aboutsummaryrefslogtreecommitdiff
path: root/voronoisplat.cpp
blob: f5aa69b8412523ce47c92515ccad0d2bb7b1982a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
#include "voronoisplat.h"

#include <algorithm>

#include <QQuickWindow>
#include <QOpenGLFunctions>
#include <QOpenGLShaderProgram>
#include <QOpenGLVertexArrayObject>

#include "colormap.h"
#include "scatterplot.h"
#include "skelft.h"

static const float DEFAULT_ALPHA = 5.0f;
static const float DEFAULT_BETA = 20.0f;

static int nextPow2(int n)
{
    // TODO: check for overflows
    n--;
    for (int shift = 1; ((n + 1) & n); shift <<= 1) {
        n |= n >> shift;
    }
    return n + 1;
}

VoronoiSplat::VoronoiSplat(QQuickItem *parent)
    : QQuickFramebufferObject(parent)
    , m_sx(0.0f, 1.0f, 0.0f, 1.0f)
    , m_sy(0.0f, 1.0f, 0.0f, 1.0f)
    , m_alpha(DEFAULT_ALPHA)
    , m_beta(DEFAULT_BETA)
{
    setTextureFollowsItemSize(false);
}

void VoronoiSplat::setSites(const arma::mat &points)
{
    if (points.n_rows < 1 || points.n_cols != 2) {
        return;
    }

    if (m_values.size() > 0 && m_values.size() != points.n_rows) {
        // Old values are no longer valid, clean up
        m_values.resize(points.n_rows);
        m_values.assign(points.n_rows, 0);
    }

    // Copy 'points' to internal data structure(s)
    // Coords are packed into 'm_sites' as [ x1, y1, x2, y2, ... ]
    m_sites.resize(2*points.n_rows);
    const double *col = points.colptr(0);
    for (unsigned i = 0; i < points.n_rows; i++) {
        m_sites[2*i] = col[i];
    }

    col = points.colptr(1);
    for (unsigned i = 0; i < points.n_rows; i++) {
        m_sites[2*i + 1] = col[i];
    }

    setSitesChanged(true);
    update();
}

void VoronoiSplat::setValues(const arma::vec &values)
{
    if (values.n_elem == 0
        || (m_sites.size() != 0 && values.n_elem != m_sites.size() / 2)) {
        return;
    }

    m_values.resize(values.n_elem);
    LinearScale<float> scale(values.min(), values.max(), 0, 1.0f);
    std::transform(values.begin(), values.end(), m_values.begin(), scale);
    emit valuesChanged(values);

    setValuesChanged(true);
    update();
}

void VoronoiSplat::setColorScale(const ColorScale &scale)
{
    m_cmap.resize(scale.numColors() * 3);
    scale.sample(scale.numColors(), m_cmap.begin());
    emit colorScaleChanged(scale);

    setColorScaleChanged(true);
    update();
}

void VoronoiSplat::setScale(const LinearScale<float> &sx,
                            const LinearScale<float> &sy)
{
    m_sx = sx;
    m_sy = sy;
    emit scaleChanged(m_sx, m_sy);
    update();
}

void VoronoiSplat::setAlpha(float alpha)
{
    m_alpha = alpha;
    emit alphaChanged(m_alpha);
    update();
}

void VoronoiSplat::setBeta(float beta)
{
    m_beta = beta;
    emit betaChanged(m_beta);
    update();
}

// ----------------------------------------------------------------------------

class VoronoiSplatRenderer
    : public QQuickFramebufferObject::Renderer
{
public:
    // 'size' must be square (and power of 2)
    VoronoiSplatRenderer();
    virtual ~VoronoiSplatRenderer();

protected:
    QOpenGLFramebufferObject *createFramebufferObject(const QSize &size);
    void render();
    void synchronize(QQuickFramebufferObject *item);

private:
    void setupShaders();
    void setupVAOs();
    void setupTextures();
    void resizeTextures();

    void updateSites();
    void updateValues();
    void updateColorScale();
    void updateTransform();
    void computeDT();

    QSize m_size;
    const std::vector<float> *m_sites, *m_values, *m_cmap;
    float m_alpha, m_beta;
    GLfloat m_transform[4][4];
    LinearScale<float> m_sx, m_sy;

    QQuickWindow *m_window; // used to reset OpenGL state (as per docs)
    QOpenGLFunctions gl;
    QOpenGLShaderProgram *m_program1, *m_program2;
    GLuint m_FBO;
    GLuint m_VBOs[3];
    GLuint m_textures[2], m_colormapTex;
    QOpenGLVertexArrayObject m_sitesVAO, m_2ndPassVAO;
    bool m_sitesChanged, m_valuesChanged, m_colorScaleChanged;
};

