ppapi_simple

native_client_sdk/src/examples/demo/life/life.c

+// Copyright 2013 The Native Client SDK Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can
+// be found in the LICENSE file.
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ppapi/c/pp_resource.h"
+#include "ppapi/c/ppb_core.h"
+#include "ppapi/c/ppb_fullscreen.h"
+#include "ppapi/c/ppb_graphics_2d.h"
+#include "ppapi/c/ppb_image_data.h"
+#include "ppapi/c/ppb_input_event.h"
+#include "ppapi/c/ppb_instance.h"
+#include "ppapi/c/ppb_view.h"
+
+#include "ppapi_simple/ppapi_event.h"
+#include "ppapi_simple/ppapi_simple_main.h"
+
+PPB_Core* g_pCore;
+PPB_Fullscreen* g_pFullscreen;
+PPB_Graphics2D* g_pGraphics2D;
+PPB_ImageData* g_pImageData;
+PPB_Instance* g_pInstance;
+PPB_View* g_pView;
+PPB_InputEvent* g_pInputEvent;
+PPB_KeyboardInputEvent* g_pKeyboardInput;
+PPB_MouseInputEvent* g_pMouseInput;
+PPB_TouchInputEvent* g_pTouchInput;
+
+struct {
+  PP_Resource ctx;
+  struct PP_Size size;
+  int bound;
+  uint8_t* cell_in;
+  uint8_t* cell_out;
+} g_Context;
+
+
+const unsigned int kInitialRandSeed = 0xC0DE533D;
+
+#define MakeRGBA(r, g, b, a)  \
+  (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))
+
+// Given a count of cells in a 3x3 grid where cells are worth 1 except for
+// the center which is worth 9, this is a color representation of how
+// "alive" that cell is making for a more interesting representation than
+// a binary alive or dead.
+const uint32_t kNeighborColors[] = {
+    MakeRGBA(0x00, 0x00, 0x00, 0xff),
+    MakeRGBA(0x00, 0x40, 0x00, 0xff),
+    MakeRGBA(0x00, 0x60, 0x00, 0xff),
+    MakeRGBA(0x00, 0x80, 0x00, 0xff),
+    MakeRGBA(0x00, 0xA0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xC0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xE0, 0x00, 0xff),
+    MakeRGBA(0x00, 0x00, 0x00, 0xff),
+    MakeRGBA(0x00, 0x40, 0x00, 0xff),
+    MakeRGBA(0x00, 0x60, 0x00, 0xff),
+    MakeRGBA(0x00, 0x80, 0x00, 0xff),
+    MakeRGBA(0x00, 0xA0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xC0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xE0, 0x00, 0xff),
+    MakeRGBA(0x00, 0xFF, 0x00, 0xff),
+    MakeRGBA(0x00, 0xFF, 0x00, 0xff),
+    MakeRGBA(0x00, 0xFF, 0x00, 0xff),
+    MakeRGBA(0x00, 0xFF, 0x00, 0xff),
+};
+
+// These represent the new health value of a cell based on its neighboring
+// values.  The health is binary: either alive or dead.
+const uint8_t kIsAlive[] = {
+      0, 0, 0, 1, 0, 0, 0, 0, 0,  // Values if the center cell is dead.
+      0, 0, 1, 1, 0, 0, 0, 0, 0  // Values if the center cell is alive.
+};
+
+
+void UpdateContext(uint32_t width, uint32_t height) {
+  size_t size = width * height;
+  size_t index;
+
+  free(g_Context.cell_in);
+  free(g_Context.cell_out);
+
+  //
+  // Create a new context
+  //
+  g_Context.cell_in = (uint8_t*) malloc(size);
+  g_Context.cell_out = (uint8_t*) malloc(size);
+
+  memset(g_Context.cell_out, 0, size);
+  for (index = 0; index < size; index++) {
+    g_Context.cell_in[index] = rand() & 1;
+  }
+}
+
+void ProcessEvent(PSEvent* event) {
+  switch(event->type) {
+    /* If the view updates, build a new Graphics 2D Context */
+    case PS_VIEW_EVENT: {
+      struct PP_Rect rect;
+      int32_t width;
+      int32_t height;
+      if (g_Context.ctx) {
+        g_pCore->ReleaseResource(g_Context.ctx);
+        g_Context.ctx = 0;
+      }
+
+      g_pView->GetRect(event->as_resource, &rect);
+      width = rect.size.width;
+      height = rect.size.height;
+
+      if (width != g_Context.size.width || height != g_Context.size.height) {
+        UpdateContext(rect.size.width, rect.size.height);

[nfullagar1, 2013/05/28 18:28:53]

small nit - UpdateContext() sounds like it should update all aspects of the
context, but it just updates the non-ppapi parts (cell_in, cell_out buffers) 
Looking closer, updating of the ppapi graphics context actually occurs in code
below, g_Context.ctx = ...etc.  Why not have UpdateContext also do this?

