592
|
1 /**
|
|
2 * Stone of Orthanc
|
|
3 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
|
|
4 * Department, University Hospital of Liege, Belgium
|
|
5 * Copyright (C) 2017-2019 Osimis S.A., Belgium
|
|
6 *
|
|
7 * This program is free software: you can redistribute it and/or
|
|
8 * modify it under the terms of the GNU Affero General Public License
|
|
9 * as published by the Free Software Foundation, either version 3 of
|
|
10 * the License, or (at your option) any later version.
|
|
11 *
|
|
12 * This program is distributed in the hope that it will be useful, but
|
|
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
15 * Affero General Public License for more details.
|
|
16 *
|
|
17 * You should have received a copy of the GNU Affero General Public License
|
|
18 * along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
19 **/
|
|
20
|
|
21
|
|
22 #include "OpenGLLinesProgram.h"
|
|
23
|
|
24 #include <Core/OrthancException.h>
|
|
25
|
|
26
|
|
27 static const unsigned int COMPONENTS_POSITION = 3;
|
|
28 static const unsigned int COMPONENTS_MITER = 2;
|
|
29
|
|
30
|
|
31 static const char* VERTEX_SHADER =
|
|
32 "attribute vec2 a_miter_direction; \n"
|
|
33 "attribute vec4 a_position; \n"
|
|
34 "uniform float u_thickness; \n"
|
|
35 "uniform mat4 u_matrix; \n"
|
|
36 "varying float v_distance; \n"
|
|
37 "void main() \n"
|
|
38 "{ \n"
|
|
39 " v_distance = a_position.z; \n"
|
|
40 " gl_Position = u_matrix * vec4(a_position.xy + a_position.z * a_miter_direction * u_thickness, 0, 1); \n"
|
|
41 "}";
|
|
42
|
|
43
|
|
44 static const char* FRAGMENT_SHADER =
|
|
45 "uniform bool u_antialiasing; \n"
|
|
46 "uniform float u_antialiasing_start; \n"
|
|
47 "uniform vec3 u_color; \n"
|
|
48 "varying float v_distance; \n" // Distance of the point to the segment
|
|
49 "void main() \n"
|
|
50 "{ \n"
|
|
51 " float d = abs(v_distance); \n"
|
|
52 " if (!u_antialiasing || \n"
|
|
53 " d <= u_antialiasing_start) \n"
|
|
54 " gl_FragColor = vec4(u_color, 1); \n"
|
|
55 " else if (d >= 1.0) \n"
|
|
56 " gl_FragColor = vec4(0, 0, 0, 0); \n"
|
|
57 " else \n"
|
|
58 " { \n"
|
|
59 " float alpha = 1.0 - smoothstep(u_antialiasing_start, 1.0, d); \n"
|
|
60 " gl_FragColor = vec4(u_color * alpha, alpha); \n"
|
|
61 " } \n"
|
|
62 "}";
|
|
63
|
|
64
|
|
65 namespace OrthancStone
|
|
66 {
|
|
67 namespace Internals
|
|
68 {
|
|
69 class OpenGLLinesProgram::Data::Segment
|
|
70 {
|
|
71 private:
|
|
72 bool isEmpty_;
|
|
73 double x1_;
|
|
74 double y1_;
|
|
75 double x2_;
|
|
76 double y2_;
|
|
77 double miterX1_;
|
|
78 double miterY1_;
|
|
79 double miterX2_;
|
|
80 double miterY2_;
|
|
81
|
|
82 Vector lineAbove_; // In homogeneous coordinates (size = 3)
|
|
83 Vector lineBelow_;
|
|
84
|
|
85 public:
|
|
86 Segment(const PolylineSceneLayer::Chain& chain,
