usb: add video capture through the fxlink protocol

CMakeLists.txt

@@ -59,6 +59,7 @@ set(SOURCES_COMMON
   src/render/dprint.c
   src/render/drect_border.c
   src/render/dtext.c
+  src/render/dupdate_hook.c
   src/render/dvline.c
   src/render/topti.c
   src/rtc/rtc.c

include/gint/display.h

@@ -14,6 +14,7 @@ extern "C" {
 #endif
 
 #include <gint/defs/types.h>
+#include <gint/defs/call.h>
 
 /* Platform-specific functions include VRAM management and the definition of
    the color_t type. */
@@ -62,6 +63,25 @@ extern "C" {
    fx-CG 50: 11 ms */
 void dupdate(void);
 
+/* dupdate_set_hook(): Define a function to be called after each dupdate()
+
+   This functions configures the update hook, which is called after each
+   dupdate() has sent VRAM to the display (but before VRAMs are switched when
+   triple-buffering is used on fx-CG 50).
+
+   The hook is mostly useful to send a copy of the frame to another medium,
+   typically through a USB connection to a projector-style application. See
+   usb_fxlink_videocapture() in <gint/usb-ff-bulk.h> for an example.
+
+   The function is an indirect call; create one with the GINT_CALL() macro from
+   <gint/defs/call.h>. Pass GINT_CALL_NULL to disable the feature.
+
+   @function  Indirect call to perform after each dupdate(). */
+void dupdate_set_hook(gint_call_t function);
+
+/* dupdate_get_hook(): Get a copy of the dupdate() hook */
+gint_call_t dupdate_get_hook(void);
+
 //---
 //	Area rendering functions
 //---

include/gint/usb-ff-bulk.h

@@ -97,8 +97,8 @@ typedef struct
 
    Returns false if the parameters are invalid or don't fit, in this case the
    contents of the header are unchanged. */
-bool usb_fxlink_fill_header(usb_fxlink_header_t *header, char *application,
-   char *type, uint32_t data_size);
+bool usb_fxlink_fill_header(usb_fxlink_header_t *header,
+	char const *application, char const *type, uint32_t data_size);
 
 //---
 // Short functions for fxlink built-in types
@@ -168,6 +168,23 @@ void usb_fxlink_screenshot_gray(bool onscreen);
    and size allow, and 1 byte otherwise. If size is 0, strlen(text) is used. */
 void usb_fxlink_text(char const *text, int size);
 
+/* usb_fxlink_videocapture(): Send a frame for a video recording
+
+   This function is essentially the same as usb_fxlink_screenshot(). It sends a
+   capture of the VRAM to fxlink but uses the "video" type, which fxlink
+   displays in real-time or saves as a video file. The meaning of the onscreen
+   setting is identical to usb_fxlink_screenshot().
+
+   This function can be called with onscreen=false as a dupdate() hook to
+   automatically send new frames to fxlink. */
+void usb_fxlink_videocapture(bool onscreen);
+
+#ifdef FX9860G
+/* usb_fxlink_videocapture_gray(): Send a gray frame for a video recording
+   Like usb_fxlink_videocapture(), but uses VRAM data from the gray engine. */
+void usb_fxlink_videocapture_gray(bool onscreen);
+#endif
+
 #ifdef __cplusplus
 }
 #endif

src/render-cg/dupdate.c

@@ -7,6 +7,9 @@ void dupdate(void)
 {
 	r61524_display(gint_vram, 0, 224, R61524_DMA);
 
+	gint_call_t hook = dupdate_get_hook();
+	if(hook.function) gint_call(hook);
+
 	/* The DMA is still running, so we need to switch VRAMs to avoid
 	   overwriting the data which is about to be sent. */
 	dvram_switch();

src/render-fx/dupdate.c

@@ -11,16 +11,23 @@ uint32_t *gint_vram = fx_vram;
 /* The current rendering mode */
 struct rendering_mode const *dmode = NULL;
 
