From 58df17d0e7fb50901abbe96b64dbbe12eac9cdaa Mon Sep 17 00:00:00 2001
From: Benjamin Segovia <segovia.benjamin@gmail.com>
Date: Fri, 4 May 2012 19:22:44 +0000
Subject: [PATCH] Started to implement mandelbrot

---
 kernels/mandelbrot.cl     | 50 +++++++++++++++++++++++++++++++++++++++++++++++
 utests/CMakeLists.txt     |  1 +
 utests/app_mandelbrot.cpp | 46 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 97 insertions(+)
 create mode 100644 kernels/mandelbrot.cl
 create mode 100644 utests/app_mandelbrot.cpp

diff --git a/kernels/mandelbrot.cl b/kernels/mandelbrot.cl
new file mode 100644
index 0000000..66bab32
--- /dev/null
+++ b/kernels/mandelbrot.cl
@@ -0,0 +1,50 @@
+// Used to ID into the 1D array, so that we can use
+// it effectively as a 2D array
+int ID(int x, int y, int width) {
+  return 4*width*y + x*4;
+}
+
+float mapX(float x) { return x*3.25f - 2.f; }
+float mapY(float y) { return y*2.5f - 1.25f; }
+
+__kernel void mandelbrot(__global char *out) {
+  int x_dim = get_global_id(0);
+  int y_dim = get_global_id(1);
+  int width = get_global_size(0);
+  int height = get_global_size(1);
+  int idx = ID(x_dim, y_dim, width);
+
+  float x_origin = mapX((float) x_dim / (float) width);
+  float y_origin = mapY((float) y_dim / (float) height);
+
+  // The Escape time algorithm, it follows the pseduocode from Wikipedia
+  // _very_ closely
+  float x = 0.0f;
+  float y = 0.0f;
+
+  int iteration = 0;
+
+  // This can be changed, to be more or less precise
+  int max_iteration = 256;
+  while(x*x + y*y <= 4 && iteration < max_iteration) {
+    float xtemp = x*x - y*y + x_origin;
+    y = 2*x*y + y_origin;
+    x = xtemp;
+    iteration++;
+  }
+
+  if(iteration == max_iteration) {
+    // This coordinate did not escape, so it is in the Mandelbrot set
+    out[idx] = 0;
+    out[idx + 1] = 0;
+    out[idx + 2] = 0;
+    out[idx + 3] = 255;
+  } else {
+    // This coordinate did escape, so color based on quickly it escaped
+    out[idx] = iteration;
+    out[idx + 1] = iteration;
+    out[idx + 2] = iteration;
+    out[idx + 3] = 255;
+  }
+
+}
diff --git a/utests/CMakeLists.txt b/utests/CMakeLists.txt
index aa0dd0d..c66e152 100644
--- a/utests/CMakeLists.txt
+++ b/utests/CMakeLists.txt
@@ -7,6 +7,7 @@ ADD_LIBRARY(utests SHARED
             utest_file_map.cpp
             utest_assert.cpp
             utest.cpp
+            app_mandelbrot.cpp
             compiler_write_only.cpp
             compiler_copy_buffer.cpp
             compiler_copy_buffer_row.cpp
diff --git a/utests/app_mandelbrot.cpp b/utests/app_mandelbrot.cpp
new file mode 100644
index 0000000..36b645a
--- /dev/null
+++ b/utests/app_mandelbrot.cpp
@@ -0,0 +1,46 @@
+/* 
+ * Copyright © 2012 Intel Corporation
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Benjamin Segovia <benjamin.segovia@intel.com>
+ */
+
+#include "utest_helper.hpp"
+
+static int *dst = NULL;
+static const size_t w = 64;
+static const size_t h = 64; 
+static const size_t iter = 4;
+
+static void mandelbrot(void)
+{
+  const size_t global[2] = {w, h};
+  const size_t local[2] = {16, 1};
+  const size_t sz = w * h * sizeof(char[4]);
+
+  OCL_CREATE_KERNEL("mandelbrot");
+
+  cl_mem cl_dst = clCreateBuffer(ctx, 0, sz, NULL, NULL);
+  OCL_CALL (clSetKernelArg, kernel, 0, sizeof(cl_mem), &cl_dst);
+  OCL_CALL (clEnqueueNDRangeKernel, queue, kernel, 2, NULL, global, local, 0, NULL, NULL);
+  dst = (int *) clIntelMapBuffer(cl_dst, NULL);
+
+  //writeBmp(dst, w, h, "mandelbrot.bmp");
+  OCL_CALL (clIntelUnmapBuffer, cl_dst);
+  OCL_CALL (clReleaseMemObject, cl_dst);
+}
+
+MAKE_UTEST_FROM_FUNCTION(mandelbrot);
+
-- 
2.7.4