1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
7 #include <ppapi/c/ppb_input_event.h>
8 #include <ppapi/cpp/input_event.h>
9 #include <ppapi/cpp/var.h>
10 #include <ppapi/cpp/var_array.h>
11 #include <ppapi/cpp/var_array_buffer.h>
12 #include <ppapi/cpp/var_dictionary.h>
23 #include "ppapi_simple/ps.h"
24 #include "ppapi_simple/ps_context_2d.h"
25 #include "ppapi_simple/ps_event.h"
26 #include "ppapi_simple/ps_interface.h"
27 #include "ppapi_simple/ps_main.h"
28 #include "sdk_util/thread_pool.h"
30 using namespace sdk_util; // For sdk_util::ThreadPool
32 // Global properties used to setup Voronoi demo.
34 const int kMinRectSize = 4;
35 const int kStartRecurseSize = 32; // must be power-of-two
36 const float kHugeZ = 1.0e38f;
37 const float kPI = M_PI;
38 const float kTwoPI = kPI * 2.0f;
39 const unsigned int kRandomStartSeed = 0xC0DE533D;
40 const int kMaxPointCount = 1024;
41 const int kStartPointCount = 48;
42 const int kDefaultNumRegions = 256;
44 unsigned int g_rand_state = kRandomStartSeed;
46 // random number helper
47 inline unsigned char rand255() {
48 return static_cast<unsigned char>(rand_r(&g_rand_state) & 255);
51 // random number helper
52 inline float frand() {
53 return (static_cast<float>(rand_r(&g_rand_state)) /
54 static_cast<float>(RAND_MAX));
58 inline void rand_reset(unsigned int seed) {
62 inline uint32_t next_pow2(uint32_t x) {
63 // Via Hacker's Delight, section 3.2 "Rounding Up/Down to the Next Power of 2"
73 // BGRA helper function, for constructing a pixel for a BGRA buffer.
74 inline uint32_t MakeBGRA(uint32_t b, uint32_t g, uint32_t r, uint32_t a) {
75 return (((a) << 24) | ((r) << 16) | ((g) << 8) | (b));
79 // Vec2, simple 2D vector
83 Vec2(float px, float py) {
87 void Set(float px, float py) {
93 // The main object that runs Voronoi simulation.
98 // Runs a tick of the simulations, update 2D output.
100 // Handle event from user, or message from JS.
101 void HandleEvent(PSEvent* ps_event);
104 // Methods prefixed with 'w' are run on worker threads.
105 uint32_t* wGetAddr(int x, int y);
106 int wCell(float x, float y);
107 inline void wFillSpan(uint32_t *pixels, uint32_t color, int width);
108 void wRenderTile(int x, int y, int w, int h);
109 void wProcessTile(int x, int y, int w, int h);
110 void wSubdivide(int x, int y, int w, int h);
111 void wMakeRect(int region, int *x, int *y, int *w, int *h);
112 bool wTestRect(int *m, int x, int y, int w, int h);
113 void wFillRect(int x, int y, int w, int h, uint32_t color);
114 void wRenderRect(int x0, int y0, int x1, int y1);
115 void wRenderRegion(int region);
116 static void wRenderRegionEntry(int region, void *thiz);
118 // These methods are only called by the main thread.
121 void RenderDot(float x, float y, uint32_t color1, uint32_t color2);
122 void SuperimposePositions();
125 // Helper to post small update messages to JS.
126 void PostUpdateMessage(const char* message_name, double value);
128 PSContext2D_t* ps_context_;
129 Vec2 positions_[kMaxPointCount];
130 Vec2 screen_positions_[kMaxPointCount];
131 Vec2 velocities_[kMaxPointCount];
132 uint32_t colors_[kMaxPointCount];
134 const int num_regions_;
138 bool draw_interiors_;
139 ThreadPool* workers_;
143 void Voronoi::Reset() {
144 rand_reset(kRandomStartSeed);
146 for (int i = 0; i < kMaxPointCount; i++) {
147 // random initial start position
148 const float x = frand();
149 const float y = frand();
150 positions_[i].Set(x, y);
151 // random directional velocity ( -1..1, -1..1 )
152 const float speed = 0.0005f;
153 const float u = (frand() * 2.0f - 1.0f) * speed;
154 const float v = (frand() * 2.0f - 1.0f) * speed;
155 velocities_[i].Set(u, v);
156 // 'unique' color (well... unique enough for our purposes)
157 colors_[i] = MakeBGRA(rand255(), rand255(), rand255(), 255);
161 Voronoi::Voronoi() : num_regions_(kDefaultNumRegions), num_threads_(0),
162 point_count_(kStartPointCount), draw_points_(true), draw_interiors_(true) {
164 // By default, render from the dispatch thread.
