basic smooth movement

src/main.cpp

@@ -71,6 +71,7 @@ static mat4x4 inverse_view_matrix;
 static mat4x4 projection_matrix;
 static mat4x4 inverse_projection_matrix; 
 
+static SDL_Time last_time;
 static SDL_Time current_time;
 
 static bool         enable_time_tints = true;
@@ -89,6 +90,8 @@ static bool show_demo_window;
 static bool show_tile_picker;
 static bool show_settings;
 
+static float character_speed = 4.0f;
+
 #define log_error(...) SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, __VA_ARGS__)
 
 float remap(float in_a, float in_b, float out_a, float out_b, float v) {
@@ -204,6 +207,10 @@ static Map current_map;
 
 struct Player {
     i32vec2 position;
+    i32vec2 target_position;
+
+    bool is_moving;
+    vec2 visual_position;
 };
 
 static Player player;
@@ -219,6 +226,13 @@ struct alignas(16) PerFrame {
 
 static PerFrame per_frame = {};
 
+typedef enum : Uint8 {
+    DIR_DOWN,
+    DIR_UP,
+    DIR_LEFT,
+    DIR_RIGHT,
+} Direction;
+
 typedef enum : Uint8 {
     TILEKIND_ERROR = 0,
     TILEKIND_NONE  = 1,
@@ -402,6 +416,9 @@ static bool dragging_tile_change;
 static bool dragging_camera_change;
 static vec2 drag_start_pos;
 
+static bool      queued_movement;
+static Direction queued_movement_direction;
+
 static R_Texture create_texture(const char *path) {
     char path_to_load[256] = ASSETS_PATH;
     SDL_strlcat(path_to_load, path, SDL_arraysize(path_to_load));
@@ -1357,20 +1374,26 @@ static void process_event_game(SDL_Event event) {
 
     switch (event.type) {
         case SDL_EVENT_KEY_DOWN: {
+            if (event.key.repeat) return;
+
             if (event.key.key == SDLK_UP || event.key.key == SDLK_W) {
-                player.position.y = clamp(0, player.position.y + 1, current_map.size.y - 2);
+                queued_movement = true;
+                queued_movement_direction = DIR_UP;
             }
 
             if (event.key.key == SDLK_LEFT || event.key.key == SDLK_A) {
-                player.position.x = clamp(0, player.position.x - 1, current_map.size.x - 2);
+                queued_movement = true;
+                queued_movement_direction = DIR_LEFT;
             }
 
             if (event.key.key == SDLK_DOWN || event.key.key == SDLK_S) {
-                player.position.y = clamp(0, player.position.y - 1, current_map.size.y - 2);
+                queued_movement = true;
+                queued_movement_direction = DIR_DOWN;
             }
 
             if (event.key.key == SDLK_RIGHT || event.key.key == SDLK_D) {
-                player.position.x = clamp(0, player.position.x + 1, current_map.size.x - 2);
+                queued_movement = true;
+                queued_movement_direction = DIR_RIGHT;
             }
 
             if (event.key.key == SDLK_F9) {
@@ -1380,19 +1403,23 @@ static void process_event_game(SDL_Event event) {
 
         case SDL_EVENT_GAMEPAD_BUTTON_DOWN: {
             if (event.gbutton.button == SDL_GAMEPAD_BUTTON_DPAD_UP) {
-                player.position.y = clamp(0, player.position.y + 1, current_map.size.y - 2);
+                queued_movement = true;
+                queued_movement_direction = DIR_UP;
             }
 
             if (event.gbutton.button == SDL_GAMEPAD_BUTTON_DPAD_LEFT) {
-                player.position.x = clamp(0, player.position.x - 1, current_map.size.x - 2);
+                queued_movement = true;
+                queued_movement_direction = DIR_LEFT;
             }
 
             if (event.gbutton.button == SDL_GAMEPAD_BUTTON_DPAD_DOWN) {
-                player.position.y = clamp(0, player.position.y - 1, current_map.size.y - 2);
+                queued_movement = true;
+                queued_movement_direction = DIR_DOWN;
             }
 
             if (event.gbutton.button == SDL_GAMEPAD_BUTTON_DPAD_RIGHT) {
-                player.position.x = clamp(0, player.position.x + 1, current_map.size.x - 2);
+                queued_movement = true;
+                queued_movement_direction = DIR_RIGHT;
             }
         } break;
     }
@@ -1401,6 +1428,32 @@ static void process_event_game(SDL_Event event) {
 static void update_state_game() {
     ZoneScopedN("update_state_game");
 
