Initial SIMD demos life and earth for PNaCl.

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

 /* Copyright (c) 2013 The Chromium 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 <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
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 const unsigned int kInitialRandSeed = 0xC0DE533D;
 
 /* BGRA helper macro, for constructing a pixel for a BGRA buffer. */
 #define MakeBGRA(b, g, r, 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.
+ * Convert a count value into a live (green) or dead color value.
  */
 const uint32_t kNeighborColors[] = {
-    MakeBGRA(0x00, 0x00, 0x00, 0xff),
-    MakeBGRA(0x00, 0x40, 0x00, 0xff),
-    MakeBGRA(0x00, 0x60, 0x00, 0xff),
-    MakeBGRA(0x00, 0x80, 0x00, 0xff),
-    MakeBGRA(0x00, 0xA0, 0x00, 0xff),
-    MakeBGRA(0x00, 0xC0, 0x00, 0xff),
-    MakeBGRA(0x00, 0xE0, 0x00, 0xff),
-    MakeBGRA(0x00, 0x00, 0x00, 0xff),
-    MakeBGRA(0x00, 0x40, 0x00, 0xff),
-    MakeBGRA(0x00, 0x60, 0x00, 0xff),
-    MakeBGRA(0x00, 0x80, 0x00, 0xff),
-    MakeBGRA(0x00, 0xA0, 0x00, 0xff),
-    MakeBGRA(0x00, 0xC0, 0x00, 0xff),
-    MakeBGRA(0x00, 0xE0, 0x00, 0xff),
-    MakeBGRA(0x00, 0xFF, 0x00, 0xff),
-    MakeBGRA(0x00, 0xFF, 0x00, 0xff),
-    MakeBGRA(0x00, 0xFF, 0x00, 0xff),
-    MakeBGRA(0x00, 0xFF, 0x00, 0xff),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0xFF, 0x00, 0xFF),
+    MakeBGRA(0x00, 0xFF, 0x00, 0xFF),
+    MakeBGRA(0x00, 0xFF, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 0x00, 0xFF),
+    MakeBGRA(0x00, 0x00, 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. */
+      0, 0, 0, 0, 0, 1, 1, 1, 0,
+      0, 0, 0, 0, 0, 0, 0, 0, 0
 };
 
 void UpdateContext(uint32_t width, uint32_t height) {
   if (width != g_Context.size.width || height != g_Context.size.height) {
     size_t size = width * height;
     size_t index;
 
     free(g_Context.cell_in);
     free(g_Context.cell_out);
 
@@ skipping 150 matching lines @@
   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];
+      /* Jitter and sum neighbors. */
+      count = src0[-1] + src0[0] + src0[1] +
+              src1[-1] +         + src1[1] +
+              src2[-1] + src2[0] + src2[1];
+      /* Include center cell. */
+      count = count + count + src1[0];
+      /* Use table lookup indexed by count to determine pixel & alive state. */
       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;
@@ skipping 47 matching lines @@
     }
   }
   return 0;
 }
 
 /*
  * Register the function to call once the Instance Object is initialized.
  * see: pappi_simple/ps_main.h
  */
 PPAPI_SIMPLE_REGISTER_MAIN(example_main);