indicating whether this LightRampAttrib is equivalent to the
209  * other one.
210  *
211  * This should return 0 if the two LightRampAttrib objects are equivalent, a
212  * number less than zero if this one should be sorted before the other one,
213  * and a number greater than zero otherwise.
214  *
215  * This will only be called with two LightRampAttrib objects whose get_type()
216  * functions return the same.
217  */
218 int LightRampAttrib::
219 compare_to_impl(const RenderAttrib *other) const {
220  const LightRampAttrib *ta = (const LightRampAttrib *)other;
221 
222  int compare_result = ((int)_mode - (int)ta->_mode) ;
223  if (compare_result != 0) {
224  return compare_result;
225  }
226  for (int i = 0; i < 2; i++) {
227  if (_level[i] != ta->_level[i]) {
228  return (_level[i] < ta->_level[i]) ? -1 : 1;
229  }
230  }
231  for (int i = 0; i < 2; i++) {
232  if (_threshold[i] != ta->_threshold[i]) {
233  return (_threshold[i] < ta->_threshold[i]) ? -1 : 1;
234  }
235  }
236  return 0;
237 }
238 
239 /**
240  * Intended to be overridden by derived RenderAttrib types to return a unique
241  * hash for these particular properties. RenderAttribs that compare the same
242  * with compare_to_impl(), above, should return the same hash; RenderAttribs
243  * that compare differently should return a different hash.
244  */
245 size_t LightRampAttrib::
246 get_hash_impl() const {
247  size_t hash = 0;
248  hash = int_hash::add_hash(hash, (int)_mode);
249  float_hash fh;
250  for (int i = 0; i < 2; i++) {
251  hash = fh.add_hash(hash, _level[i]);
252  hash = fh.add_hash(hash, _threshold[i]);
253  }
254  return hash;
255 }
256 
257 /**
258  * Tells the BamReader how to create objects of type LightRampAttrib.
259  */
262  BamReader::get_factory()->register_factory(get_class_type(), make_from_bam);
263 }
264 
265 /**
266  * Writes the contents of this object to the datagram for shipping out to a
267  * Bam file.
268  */
270 write_datagram(BamWriter *manager, Datagram &dg) {
271  RenderAttrib::write_datagram(manager, dg);
272 
273  dg.add_int8(_mode);
274  for (int i=0; i<2; i++) {
275  dg.add_stdfloat(_level[i]);
276  }
277  for (int i=0; i<2; i++) {
278  dg.add_stdfloat(_threshold[i]);
279  }
280 }
281 
282 /**
283  * This function is called by the BamReader's factory when a new object of
284  * type LightRampAttrib is encountered in the Bam file. It should create the
285  * LightRampAttrib and extract its information from the file.
286  */
287 TypedWritable *LightRampAttrib::
288 make_from_bam(const FactoryParams &params) {
289  LightRampAttrib *attrib = new LightRampAttrib;
290  DatagramIterator scan;
291  BamReader *manager;
292 
293  parse_params(params, scan, manager);
294  attrib->fillin(scan, manager);
295 
296  return attrib;
297 }
298 
299 /**
300  * This internal function is called by make_from_bam to read in all of the
301  * relevant data from the BamFile for the new LightRampAttrib.
302  */
303 void LightRampAttrib::
304 fillin(DatagramIterator &scan, BamReader *manager) {
305  RenderAttrib::fillin(scan, manager);
306 
307  _mode = (LightRampMode)scan.get_int8();
308  for (int i=0; i<2; i++) {
309  _level[i] = scan.get_stdfloat();
310  }
311  for (int i=0; i<2; i++) {
312  _threshold[i] = scan.get_stdfloat();
313  }
314 }
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
void parse_params(const FactoryParams &params, DatagramIterator &scan, BamReader *&manager)
Takes in a FactoryParams, passed from a WritableFactory into any TypedWritable's make function,...
Definition: bamReader.I:275
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
This is the fundamental interface for extracting binary objects from a Bam file, as generated by a Ba...
Definition: bamReader.h:110
static WritableFactory * get_factory()
Returns the global WritableFactory for generating TypedWritable objects.
Definition: bamReader.I:177
This is the fundamental interface for writing binary objects to a Bam file, to be extracted later by ...
Definition: bamWriter.h:63
A class to retrieve the individual data elements previously stored in a Datagram.
PN_stdfloat get_stdfloat()
Extracts either a 32-bit or a 64-bit floating-point number, according to Datagram::set_stdfloat_doubl...
int8_t get_int8()
Extracts a signed 8-bit integer.
An ordered list of data elements, formatted in memory for transmission over a socket or writing to a ...
Definition: datagram.h:38
void add_stdfloat(PN_stdfloat value)
Adds either a 32-bit or a 64-bit floating-point number, according to set_stdfloat_double().
Definition: datagram.I:133
void add_int8(int8_t value)
Adds a signed 8-bit integer to the datagram.
Definition: datagram.I:42
An instance of this class is passed to the Factory when requesting it to do its business and construc...
Definition: factoryParams.h:36
void register_factory(TypeHandle handle, CreateFunc *func, void *user_data=nullptr)
Registers a new kind of thing the Factory will be able to create.
Definition: factory.I:73
A Light Ramp is any unary operator that takes a rendered pixel as input, and adjusts the brightness o...
virtual void write_datagram(BamWriter *manager, Datagram &dg)
Writes the contents of this object to the datagram for shipping out to a Bam file.
static void register_with_read_factory()
Tells the BamReader how to create objects of type LightRampAttrib.
This is the base class for a number of render attributes (other than transform) that may be set on sc...
Definition: renderAttrib.h:51
virtual void write_datagram(BamWriter *manager, Datagram &dg)
Writes the contents of this object to the datagram for shipping out to a Bam file.
TypeHandle is the identifier used to differentiate C++ class types.
Definition: typeHandle.h:81
Base class for objects that can be written to and read from Bam files.
Definition: typedWritable.h:35
This hash_compare class hashes a float or a double.
Definition: stl_compares.h:140
size_t add_hash(size_t start, const Key &key) const
Adds the indicated key into a running hash.
Definition: stl_compares.I:149
static size_t add_hash(size_t start, const Key &key)
Adds the indicated key into a running hash.
Definition: stl_compares.I:101
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
CPT(RenderAttrib) LightRampAttrib CPT(RenderAttrib) LightRampAttrib
Constructs a new LightRampAttrib object.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.