Mercurial > hg > orthanc-stone
annotate Framework/Scene2D/Internals/OpenGLLinesProgram.cpp @ 611:e3f21a265be5
Added version directive to GLSL shader code + glew init function in sample code
AND commented-out glew init function in StoneInitialize
author | Benjamin Golinvaux <bgo@osimis.io> |
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date | Tue, 30 Apr 2019 16:07:48 +0200 |
parents | bbe29efd3d1c |
children | 9a474e90e832 8b6adfb62a2f |
rev | line source |
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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" | |
611
e3f21a265be5
Added version directive to GLSL shader code + glew init function in sample code
Benjamin Golinvaux <bgo@osimis.io>
parents:
592
diff
changeset
|
23 #include "OpenGLShaderVersionDirective.h" |
592 | 24 |
25 #include <Core/OrthancException.h> | |
26 | |
27 | |
28 static const unsigned int COMPONENTS_POSITION = 3; | |
29 static const unsigned int COMPONENTS_MITER = 2; | |
30 | |
31 | |
32 static const char* VERTEX_SHADER = | |
611
e3f21a265be5
Added version directive to GLSL shader code + glew init function in sample code
Benjamin Golinvaux <bgo@osimis.io>
parents:
592
diff
changeset
|
33 ORTHANC_STONE_OPENGL_SHADER_VERSION_DIRECTIVE |
592 | 34 "attribute vec2 a_miter_direction; \n" |
35 "attribute vec4 a_position; \n" | |
36 "uniform float u_thickness; \n" | |
37 "uniform mat4 u_matrix; \n" | |
38 "varying float v_distance; \n" | |
39 "void main() \n" | |
40 "{ \n" | |
41 " v_distance = a_position.z; \n" | |
42 " gl_Position = u_matrix * vec4(a_position.xy + a_position.z * a_miter_direction * u_thickness, 0, 1); \n" | |
43 "}"; | |
44 | |
45 | |
46 static const char* FRAGMENT_SHADER = | |
611
e3f21a265be5
Added version directive to GLSL shader code + glew init function in sample code
Benjamin Golinvaux <bgo@osimis.io>
parents:
592
diff
changeset
|
47 ORTHANC_STONE_OPENGL_SHADER_VERSION_DIRECTIVE |
592 | 48 "uniform bool u_antialiasing; \n" |
49 "uniform float u_antialiasing_start; \n" | |
50 "uniform vec3 u_color; \n" | |
51 "varying float v_distance; \n" // Distance of the point to the segment | |
52 "void main() \n" | |
53 "{ \n" | |
54 " float d = abs(v_distance); \n" | |
55 " if (!u_antialiasing || \n" | |
56 " d <= u_antialiasing_start) \n" | |
57 " gl_FragColor = vec4(u_color, 1); \n" | |
58 " else if (d >= 1.0) \n" | |
59 " gl_FragColor = vec4(0, 0, 0, 0); \n" | |
60 " else \n" | |
61 " { \n" | |
62 " float alpha = 1.0 - smoothstep(u_antialiasing_start, 1.0, d); \n" | |
63 " gl_FragColor = vec4(u_color * alpha, alpha); \n" | |
64 " } \n" | |
65 "}"; | |
66 | |
67 | |
68 namespace OrthancStone | |
69 { | |
70 namespace Internals | |
71 { | |
72 class OpenGLLinesProgram::Data::Segment | |
73 { | |
74 private: | |
75 bool isEmpty_; | |
76 double x1_; | |
77 double y1_; | |
78 double x2_; | |
79 double y2_; | |
80 double miterX1_; | |
81 double miterY1_; | |
82 double miterX2_; | |
83 double miterY2_; | |
84 | |
85 Vector lineAbove_; // In homogeneous coordinates (size = 3) | |
86 Vector lineBelow_; | |
87 | |
88 public: | |
89 Segment(const PolylineSceneLayer::Chain& chain, | |
90 size_t index1, | |
91 size_t index2) : | |
92 isEmpty_(false) | |
93 { | |
94 if (index1 >= chain.size() || | |
95 index2 >= chain.size()) | |
96 { | |
97 throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange); | |
98 } | |
99 else | |
100 { | |
101 const ScenePoint2D& p = chain[index1]; | |
102 const ScenePoint2D& q = chain[index2]; | |
103 | |
104 x1_ = p.GetX(); | |
105 y1_ = p.GetY(); | |
106 x2_ = q.GetX(); | |
107 y2_ = q.GetY(); | |
108 | |
109 const double dx = x2_ - x1_; | |
110 const double dy = y2_ - y1_; | |
111 const double norm = sqrt(dx * dx + dy * dy); | |
