Initialise UI context

include/ui.h

@@ -35,16 +35,17 @@ struct ui_ctx {
   u64 count;
   i64 hovered;
   i64 active;
-  i64 mouse_x;
-  i64 mouse_y;
-  i64 rel_x;
-  i64 rel_y;
+  i32 mouse_x;
+  i32 mouse_y;
+  i32 rel_x;
+  i32 rel_y;
   bool mouse_down;
   bool mouse_up;
   const window_t *wnd;
   ui_elem_t elements[MAX_UI_ELEMENTS];
 };
 
+void init_ui_ctx(ui_ctx_t *ctx);
 void reset_ui_ctx(ui_ctx_t *ctx);
 void handle_ui_events(const window_t *wnd, ui_ctx_t *ctx,
                       const SDL_Event *event);

src/compositor.c

@@ -42,6 +42,9 @@ i32 run_main_loop(void) {
   }
 
   compositor_t comp = {0};
+
+  init_ui_ctx(&(comp.ctx));
+
   comp.rects = (rect_t *)malloc(sizeof(rect_t) * MAX_NODES);
   comp.nodes = (node_t *)malloc(sizeof(node_t) * MAX_NODES);
 

src/ui.c

@@ -2,7 +2,6 @@
 #include "SDL_events.h"
 #include "aliases/aliases.h"
 #include "window.h"
-#include <stdio.h>
 
 typedef struct ui_elem_colours ui_elem_colours_t;
 struct ui_elem_colours {
@@ -28,21 +27,22 @@ bool aabb(const ui_elem_t *elem, i32 x, i32 y) {
          y > elem->rect.topleft.y && y <= elem->rect.topleft.y + elem->rect.h;
 }
 
+void init_ui_ctx(ui_ctx_t *ctx) {
+  *ctx = (ui_ctx_t){0};
+  ctx->hovered = -1;
+  ctx->active = -1;
+}
+
 void reset_ui_ctx(ui_ctx_t *ctx) {
   ctx->count = 0;
   ctx->mouse_down = false;
   ctx->mouse_up = false;
-  ctx->rel_x = 0;
-  ctx->rel_y = 0;
 }
 
 void handle_ui_events(const window_t *wnd, ui_ctx_t *ctx,
                       const SDL_Event *event) {
   switch (event->type) {
   case SDL_MOUSEMOTION:
-    ctx->rel_x = event->motion.xrel;
-    ctx->rel_y = event->motion.yrel;
-
     if (wnd->id == event->motion.windowID) {
       ctx->mouse_x = event->motion.x;
       ctx->mouse_y = event->motion.y;
@@ -85,7 +85,7 @@ bool button(const window_t *wnd, ui_ctx_t *ctx, rect_t rect) {
   fill_rect(wnd, rect, colours[UI_ELEM_BUTTON].fill);
   draw_rect(wnd, rect, colours[UI_ELEM_BUTTON].border);
 
-  if (wnd != ctx->wnd) {
+  if (wnd != ctx->wnd || (ctx->active >= 0 && ctx->active != elem.id)) {
     return false;
   }
 
@@ -115,24 +115,26 @@ rect_t node(const window_t *wnd, ui_ctx_t *ctx, rect_t rect) {
   ui_elem_t elem = (ui_elem_t){
       .id = (ctx->count)++,
       .rect = rect,
-      .type = UI_ELEM_BUTTON,
+      .type = UI_ELEM_NODE,
   };
 
-  fill_rect(wnd, rect, colours[UI_ELEM_BUTTON].fill);
-  draw_rect(wnd, rect, colours[UI_ELEM_BUTTON].border);
+  fill_rect(wnd, rect, colours[UI_ELEM_NODE].fill);
+  draw_rect(wnd, rect, colours[UI_ELEM_NODE].border);
 
-  if (wnd != ctx->wnd) {
+  if (wnd != ctx->wnd || (ctx->active >= 0 && ctx->active != elem.id)) {
     return rect;
   }
 
   if (ctx->mouse_up) {
     ctx->hovered = ctx->active = -1;
+    ctx->rel_x = ctx->rel_y = 0;
+    return rect;
   }
 
   if (ctx->hovered == elem.id && ctx->active == elem.id) {
     return (rect_t){
-        .topleft.x = rect.topleft.x + ctx->rel_x,
-        .topleft.y = rect.topleft.y + ctx->rel_y,
+        .topleft.x = ctx->mouse_x + ctx->rel_x,
+        .topleft.y = ctx->mouse_y + ctx->rel_y,
         .w = rect.w,
         .h = rect.h,
     };
@@ -146,6 +148,8 @@ rect_t node(const window_t *wnd, ui_ctx_t *ctx, rect_t rect) {
 
   if (ctx->mouse_down) {
     ctx->active = elem.id;
+    ctx->rel_x = rect.topleft.x - ctx->mouse_x;
+    ctx->rel_y = rect.topleft.y - ctx->mouse_y;
   }
 
   return rect;