Enable absolute mouse (todo: add flag to turn it off)

&& fix(?) a crash if mouse events were delivered too early

include/scc.h

@@ -35,6 +35,8 @@ void    scc_write(unsigned int address, uint8_t data);
 uint8_t scc_read(unsigned int address);
 /* Set a new state for the DCD pins: */
 void    scc_set_dcd(int a, int b);
+/* check if scc master interrupt is enabled */
+int scc_get_mie();
 
 #endif
 

include/umac.h

@@ -34,6 +34,7 @@ int     umac_loop(void);
 void    umac_reset(void);
 void    umac_opt_disassemble(int enable);
 void    umac_mouse(int deltax, int deltay, int button);
+void    umac_absmouse(int x, int y, int button);
 void    umac_kbd_event(uint8_t scancode, int down);
 
 static inline void      umac_vsync_event(void)

src/main.c

@@ -618,13 +618,39 @@ void    umac_opt_disassemble(int enable)
  *
  * X is positive going right; Y is positive going upwards.
  */
-void    umac_mouse(int deltax, int deltay, int button)
+void    umac_absmouse(int x, int y, int button)
 {
+    if (!scc_get_mie()) return;
 #define MTemp_h 0x82a
 #define MTemp_v 0x828
 #define CrsrNew 0x8ce
 #define CrsrCouple 0x8cf
 
+        int oldx = RAM_RD16(MTemp_h);
+        int oldy = RAM_RD16(MTemp_v);
+
+        if(x != oldx) {
+            RAM_WR16(MTemp_h, x);
+        }
+
+        if (y != oldy) {
+            RAM_WR16(MTemp_v, y);
+        }
+
+        if(x != oldx || y != oldy) {
+            RAM_WR8(CrsrNew, RAM_RD8(CrsrCouple));
+        }
+
+        via_mouse_pressed = button;
+}
+
+/* Provide mouse input (movement, button) data.
+ *
+ * X is positive going right; Y is positive going upwards.
+ */
+void    umac_mouse(int deltax, int deltay, int button)
+{
+    if (!scc_get_mie()) return;
         if(deltax) {
             int16_t temp_h = RAM_RD16(MTemp_h) + deltax;
             RAM_WR16(MTemp_h, temp_h);

src/scc.c

@@ -126,6 +126,8 @@ static void     scc_wr3(int AnB, uint8_t data)
         }
 }
 
+int scc_get_mie() { return scc_mie; }
+
 // WR9: Master Interrupt control and reset commands
 static void     scc_wr9(uint8_t data)
 {

src/unix_main.c

@@ -287,8 +287,14 @@ int     main(int argc, char *argv[])
                 perror("SDL window");
                 return 1;
         }
-        SDL_SetWindowGrab(window, SDL_TRUE);
-        SDL_SetRelativeMouseMode(SDL_TRUE);
+
+        static const int absmouse = 1;
+        if (!absmouse) {
+            SDL_SetWindowGrab(window, SDL_TRUE);
+            SDL_SetRelativeMouseMode(SDL_TRUE);
+        } else {
+            SDL_ShowCursor(SDL_DISABLE);
+        }
 
         SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear");
 
@@ -355,7 +361,8 @@ int     main(int argc, char *argv[])
                 SDL_Event event;
                 int mousex = 0;
                 int mousey = 0;
-
+                int send_mouse = 0;
+                static int absmousex, absmousey;
                 if (SDL_PollEvent(&event)) {
                         switch (event.type) {
                         case SDL_QUIT:
@@ -372,21 +379,32 @@ int     main(int argc, char *argv[])
                         } break;
 
                         case SDL_MOUSEMOTION:
+                                send_mouse = 1;
+                                absmousex = event.motion.x / DISP_SCALE;
+                                absmousey = event.motion.y / DISP_SCALE;
                                 mousex = event.motion.xrel;
                                 mousey = -event.motion.yrel;
                                 break;
 
                         case SDL_MOUSEBUTTONDOWN:
+                                send_mouse = 1;
                                 mouse_button = 1;
                                 break;
 
                         case SDL_MOUSEBUTTONUP:
+                                send_mouse = 1;
                                 mouse_button = 0;
                                 break;
                         }
                 }
 
-                umac_mouse(mousex, mousey, mouse_button);
+                if (send_mouse) {
+                    if(absmouse) {
+                        umac_absmouse(absmousex, absmousey, mouse_button);
+                    } else {
+                        umac_mouse(mousex, mousey, mouse_button);
+                    }
+                }
 
                 done |= umac_loop();