|
|
87 size_t index1,
|
|
88 size_t index2) :
|
|
89 isEmpty_(false)
|
|
90 {
|
|
91 if (index1 >= chain.size() ||
|
|
92 index2 >= chain.size())
|
|
93 {
|
|
94 throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange);
|
|
95 }
|
|
96 else
|
|
97 {
|
|
98 const ScenePoint2D& p = chain[index1];
|
|
99 const ScenePoint2D& q = chain[index2];
|
|
100
|
|
101 x1_ = p.GetX();
|
|
102 y1_ = p.GetY();
|
|
103 x2_ = q.GetX();
|
|
104 y2_ = q.GetY();
|
|
105
|
|
106 const double dx = x2_ - x1_;
|
|
107 const double dy = y2_ - y1_;
|
|
108 const double norm = sqrt(dx * dx + dy * dy);
|
|
109
|
|
110 if (LinearAlgebra::IsCloseToZero(norm))
|
|
111 {
|
|
112 isEmpty_ = true;
|
|
113 }
|
|
114 else
|
|
115 {
|
|
116 isEmpty_ = false;
|
|
117 const double normalX = -dy / norm;
|
|
118 const double normalY = dx / norm;
|
|
119
|
|
120 miterX1_ = normalX;
|
|
121 miterY1_ = normalY;
|
|
122 miterX2_ = normalX;
|
|
123 miterY2_ = normalY;
|
|
124
|
|
125 Vector a = LinearAlgebra::CreateVector(x1_ + normalX, y1_ + normalY, 1);
|
|
126 Vector b = LinearAlgebra::CreateVector(x2_ + normalX, y2_ + normalY, 1);
|
|
127 LinearAlgebra::CrossProduct(lineAbove_, a, b);
|
|
128
|
|
129 a = LinearAlgebra::CreateVector(x1_ - normalX, y1_ - normalY, 1);
|
|
130 b = LinearAlgebra::CreateVector(x2_ - normalX, y2_ - normalY, 1);
|
|
131 LinearAlgebra::CrossProduct(lineBelow_, a, b);
|
|
132 }
|
|
133 }
|
|
134 }
|
|
135
|
|
136 bool IsEmpty() const
|
|
137 {
|
|
138 return isEmpty_;
|
|
139 }
|
|
140
|
|
141 static double ComputeSignedArea(double x1,
|
|
142 double y1,
|
|
143 double x2,
|
|
144 double y2,
|
|
145 double x3,
|
|
146 double y3)
|
|
147 {
|
|
148 // This computes the signed area of a 2D triangle. This
|
|
149 // formula is e.g. used in the sorting algorithm of Graham's
|
|
150 // scan to compute the convex hull.
|
|
151 // https://en.wikipedia.org/wiki/Graham_scan
|
|
152 return (x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1);
|
|
153 }
|
|
154
|
|
155 static void CreateMiter(Segment& left,
|
|
156 Segment& right)
|
|
157 {
|
|
158 if (!left.IsEmpty() &&
|
|
159 !right.IsEmpty())
|
|
160 {
|
|
161 Vector above, below;
|
|
162 LinearAlgebra::CrossProduct(above, left.lineAbove_, right.lineAbove_);
|
|
163 LinearAlgebra::CrossProduct(below, left.lineBelow_, right.lineBelow_);
|
|
164
|
|
165 if (!LinearAlgebra::IsCloseToZero(above[2]) &&
|
|
166 !LinearAlgebra::IsCloseToZero(below[2]))
|
|
167 {
|
|
168 // Back to inhomogeneous 2D coordinates
|
|
169 above /= above[2];
|
|
170 below /= below[2];
|
|
171
|
|
172 // Check whether "above" and "below" intersection points
|
|
173 // are on the half-plane defined by the endpoints of the
|
|
174 // two segments. This is an indicator of whether the angle
|
|
175 // is too acute.
