Add transperency when units are behind

engine/breeze/map/map.c

@@ -465,6 +465,27 @@ void bzTileMapDrawCollisions(BzTileMap *map) {
     }
 }
 
+void bzTileMapClearCollisions(BzTileMap *map) {
+    BZ_ASSERT(map->collisionMap);
+    for (i32 y = 0; y < map->width; y++) {
+        for (i32 x = 0; x < map->height; x++) {
+            i32 idxOffset = y * map->width + x;
+            u8 *cell = map->collisionMap + idxOffset;
+            *cell = 0;
+        }
+    }
+}
+void bzTileMapClearCollisionLayer(BzTileMap *map, i32 layer) {
+    BZ_ASSERT(map->collisionMap);
+    BZ_ASSERT(layer >= 0 && layer < 8);
+    for (i32 y = 0; y < map->width; y++) {
+        for (i32 x = 0; x < map->height; x++) {
+            i32 idxOffset = y * map->width + x;
+            u8 *cell = map->collisionMap + idxOffset;
+            *cell &= ~(1 << layer);
+        }
+    }
+}
 bool bzTileMapHasAnyCollision(BzTileMap *map, i32 x, i32 y) {
     if (!map->collisionMap) return false;
     i32 idx = y * map->width + x;

engine/breeze/map/map.h

@@ -132,6 +132,8 @@ bool bzTileMapCanRayCastLine(BzTileMap *map, Vector2 from, Vector2 to);
 void bzTileMapDraw(BzTileMap *map);
 
 void bzTileMapDrawCollisions(BzTileMap *map);
+void bzTileMapClearCollisions(BzTileMap *map);
+void bzTileMapClearCollisionLayer(BzTileMap *map, i32 layer);
 bool bzTileMapHasAnyCollision(BzTileMap *map, i32 x, i32 y);
 bool bzTileMapHasCollision(BzTileMap *map, i32 layer, i32 x, i32 y);
 void bzTileMapSetCollisions(BzTileMap *map, bool collision, i32 layer, i32 startX, i32 startY, i32 sizeX, i32 sizeY);

game/constants.h

@@ -4,6 +4,7 @@
 enum {
     COLL_LAYER_TERRAIN = 0,
     COLL_LAYER_BUILDINGS = 1,
+    COLL_LAYER_TRANSPARENCY = 7,
 };
 
 #endif //PIXELDEFENSE_CONSTANTS_H

game/game_state.h

@@ -18,6 +18,7 @@ typedef struct DrawData {
     Rectangle dst;
     Vector2   origin;
     f32       rotation;
+    bool      canHaveAlpha;
 } DrawData;
 
 typedef struct Options {

game/main.c

@@ -350,7 +350,8 @@ static void renderGame(Game *game, float dt) {
     BeginMode2D(game->camera);
 
     // Map
-    bzTileMapDraw(&game->map);
+    BzTileMap *map = &game->map;
+    bzTileMapDraw(map);
     // Ground UI
     drawPlayerInputUIGround();
     // Entities
@@ -380,12 +381,22 @@ static void renderGame(Game *game, float dt) {
             src.height -= 0.02f;
             if (t[i].flipX) src.width *= -1.0f;
             if (t[i].flipY) src.height *= -1.0f;
-            drawData[drawIdx++] = (DrawData) {
+            DrawData draw = (DrawData) {
                 .src = src,
                 .dst = dst,
                 .origin = origin,
-                .rotation = r[i]
+                .rotation = r[i],
+                .canHaveAlpha = true,
             };
+            if (ecs_has_id(ECS, it.entities[i], ecs_id(Unit)) ||
+                ecs_has_id(ECS, it.entities[i], ecs_id(Arm))) {
+                Vector2 pos = {dst.x, dst.y};
+                Vec2i cellPos = bzTileMapPosToTile(map, pos);
+                bzTileMapSetCollisions(map, true, COLL_LAYER_TRANSPARENCY,
+                                       cellPos.x, cellPos.y, 1, 1);
+                draw.canHaveAlpha = false;
+            }
+            drawData[drawIdx++] = draw;
         }
     }
     BZ_ASSERT(drawIdx == numDraws);
@@ -394,8 +405,20 @@ static void renderGame(Game *game, float dt) {
     Texture2D tex = game->tileset.tiles;
     for (i32 i = 0; i < numDraws; i++) {
         DrawData draw = drawData[i];
-        DrawTexturePro(tex, draw.src, draw.dst, draw.origin, draw.rotation, WHITE);
+        Vector2 pos = {
+                draw.dst.x,
+                draw.dst.y - draw.dst.height * 0.5f,
+        };
+        Color c = WHITE;
+        if (draw.canHaveAlpha) {
+            Vec2i mapPos = bzTileMapPosToTile(map, pos);
+            if (bzTileMapHasCollision(map, COLL_LAYER_TRANSPARENCY, mapPos.x, mapPos.y)) {
+                c.a = 180;
+            }
+        }
+        DrawTexturePro(tex, draw.src, draw.dst, draw.origin, draw.rotation, c);
     }
+    bzTileMapClearCollisionLayer(&game->map, COLL_LAYER_TRANSPARENCY);
     Vector2 target = GetMousePosition();
     target = GetScreenToWorld2D(target, game->camera);
     static f32 elapsed = 0;