165 workers_ = new ThreadPool(num_threads_);
166 PSEventSetFilter(PSE_ALL);
167 ps_context_ = PSContext2DAllocate(PP_IMAGEDATAFORMAT_BGRA_PREMUL);
170 Voronoi::~Voronoi() {
172 PSContext2DFree(ps_context_);
175 inline uint32_t* Voronoi::wGetAddr(int x, int y) {
176 return ps_context_->data + x + y * ps_context_->stride / sizeof(uint32_t);
179 // This is the core of the Voronoi calculation. At a given point on the
180 // screen, iterate through all voronoi positions and render them as 3D cones.
181 // We're looking for the voronoi cell that generates the closest z value.
182 // (not really cones - since it is all relative, we avoid doing the
183 // expensive sqrt and test against z*z instead)
184 // If multithreading, this function is only called by the worker threads.
185 int Voronoi::wCell(float x, float y) {
186 int closest_cell = 0;
188 Vec2* pos = screen_positions_;
189 for (int i = 0; i < point_count_; ++i) {
190 // measured 5.18 cycles per iteration on a core2
191 float dx = x - pos[i].x;
192 float dy = y - pos[i].y;
193 float dd = (dx * dx + dy * dy);
202 // Given a region r, derive a non-overlapping rectangle for a thread to
204 // If multithreading, this function is only called by the worker threads.
205 void Voronoi::wMakeRect(int r, int* x, int* y, int* w, int* h) {
206 const int parts = 16;
207 assert(parts * parts == num_regions_);
208 // Round up to the nearest power of two so we can divide by parts cleanly. We
209 // could round up to the nearest 16 pixels, but it runs much faster when
210 // subdividing power-of-two squares.
212 // Many of these squares are outside of the canvas, but they will be
213 // trivially culled by wRenderRect.
214 *w = static_cast<int>(next_pow2(ps_context_->width)) / parts;
215 *h = static_cast<int>(next_pow2(ps_context_->height)) / parts;
216 *x = *w * (r % parts);
217 *y = *h * ((r / parts) % parts);
220 // Test 4 corners of a rectangle to see if they all belong to the same
221 // voronoi cell. Each test is expensive so bail asap. Returns true
222 // if all 4 corners match.
223 // If multithreading, this function is only called by the worker threads.
224 bool Voronoi::wTestRect(int* m, int x, int y, int w, int h) {
225 // each test is expensive, so exit ASAP
226 const int m0 = wCell(x, y);
227 const int m1 = wCell(x + w - 1, y);
228 if (m0 != m1) return false;
229 const int m2 = wCell(x, y + h - 1);
230 if (m0 != m2) return false;
231 const int m3 = wCell(x + w - 1, y + h - 1);
232 if (m0 != m3) return false;
233 // all 4 corners belong to the same cell
238 // Quickly fill a span of pixels with a solid color.
239 // If multithreading, this function is only called by the worker threads.
240 inline void Voronoi::wFillSpan(uint32_t* pixels, uint32_t color, int width) {
241 if (!draw_interiors_) {
242 const uint32_t gray = MakeBGRA(128, 128, 128, 255);
246 for (int i = 0; i < width; ++i)
250 // Quickly fill a rectangle with a solid color.
251 // If multithreading, this function is only called by the worker threads.
252 void Voronoi::wFillRect(int x, int y, int w, int h, uint32_t color) {
253 const uint32_t stride_in_pixels = ps_context_->stride / sizeof(uint32_t);
254 uint32_t* pixels = wGetAddr(x, y);
255 for (int j = 0; j < h; j++) {
256 wFillSpan(pixels, color, w);
257 pixels += stride_in_pixels;
261 // When recursive subdivision reaches a certain minimum without finding a
262 // rectangle that has four matching corners belonging to the same voronoi
263 // cell, this function will break the retangular 'tile' into smaller scanlines
264 // and look for opportunities to quick fill at the scanline level. If the
265 // scanline can't be quick filled, it will slow down even further and compute
266 // voronoi membership per pixel.
