From 0eca065c6e09468ea546d23b11d19258f1e9b692 Mon Sep 17 00:00:00 2001 From: doyle Date: Sun, 17 Sep 2023 21:55:59 +1000 Subject: [PATCH] fp: Add basic collision detection --- feely_pona.cpp | 68 ++++++++++++++++++++++++++++++++++++++------- feely_pona_game.cpp | 2 +- 2 files changed, 59 insertions(+), 11 deletions(-) diff --git a/feely_pona.cpp b/feely_pona.cpp index 36a6449..69c4a60 100644 --- a/feely_pona.cpp +++ b/feely_pona.cpp @@ -406,6 +406,8 @@ void FP_GameUpdate(TELY_Platform *platform, FP_Game *game, TELY_Renderer *render } } + // NOTE: Stalk entity ====================================================================== +#if 0 Dqn_V2 entity_world_pos = FP_Game_CalcEntityWorldPos(game, entity->handle); if (entity->name == DQN_STRING8("Enemy")) { if (entity->handle != game->clicked_entity && entity->stalk_entity != game->clicked_entity) { @@ -463,6 +465,7 @@ void FP_GameUpdate(TELY_Platform *platform, FP_Game *game, TELY_Renderer *render entity->local_pos += entity_to_target_pos_norm * (entity->local_hit_box_size.x * .05f); } } +#endif // NOTE: Core equations of motion ========================================================== { @@ -472,23 +475,69 @@ void FP_GameUpdate(TELY_Platform *platform, FP_Game *game, TELY_Renderer *render Dqn_f32 t = DQN_CAST(Dqn_f32)DQN_SQUARED(input->delta_s); Dqn_f32 t_squared = DQN_SQUARED(t); entity->velocity = (acceleration * t) + entity->velocity * 0.82f; + Dqn_V2 delta_pos = (acceleration * 0.5f * t_squared) + (entity->velocity * t); - Dqn_V2 delta_p = (acceleration * 0.5f * t_squared) + (entity->velocity * t); - entity->local_pos += delta_p; - - Dqn_Rect world_hit_box = FP_Game_CalcEntityWorldHitBox(game, entity->handle); - Dqn_Rect new_world_hit_box = world_hit_box; - new_world_hit_box.pos += delta_p; + Dqn_V2 entity_new_pos = entity->local_pos + delta_pos; + Dqn_Rect entity_world_hit_box = FP_Game_CalcEntityWorldHitBox(game, entity->handle); + bool has_collision = false; for (FP_GameEntityIterator collider_it = {}; FP_Game_DFSPostOrderWalkEntityTree(game, &collider_it, game->root_entity); ) { FP_GameEntity *collider = collider_it.entity; if (collider->handle == entity->handle) continue; - // TODO(doyle): Minkowski sweep? + // NOTE: Sweep collider with half the radius of the source entity Dqn_Rect collider_world_hit_box = FP_Game_CalcEntityWorldHitBox(game, collider->handle); - if (Dqn_Rect_Intersects(new_world_hit_box, collider_world_hit_box)) { + collider_world_hit_box.pos -= (entity_world_hit_box.size * .5f); + collider_world_hit_box.size += entity_world_hit_box.size; + + if (!Dqn_Rect_ContainsPoint(collider_world_hit_box, entity_new_pos)) + continue; + + // NOTE: Solve collision by determining the 't' value at which + // we hit one of the walls of the collider and move the entity + // at exactly that point. + + // O + td = x + // td = x - O + // t = (x - O) / d + + Dqn_f32 collider_left_wall_x = collider_world_hit_box.pos.x; + Dqn_f32 collider_right_wall_x = collider_world_hit_box.pos.x + collider_world_hit_box.size.w; + Dqn_f32 collider_top_wall_y = collider_world_hit_box.pos.y; + Dqn_f32 collider_bottom_wall_y = collider_world_hit_box.pos.y + collider_world_hit_box.size.h; + + Dqn_V2 o = entity_world_hit_box.pos; + Dqn_V2 d = delta_pos; + + Dqn_f32 earliest_t = 999.f; + if (d.x != 0.f) { + Dqn_f32 left_t = (collider_left_wall_x - o.x / d.x); + Dqn_f32 right_t = (collider_right_wall_x - o.x / d.x); + if (left_t >= 0.f) + earliest_t = DQN_MIN(earliest_t, left_t); + if (right_t >= 0.f) + earliest_t = DQN_MIN(earliest_t, right_t); } + + if (d.y != 0.f) { + Dqn_f32 top_t = (collider_top_wall_y - o.y / d.y); + Dqn_f32 bottom_t = (collider_bottom_wall_y - o.y / d.y); + if (top_t >= 0.f) + earliest_t = DQN_MIN(earliest_t, top_t); + if (bottom_t >= 0.f) + earliest_t = DQN_MIN(earliest_t, bottom_t); + } + + Dqn_V2 pos_just_before_collide = entity_world_hit_box.pos + (d * t); + Dqn_V2 new_delta_p = pos_just_before_collide - entity_world_hit_box.pos; + entity->local_pos += new_delta_p; + entity->velocity = {}; + has_collision = true; + } + + if (!has_collision) { + entity->local_pos += delta_pos; } } @@ -707,10 +756,9 @@ void FP_GameRender(FP_Game *game, TELY_Platform *platform, TELY_Renderer *render } else if (game->hot_entity == entity->handle || (entity->flags & FP_EntityFlag_DrawHitBox)) { Dqn_V4 hot_colour = game->hot_entity == entity->handle ? TELY_COLOUR_RED_TOMATO_V4 : TELY_Colour_V4Alpha(TELY_COLOUR_YELLOW_SANDY_V4, .5f); TELY_Render_RectColourV4(renderer, world_hit_box, TELY_RenderShapeMode_Line, hot_colour); - } - if (game->clicked_entity == entity->handle || game->hot_entity == entity->handle) { + if (game->hot_entity == entity->handle) { if (entity->name.size) { Dqn_V2I player_tile = Dqn_V2I_InitNx2(world_pos.x / FP_TILE_SIZE, world_pos.y / FP_TILE_SIZE); Dqn_V2 entity_world_pos = FP_Game_CalcEntityWorldPos(game, entity->handle); diff --git a/feely_pona_game.cpp b/feely_pona_game.cpp index 291f3ca..6ea1402 100644 --- a/feely_pona_game.cpp +++ b/feely_pona_game.cpp @@ -355,7 +355,7 @@ static Dqn_Rect FP_Game_CalcEntityLocalHitBox(FP_Game const *game, FP_GameEntity static Dqn_Rect FP_Game_CalcEntityWorldHitBox(FP_Game const *game, FP_GameEntityHandle handle) { - FP_GameEntity *entity = FP_Game_GetEntity(DQN_CAST(FP_Game *) game, handle); + FP_GameEntity *entity = FP_Game_GetEntity(DQN_CAST(FP_Game *) game, handle); Dqn_V2 world_pos = FP_Game_CalcEntityWorldPos(game, handle); Dqn_Rect local_hit_box = FP_Game_CalcEntityLocalHitBox(game, entity->handle); Dqn_Rect result = Dqn_Rect_InitV2x2(world_pos + local_hit_box.pos, local_hit_box.size);