build mode straight lines support

code/game/src/gui/build_mode.c

@@ -17,6 +17,11 @@ void buildmode_clear_buffers(void) {
     }
 }
 
+// TODO(zaklaus): 
+#ifndef zpl_sign0
+#define zpl_sign0(x) (x == 0.0f) ? 0.0f : ((x) >= 0.0f ? 1.0f : -1.0f)
+#endif
+
 void buildmode_draw(void) {
     camera cam = camera_get();
     camera old_cam = cam;
@@ -44,19 +49,39 @@ void buildmode_draw(void) {
         buildmode_clear_buffers();
     }
     
-    if (e->has_items && !e->inside_vehicle && e->items[e->selected_item].quantity > 0 && !is_outside_range) {
+    ItemDrop *item = &e->items[e->selected_item];
+    
+    if (e->has_items && !e->inside_vehicle && item->quantity > 0 && !is_outside_range) {
+        uint16_t item_id = item_find(item->kind);
+        item_usage usage = item_get_usage(item_id);
+        if (usage < UKIND_END_PLACE) {
             if (IsMouseButtonPressed(MOUSE_RIGHT_BUTTON) && !build_is_in_draw_mode) {
                 build_is_in_draw_mode = true;
                 build_num_placements = 0;
                 buildmode_clear_buffers();
             }
             
-        uint32_t qty = e->items[e->selected_item].quantity;
+            uint32_t qty = item->quantity;
+            bool directional = item_get_place_directional(item_id);
             
             if (build_is_in_draw_mode) {
                 for (size_t i = 0; i < BUILD_MAX_PLACEMENTS; i++) {
                     item_placement *it = &build_placements[i];
                     if (it->kind == -1) {
+                        if (directional && build_num_placements > 2) {
+                            float p1x = build_placements[0].x;
+                            float p1y = build_placements[0].y;
+                            float p2x = build_placements[1].x;
+                            float p2y = build_placements[1].y;
+                            float p3x = (float)cam.x;
+                            float p3y = (float)cam.y;
+                            float sx = zpl_sign0(p2x-p1x);
+                            float sy = zpl_sign0(p2y-p1y);
+                            float sxx = zpl_sign0(p3x-p1x);
+                            float syy = zpl_sign0(p3y-p1y);
+                            
+                            if (sx != sxx || sy != syy) break;
+                        }
                         it->x = (float)cam.x;
                         it->y = (float)cam.y;
                         it->kind = 0;
@@ -74,6 +99,7 @@ void buildmode_draw(void) {
             
             build_num_placements = zpl_min(build_num_placements, qty);
         }
+    }
     
     for (size_t i = 0; i < build_num_placements; i++) {
         item_placement *it = &build_placements[i];

code/game/src/items.h

@@ -6,11 +6,14 @@
 #include "modules/components.h"
 
 typedef enum {
-    UKIND_HOLD,
-    UKIND_PROXY,
+    // NOTE(zaklaus): hardcoded fields for placement ops
     UKIND_PLACE,
     UKIND_PLACE_ITEM,
     UKIND_END_PLACE,
+    
+    // NOTE(zaklaus): the rest of possible actions
+    UKIND_HOLD,
+    UKIND_PROXY,
 } item_usage;
 
 typedef struct {

code/modules/source/system_items.c

@@ -182,8 +182,9 @@ void SwapItems(ecs_iter_t *it) {
     }
 }
 
+// TODO(zaklaus): 
 #ifndef zpl_sign0
-#define zpl_sign0(x) (x == 0.0f) ? 0 : ((x) >= 0 ? 1 : -1)
+#define zpl_sign0(x) (x == 0.0f) ? 0.0f : ((x) >= 0.0f ? 1.0f : -1.0f)
 #endif
 
 void UseItem(ecs_iter_t *it) {