QQuickFramebufferObject::Renderer *VoronoiSplat::createRenderer() const
{
    return new VoronoiSplatRenderer;
}

VoronoiSplatRenderer::VoronoiSplatRenderer()
    : m_transform{ 
        { 0.0f,  0.0f,  0.0f,  0.0f },
        { 0.0f,  0.0f,  0.0f,  0.0f },
        { 0.0f,  0.0f,  0.0f,  0.0f },
        { 0.0f,  0.0f,  0.0f,  1.0f },
      }
    , m_sx(0.0f, 1.0f, 0.0f, 1.0f)
    , m_sy(0.0f, 1.0f, 0.0f, 1.0f)
    , gl(QOpenGLContext::currentContext())
{
    m_transform[3][3] = 1.0f;

    gl.glGenFramebuffers(1, &m_FBO);

    setupShaders();
    setupVAOs();
    setupTextures();
}

void VoronoiSplatRenderer::setupShaders()
{
    m_program1 = new QOpenGLShaderProgram;
    m_program1->addShaderFromSourceCode(QOpenGLShader::Vertex,
R"EOF(#version 440

uniform float rad_blur;
uniform float rad_max;
uniform mat4 transform;

in vec2 vert;
in float scalar;

out float value;

void main() {
  gl_PointSize = 2.0 * (rad_max + rad_blur);
  gl_Position = transform * vec4(vert, 0.0, 1.0);
  value = scalar;
}
)EOF");
    m_program1->addShaderFromSourceCode(QOpenGLShader::Fragment,
R"EOF(#version 440

uniform float rad_blur;
uniform float rad_max;
uniform sampler2D siteDT;

in float value;

layout (location = 0) out vec4 fragColor;

void main() {
  float dt = texelFetch(siteDT, ivec2(gl_FragCoord.xy), 0).r;
  if (dt > rad_max)
    discard;
  else {
    float r = 2.0 * distance(gl_PointCoord, vec2(0.5, 0.5)) * (rad_max + rad_blur);
    float r2 = r * r;
    float rad = dt + rad_blur;
    float rad2 = rad * rad;
    if (r2 > rad2)
      discard;
    else {
      float w = exp(-5.0 * r2 / rad2);
      fragColor = vec4(w * value, w, 0.0, 0.0);
    }
  }
}
)EOF");
    m_program1->link();

    m_program2 = new QOpenGLShaderProgram;
    m_program2->addShaderFromSourceCode(QOpenGLShader::Vertex,
R"EOF(#version 440

in vec2 vert;

void main() {
  gl_Position = vec4(vert, 0.0, 1.0);
}
)EOF");
    m_program2->addShaderFromSourceCode(QOpenGLShader::Fragment,
R"EOF(
#version 440

uniform sampler2D siteDT;
uniform sampler2D accumTex;
uniform sampler2D colorScale;
uniform float rad_max;

layout (location = 0) out vec4 fragColor;

vec3 getRGB(float value) {
  return texture(colorScale, vec2(mix(0.005, 0.995, value), 0)).rgb;
}

void main() {
  float dt = texelFetch(siteDT, ivec2(gl_FragCoord.xy), 0).r;
  if (dt > rad_max)
    discard;
  else {
    vec4 accum = texelFetch(accumTex, ivec2(gl_FragCoord.xy), 0);
    float value = (accum.g > 1.0) ? (accum.r - 1.0) / (accum.g - 1.0) : 0.0;
    fragColor = vec4(getRGB(value), 1.0 - dt / rad_max);
  }
}
)EOF");
    m_program2->link();
}

void VoronoiSplatRenderer::setupVAOs()
{
    gl.glGenBuffers(3, m_VBOs);

    // sitesVAO: VBOs 0 & 1 are for sites & their values (init'd later)
    m_sitesVAO.create();
    m_sitesVAO.bind();
    gl.glBindBuffer(GL_ARRAY_BUFFER, m_VBOs[0]);
    int vertAttrib = m_program1->attributeLocation("vert");
    gl.glVertexAttribPointer(vertAttrib, 2, GL_FLOAT, GL_FALSE, 0, 0);
    gl.glEnableVertexAttribArray(vertAttrib);

    gl.glBindBuffer(GL_ARRAY_BUFFER, m_VBOs[1]);
    int valueAttrib = m_program1->attributeLocation("scalar");
    gl.glVertexAttribPointer(valueAttrib, 1, GL_FLOAT, GL_FALSE, 0, 0);
    gl.glEnableVertexAttribArray(valueAttrib);
    m_sitesVAO.release();