[noelallen_use_chromium, 2013/05/30 00:25:07]

Done.

+      }
+      if (width != g_Context.size.width || height != g_Context.size.height ||
+          !g_Context.bound) {
+        g_Context.ctx =
+            g_pGraphics2D->Create(PSGetInstanceId(), &rect.size, PP_TRUE);
+        g_Context.bound =
+            g_pInstance->BindGraphics(PSGetInstanceId(), g_Context.ctx);
+        g_Context.size = rect.size;
+      }
+      break;
+    }
+
+    case PS_INPUT_EVENT: {

[nfullagar1, 2013/05/28 18:28:53]

small nit on PS_INPUT_EVENT: PPAPI doesn't have an _ between INPUT and EVENT on
PP_INPUTEVENT_TYPE_... 

[noelallen_use_chromium, 2013/05/30 00:25:07]

Done.

+      PP_InputEvent_Type type = g_pInputEvent->GetType(event->as_resource);
+      PP_InputEvent_Modifier modifiers =
+          g_pInputEvent->GetModifiers(event->as_resource);
+      int32_t width = g_Context.size.width;
+      int32_t height = g_Context.size.height;
+
+      switch(type) {
+        case PP_INPUTEVENT_TYPE_MOUSEMOVE:
+          {
+            struct PP_Point location =
+                g_pMouseInput->GetPosition(event->as_resource);
+
+            if (!g_Context.cell_in) break;
+
+            // If the button is down, draw
+            if (modifiers & PP_INPUTEVENT_MODIFIER_LEFTBUTTONDOWN) {
+              int x = location.x;
+              int y = location.y;
+
+              if (x > 0 && x < width && y > 0 && y < height) {
+                g_Context.cell_in[x - 1 + y * width] = 1;
+                g_Context.cell_in[x + 1 + y * width] = 1;
+                g_Context.cell_in[x + (y - 1) * width] = 1;
+                g_Context.cell_in[x + (y + 1) * width] = 1;
+              }
+            }
+          }
+          break;
+
+        case PP_INPUTEVENT_TYPE_KEYUP: {
+          PP_Bool fullscreen = g_pFullscreen->IsFullscreen(PSGetInstanceId());
+          g_pFullscreen->SetFullscreen(PSGetInstanceId(),
+                                       fullscreen ? PP_FALSE : PP_TRUE);
+          break;
+        }
+
+        default:
+          break;
+      }
+      break;
+    }
+
+    default:
+      break;
+  }
+}
+
+
+void Stir(uint32_t width, uint32_t height) {
+  int i;
+  if (g_Context.cell_in == NULL || g_Context.cell_out == NULL)
+    return;
+
+  for (i = 0; i < width; ++i) {
+    g_Context.cell_in[i] = rand() & 1;
+    g_Context.cell_in[i + (height - 1) * width] = rand() & 1;
+  }
+  for (i = 0; i < height; ++i) {
+    g_Context.cell_in[i * width] = rand() & 1;
+    g_Context.cell_in[i * width + (width - 1)] = rand() & 1;
+  }
+}
+
+void Render() {
+  struct PP_Size* psize = &g_Context.size;
+  PP_ImageDataFormat format = g_pImageData->GetNativeImageDataFormat();
+
+  // Create a buffer to draw into.  Since we are waiting until the next flush
+  // chrome has an opportunity to cache this buffer see ppb_graphics_2d.h.
+  PP_Resource image =
+      g_pImageData->Create(PSGetInstanceId(), format, psize, PP_FALSE);
+  uint8_t* pixels = g_pImageData->Map(image);
+
+  struct PP_ImageDataDesc desc;
+  uint8_t* cell_temp;
+  uint32_t x, y;
+
+  // If we somehow have not allocated these pointers yet, skip this frame.
+  if (!g_Context.cell_in || !g_Context.cell_out) return;
+
+  // Get the stride
+  g_pImageData->Describe(image, &desc);