|
|
176 double s1 = ComputeSignedArea(left.x1_, left.y1_,
|
|
177 above[0], above[1],
|
|
178 right.x2_, right.y2_);
|
|
179 double s2 = ComputeSignedArea(left.x1_, left.y1_,
|
|
180 below[0], below[1],
|
|
181 right.x2_, right.y2_);
|
|
182
|
|
183 // The two signed areas must have the same sign
|
|
184 if (s1 * s2 >= 0)
|
|
185 {
|
|
186 left.miterX2_ = above[0] - left.x2_;
|
|
187 left.miterY2_ = above[1] - left.y2_;
|
|
188
|
|
189 right.miterX1_ = left.miterX2_;
|
|
190 right.miterY1_ = left.miterY2_;
|
|
191 }
|
|
192 }
|
|
193 }
|
|
194 }
|
|
195
|
|
196 void AddTriangles(std::vector<float>& coords,
|
|
197 std::vector<float>& miterDirections)
|
|
198 {
|
|
199 if (isEmpty_)
|
|
200 {
|
|
201 throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
|
|
202 }
|
|
203
|
|
204 // First triangle
|
|
205 coords.push_back(x1_);
|
|
206 coords.push_back(y1_);
|
|
207 coords.push_back(1);
|
|
208 coords.push_back(x2_);
|
|
209 coords.push_back(y2_);
|
|
210 coords.push_back(-1);
|
|
211 coords.push_back(x2_);
|
|
212 coords.push_back(y2_);
|
|
213 coords.push_back(1);
|
|
214
|
|
215 miterDirections.push_back(miterX1_);
|
|
216 miterDirections.push_back(miterY1_);
|
|
217 miterDirections.push_back(miterX2_);
|
|
218 miterDirections.push_back(miterY2_);
|
|
219 miterDirections.push_back(miterX2_);
|
|
220 miterDirections.push_back(miterY2_);
|
|
221
|
|
222 // Second triangle
|
|
223 coords.push_back(x1_);
|
|
224 coords.push_back(y1_);
|
|
225 coords.push_back(1);
|
|
226 coords.push_back(x1_);
|
|
227 coords.push_back(y1_);
|
|
228 coords.push_back(-1);
|
|
229 coords.push_back(x2_);
|
|
230 coords.push_back(y2_);
|
|
231 coords.push_back(-1);
|
|
232
|
|
233 miterDirections.push_back(miterX1_);
|
|
234 miterDirections.push_back(miterY1_);
|
|
235 miterDirections.push_back(miterX1_);
|
|
236 miterDirections.push_back(miterY1_);
|
|
237 miterDirections.push_back(miterX2_);
|
|
238 miterDirections.push_back(miterY2_);
|
|
239 }
|
|
240 };
|
|
241
|
|
242
|
|
243 OpenGLLinesProgram::Data::Data(OpenGL::IOpenGLContext& context,
|
|
244 const PolylineSceneLayer& layer) :
|
|
245 context_(context),
|
|
246 verticesCount_(0),
|
|
247 thickness_(layer.GetThickness()),
|
|
248 red_(layer.GetRedAsFloat()),
|
|
249 green_(layer.GetGreenAsFloat()),
|
|
250 blue_(layer.GetBlueAsFloat())
|
|
251 {
|
|
252 // High-level reference:
|
|
253 // https://mattdesl.svbtle.com/drawing-lines-is-hard
|
|
254 // https://forum.libcinder.org/topic/smooth-thick-lines-using-geometry-shader
|
|
255
|
|
256 size_t countVertices = 0;
|
|
257 for (size_t i = 0; i < layer.GetChainsCount(); i++)
|
|
258 {
|
|
259 size_t countSegments = layer.GetChain(i).size() - 1;
|
|
260
|
|
261 if (layer.IsClosedChain(i))
|
|
262 {
|
|
263 countSegments++;
|
|
264 }
|
|
265
|
|
266 // Each segment is made of 2 triangles. One triangle is
|
|
267 // defined by 3 points in 2D => 6 vertices per segment.
