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      1 // Copyright (c) 2012 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.
      4 
      5 #include <math.h>
      6 #include <stdio.h>
      7 
      8 #include "ppapi_simple/ps.h"
      9 #include "ppapi_simple/ps_context_2d.h"
     10 #include "ppapi_simple/ps_event.h"
     11 #include "ppapi_simple/ps_interface.h"
     12 #include "ppapi_simple/ps_main.h"
     13 
     14 #ifdef WIN32
     15 #undef PostMessage
     16 #endif
     17 
     18 namespace {
     19 
     20 const int kMaxPointCount = 1000000000;  // The total number of points to draw.
     21 const double kSecsPerFrame = 0.005;  // How long to draw points before swapping.
     22 const uint32_t kOpaqueColorMask = 0xff000000;  // Opaque pixels.
     23 const uint32_t kRedMask = 0xff0000;
     24 const uint32_t kBlueMask = 0xff;
     25 const uint32_t kRedShift = 16;
     26 const uint32_t kBlueShift = 0;
     27 
     28 int g_points_in_circle = 0;
     29 int g_total_points = 0;
     30 double g_pi = 0;
     31 
     32 }  // namespace
     33 
     34 bool Render(PSContext2D_t* ctx) {
     35   PSContext2DGetBuffer(ctx);
     36 
     37   if (NULL == ctx->data)
     38     return true;
     39 
     40   PP_TimeTicks start_time = PSInterfaceCore()->GetTimeTicks();
     41   while (PSInterfaceCore()->GetTimeTicks() - start_time < kSecsPerFrame) {
     42     double x = static_cast<double>(rand()) / RAND_MAX;
     43     double y = static_cast<double>(rand()) / RAND_MAX;
     44     double distance = sqrt(x * x + y * y);
     45     int px = x * ctx->width;
     46     int py = (1.0 - y) * ctx->height;
     47     uint32_t color = ctx->data[ctx->width * py + px];
     48 
     49     ++g_total_points;
     50     if (distance < 1.0) {
     51       ++g_points_in_circle;
     52       g_pi = 4.0 * g_points_in_circle / g_total_points;
     53       // Set color to blue.
     54       color += 4 << kBlueShift;
     55       color &= kBlueMask;
     56     } else {
     57       // Set color to red.
     58       color += 4 << kRedShift;
     59       color &= kRedMask;
     60     }
     61     ctx->data[ctx->width * py + px] = color | kOpaqueColorMask;
     62   }
     63 
     64   PSContext2DSwapBuffer(ctx);
     65   return g_total_points != kMaxPointCount;
     66 }
     67 
     68 /*
     69  * Starting point for the module.  We do not use main since it would
     70  * collide with main in libppapi_cpp.
     71  */
     72 int example_main(int argc, char* argv[]) {
     73   unsigned int seed = 1;
     74   srand(seed);
     75 
     76   PSEventSetFilter(PSE_ALL);
     77 
     78   PSContext2D_t* ctx = PSContext2DAllocate(PP_IMAGEDATAFORMAT_BGRA_PREMUL);
     79   bool running = true;
     80   while (running) {
     81     PSEvent* event;
     82 
     83     // Consume all available events
     84     while ((event = PSEventTryAcquire()) != NULL) {
     85       PSContext2DHandleEvent(ctx, event);
     86       PSEventRelease(event);
     87     }
     88 
     89     if (ctx->bound) {
     90       running = Render(ctx);
     91     }
     92 
     93     // Send the current PI value to JavaScript.
     94     PP_Var var = PP_MakeDouble(g_pi);
     95     PSInterfaceMessaging()->PostMessage(PSGetInstanceId(), var);
     96   }
     97 
     98   return 0;
     99 }
    100 
    101 /*
    102  * Register the function to call once the Instance Object is initialized.
    103  * see: pappi_simple/ps_main.h
    104  */
    105 PPAPI_SIMPLE_REGISTER_MAIN(example_main);
    106