From fa079d3a5ebb04b36d1f885fb34bdb11d1fc46d5 Mon Sep 17 00:00:00 2001
From: Thomas Lindner <tom@dl6tom.de>
Date: Wed, 21 Jun 2023 22:22:56 +0200
Subject: [PATCH] two-player version

---
 meson.build |   6 ++
 src/main.c  | 164 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 169 insertions(+), 1 deletion(-)

diff --git a/meson.build b/meson.build
index e1d21c6..77cfdda 100644
--- a/meson.build
+++ b/meson.build
@@ -5,13 +5,19 @@ project('sim', ['c'],
                      'warning_level=3',
                      'c_std=c11'])
 
+cc = meson.get_compiler('c')
+m_runtime_dep = cc.find_library('m', required : false)
+
 sdl2_runtime_dep = dependency('SDL2', modules : ['SDL2'])
+sdl2_gfx_runtime_dep = dependency('SDL2_gfx')
 
 sim_exe = executable('sim',
   sources : [
       'src/main.c',
     ],
   dependencies : [
+      m_runtime_dep,
       sdl2_runtime_dep,
+      sdl2_gfx_runtime_dep,
     ],
   install : true)
diff --git a/src/main.c b/src/main.c
index d76f344..4576ee7 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,5 +1,167 @@
 #include <SDL.h>
+#include <SDL2_gfxPrimitives.h>
+#include <err.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define ECHK(x)   \
+  do {            \
+    if (x) {      \
+      err(1, #x); \
+    }             \
+  } while (0)
+
+#define ECHK_SDL(x)                       \
+  do {                                    \
+    if (x < 0) {                          \
+      errx(1, #x ": %s", SDL_GetError()); \
+    }                                     \
+  } while (0)
+
+#define FRAMERATE 20
+
+static int selected_edge;
+static int active_player = -1;
+static int edge_color[15];
+
+#define EDGE(i, j) (5 * (i) + (j) - ((i) + 1) * (i) / 2 - 1)
+
+int loser(void) {
+  for (int i = 0; i < 6; i++) {
+    for (int j = i + 1; j < 6; j++) {
+      for (int k = j + 1; k < 6; k++) {
+        int a = edge_color[EDGE(i, j)];
+        int b = edge_color[EDGE(j, k)];
+        int c = edge_color[EDGE(i, k)];
+        if (a && a == b && a == c) {
+          return a;
+        }
+      }
+    }
+  }
+  return 0;
+}
+
+void input(SDL_KeyboardEvent *event) {
+  switch (event->keysym.scancode) {
+    case SDL_SCANCODE_UP:
+      if (selected_edge != -1) {
+        do {
+          selected_edge = (selected_edge + 1) % 15;
+        } while (edge_color[selected_edge]);
+      }
+      break;
+    case SDL_SCANCODE_DOWN:
+      if (selected_edge != -1) {
+        do {
+          selected_edge = (selected_edge + 14) % 15;
+        } while (edge_color[selected_edge]);
+      }
+      break;
+    case SDL_SCANCODE_SPACE:
+      if (selected_edge != -1) {
+        edge_color[selected_edge] = active_player;
+        active_player = -active_player;
+        if (loser()) {
+          selected_edge = -1;
+        } else {
+          do {
+            selected_edge = (selected_edge + 1) % 15;
+          } while (edge_color[selected_edge]);
+        }
+      } else {
+        selected_edge = 0;
+        memset(edge_color, 0, sizeof(edge_color));
+      }
+      break;
+    case SDL_SCANCODE_ESCAPE:
+    case SDL_SCANCODE_Q:
+      exit(0);
+    default:
+      break;
+  }
+}
+
+void draw(SDL_Renderer *renderer) {
+  int width, height;
+  ECHK_SDL(SDL_GetRendererOutputSize(renderer, &width, &height));
+
+  int unit_length = (width < height ? width : height) / 2;
+  int x_offset = width / 2;
+  int y_offset = height / 2;
+#define X(x) (x_offset + unit_length * (x))
+#define Y(y) (y_offset + unit_length * (y))
+
+#define BLACK 0, 0, 0, 0xff
+#define GRAY 0x80, 0x80, 0x80, 0xff
+#define SILVER 0xc0, 0xc0, 0xc0, 0xff
+#define WHITE 0xff, 0xff, 0xff, 0xff
+#define RED 0xff, 0, 0, 0xff
+#define GREEN 0, 0xff, 0, 0xff
+#define BLUE 0, 0, 0xff, 0xff
+
+  if (selected_edge != -1) {
+    ECHK_SDL(SDL_SetRenderDrawColor(renderer, BLACK));
+  } else {
+    ECHK_SDL(SDL_SetRenderDrawColor(renderer, RED));
+  }
+  ECHK_SDL(SDL_RenderClear(renderer));
+
+#define VERTEX(i) \
+  X(0.7 * cosf(2 * M_PI * (i) / 6)), Y(0.7 * sinf(2 * M_PI * (i) / 6))
+
+  for (int i = 0; i < 6; i++) {
+    for (int j = i + 1; j < 6; j++) {
+      if (EDGE(i, j) == selected_edge) {
+        ECHK_SDL(thickLineRGBA(renderer, VERTEX(i), VERTEX(j), 10, WHITE));
+      } else {
+        switch (edge_color[EDGE(i, j)]) {
+          case -1:
+            ECHK_SDL(thickLineRGBA(renderer, VERTEX(i), VERTEX(j), 10, GREEN));
+            break;
+          case 1:
+            ECHK_SDL(thickLineRGBA(renderer, VERTEX(i), VERTEX(j), 10, BLUE));
+            break;
+          default:
+            ECHK_SDL(thickLineRGBA(renderer, VERTEX(i), VERTEX(j), 10, GRAY));
+        }
+      }
+    }
+    ECHK_SDL(filledCircleRGBA(renderer, VERTEX(i), 30, SILVER));
+  }
+}
+
+int main(int argc, char **argv) {
+  (void)argc, (void)argv;
+
+  ECHK_SDL(SDL_Init(SDL_INIT_EVERYTHING));
+  ECHK(atexit(SDL_Quit));
+
+  SDL_Window *window;
+  SDL_Renderer *renderer;
+  ECHK_SDL(SDL_CreateWindowAndRenderer(-1, -1, SDL_WINDOW_FULLSCREEN_DESKTOP,
+                                       &window, &renderer));
+  SDL_SetWindowTitle(window, "SIM");
+
+  while (true) {
+    SDL_Event event;
+    while (SDL_WaitEventTimeout(&event, 1000 / FRAMERATE)) {
+      switch (event.type) {
+        case SDL_QUIT:
+          exit(0);
+        case SDL_KEYDOWN:
+          input(&event.key);
+          break;
+        default:
+          break;
+      }
+    }
+
+    draw(renderer);
+    SDL_RenderPresent(renderer);
+  }
 
-int main() {
   return 0;
 }