|
|
268 countVertices += countSegments * 2 * 3;
|
|
269 }
|
|
270
|
|
271 std::vector<float> coords, miterDirections;
|
|
272 coords.reserve(countVertices * COMPONENTS_POSITION);
|
|
273 miterDirections.reserve(countVertices * COMPONENTS_MITER);
|
|
274
|
|
275 for (size_t i = 0; i < layer.GetChainsCount(); i++)
|
|
276 {
|
|
277 const PolylineSceneLayer::Chain& chain = layer.GetChain(i);
|
|
278
|
|
279 if (chain.size() > 1)
|
|
280 {
|
|
281 std::vector<Segment> segments;
|
|
282 for (size_t j = 1; j < chain.size(); j++)
|
|
283 {
|
|
284 segments.push_back(Segment(chain, j - 1, j));
|
|
285 }
|
|
286
|
|
287 if (layer.IsClosedChain(i))
|
|
288 {
|
|
289 segments.push_back(Segment(chain, chain.size() - 1, 0));
|
|
290 }
|
|
291
|
|
292 // Try and create nice miters
|
|
293 for (size_t j = 1; j < segments.size(); j++)
|
|
294 {
|
|
295 Segment::CreateMiter(segments[j - 1], segments[j]);
|
|
296 }
|
|
297
|
|
298 if (layer.IsClosedChain(i))
|
|
299 {
|
|
300 Segment::CreateMiter(segments.back(), segments.front());
|
|
301 }
|
|
302
|
|
303 for (size_t j = 0; j < segments.size(); j++)
|
|
304 {
|
|
305 if (!segments[j].IsEmpty())
|
|
306 {
|
|
307 segments[j].AddTriangles(coords, miterDirections);
|
|
308 }
|
|
309 }
|
|
310 }
|
|
311 }
|
|
312
|
|
313 if (!coords.empty())
|
|
314 {
|
|
315 verticesCount_ = coords.size() / COMPONENTS_POSITION;
|
|
316
|
|
317 context_.MakeCurrent();
|
|
318 glGenBuffers(2, buffers_);
|
|
319
|
|
320 glBindBuffer(GL_ARRAY_BUFFER, buffers_[0]);
|
|
321 glBufferData(GL_ARRAY_BUFFER, sizeof(float) * coords.size(), &coords[0], GL_STATIC_DRAW);
|
|
322
|
|
323 glBindBuffer(GL_ARRAY_BUFFER, buffers_[1]);
|
|
324 glBufferData(GL_ARRAY_BUFFER, sizeof(float) * miterDirections.size(), &miterDirections[0], GL_STATIC_DRAW);
|
|
325 }
|
|
326 }
|
|
327
|
|
328
|
|
329 OpenGLLinesProgram::Data::~Data()
|
|
330 {
|
|
331 if (!IsEmpty())
|
|
332 {
|
|
333 context_.MakeCurrent();
|
|
334 glDeleteBuffers(2, buffers_);
|
|
335 }
|
|
336 }
|
|
337
|
|
338
|
|
339 GLuint OpenGLLinesProgram::Data::GetVerticesBuffer() const
|
|
340 {
|
|
341 if (IsEmpty())
|
|
342 {
|
|
343 throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
|
|
344 }
|
|
345 else
|
|
346 {
|
|
347 return buffers_[0];
|
|
348 }
|
|
349 }
|
|
350
|
|
351
|
|
352 GLuint OpenGLLinesProgram::Data::GetMiterDirectionsBuffer() const
|
|
353 {
|
|
354 if (IsEmpty())
|
|
355 {
|
|
356 throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
|
|
357 }
|
|
358 else
|
|
359 {
|
|
360 return buffers_[1];
|
|
361 }
|
|
362 }
|
|
363
|
|
364
|
|
365 OpenGLLinesProgram::OpenGLLinesProgram(OpenGL::IOpenGLContext& context) :
|
|
366 context_(context)
|
|
367 {
|
|
368
|
|
369 context_.MakeCurrent();
|
|
370
|
|
371 program_.reset(new OpenGL::OpenGLProgram);
|
|
372 program_->CompileShaders(VERTEX_SHADER, FRAGMENT_SHADER);
|
|
373 }
|
|
374
|
|
375
|
|
376 void OpenGLLinesProgram::Apply(const Data& data,
|
|
377 const AffineTransform2D& transform,
|
|
378 bool antialiasing,
|
|