267 void Voronoi::wRenderTile(int x, int y, int w, int h) {
268 // rip through a tile
269 const uint32_t stride_in_pixels = ps_context_->stride / sizeof(uint32_t);
270 uint32_t* pixels = wGetAddr(x, y);
271 for (int j = 0; j < h; j++) {
272 // get start and end cell values
273 int ms = wCell(x + 0, y + j);
274 int me = wCell(x + w - 1, y + j);
275 // if the end points are the same, quick fill the span
277 wFillSpan(pixels, colors_[ms], w);
279 // else compute each pixel in the span... this is the slow part!
280 uint32_t* p = pixels;
282 for (int i = 1; i < (w - 1); i++) {
283 int m = wCell(x + i, y + j);
288 pixels += stride_in_pixels;
292 // Take a rectangular region and do one of -
293 // If all four corners below to the same voronoi cell, stop recursion and
294 // quick fill the rectangle.
295 // If the minimum rectangle size has been reached, break out of recursion
296 // and process the rectangle. This small rectangle is called a tile.
297 // Otherwise, keep recursively subdividing the rectangle into 4 equally
298 // sized smaller rectangles.
299 // If multithreading, this function is only called by the worker threads.
300 void Voronoi::wSubdivide(int x, int y, int w, int h) {
302 // if all 4 corners are equal, quick fill interior
303 if (wTestRect(&m, x, y, w, h)) {
304 wFillRect(x, y, w, h, colors_[m]);
306 // did we reach the minimum rectangle size?
307 if ((w <= kMinRectSize) || (h <= kMinRectSize)) {
308 wRenderTile(x, y, w, h);
310 // else recurse into smaller rectangles
311 const int half_w = w / 2;
312 const int half_h = h / 2;
313 wSubdivide(x, y, half_w, half_h);
314 wSubdivide(x + half_w, y, w - half_w, half_h);
315 wSubdivide(x, y + half_h, half_w, h - half_h);
316 wSubdivide(x + half_w, y + half_h, w - half_w, h - half_h);
321 // This function cuts up the rectangle into squares (preferably power-of-two).
322 // If multithreading, this function is only called by the worker threads.
323 void Voronoi::wRenderRect(int x, int y, int w, int h) {
324 for (int iy = y; iy < (y + h); iy += kStartRecurseSize) {
325 for (int ix = x; ix < (x + w); ix += kStartRecurseSize) {
326 int iw = kStartRecurseSize;
327 int ih = kStartRecurseSize;
328 // Clamp width + height.
329 if (ix + iw > ps_context_->width)
330 iw = ps_context_->width - ix;
331 if (iy + ih > ps_context_->height)
332 ih = ps_context_->height - iy;
333 if (iw <= 0 || ih <= 0)
336 wSubdivide(ix, iy, iw, ih);
341 // If multithreading, this function is only called by the worker threads.
342 void Voronoi::wRenderRegion(int region) {
343 // convert region # into x0, y0, x1, y1 rectangle
345 wMakeRect(region, &x, &y, &w, &h);
346 // render this rectangle
347 wRenderRect(x, y, w, h);
350 // Entry point for worker thread. Can't pass a member function around, so we
351 // have to do this little round-about.
352 void Voronoi::wRenderRegionEntry(int region, void* thiz) {
353 static_cast<Voronoi*>(thiz)->wRenderRegion(region);
356 // Function Voronoi::UpdateSim()
357 // Run a simple sim to move the voronoi positions. This update loop
358 // is run once per frame. Called from the main thread only, and only
359 // when the worker threads are idle.
360 void Voronoi::UpdateSim() {
363 ang_ = ang_ - kTwoPI;
365 float z = cosf(ang_) * 3.0f;
366 // push the points around on the screen for animation
367 for (int j = 0; j < kMaxPointCount; j++) {
368 positions_[j].x += (velocities_[j].x) * z;
369 positions_[j].y += (velocities_[j].y) * z;
370 screen_positions_[j].x = positions_[j].x * ps_context_->width;
371 screen_positions_[j].y = positions_[j].y * ps_context_->height;
375 // Renders a small diamond shaped dot at x, y clipped against the window
376 void Voronoi::RenderDot(float x, float y, uint32_t color1, uint32_t color2) {
377 const int ix = static_cast<int>(x);
378 const int iy = static_cast<int>(y);
379 const uint32_t stride_in_pixels = ps_context_->stride / sizeof(uint32_t);
380 // clip it against window
382 if (ix >= (ps_context_->width - 1)) return;
384 if (iy >= (ps_context_->height - 1)) return;
385 uint32_t* pixel = wGetAddr(ix, iy);
386 // render dot as a small diamond
388 *(pixel - 1) = color2;
389 *(pixel + 1) = color2;
390 *(pixel - stride_in_pixels) = color2;
391 *(pixel + stride_in_pixels) = color2;
394 // Superimposes dots on the positions.
