Skeleton of the multiplayer architecture

.vscode/settings.json

@@ -23,6 +23,8 @@
         "xlocale": "c",
         "xlocbuf": "c",
         "xstring": "c",
-        "algorithm": "c"
+        "algorithm": "c",
+        "sokol_gp.h": "c",
+        "stdbool.h": "c"
     }
 }

build_debug.bat

@@ -7,4 +7,4 @@ IF %ERRORLEVEL% NEQ 0 ECHO ERROR download sokol-shdc from https://github.com/flo
 
 @REM example of how to compile shaders: sokol-shdc.exe --input triangle.glsl --output triangle.gen.h --slang glsl330:hlsl5:metal_macos
 
-cl /MP /Zi /Fd"flight.pdb" /I"thirdparty" /Fe"flight" main.c
+cl /MP /Zi /Fd"flight.pdb" /I"thirdparty" /Fe"flight" main.c gamestate.c server.c

gamestate.c

@@ -0,0 +1,29 @@
+#include "types.h"
+
+// do not use any global variables to process gamestate
+
+
+static void process_body(struct Body *body, float dt)
+{
+    V2 current = body->position;
+    body->position = V2add(body->position, V2sub(current, body->old_position));
+    body->position = V2add(body->position, V2scale(body->acceleration, dt*dt));
+    body->old_position = current;
+}
+
+
+void process(struct GameState * gs, float dt) {
+    for(int i = 0; i < MAX_PLAYERS; i++)
+    {
+        struct Player * p = &gs->players[i];
+        if(!p->connected)
+            continue;
+        p->body.acceleration = V2scale(p->input, 5.0f);
+        process_body(&p->body, dt);
+    }
+
+    for(int i = 0; i < gs->num_boxes; i++)
+    {
+        process_body(&gs->boxes[i].body, dt);
+    }
+}

main.c

@@ -8,35 +8,16 @@
 #include "sokol_gp.h"
 #include "sokol_app.h"
 #include "sokol_glue.h"
+#include <winsock.h>
 
-#define MAX_BOXES 32
+#include "types.h"
-#define BOX_SIZE 0.5f
-#define TIMESTEP 1.0f / 60.0f
-struct Body
-{
-    sgp_point position;
-    sgp_point old_position;
-    sgp_vec2 acceleration;
-};
 
-struct GameState
+static struct GameState gs = {0};
-{
+static int myplayer = -1;
-    struct Player
+static bool mouse_down = false;
-    {
+static bool keydown[SAPP_KEYCODE_MENU] = {0};
-        struct Body body;
+static float funval = 0.0f; // easy to play with value controlled by left mouse button when held down @BeforeShip remove on release builds
-    } player;
+static bool is_host = false;
-
-    int num_boxes;
-    struct Box
-    {
-        struct Body body;
-    } boxes[MAX_BOXES];
-};
-
-struct GameState gs = {0};
-bool mouse_down = false;
-bool keydown[SAPP_KEYCODE_MENU] = {0};
-float funval = 0.0f; // easy to play with value controlled by left mouse button when held down @BeforeShip remove on release builds
 
 void init(void)
 {
@@ -52,12 +33,12 @@ void init(void)
 
     gs.boxes[0] = (struct Box){
         .body = (struct Body){
-            .position = (sgp_point){.x = 0.75f, .y = 0.0}},
+            .position = (P2){.x = 0.75f, .y = 0.0}},
     };
     gs.boxes[0].body.old_position = gs.boxes[0].body.position;
     gs.boxes[1] = (struct Box){
         .body = (struct Body){
-            .position = (sgp_point){.x = 0.75f, .y = 0.5f}},
+            .position = (P2){.x = 0.75f, .y = 0.5f}},
     };
     gs.boxes[1].body.old_position = gs.boxes[1].body.position;
     gs.num_boxes = 2;
@@ -71,38 +52,6 @@ void init(void)
     }
 }
 
-sgp_vec2 v2add(sgp_vec2 a, sgp_vec2 b)
-{
-    return (sgp_vec2){
-        .x = a.x + b.x,
-        .y = a.y + b.y,
-    };
-}
-
-sgp_vec2 v2scale(sgp_vec2 a, float f)
-{
-    return (sgp_vec2){
-        .x = a.x * f,
-        .y = a.y * f,
-    };
-}
-
-sgp_vec2 v2sub(sgp_vec2 a, sgp_vec2 b)
-{
-    return (sgp_vec2){
-        .x = a.x - b.x,
-        .y = a.y - b.y,
-    };
-}
-
-void process_body(struct Body *body)
-{
-    sgp_vec2 current = body->position;
-    body->position = v2add(body->position, v2sub(current, body->old_position));
-    body->position = v2add(body->position, v2scale(body->acceleration, TIMESTEP*TIMESTEP));
-    body->old_position = current;
-}
-
 void frame(void)
 {
     int width = sapp_width(), height = sapp_height();
@@ -110,18 +59,15 @@ void frame(void)
     float time = sapp_frame_count() * sapp_frame_duration();
 