+    SDL_Time delta_time = current_time - last_time;
+    float    delta_t    = delta_time / (float)SDL_NS_PER_SECOND;
+
+    const bool *keyboard_state = SDL_GetKeyboardState(NULL);
+
+    if (player.is_moving) {
+        vec2 leftover_movement = vec2(player.target_position) - player.visual_position;
+        vec2 movement = clamp(min(vec2(0, 0), leftover_movement), normalize(leftover_movement) * (delta_t * character_speed * (keyboard_state[SDL_SCANCODE_LSHIFT] ? 2.0f : 1.0f)), max(vec2(0, 0), leftover_movement));
+        player.visual_position += movement;
+
+        if (movement == leftover_movement) {
+            player.is_moving = false;
+            player.position = player.target_position;
+        }
+    }
+
+    if (!player.is_moving && (queued_movement || keyboard_state[SDL_SCANCODE_W] || keyboard_state[SDL_SCANCODE_A] || keyboard_state[SDL_SCANCODE_S] || keyboard_state[SDL_SCANCODE_D])) {
+        switch (queued_movement_direction) {
+            case DIR_UP:    { player.target_position = player.position + ivec2( 0,  1); if (player.target_position != player.position) player.is_moving = true; } break;
+            case DIR_LEFT:  { player.target_position = player.position + ivec2(-1,  0); if (player.target_position != player.position) player.is_moving = true; } break;
+            case DIR_DOWN:  { player.target_position = player.position + ivec2( 0, -1); if (player.target_position != player.position) player.is_moving = true; } break;
+            case DIR_RIGHT: { player.target_position = player.position + ivec2( 1,  0); if (player.target_position != player.position) player.is_moving = true; } break;
+        }
+    }
+    queued_movement = false;
+
     if (!MIX_TrackPlaying(music_track)) {
         MIX_SetTrackAudio(music_track, music_setting_off_piano);
         MIX_PlayTrack(music_track, 0);
@@ -1414,7 +1467,7 @@ static void render_game() {
         ZoneScopedN("update buffers");
         {
             ZoneScopedN("player_instance_buffer");
-            player_instance.pos = player.position;
+            player_instance.pos = player.visual_position;
 
             renderer_buffer_update(player_instance_buffer, 0, sizeof(player_instance), &player_instance);
         }
@@ -1424,8 +1477,8 @@ static void render_game() {
 
             float aspect_ratio = ((float)window_size.x / (float)window_size.y);
 
-            view_matrix         = view        (vec3(player.position, 0), radians(camera_tilt), camera_distance);
+            view_matrix         = view        (vec3(player.visual_position, 0), radians(camera_tilt), camera_distance);
-            inverse_view_matrix = inverse_view(vec3(player.position, 0), radians(camera_tilt), camera_distance);
+            inverse_view_matrix = inverse_view(vec3(player.visual_position, 0), radians(camera_tilt), camera_distance);
 
             projection_matrix         = projection        (radians(camera_fovy_degrees), aspect_ratio, NEAR_PLANE);
             inverse_projection_matrix = inverse_projection(radians(camera_fovy_degrees), aspect_ratio, NEAR_PLANE);
@@ -1530,6 +1583,7 @@ static void process_events() {
 static void update_state() {
     ZoneScopedN("update_state");
 
+    last_time = current_time;
     SDL_GetCurrentTime(&current_time);
 
     if (use_actual_time)