Implement sprite rendering anchor

engine/EC.h

@@ -192,10 +192,25 @@ typedef struct Sprite {
 } Sprite_t;
 
 typedef unsigned int (*sprite_transition_func_t)(Entity_t *ent); // Transition requires knowledge of the entity
+
+typedef enum AnchorPoint {
+    AP_TOP_LEFT,
+    AP_TOP_CENTER,
+    AP_TOP_RIGHT,
+    AP_MID_LEFT,
+    AP_MID_CENTER,
+    AP_MID_RIGHT,
+    AP_BOT_LEFT,
+    AP_BOT_CENTER,
+    AP_BOT_RIGHT,
+} AnchorPoint_t;
+
 typedef struct _SpriteRenderInfo
 {
     Sprite_t* sprite;
     Vector2 offset;
+    Vector2 src_anchor;
+    AnchorPoint_t dest_anchor;
 } SpriteRenderInfo_t;
 
 typedef struct _CSprite_t {

engine/assets.c

@@ -1,6 +1,7 @@
 #include "assets.h"
 #include "assert.h"
 #include "engine_conf.h"
+#include "raymath.h"
 
 #define RRES_RAYLIB_IMPLEMENTATION
 #include "rres.h"
@@ -551,15 +552,20 @@ void draw_sprite_pro(Sprite_t* spr, int frame_num, Vector2 pos, float rotation,
         spr->frame_size.x * ((flip & 1) ? -1 : 1),
         spr->frame_size.y * ((flip & 2) ? -1 : 1),
     };
-    Rectangle dest = {
+
-        .x = pos.x,
+    // The anchor here is only for rotation and scaling.
-        .y = pos.y,
+    // Translational anchor is expected to be accounted for
-        .width = spr->frame_size.x * scale.x,
+    // So need to offset render position with anchor position
-        .height = spr->frame_size.y * scale.y
-    };
     Vector2 anchor = spr->anchor;
     anchor.x *= scale.x;
     anchor.y *= scale.y;
+
+    Rectangle dest = {
+        .x = pos.x + anchor.x,
+        .y = pos.y + anchor.y,
+        .width = spr->frame_size.x * scale.x,
+        .height = spr->frame_size.y * scale.y
+    };
     DrawTexturePro(
         *spr->texture,
         rec,
@@ -568,3 +574,54 @@ void draw_sprite_pro(Sprite_t* spr, int frame_num, Vector2 pos, float rotation,
         rotation, colour
     );
 }
+
+Vector2 shift_bbox(Vector2 bbox, Vector2 new_bbox, AnchorPoint_t anchor)
+{
+    Vector2 p1 = get_anchor_offset(bbox, anchor);
+    Vector2 p2 = get_anchor_offset(new_bbox, anchor);
+
+    return Vector2Subtract(p1, p2);
+}
+
+Vector2 get_anchor_offset(Vector2 bbox, AnchorPoint_t anchor)
+{
+    Vector2 offset = {0};
+    switch (anchor)
+    {
+        case AP_TOP_LEFT:
+        break;
+        case AP_TOP_CENTER:
+            offset.x = bbox.x / 2;
+        break;
+        case AP_TOP_RIGHT:
+            offset.x = bbox.x;
+        break;
+        case AP_MID_LEFT:
+            offset.x = 0;
+            offset.y = bbox.y / 2;
+        break;
+        case AP_MID_CENTER:
+            offset.x = bbox.x / 2;
+            offset.y = bbox.y / 2;
+        break;
+        case AP_MID_RIGHT:
+            offset.x = bbox.x;
+            offset.y = bbox.y / 2;
+        break;
+        case AP_BOT_LEFT:
+            offset.x = 0;
+            offset.y = bbox.y;
+        break;
+        case AP_BOT_CENTER:
+            offset.x = bbox.x / 2;
+            offset.y = bbox.y;
+        break;
+        case AP_BOT_RIGHT:
+            offset.x = bbox.x;
+            offset.y = bbox.y;
+        break;
+    }
+    return offset;
+}
+
+

engine/assets.h

@@ -83,6 +83,8 @@ LevelPack_t* get_level_pack(Assets_t* assets, const char* name);
 
 void draw_sprite(Sprite_t* spr, int frame_num, Vector2 pos, float rotation, bool flip_x);
 void draw_sprite_pro(Sprite_t* spr, int frame_num, Vector2 pos, float rotation, uint8_t flip, Vector2 scale, Color colour);
+Vector2 get_anchor_offset(Vector2 bbox, AnchorPoint_t anchor);
+Vector2 shift_bbox(Vector2 bbox, Vector2 new_bbox, AnchorPoint_t anchor);
 
 typedef struct SFX
 {

scenes/editor_scene.c

@@ -220,6 +220,7 @@ static void render_editor_game_scene(Scene_t* scene)
                 int y = tile_y * TILE_SIZE;
 
