acc_scroll

app/src/hid/hid_mouse.c

@@ -151,6 +151,11 @@ sc_hid_buttons_from_buttons_state(uint8_t buttons_state) {
     return c;
 }
 
+void
+sc_hid_mouse_init(struct sc_hid_mouse *hid) {
+    hid->acc_vscroll = 0;
+}
+
 void
 sc_hid_mouse_generate_input_from_motion(struct sc_hid_input *hid_input,
                                     const struct sc_mouse_motion_event *event) {
@@ -175,8 +180,9 @@ sc_hid_mouse_generate_input_from_click(struct sc_hid_input *hid_input,
     data[3] = 0; // wheel coordinates only used for scrolling
 }
 
-void
-sc_hid_mouse_generate_input_from_scroll(struct sc_hid_input *hid_input,
+bool
+sc_hid_mouse_generate_input_from_scroll(struct sc_hid_mouse *hid,
+                                        struct sc_hid_input *hid_input,
                                     const struct sc_mouse_scroll_event *event) {
     sc_hid_mouse_input_init(hid_input);
 
@@ -184,9 +190,19 @@ sc_hid_mouse_generate_input_from_scroll(struct sc_hid_input *hid_input,
     data[0] = 0; // buttons state irrelevant (and unknown)
     data[1] = 0; // no x motion
     data[2] = 0; // no y motion
-    // In practice, vscroll is always -1, 0 or 1, but in theory other values
-    // are possible
-    data[3] = CLAMP(event->vscroll, -127, 127);
+
+    hid->acc_vscroll += event->vscroll;
+    if (hid->acc_vscroll > -1 && hid->acc_vscroll < 1) {
+        // Not enough scrolling to inject a scroll tick
+        return false;
+    }
+
+    hid->acc_vscroll = CLAMP(hid->acc_vscroll, -127, 127);
+    int8_t consume = hid->acc_vscroll; // truncate towards 0
+    assert(consume);
+    hid->acc_vscroll -= consume;
+    data[3] = consume;
+    return true;
     // Horizontal scrolling ignored
 }
 

app/src/hid/hid_mouse.h

@@ -8,6 +8,13 @@
 
 #define SC_HID_ID_MOUSE 2
 
+struct sc_hid_mouse {
+    float acc_vscroll;
+};
+
+void
+sc_hid_mouse_init(struct sc_hid_mouse *hid);
+
 void
 sc_hid_mouse_generate_open(struct sc_hid_open *hid_open);
 
@@ -22,8 +29,9 @@ void
 sc_hid_mouse_generate_input_from_click(struct sc_hid_input *hid_input,
                                     const struct sc_mouse_click_event *event);
 
-void
-sc_hid_mouse_generate_input_from_scroll(struct sc_hid_input *hid_input,
+bool
+sc_hid_mouse_generate_input_from_scroll(struct sc_hid_mouse *hid,
+                                        struct sc_hid_input *hid_input,
                                     const struct sc_mouse_scroll_event *event);
 
 #endif

app/src/uhid/mouse_uhid.c

@@ -55,7 +55,10 @@ sc_mouse_processor_process_mouse_scroll(struct sc_mouse_processor *mp,
     struct sc_mouse_uhid *mouse = DOWNCAST(mp);
 
     struct sc_hid_input hid_input;
-    sc_hid_mouse_generate_input_from_scroll(&hid_input, event);
+    if (!sc_hid_mouse_generate_input_from_scroll(&mouse->hid, &hid_input,
+                                                 event)) {
+        return;
+    }
 
     sc_mouse_uhid_send_input(mouse, &hid_input, "mouse scroll");
 }
@@ -63,6 +66,8 @@ sc_mouse_processor_process_mouse_scroll(struct sc_mouse_processor *mp,
 bool
 sc_mouse_uhid_init(struct sc_mouse_uhid *mouse,
                    struct sc_controller *controller) {
+    sc_hid_mouse_init(&mouse->hid);
+
     mouse->controller = controller;
 
     static const struct sc_mouse_processor_ops ops = {

app/src/uhid/mouse_uhid.h

@@ -4,11 +4,13 @@
 #include <stdbool.h>
 
 #include "controller.h"
+#include "hid/hid_mouse.h"
 #include "trait/mouse_processor.h"
 
 struct sc_mouse_uhid {
     struct sc_mouse_processor mouse_processor; // mouse processor trait
 
+    struct sc_hid_mouse hid;
     struct sc_controller *controller;
 };
 

app/src/usb/mouse_aoa.c

@@ -42,7 +42,7 @@ sc_mouse_processor_process_mouse_scroll(struct sc_mouse_processor *mp,
     struct sc_mouse_aoa *mouse = DOWNCAST(mp);
 
     struct sc_hid_input hid_input;
-    sc_hid_mouse_generate_input_from_scroll(&hid_input, event);
+    sc_hid_mouse_generate_input_from_scroll(&mouse->hid, &hid_input, event);
 
     if (!sc_aoa_push_input(mouse->aoa, &hid_input)) {
         LOGW("Could not push AOA HID input (mouse scroll)");
@@ -62,6 +62,8 @@ sc_mouse_aoa_init(struct sc_mouse_aoa *mouse, struct sc_aoa *aoa) {
         return false;
     }
 
+    sc_hid_mouse_init(&mouse->hid);
+
     static const struct sc_mouse_processor_ops ops = {
         .process_mouse_motion = sc_mouse_processor_process_mouse_motion,
         .process_mouse_click = sc_mouse_processor_process_mouse_click,

app/src/usb/mouse_aoa.h

@@ -5,12 +5,14 @@
 
 #include <stdbool.h>
 
+#include "hid/hid_mouse.h"
 #include "usb/aoa_hid.h"
 #include "trait/mouse_processor.h"
 
 struct sc_mouse_aoa {
     struct sc_mouse_processor mouse_processor; // mouse processor trait
 
+    struct sc_hid_mouse hid;
     struct sc_aoa *aoa;
 };