379 bool scaleIndependantThickness)
|
|
380 {
|
|
381 if (!data.IsEmpty())
|
|
382 {
|
|
383 context_.MakeCurrent();
|
|
384 program_->Use();
|
|
385
|
|
386 GLint locationPosition = program_->GetAttributeLocation("a_position");
|
|
387 GLint locationMiterDirection = program_->GetAttributeLocation("a_miter_direction");
|
|
388
|
|
389 float m[16];
|
|
390 transform.ConvertToOpenGLMatrix(m, context_.GetCanvasWidth(), context_.GetCanvasHeight());
|
|
391
|
|
392 glUniformMatrix4fv(program_->GetUniformLocation("u_matrix"), 1, GL_FALSE, m);
|
|
393 glUniform3f(program_->GetUniformLocation("u_color"),
|
|
394 data.GetRed(), data.GetGreen(), data.GetBlue());
|
|
395
|
|
396 glBindBuffer(GL_ARRAY_BUFFER, data.GetVerticesBuffer());
|
|
397 glEnableVertexAttribArray(locationPosition);
|
|
398 glVertexAttribPointer(locationPosition, COMPONENTS_POSITION, GL_FLOAT, GL_FALSE, 0, 0);
|
|
399
|
|
400 glBindBuffer(GL_ARRAY_BUFFER, data.GetMiterDirectionsBuffer());
|
|
401 glEnableVertexAttribArray(locationMiterDirection);
|
|
402 glVertexAttribPointer(locationMiterDirection, COMPONENTS_MITER, GL_FLOAT, GL_FALSE, 0, 0);
|
|
403
|
|
404 glUniform1i(program_->GetUniformLocation("u_antialiasing"), (antialiasing ? 1 : 0));
|
|
405
|
|
406 const double zoom = transform.ComputeZoom();
|
|
407 const double thickness = data.GetThickness() / 2.0;
|
|
408 const double aliasingBorder = 2.0; // Border for antialiasing ramp, in pixels
|
|
409 assert(aliasingBorder > 0); // Prevent division by zero with "t1"
|
|
410
|
|
411 if (scaleIndependantThickness)
|
|
412 {
|
|
413 if (antialiasing)
|
|
414 {
|
|
415 double t1 = std::max(thickness, aliasingBorder);
|
|
416 double t0 = std::max(0.0, thickness - aliasingBorder);
|
|
417
|
|
418 glUniform1f(program_->GetUniformLocation("u_thickness"), t1 / zoom);
|
|
419 glUniform1f(program_->GetUniformLocation("u_antialiasing_start"), t0 / t1);
|
|
420 }
|
|
421 else
|
|
422 {
|
|
423 glUniform1f(program_->GetUniformLocation("u_thickness"), thickness / zoom);
|
|
424 }
|
|
425 }
|
|
426 else
|
|
427 {
|
|
428 if (antialiasing)
|
|
429 {
|
|
430 double t1 = std::max(thickness, aliasingBorder / zoom);
|
|
431 double t0 = std::max(0.0, thickness - aliasingBorder / zoom);
|
|
432
|
|
433 glUniform1f(program_->GetUniformLocation("u_thickness"), t1);
|
|
434 glUniform1f(program_->GetUniformLocation("u_antialiasing_start"), t0 / t1);
|
|
435 }
|
|
436 else
|
|
437 {
|
|
438 glUniform1f(program_->GetUniformLocation("u_thickness"), thickness);
|
|
439 }
|
|
440 }
|
|
441
|
|
442 if (antialiasing)
|
|
443 {
|
|
444 glEnable(GL_BLEND);
|
|
445 glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
|
|
446 glDrawArrays(GL_TRIANGLES, 0, data.GetVerticesCount());
|
|
447 glDisable(GL_BLEND);
|
|
448 }
|
|
449 else
|
|
450 {
|
|
451 glDrawArrays(GL_TRIANGLES, 0, data.GetVerticesCount());
|
|
452 }
|
|
453
|
|
454 glDisableVertexAttribArray(locationPosition);
|
|
455 glDisableVertexAttribArray(locationMiterDirection);
|
|
456 }
|
|
457 }
|
|
458 }
|
|
459 }
|