112 | |
113 if (LinearAlgebra::IsCloseToZero(norm)) | |
114 { | |
115 isEmpty_ = true; | |
116 } | |
117 else | |
118 { | |
119 isEmpty_ = false; | |
120 const double normalX = -dy / norm; | |
121 const double normalY = dx / norm; | |
122 | |
123 miterX1_ = normalX; | |
124 miterY1_ = normalY; | |
125 miterX2_ = normalX; | |
126 miterY2_ = normalY; | |
127 | |
128 Vector a = LinearAlgebra::CreateVector(x1_ + normalX, y1_ + normalY, 1); | |
129 Vector b = LinearAlgebra::CreateVector(x2_ + normalX, y2_ + normalY, 1); | |
130 LinearAlgebra::CrossProduct(lineAbove_, a, b); | |
131 | |
132 a = LinearAlgebra::CreateVector(x1_ - normalX, y1_ - normalY, 1); | |
133 b = LinearAlgebra::CreateVector(x2_ - normalX, y2_ - normalY, 1); | |
134 LinearAlgebra::CrossProduct(lineBelow_, a, b); | |
135 } | |
136 } | |
137 } | |
138 | |
139 bool IsEmpty() const | |
140 { | |
141 return isEmpty_; | |
142 } | |
143 | |
144 static double ComputeSignedArea(double x1, | |
145 double y1, | |
146 double x2, | |
147 double y2, | |
148 double x3, | |
149 double y3) | |
150 { | |
151 // This computes the signed area of a 2D triangle. This | |
152 // formula is e.g. used in the sorting algorithm of Graham's | |
153 // scan to compute the convex hull. | |
154 // https://en.wikipedia.org/wiki/Graham_scan | |
155 return (x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1); | |
156 } | |
157 | |
158 static void CreateMiter(Segment& left, | |
159 Segment& right) | |
160 { | |
161 if (!left.IsEmpty() && | |
162 !right.IsEmpty()) | |
163 { | |
164 Vector above, below; | |
165 LinearAlgebra::CrossProduct(above, left.lineAbove_, right.lineAbove_); | |
166 LinearAlgebra::CrossProduct(below, left.lineBelow_, right.lineBelow_); | |
167 | |
168 if (!LinearAlgebra::IsCloseToZero(above[2]) && | |
169 !LinearAlgebra::IsCloseToZero(below[2])) | |
170 { | |
171 // Back to inhomogeneous 2D coordinates | |
172 above /= above[2]; | |
173 below /= below[2]; | |
174 | |
175 // Check whether "above" and "below" intersection points | |
176 // are on the half-plane defined by the endpoints of the | |
177 // two segments. This is an indicator of whether the angle | |
178 // is too acute. | |
179 double s1 = ComputeSignedArea(left.x1_, left.y1_, | |
180 above[0], above[1], | |
181 right.x2_, right.y2_); | |
182 double s2 = ComputeSignedArea(left.x1_, left.y1_, | |
183 below[0], below[1], | |
184 right.x2_, right.y2_); | |
185 | |
186 // The two signed areas must have the same sign | |
187 if (s1 * s2 >= 0) | |
188 { | |
189 left.miterX2_ = above[0] - left.x2_; | |
190 left.miterY2_ = above[1] - left.y2_; | |
191 | |
192 right.miterX1_ = left.miterX2_; | |
193 right.miterY1_ = left.miterY2_; | |
194 } | |
195 } | |
196 } | |
197 } | |
198 | |
199 void AddTriangles(std::vector<float>& coords, | |
200 std::vector<float>& miterDirections) | |
201 { | |
202 if (isEmpty_) | |
203 { | |
204 throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls); | |
205 } | |
206 | |
207 // First triangle | |
208 coords.push_back(x1_); | |
209 coords.push_back(y1_); | |
210 coords.push_back(1); | |
211 coords.push_back(x2_); | |
212 coords.push_back(y2_); | |
213 coords.push_back(-1); | |
214 coords.push_back(x2_); | |
215 coords.push_back(y2_); | |
216 coords.push_back(1); | |
217 | |
218 miterDirections.push_back(miterX1_); | |
219 miterDirections.push_back(miterY1_); | |
220 miterDirections.push_back(miterX2_); | |
221 miterDirections.push_back(miterY2_); | |
222 miterDirections.push_back(miterX2_); | |
223 miterDirections.push_back(miterY2_); | |
224 | |
225 // Second triangle | |
226 coords.push_back(x1_); | |
227 coords.push_back(y1_); | |
228 coords.push_back(1); | |
229 coords.push_back(x1_); | |
