Add 3d box esp

Sometimes shows "ghost" boxes with weird strings (not player names but
the coordinates that are drawn bellow the watermark)

src/features/esp.c

@@ -1,9 +1,65 @@
 
+#include <stdint.h>
 #include "features.h"
 #include "../include/globals.h"
 #include "../include/cvars.h"
 #include "../include/util.h"
 
+static bool gl_draw3dbox(vec3_t o, int bh, int bw, int lw) {
+    /*
+     * Parameters:
+     *   bw: 3d box width (game units)
+     *   bh: 3d box height (game units)
+     *   lw: Line width
+     */
+
+    if (vec_is_zero(o))
+        return false;
+
+    const rgb_t col = { 255, 255, 255 }; /* Color */
+
+    /*
+     * (Origin would be in the middle of the cube)
+     *
+     *     1---2      y(+)
+     *    /|  /|     /
+     *   3---4 |    *--x(+)
+     *   | 5-|-6    |
+     *   |/ O|/     z(-)
+     *   7---8
+     */
+    vec3_t p1 = vec3(o[0] - bw / 2, o[1] + bw / 2, o[2] + bh / 2);
+    vec3_t p2 = vec3(o[0] + bw / 2, o[1] + bw / 2, o[2] + bh / 2);
+    vec3_t p3 = vec3(o[0] - bw / 2, o[1] - bw / 2, o[2] + bh / 2);
+    vec3_t p4 = vec3(o[0] + bw / 2, o[1] - bw / 2, o[2] + bh / 2);
+    vec3_t p5 = vec3(o[0] - bw / 2, o[1] + bw / 2, o[2] - bh / 2);
+    vec3_t p6 = vec3(o[0] + bw / 2, o[1] + bw / 2, o[2] - bh / 2);
+    vec3_t p7 = vec3(o[0] - bw / 2, o[1] - bw / 2, o[2] - bh / 2);
+    vec3_t p8 = vec3(o[0] + bw / 2, o[1] - bw / 2, o[2] - bh / 2);
+
+    vec2_t s1, s2, s3, s4, s5, s6, s7, s8;
+    if (!world_to_screen(p1, s1) || !world_to_screen(p2, s2) ||
+        !world_to_screen(p3, s3) || !world_to_screen(p4, s4) ||
+        !world_to_screen(p5, s5) || !world_to_screen(p6, s6) ||
+        !world_to_screen(p7, s7) || !world_to_screen(p8, s8))
+        return false;
+
+    gl_drawline_points(s1, s2, lw, col);
+    gl_drawline_points(s1, s3, lw, col);
+    gl_drawline_points(s1, s5, lw, col);
+    gl_drawline_points(s2, s4, lw, col);
+    gl_drawline_points(s2, s6, lw, col);
+    gl_drawline_points(s3, s4, lw, col);
+    gl_drawline_points(s3, s7, lw, col);
+    gl_drawline_points(s4, s8, lw, col);
+    gl_drawline_points(s5, s6, lw, col);
+    gl_drawline_points(s5, s7, lw, col);
+    gl_drawline_points(s6, s8, lw, col);
+    gl_drawline_points(s7, s8, lw, col);
+
+    return true;
+}
+
 void esp(void) {
     if (!CVAR_ON(esp))
         return;
@@ -15,12 +71,20 @@ void esp(void) {
         if (!valid_client(ent) || vec_is_zero(ent->origin))
             continue;
 
-        float screen_point[2];
-        if (world_to_screen(ent->origin, screen_point)) {
-            /* TODO: Draw name at bottom-left of box ESP */
-            i_engine->pfnDrawSetTextColor(1, 1, 1);
-            i_engine->pfnDrawConsoleString(screen_point[0], screen_point[1],
-                                           get_name(ent->index));
-        }
+        const int bh = 70;
+        const int bw = 25;
+
+        if (!gl_draw3dbox(ent->origin, bh, bw, 1))
+            continue;
+
+        vec3_t top = vec3(ent->origin[0], ent->origin[1], ent->origin[2] + bh);
+        vec2_t s_top;
+
+        if (!world_to_screen(top, s_top))
+            continue;
+
+        i_engine->pfnDrawSetTextColor(1, 1, 1);
+        i_engine->pfnDrawConsoleString(s_top[0], s_top[1],
+                                       get_name(ent->index));
     }
 }