init: HW2

part2/mandelbrot_serial.cpp

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+/*
+
+  Note: This code was modified from example code
+  originally provided by Intel.  To comply with Intel's open source
+  licensing agreement, their copyright is retained below.
+
+  -----------------------------------------------------------------
+
+  Copyright (c) 2010-2011, Intel Corporation
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are
+  met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+    * Neither the name of Intel Corporation nor the names of its
+      contributors may be used to endorse or promote products derived from
+      this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+   PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+   OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+namespace
+{
+
+int mandel(float c_re, float c_im, int count)
+{
+    float z_re = c_re, z_im = c_im;
+    int i;
+    for (i = 0; i < count; ++i)
+    {
+
+        if (z_re * z_re + z_im * z_im > 4.f)
+            break;
+
+        float new_re = (z_re * z_re) - (z_im * z_im);
+        float new_im = 2.f * z_re * z_im;
+        z_re = c_re + new_re;
+        z_im = c_im + new_im;
+    }
+
+    return i;
+}
+
+} // namespace
+
+//
+// MandelbrotSerial --
+//
+// Compute an image visualizing the mandelbrot set.  The resulting
+// array contains the number of iterations required before the complex
+// number corresponding to a pixel could be rejected from the set.
+//
+// * x0, y0, x1, y1 describe the complex coordinates mapping
+//   into the image viewport.
+// * width, height describe the size of the output image
+// * startRow, totalRows describe how much of the image to compute
+void mandelbrot_serial(float x0,
+                       float y0,
+                       float x1,
+                       float y1,
+                       int width,
+                       int height,
+                       int start_row,
+                       int total_rows,
+                       int max_iterations,
+                       int *output)
+{
+    float dx = (x1 - x0) / (float)width;
+    float dy = (y1 - y0) / (float)height;
+
+    int end_row = start_row + total_rows;
+
+    for (int j = start_row; j < end_row; j++)
+    {
+        for (int i = 0; i < width; ++i)
+        {
+            float x = x0 + ((float)i * dx);
+            float y = y0 + ((float)j * dy);
+
+            int index = ((j * width) + i);
+            output[index] = mandel(x, y, max_iterations);
+        }
+    }
+}