+
+  // Stir up the edges to prevent the simulation from reaching steady state.
+  Stir(desc.size.width, desc.size.height);
+
+  // Do neighbor summation; apply rules, output pixel color.
+  for (y = 1; y < desc.size.height - 1; ++y) {
+    uint8_t *src0 = (g_Context.cell_in + (y - 1) * desc.size.width) + 1;
+    uint8_t *src1 = src0 + desc.size.width;
+    uint8_t *src2 = src1 + desc.size.width;
+    int count;
+    uint32_t color;
+    uint8_t *dst = (g_Context.cell_out + y * desc.size.width) + 1;
+    uint32_t *pixel_line =  (uint32_t*) (pixels + y * desc.stride);
+
+    for (x = 1; x < (desc.size.width - 1); ++x) {
+      // Build sum, weight center by 9x.
+      count = src0[-1] + src0[0] +     src0[1] +
+              src1[-1] + src1[0] * 9 + src1[1] +
+              src2[-1] + src2[0] +     src2[1];
+      color = kNeighborColors[count];
+
+      *pixel_line++ = color;
+      *dst++ = kIsAlive[count];
+      ++src0;
+      ++src1;
+      ++src2;
+    }
+  }
+
+  cell_temp = g_Context.cell_in;
+  g_Context.cell_in = g_Context.cell_out;
+  g_Context.cell_out = cell_temp;
+
+  /* Unmap the range, we no longer need it. */
+  g_pImageData->Unmap(image);
+
+  /* Replace the contexts, and block until it's on the screen. */
+  g_pGraphics2D->ReplaceContents(g_Context.ctx, image);
+  g_pGraphics2D->Flush(g_Context.ctx, PP_BlockUntilComplete());
+
+  /* Release the image data, we no longer need it. */
+  g_pCore->ReleaseResource(image);
+}
+
+// Starting point for the module.  We do not use main since it would
+// collide with main in libppapi_cpp.
+int example_main(int argc, const char *argv[]) {
+  fprintf(stdout,"Started main.\n");
+  g_pCore = (PPB_Core*)PSGetInterface(PPB_CORE_INTERFACE);
+  g_pFullscreen = (PPB_Fullscreen*)PSGetInterface(PPB_FULLSCREEN_INTERFACE);
+  g_pGraphics2D = (PPB_Graphics2D*)PSGetInterface(PPB_GRAPHICS_2D_INTERFACE);
+  g_pInstance = (PPB_Instance*)PSGetInterface(PPB_INSTANCE_INTERFACE);
+  g_pImageData = (PPB_ImageData*)PSGetInterface(PPB_IMAGEDATA_INTERFACE);
+  g_pView = (PPB_View*)PSGetInterface(PPB_VIEW_INTERFACE);
+
+  g_pInputEvent =
+      (PPB_InputEvent*) PSGetInterface(PPB_INPUT_EVENT_INTERFACE);
+  g_pKeyboardInput = (PPB_KeyboardInputEvent*)
+      PSGetInterface(PPB_KEYBOARD_INPUT_EVENT_INTERFACE);
+  g_pMouseInput =
+      (PPB_MouseInputEvent*) PSGetInterface(PPB_MOUSE_INPUT_EVENT_INTERFACE);
+  g_pTouchInput =
+      (PPB_TouchInputEvent*) PSGetInterface(PPB_TOUCH_INPUT_EVENT_INTERFACE);
+
+  PSSetEventFilter(PS_ALL_EVENTS);
+  while (1) {
+    /* Process all waiting events without blocking */
+    PSEvent* event;
+    while ((event = PSTryToAcquireEvent()) != NULL) {
+      ProcessEvent(event);
+      PSReleaseEvent(event);
+    }
+
+    /* Render a frame, blocking until complete. */
+    if (g_Context.bound) {
+      Render();
+    }
+  }
+  return 0;
+}
+
+// Regsiter the function to call once the Instance Object is initialized.
+// see: pappi_simple/ppapi_simple.h

[nfullagar1, 2013/05/28 18:28:53]

small nit for comment above: ppapi_simple.h has PPAPI_SIMPLE_USE_MAIN but it is
ppapi_simple_main.h that defines PPAPI_SIMPLE_REGISTER_MAIN

[noelallen_use_chromium, 2013/05/30 00:25:07]

Done.

+PPAPI_SIMPLE_REGISTER_MAIN(example_main);