230 coords.push_back(y1_); | |
231 coords.push_back(-1); | |
232 coords.push_back(x2_); | |
233 coords.push_back(y2_); | |
234 coords.push_back(-1); | |
235 | |
236 miterDirections.push_back(miterX1_); | |
237 miterDirections.push_back(miterY1_); | |
238 miterDirections.push_back(miterX1_); | |
239 miterDirections.push_back(miterY1_); | |
240 miterDirections.push_back(miterX2_); | |
241 miterDirections.push_back(miterY2_); | |
242 } | |
243 }; | |
244 | |
245 | |
246 OpenGLLinesProgram::Data::Data(OpenGL::IOpenGLContext& context, | |
247 const PolylineSceneLayer& layer) : | |
248 context_(context), | |
249 verticesCount_(0), | |
250 thickness_(layer.GetThickness()), | |
251 red_(layer.GetRedAsFloat()), | |
252 green_(layer.GetGreenAsFloat()), | |
253 blue_(layer.GetBlueAsFloat()) | |
254 { | |
255 // High-level reference: | |
256 // https://mattdesl.svbtle.com/drawing-lines-is-hard | |
257 // https://forum.libcinder.org/topic/smooth-thick-lines-using-geometry-shader | |
258 | |
259 size_t countVertices = 0; | |
260 for (size_t i = 0; i < layer.GetChainsCount(); i++) | |
261 { | |
262 size_t countSegments = layer.GetChain(i).size() - 1; | |
263 | |
264 if (layer.IsClosedChain(i)) | |
265 { | |
266 countSegments++; | |
267 } | |
268 | |
269 // Each segment is made of 2 triangles. One triangle is | |
270 // defined by 3 points in 2D => 6 vertices per segment. | |
271 countVertices += countSegments * 2 * 3; | |
272 } | |
273 | |
274 std::vector<float> coords, miterDirections; | |
275 coords.reserve(countVertices * COMPONENTS_POSITION); | |
276 miterDirections.reserve(countVertices * COMPONENTS_MITER); | |
277 | |
278 for (size_t i = 0; i < layer.GetChainsCount(); i++) | |
279 { | |
280 const PolylineSceneLayer::Chain& chain = layer.GetChain(i); | |
281 | |
282 if (chain.size() > 1) | |
283 { | |
284 std::vector<Segment> segments; | |
285 for (size_t j = 1; j < chain.size(); j++) | |
286 { | |
287 segments.push_back(Segment(chain, j - 1, j)); | |
288 } | |
289 | |
290 if (layer.IsClosedChain(i)) | |
291 { | |
292 segments.push_back(Segment(chain, chain.size() - 1, 0)); | |
293 } | |
294 | |
295 // Try and create nice miters | |
296 for (size_t j = 1; j < segments.size(); j++) | |
297 { | |
298 Segment::CreateMiter(segments[j - 1], segments[j]); | |
299 } | |
300 | |
301 if (layer.IsClosedChain(i)) | |
302 { | |
303 Segment::CreateMiter(segments.back(), segments.front()); | |
304 } | |
305 | |
306 for (size_t j = 0; j < segments.size(); j++) | |
307 { | |
308 if (!segments[j].IsEmpty()) | |
309 { | |
310 segments[j].AddTriangles(coords, miterDirections); | |
311 } | |
312 } | |
313 } | |
314 } | |
315 | |
316 if (!coords.empty()) | |
317 { | |
318 verticesCount_ = coords.size() / COMPONENTS_POSITION; | |
319 | |
320 context_.MakeCurrent(); | |
321 glGenBuffers(2, buffers_); | |
322 | |
323 glBindBuffer(GL_ARRAY_BUFFER, buffers_[0]); | |
324 glBufferData(GL_ARRAY_BUFFER, sizeof(float) * coords.size(), &coords[0], GL_STATIC_DRAW); | |
325 | |
326 glBindBuffer(GL_ARRAY_BUFFER, buffers_[1]); | |
327 glBufferData(GL_ARRAY_BUFFER, sizeof(float) * miterDirections.size(), &miterDirections[0], GL_STATIC_DRAW); | |
328 } | |
329 } | |
330 | |
331 | |
332 OpenGLLinesProgram::Data::~Data() | |
333 { | |
334 if (!IsEmpty()) | |
335 { | |
336 context_.MakeCurrent(); | |
337 glDeleteBuffers(2, buffers_); | |
338 } | |
339 } | |
340 | |
341 | |
342 GLuint OpenGLLinesProgram::Data::GetVerticesBuffer() const | |
343 { | |
344 if (IsEmpty()) | |
345 { | |
346 throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls); | |
347 } | |
348 else | |
349 { | |
350 return buffers_[0]; | |
351 } | |
352 } | |
353 | |
354 | |