 
+
                 //if (!tilemap.tiles[i].moveable)
                 //{
                 //    // Draw water tile
@@ -432,7 +433,17 @@ static void render_editor_game_scene(Scene_t* scene)
                 const SpriteRenderInfo_t spr = p_cspr->sprites[p_cspr->current_idx];
                 if (spr.sprite != NULL)
                 {
-                    Vector2 pos = Vector2Add(p_ent->position, spr.offset);
+                    Vector2 pos = p_ent->position;
+                    if (p_bbox != NULL)
+                    {
+                        pos = Vector2Add(
+                            pos,
+                            get_anchor_offset(p_bbox->size, spr.dest_anchor)
+                        );
+                        pos = Vector2Subtract(pos, spr.src_anchor);
+                    }
+
+                    pos = Vector2Add(pos, spr.offset);
                     draw_sprite(spr.sprite, p_cspr->current_frame, pos, 0.0f, p_cspr->flip_x);
                 }
             }

scenes/game_systems.c

@@ -12,17 +12,6 @@ bool check_in_water(const ParticleEmitter_t* emitter, float delta_time);
 
 static const Vector2 GRAVITY = {0, GRAV_ACCEL};
 static const Vector2 UPTHRUST = {0, -GRAV_ACCEL * 1.1};
-typedef enum AnchorPoint {
-    AP_TOP_LEFT,
-    AP_TOP_CENTER,
-    AP_TOP_RIGHT,
-    AP_MID_LEFT,
-    AP_MID_CENTER,
-    AP_MID_RIGHT,
-    AP_BOT_LEFT,
-    AP_BOT_CENTER,
-    AP_BOT_RIGHT,
-} AnchorPoint_t;
 
 static inline unsigned int get_tile_idx(int x, int y, TileGrid_t gridmap)
 {
@@ -160,73 +149,6 @@ collision_end:
     return overlap_mode > 0;
 }
 
-static Vector2 shift_bbox(Vector2 bbox, Vector2 new_bbox, AnchorPoint_t anchor)
-{
-    Vector2 p1;
-    Vector2 p2;
-
-    Vector2 offset = {0};
-    switch (anchor)
-    {
-        case AP_TOP_LEFT:
-            // When resizing bbox, it is implicitly assumed that to be already in topleft
-            // due to the coordindate system (+ve towards right and downwards)
-            // So do nothing
-        return offset;
-        case AP_TOP_CENTER:
-            p1.x = bbox.x / 2;
-            p1.y = 0;
-            p2.x = new_bbox.x / 2;
-            p2.y = 0;
-        break;
-        case AP_TOP_RIGHT:
-            p1.x = bbox.x;
-            p1.y = 0;
-            p2.x = new_bbox.x;
-            p2.y = 0;
-        break;
-        case AP_MID_LEFT:
-            p1.x = 0;
-            p1.y = bbox.y / 2;
-            p2.x = 0;
-            p2.y = new_bbox.y / 2;
-        break;
-        case AP_MID_CENTER:
-            p1.x = bbox.x / 2;
-            p1.y = bbox.y / 2;
-            p2.x = new_bbox.x / 2;
-            p2.y = new_bbox.y / 2;
-        break;
-        case AP_MID_RIGHT:
-            p1.x = bbox.x;
-            p1.y = bbox.y / 2;
-            p2.x = new_bbox.x;
-            p2.y = new_bbox.y / 2;
-        break;
-        case AP_BOT_LEFT:
-            p1.x = 0;
-            p1.y = bbox.y;
-            p2.x = 0;
-            p2.y = new_bbox.y;
-        break;
-        case AP_BOT_CENTER:
-            p1.x = bbox.x / 2;
-            p1.y = bbox.y;
-            p2.x = new_bbox.x / 2;
-            p2.y = new_bbox.y;
-        break;
-        case AP_BOT_RIGHT:
-            p1.x = bbox.x;
-            p1.y = bbox.y;
-            p2.x = new_bbox.x;
-            p2.y = new_bbox.y;
-        break;
-    }
-    offset.x = p1.x - p2.x;
-    offset.y = p1.y - p2.y;
-    return offset;
-}
-
 void destroy_entity(Scene_t* scene, TileGrid_t* tilemap, Entity_t* p_ent)
 {
     Vector2 half_size = {0,0};

scenes/player_ent.c

@@ -172,8 +172,13 @@ static bool init_player_file(FILE* in_file, Assets_t* assets)
             return false;
         }
         Sprite_t* spr = get_sprite(assets, name);
+        spr->anchor = Vector2Scale(spr->frame_size, 0.5f);
         player_sprite_map[i].sprite = spr;
-        player_sprite_map[i].offset = offset;
+        //player_sprite_map[i].offset = offset;
+        player_sprite_map[i].offset = (Vector2){0};
+        player_sprite_map[i].src_anchor = spr->frame_size;
+        player_sprite_map[i].src_anchor.x /= 2.0f;
+        player_sprite_map[i].dest_anchor = AP_BOT_CENTER;
         i++;
     }
     already_init = true;