    // 2ndPassVAO: VBO 2 is a quad mapping the final texture to the framebuffer
    m_2ndPassVAO.create();
    m_2ndPassVAO.bind();
    GLfloat verts[] = { -1.0f, -1.0f, -1.0f,  1.0f,
                         1.0f, -1.0f,  1.0f,  1.0f };
    gl.glBindBuffer(GL_ARRAY_BUFFER, m_VBOs[2]);
    gl.glBufferData(GL_ARRAY_BUFFER, sizeof(verts), verts, GL_STATIC_DRAW);
    vertAttrib = m_program2->attributeLocation("vert");
    gl.glVertexAttribPointer(vertAttrib, 2, GL_FLOAT, GL_FALSE, 0, 0);
    gl.glEnableVertexAttribArray(vertAttrib);
    m_2ndPassVAO.release();
}

void VoronoiSplatRenderer::setupTextures()
{
    gl.glGenTextures(2, m_textures);

    // Used for colorScale lookup in the frag shader
    // (2D texture for compatibility; used to be a 1D texture)
    gl.glGenTextures(1, &m_colormapTex);
    gl.glBindTexture(GL_TEXTURE_2D, m_colormapTex);
    gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
}

VoronoiSplatRenderer::~VoronoiSplatRenderer()
{
    gl.glDeleteBuffers(3, m_VBOs);
    gl.glDeleteTextures(2, m_textures);
    gl.glDeleteTextures(1, &m_colormapTex);

    gl.glDeleteFramebuffers(1, &m_FBO);

    delete m_program1;
    delete m_program2;

    skelft2DDeinitialization();
}

void VoronoiSplatRenderer::resizeTextures()
{
    // textures[0] stores the DT values for each pixel
    gl.glBindTexture(GL_TEXTURE_2D, m_textures[0]);
    gl.glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, m_size.width(),
            m_size.height(), 0, GL_RED, GL_FLOAT, 0);
    gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // textures[1] is the result of the first pass
    gl.glBindTexture(GL_TEXTURE_2D, m_textures[1]);
    gl.glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, m_size.width(),
            m_size.height(), 0, GL_RGBA, GL_FLOAT, 0);
    gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
}

QOpenGLFramebufferObject *VoronoiSplatRenderer::createFramebufferObject(const QSize &size)
{
    int baseSize = nextPow2(std::min(size.width(), size.height()));
    m_size.setWidth(baseSize);
    m_size.setHeight(baseSize);
    resizeTextures();

    skelft2DInitialization(m_size.width());

    return QQuickFramebufferObject::Renderer::createFramebufferObject(m_size);
}

void VoronoiSplatRenderer::render()
{
    // Update OpenGL buffers and textures as needed
    if (m_sitesChanged) {
        updateSites();
    }
    if (m_valuesChanged) {
        updateValues();
    }
    if (m_colorScaleChanged) {
        updateColorScale();
    }

    int originalFBO;
    gl.glGetIntegerv(GL_FRAMEBUFFER_BINDING, &originalFBO);

    gl.glBindFramebuffer(GL_FRAMEBUFFER, m_FBO);

    // First pass
    m_program1->bind();
    m_program1->setUniformValue("rad_max", m_beta);
    m_program1->setUniformValue("rad_blur", m_alpha);
    m_program1->setUniformValue("transform", m_transform);

    gl.glActiveTexture(GL_TEXTURE0);
    gl.glBindTexture(GL_TEXTURE_2D, m_textures[0]);
    m_program1->setUniformValue("siteDT", 0);

    gl.glEnable(GL_POINT_SPRITE);
    gl.glEnable(GL_PROGRAM_POINT_SIZE);
    gl.glEnable(GL_BLEND);
    gl.glBlendFunc(GL_ONE, GL_ONE);

    // First, we draw to an intermediate texture, which is used as input for the
    // second pass
    gl.glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
            GL_TEXTURE_2D, m_textures[1], 0);

    gl.glClearColor(1, 1, 1, 1);
    gl.glClear(GL_COLOR_BUFFER_BIT);

    m_sitesVAO.bind();
    gl.glDrawArrays(GL_POINTS, 0, m_values->size());
    m_sitesVAO.release();

    m_program1->release();

    // For some reason this call makes the splat circle of the correct size
    //m_window->resetOpenGLState();