395 void Voronoi::SuperimposePositions() {
396 const uint32_t white = MakeBGRA(255, 255, 255, 255);
397 const uint32_t gray = MakeBGRA(192, 192, 192, 255);
398 for (int i = 0; i < point_count_; i++) {
400 screen_positions_[i].x, screen_positions_[i].y, white, gray);
404 // Renders the Voronoi diagram, dispatching the work to multiple threads.
405 void Voronoi::Render() {
406 workers_->Dispatch(num_regions_, wRenderRegionEntry, this);
408 SuperimposePositions();
411 // Handle input events from the user and messages from JS.
412 void Voronoi::HandleEvent(PSEvent* ps_event) {
413 // Give the 2D context a chance to process the event.
414 if (0 != PSContext2DHandleEvent(ps_context_, ps_event))
416 if (ps_event->type == PSE_INSTANCE_HANDLEINPUT) {
417 // Convert Pepper Simple event to a PPAPI C++ event
418 pp::InputEvent event(ps_event->as_resource);
419 switch (event.GetType()) {
420 case PP_INPUTEVENT_TYPE_TOUCHSTART:
421 case PP_INPUTEVENT_TYPE_TOUCHMOVE: {
422 pp::TouchInputEvent touches = pp::TouchInputEvent(event);
423 uint32_t count = touches.GetTouchCount(PP_TOUCHLIST_TYPE_TOUCHES);
424 // Touch points 0..n directly set position of points 0..n in
426 for (uint32_t i = 0; i < count; i++) {
427 pp::TouchPoint touch =
428 touches.GetTouchByIndex(PP_TOUCHLIST_TYPE_TOUCHES, i);
429 pp::FloatPoint point = touch.position();
430 positions_[i].Set(point.x() / ps_context_->width,
431 point.y() / ps_context_->height);
438 } else if (ps_event->type == PSE_INSTANCE_HANDLEMESSAGE) {
439 // Convert Pepper Simple message to PPAPI C++ var
440 pp::Var var(ps_event->as_var);
441 if (var.is_dictionary()) {
442 pp::VarDictionary dictionary(var);
443 std::string message = dictionary.Get("message").AsString();
444 if (message == "draw_points")
445 draw_points_ = dictionary.Get("value").AsBool();
446 else if (message == "draw_interiors")
447 draw_interiors_ = dictionary.Get("value").AsBool();
448 else if (message == "set_points") {
449 int num_points = dictionary.Get("value").AsInt();
450 point_count_ = std::min(kMaxPointCount, std::max(0, num_points));
451 } else if (message == "set_threads") {
452 int thread_count = dictionary.Get("value").AsInt();
454 workers_ = new ThreadPool(thread_count);
460 // PostUpdateMessage() helper function for sendimg small messages to JS.
461 void Voronoi::PostUpdateMessage(const char* message_name, double value) {
462 pp::VarDictionary message;
463 message.Set("message", message_name);
464 message.Set("value", value);
465 PSInterfaceMessaging()->PostMessage(PSGetInstanceId(), message.pp_var());
468 void Voronoi::Update() {
469 PSContext2DGetBuffer(ps_context_);
470 if (NULL == ps_context_->data)
476 PSContext2DSwapBuffer(ps_context_);
479 // Starting point for the module. We do not use main since it would
480 // collide with main in libppapi_cpp.
481 int example_main(int argc, char* argv[]) {
485 // Consume all available events.
486 while ((ps_event = PSEventTryAcquire()) != NULL) {
487 voronoi.HandleEvent(ps_event);
488 PSEventRelease(ps_event);
490 // Do simulation, render and present.
497 // Register the function to call once the Instance Object is initialized.
498 // see: pappi_simple/ps_main.h
499 PPAPI_SIMPLE_REGISTER_MAIN(example_main);