Multithreaded drawing working.

main.cpp

@@ -3,6 +3,7 @@
 #include <Magick++.h>
 #include <complex>
 #include <cmath>
+#include <sstream>
 
 #define IMG_WIDTH 800
 #define IMG_HEIGHT 600
@@ -17,6 +18,8 @@
 using namespace std;
 using namespace Magick;
 
+int effective_height = IMG_HEIGHT;
+
 struct MandelResult
 {
     unsigned int end_iterations;
@@ -58,30 +61,36 @@ MandelResult IsMandelbrotPoint(int x, int y, unsigned int iterations)
 int main(int argc, char** argv)
 {
     int id;
-    int numprocs;
+    int procs;
 
     MPI_Init(&argc, &argv);
+    MPI_Comm_size(MPI_COMM_WORLD, &procs);
     MPI_Comm_rank(MPI_COMM_WORLD, &id);
 
-    cout << id << endl;
 
-    Image my_image(IMG_SIZE, "white");
+    // Calculate this threads working area.
+    effective_height /= procs;
+
+    Image my_image(Geometry(IMG_WIDTH, effective_height), "white");
 
     for (int x = 0; x < IMG_WIDTH; ++x)
     {
-        for (int y = 0; y < IMG_HEIGHT; ++y)
+        for (int y = effective_height * id; y < effective_height * (id + 1); ++y)
         {
             MandelResult result = IsMandelbrotPoint(x, y, ITERATIONS);
 
             if (result.belongs)
-                my_image.pixelColor(x, y, Color("purple"));
+                my_image.pixelColor(x, y - effective_height * id, Color("purple"));
             else
-                my_image.pixelColor(x, y, Color(0, 0, MaxRGB / ITERATIONS * result.end_iterations));
+                my_image.pixelColor(x, y - effective_height * id, Color(0, 0, MaxRGB / ITERATIONS * result.end_iterations));
         }
     }
     
 
-    my_image.write("mandelbrot.png");
+    stringstream ss;
+    ss << id << ".png";
+
+    my_image.write(ss.str());
 
 
     MPI_Finalize();