    // Second pass
    m_program2->bind();
    m_program2->setUniformValue("rad_max", m_beta);

    gl.glActiveTexture(GL_TEXTURE0);
    gl.glBindTexture(GL_TEXTURE_2D, m_textures[0]);
    m_program2->setUniformValue("siteDT", 0);
    gl.glActiveTexture(GL_TEXTURE1);
    gl.glBindTexture(GL_TEXTURE_2D, m_textures[1]);
    m_program2->setUniformValue("accumTex", 1);
    gl.glActiveTexture(GL_TEXTURE2);
    gl.glBindTexture(GL_TEXTURE_2D, m_colormapTex);
    m_program2->setUniformValue("colorScale", 2);

    gl.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    // We now render to the QQuickFramebufferObject's FBO
    gl.glBindFramebuffer(GL_FRAMEBUFFER, originalFBO);

    gl.glClearColor(0, 0, 0, 0);
    gl.glClear(GL_COLOR_BUFFER_BIT);

    m_2ndPassVAO.bind();
    gl.glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    m_2ndPassVAO.release();

    m_program2->release();

    m_window->resetOpenGLState();
}

void VoronoiSplatRenderer::synchronize(QQuickFramebufferObject *item)
{
    VoronoiSplat *splat = static_cast<VoronoiSplat *>(item);

    m_sitesChanged    = splat->sitesChanged();
    m_valuesChanged   = splat->valuesChanged();
    m_colorScaleChanged = splat->colorScaleChanged();

    // Reset so that we have the correct values by the next synchronize()
    splat->setSitesChanged(false);
    splat->setValuesChanged(false);
    splat->setColorScaleChanged(false);

    m_sites  = &(splat->sites());
    m_values = &(splat->values());
    m_cmap   = &(splat->colorScale());
    m_sx     = splat->scaleX();
    m_sy     = splat->scaleY();
    m_alpha  = splat->alpha();
    m_beta   = splat->beta();
    m_window = splat->window();
}

void VoronoiSplatRenderer::updateTransform()
{
    GLfloat w = m_size.width(), h = m_size.height();

    GLfloat rangeOffset = Scatterplot::PADDING / w;
    m_sx.setRange(rangeOffset, 1.0f - rangeOffset);
    GLfloat sx = 2.0f * m_sx.slope();
    GLfloat tx = 2.0f * m_sx.offset() - 1.0f;

    rangeOffset = Scatterplot::PADDING / h;
    m_sy.setRange(1.0f - rangeOffset, rangeOffset);
    GLfloat sy = 2.0f * m_sy.slope();
    GLfloat ty = 2.0f * m_sy.offset() - 1.0f;

    // The transform matrix should be this (but transposed -- column major):
    // [   sx  0.0f  0.0f   -tx ]
    // [ 0.0f    sy  0.0f   -ty ]
    // [ 0.0f  0.0f  0.0f  0.0f ]
    // [ 0.0f  0.0f  0.0f  1.0f ]
    m_transform[0][0] = sx;
    m_transform[1][1] = sy;
    m_transform[3][0] = tx;
    m_transform[3][1] = ty;
}

void VoronoiSplatRenderer::updateSites()
{
    gl.glBindBuffer(GL_ARRAY_BUFFER, m_VBOs[0]);
    gl.glBufferData(GL_ARRAY_BUFFER, m_sites->size() * sizeof(float),
            m_sites->data(), GL_DYNAMIC_DRAW);

    // Compute DT values for the new positions
    computeDT();

    // Update transform used when drawing sites
    updateTransform();

    m_sitesChanged = false;
}

void VoronoiSplatRenderer::updateValues()
{
    gl.glBindBuffer(GL_ARRAY_BUFFER, m_VBOs[1]);
    gl.glBufferData(GL_ARRAY_BUFFER, m_values->size() * sizeof(float),
            m_values->data(), GL_DYNAMIC_DRAW);

    m_valuesChanged = false;
}

void VoronoiSplatRenderer::updateColorScale()
{
    gl.glBindTexture(GL_TEXTURE_2D, m_colormapTex);
    gl.glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, m_cmap->size() / 3, 1, 0, GL_RGB,
            GL_FLOAT, m_cmap->data());

    m_colorScaleChanged = false;
}

void VoronoiSplatRenderer::computeDT()
{
    int w = m_size.width(), h = m_size.height();

    // Compute FT of the sites
    m_sx.setRange(Scatterplot::PADDING, w - Scatterplot::PADDING);
    m_sy.setRange(h - Scatterplot::PADDING, Scatterplot::PADDING);
    const std::vector<float> &sites = *m_sites;
    std::vector<float> buf(w*h);
    for (unsigned i = 0; i < sites.size(); i += 2) {
        buf[int(m_sy(sites[i + 1]))*h + int(m_sx(sites[i]))] = i/2.0f + 1.0f;
    }
    skelft2DFT(0, buf.data(), 0, 0, w, h, w);

    // Compute DT of the sites (from the resident FT)
    skelft2DDT(buf.data(), 0, 0, w, h);

    // Upload result to lookup texture
    gl.glActiveTexture(GL_TEXTURE0);
    gl.glBindTexture(GL_TEXTURE_2D, m_textures[0]);
    gl.glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, w, h, GL_RED, GL_FLOAT,
            buf.data());
}