Entirely expanded upon existing proof-of-concept

src/world.c

@@ -0,0 +1,133 @@
+#include <stddef.h>
+#include "world.h"
+
+const float scale = 43.7445319335f;
+const float g = 9.81f * scale;
+
+const float PLAYER_FORCE = 3500.0f;
+const float JUMP_FORCE = 22000.0f;
+
+const float AIR_DRAG = 0.999f;
+
+const float GROUND_FRICTION = 1200.0f;
+const float MAX_PLAYER_SPEED = 300.0f;
+
+const float BOUNCE = 0.45f;
+
+const float ground_y = 550.0f;
+
+Entity entities[MAX_ENTITIES];
+
+Entity *player = NULL;
+
+bool isSimulating = true;
+
+float simTime = 0.0f;
+
+void ApplyForce(Entity *e, Vector2 force)
+{
+    if (!e || !e->active)
+        return;
+
+    e->force.x += force.x;
+    e->force.y += force.y;
+}
+
+bool IsGrounded(Entity *e)
+{
+    if (!e)
+        return false;
+
+    return (
+        e->position.y +
+        e->size * 0.5f >=
+        ground_y - 2.0f
+    );
+}
+
+Entity *SpawnEntity(
+    float x,
+    float y,
+    float size,
+    float mass,
+    Color color)
+{
+    for (int i = 0; i < MAX_ENTITIES; i++)
+    {
+        if (!entities[i].active)
+        {
+            Entity *e = &entities[i];
+
+            e->active = true;
+
+            e->isPlayer = false;
+            e->affectedByGravity = true;
+
+            e->mass = mass;
+            e->size = size;
+
+            e->position = (Vector2){x, y};
+            e->velocity = (Vector2){0, 0};
+            e->acceleration = (Vector2){0, 0};
+            e->force = (Vector2){0, 0};
+
+            e->color = color;
+
+            return e;
+        }
+    }
+
+    return NULL;
+}
+
+void ClearWorld(void)
+{
+    for (int i = 0; i < MAX_ENTITIES; i++)
+    {
+        entities[i].active = false;
+    }
+
+    player = NULL;
+}
+
+void InitWorld(void)
+{
+    ClearWorld();
+
+    player = SpawnEntity(
+        120,
+        120,
+        40,
+        1.0f,
+        BLUE);
+
+    if (player)
+    {
+        player->isPlayer = true;
+    }
+
+    for (int i = 0; i < 8; i++)
+    {
+        SpawnEntity(
+            300 + i * 50,
+            50,
+            25,
+            1.0f,
+            RED);
+    }
+
+    simTime = 0.0f;
+}
+
+int CountEntities(void)
+{
+    int count = 0;
+
+    for (int i = 0; i < MAX_ENTITIES; i++)
+    {
+        if (entities[i].active)
+            count++;
+    }
+
+    return count;
+}