     // gameplay
+    struct ClientToServer curmsg = {0};
     {
-        sgp_vec2 input = (sgp_vec2){
+        V2 input = (V2){
             .x = (float)keydown[SAPP_KEYCODE_D] - (float)keydown[SAPP_KEYCODE_A],
             .y = (float)keydown[SAPP_KEYCODE_S] - (float)keydown[SAPP_KEYCODE_W],
         };
-        gs.player.body.acceleration = v2scale(input, 5.0f);
+        curmsg.input = input;
 
-        process_body(&gs.player.body);
+        process(&gs, (float)sapp_frame_duration());
-        for(int i = 0; i < gs.num_boxes; i++)
-        {
-            process_body(&gs.boxes[i].body);
-        }
     }
 
     // drawing
@@ -138,7 +84,10 @@ void frame(void)
         // Drawing in world space now
         sgp_translate(width / 2, height / 2);
         sgp_scale_at(300.0f + funval, 300.0f + funval, 0.0f, 0.0f);
-        sgp_translate(-gs.player.body.position.x, -gs.player.body.position.y);
+        if(myplayer != -1)
+        {
+            sgp_translate(-gs.players[myplayer].body.position.x, -gs.players[myplayer].body.position.y);
+        }
 
         sgp_set_color(1.0f, 1.0f, 1.0f, 1.0f);
         sgp_draw_filled_rect(100.0f, 100.0f, 400.0f, 400.0f);
@@ -156,9 +105,12 @@ void frame(void)
         float halfbox = BOX_SIZE / 2.0f;
 
         // player
-        {
+        for(int i = 0; i < MAX_PLAYERS; i++){
+            struct Player * p = &gs.players[i];
+            if(!p->connected)
+                continue;
             sgp_set_color(1.0f, 1.0f, 1.0f, 1.0f);
-            sgp_draw_filled_rect(gs.player.body.position.x - halfbox, gs.player.body.position.y - halfbox, BOX_SIZE, BOX_SIZE);
+            sgp_draw_filled_rect(p->body.position.x - halfbox, p->body.position.y - halfbox, BOX_SIZE, BOX_SIZE);
         }
 
         // boxes
@@ -220,7 +172,7 @@ void event(const sapp_event *e)
 
 sapp_desc sokol_main(int argc, char *argv[])
 {
-    (void)argc;
+    is_host = argc >= 1;
     (void)argv;
     return (sapp_desc){
         .init_cb = init,

server.c

@@ -0,0 +1,6 @@
+#include <winsock.h>
+
+// started in a thread from host
+void server() {
+    // SOCKET s = socket();
+}

tooling.ahk

@@ -14,5 +14,5 @@ WinKill, Flight
 WinActivate, flightbuild
 If WinActive("flightbuild")
 {
-    Send, build_debug.bat && START /B flight.exe && flight.exe{Enter}
+    Send, build_debug.bat && START /B flight.exe && flight.exe --host{Enter}
 }

types.h

@@ -0,0 +1,100 @@
+#pragma once
+
+// including headers from headers bad
+#ifndef SOKOL_GP_INCLUDED
+
+typedef struct sgp_vec2
+{
+    float x, y;
+} sgp_vec2;
+
+typedef sgp_vec2 sgp_point;
+
+#endif
+
+#include <stdbool.h>
+
+#ifndef _STDBOOL
+
+#define bool  _Bool
+#define false 0
+#define true  1
+
+#endif
+
+typedef sgp_vec2 V2;
+typedef sgp_point P2;
+
+#define MAX_BOXES 32
+#define MAX_PLAYERS 2
+#define BOX_SIZE 0.5f
+#define TIMESTEP 1.0f / 60.0f
+
+struct Body
+{
+    P2 position;
+    P2 old_position;
+    V2 acceleration;
+};
+
+struct Player
+{
+    struct Body body;
+    bool connected;
+    V2 input;
+};
+
+struct GameState
+{
+    struct Player players[MAX_PLAYERS];
+
+    int num_boxes;
+    struct Box
+    {
+        struct Body body;
+    } boxes[MAX_BOXES];
+};
+
+struct ServerToClient
+{
+    struct GameState cur_gs;
+    int your_player;
+};
+
+struct ClientToServer
+{
+    V2 input;
+};
+
+// server
+void server();
+
+// gamestate
+void process(struct GameState * gs, float dt); // does in place
+
+
+// all the math is static so that it can be defined in each compilation unit its included in
+
+static V2 V2add(V2 a, V2 b)
+{
+    return (V2){
+        .x = a.x + b.x,
+        .y = a.y + b.y,
+    };
+}
+
+static V2 V2scale(V2 a, float f)
+{
+    return (V2){
+        .x = a.x * f,
+        .y = a.y * f,
+    };
+}
+
+static V2 V2sub(V2 a, V2 b)
+{
+    return (V2){
+        .x = a.x - b.x,
+        .y = a.y - b.y,
+    };
+}