Add marker visualization

euler.cxx

@@ -1,45 +1,89 @@
 #include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <math.h>
+
+#include <algorithm>
+#include <random>
 
 #include "math/vec2f.h"
 #include "misc/terminal.h"
 
 const size_t X = 10;
 const size_t Y = 10;
 
-float g_p[X][Y];
-float g_u[X][Y];
+const float k_s = 1; // side length
+const float k_invs = 1/k_s;
+const float k_d = 1.0; // density
+const float k_invd = 1/k_d;
+
+float g_p[Y][X];
+float g_u[Y][X];
+float g_v[Y][X];
+float g_utmp[Y][X];
+float g_vtmp[Y][X];
+
+bool g_solid[Y][X];
 
-float g_q[X][Y];
-bool g_solid[X][Y];
+const size_t N = 4*4*4;
+vec2f g_markers[N];
 
-const vec2f k_g{0,-9.81};
+const float k_g = -9.81;
 
 void sim_init() {
   // setup walls
   for (size_t i = 0; i < X; ++i) {
-    g_solid[i][0] = true;
+    g_solid[0][i] = true;
   }
   for (size_t i = 0; i < Y; ++i) {
-    g_solid[0][i] = true;
-    g_solid[X-1][i] = true;
+    g_solid[i][0] = true;
+    g_solid[i][X-1] = true;
+  }
+
+  std::mt19937 rng_engine(123456789u);
+  std::uniform_real_distribution<float> distribution(0.f, 0.25f);
+  auto rng = [&](){ return distribution(rng_engine); };
+
+  // setup fluid markers
+  size_t idx = 0;
+  for (size_t i = 1; i < 5; ++i) {
+    for (size_t j = 1; j < 5; ++j) {
+      for (size_t k = 0; k < 4; ++k) {
+        float x = i + (k < 2 ? 0 : 0.5f) + rng();
+        float y = j + (k % 2 ? 0 : 0.5f) + rng();
+        g_markers[idx++] = k_s*vec2f{x,y};
+      }
+    }
   }
 }
 
 void sim_step() {
 }
 
 void draw_rows(struct buffer* buf) {
-  for (size_t y = 0; y < Y; y++) {
-    buffer_append(buf, "~", 1);
-    if (y < Y - 1) {
+  unsigned char marker_count[Y][X] = {};
+  for (size_t i = 0; i < N; ++i) {
+    size_t x = (size_t)floor(g_markers[i].x());
+    size_t y = Y-1-(size_t)floor(g_markers[i].y());
+    marker_count[y][x]++;
+  }
+  const char* symbol[4] = {" ","o","O","0"};
+  const unsigned char max_symbol = 3;
+  for (int y = Y; y-- > 0;) {
+    for (size_t x = 0; x < X; x++) {
+      if (g_solid[y][x]) {
+        buffer_append(buf, "X", 1);
+      } else {
+        unsigned char i = std::min(marker_count[y][x], max_symbol);
+        buffer_append(buf, symbol[i], 1);
+      }
+    }
+    if (y > 0) {
       buffer_append(buf, "\r\n", 2);
     }
   }
 }
 
-#include <errno.h>
-#include <unistd.h>
-
 void refresh_screen(buffer* buf) {
   buffer_clear(buf);
 
@@ -69,7 +113,6 @@ int main(int argc, char** argv) {
 
   enable_raw_mode();
   buffer buf = { 0, 0 };
-  clear_screen(&buf);
 
   sim_init();