355 GLuint OpenGLLinesProgram::Data::GetMiterDirectionsBuffer() const | |
356 { | |
357 if (IsEmpty()) | |
358 { | |
359 throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls); | |
360 } | |
361 else | |
362 { | |
363 return buffers_[1]; | |
364 } | |
365 } | |
366 | |
367 | |
368 OpenGLLinesProgram::OpenGLLinesProgram(OpenGL::IOpenGLContext& context) : | |
369 context_(context) | |
370 { | |
371 | |
372 context_.MakeCurrent(); | |
373 | |
374 program_.reset(new OpenGL::OpenGLProgram); | |
375 program_->CompileShaders(VERTEX_SHADER, FRAGMENT_SHADER); | |
376 } | |
377 | |
378 | |
379 void OpenGLLinesProgram::Apply(const Data& data, | |
380 const AffineTransform2D& transform, | |
381 bool antialiasing, | |
382 bool scaleIndependantThickness) | |
383 { | |
384 if (!data.IsEmpty()) | |
385 { | |
386 context_.MakeCurrent(); | |
387 program_->Use(); | |
388 | |
389 GLint locationPosition = program_->GetAttributeLocation("a_position"); | |
390 GLint locationMiterDirection = program_->GetAttributeLocation("a_miter_direction"); | |
391 | |
392 float m[16]; | |
393 transform.ConvertToOpenGLMatrix(m, context_.GetCanvasWidth(), context_.GetCanvasHeight()); | |
394 | |
395 glUniformMatrix4fv(program_->GetUniformLocation("u_matrix"), 1, GL_FALSE, m); | |
396 glUniform3f(program_->GetUniformLocation("u_color"), | |
397 data.GetRed(), data.GetGreen(), data.GetBlue()); | |
398 | |
399 glBindBuffer(GL_ARRAY_BUFFER, data.GetVerticesBuffer()); | |
400 glEnableVertexAttribArray(locationPosition); | |
401 glVertexAttribPointer(locationPosition, COMPONENTS_POSITION, GL_FLOAT, GL_FALSE, 0, 0); | |
402 | |
403 glBindBuffer(GL_ARRAY_BUFFER, data.GetMiterDirectionsBuffer()); | |
404 glEnableVertexAttribArray(locationMiterDirection); | |
405 glVertexAttribPointer(locationMiterDirection, COMPONENTS_MITER, GL_FLOAT, GL_FALSE, 0, 0); | |
406 | |
407 glUniform1i(program_->GetUniformLocation("u_antialiasing"), (antialiasing ? 1 : 0)); | |
408 | |
409 const double zoom = transform.ComputeZoom(); | |
410 const double thickness = data.GetThickness() / 2.0; | |
411 const double aliasingBorder = 2.0; // Border for antialiasing ramp, in pixels | |
412 assert(aliasingBorder > 0); // Prevent division by zero with "t1" | |
413 | |
414 if (scaleIndependantThickness) | |
415 { | |
416 if (antialiasing) | |
417 { | |
418 double t1 = std::max(thickness, aliasingBorder); | |
419 double t0 = std::max(0.0, thickness - aliasingBorder); | |
420 | |
421 glUniform1f(program_->GetUniformLocation("u_thickness"), t1 / zoom); | |
422 glUniform1f(program_->GetUniformLocation("u_antialiasing_start"), t0 / t1); | |
423 } | |
424 else | |
425 { | |
426 glUniform1f(program_->GetUniformLocation("u_thickness"), thickness / zoom); | |
427 } | |
428 } | |
429 else | |
430 { | |
431 if (antialiasing) | |
432 { | |
433 double t1 = std::max(thickness, aliasingBorder / zoom); | |
434 double t0 = std::max(0.0, thickness - aliasingBorder / zoom); | |
435 | |
436 glUniform1f(program_->GetUniformLocation("u_thickness"), t1); | |
437 glUniform1f(program_->GetUniformLocation("u_antialiasing_start"), t0 / t1); | |
438 } | |
439 else | |
440 { | |
441 glUniform1f(program_->GetUniformLocation("u_thickness"), thickness); | |
442 } | |
443 } | |
444 | |
445 if (antialiasing) | |
446 { | |
447 glEnable(GL_BLEND); | |
448 glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); | |
449 glDrawArrays(GL_TRIANGLES, 0, data.GetVerticesCount()); | |
450 glDisable(GL_BLEND); | |
451 } | |
452 else | |
453 { | |
454 glDrawArrays(GL_TRIANGLES, 0, data.GetVerticesCount()); | |
455 } | |
456 | |
457 glDisableVertexAttribArray(locationPosition); | |
458 glDisableVertexAttribArray(locationMiterDirection); | |
459 } | |
460 } | |
461 } | |
462 } |