-/* dupdate() - push the video RAM to the display driver */
+/* dupdate(): Push the video RAM to the display driver */
 void dupdate(void)
 {
+	bool run_default = true;
+
 	if(dmode && dmode->dupdate)
 	{
-		/* Call the overridden dupdate(), but continue if itreturns
+		/* Call the overridden dupdate(), but continue if it returns
 		   non-zero (this is used when stopping the gray engine) */
 		int rc = dmode->dupdate();
-		if(rc == 0) return;
+		run_default = (rc != 0);
+	}
+	if(run_default)
+	{
+		t6k11_display(gint_vram, 0, 64, 16);
 	}
 
-	t6k11_display(gint_vram, 0, 64, 16);
+	gint_call_t hook = dupdate_get_hook();
+	if(hook.function) gint_call(hook);
 }

src/render/dupdate_hook.c

@@ -0,0 +1,16 @@
+#include <gint/display.h>
+
+/* Hook to be called after each dupdate(). */
+static gint_call_t hook = GINT_CALL_NULL;
+
+/* dupdate_set_hook(): Define a function to be called after each dupdate() */
+void dupdate_set_hook(gint_call_t function)
+{
+	hook = function;
+}
+
+/* dupdate_get_hook(): Get a copy of the dupdate() hook */
+gint_call_t dupdate_get_hook(void)
+{
+	return hook;
+}

src/usb/classes/ff-bulk-gray.c

@@ -5,7 +5,7 @@
 #include <gint/display.h>
 #include <gint/gray.h>
 
-void usb_fxlink_screenshot_gray(GUNUSED bool onscreen)
+static void capture_vram_gray(GUNUSED bool onscreen, char const *type)
 {
 	uint32_t *light, *dark;
 	if(onscreen) dgray_getscreen(&light, &dark);
@@ -14,7 +14,7 @@ void usb_fxlink_screenshot_gray(GUNUSED bool onscreen)
 	usb_fxlink_header_t header;
 	usb_fxlink_image_t subheader;
 
-	usb_fxlink_fill_header(&header, "fxlink", "image",
+	usb_fxlink_fill_header(&header, "fxlink", type,
 		2048 + sizeof subheader);
 
 	subheader.width = htole32(DWIDTH);
@@ -29,4 +29,14 @@ void usb_fxlink_screenshot_gray(GUNUSED bool onscreen)
 	usb_commit_sync(pipe);
 }
 
+void usb_fxlink_screenshot_gray(bool onscreen)
+{
+	capture_vram_gray(onscreen, "image");
+}
+
+void usb_fxlink_videocapture_gray(bool onscreen)
+{
+	capture_vram_gray(onscreen, "video");
+}
+
 #endif /* FX9860G */

src/usb/classes/ff-bulk.c

@@ -60,8 +60,8 @@ int usb_ff_bulk_output(void)
 // fxlink protocol
 //---
 
-bool usb_fxlink_fill_header(usb_fxlink_header_t *header, char *application,
-   char *type, uint32_t data_size)
+bool usb_fxlink_fill_header(usb_fxlink_header_t *header,
+	char const *application, char const *type, uint32_t data_size)
 {
 	if(strlen(application) > 16 || strlen(type) > 16) return false;
 
@@ -77,7 +77,7 @@ bool usb_fxlink_fill_header(usb_fxlink_header_t *header, char *application,
 	return true;
 }
 
-void usb_fxlink_screenshot(GUNUSED bool onscreen)
+static void capture_vram(GUNUSED bool onscreen, char const *type)
 {
 	void *source = gint_vram;
 	int size, format;
@@ -100,7 +100,7 @@ void usb_fxlink_screenshot(GUNUSED bool onscreen)
 	usb_fxlink_header_t header;
 	usb_fxlink_image_t subheader;
 
-	usb_fxlink_fill_header(&header, "fxlink", "image",
+	usb_fxlink_fill_header(&header, "fxlink", type,
 		size + sizeof subheader);
 
 	subheader.width = htole32(DWIDTH);
@@ -114,6 +114,11 @@ void usb_fxlink_screenshot(GUNUSED bool onscreen)
 	usb_commit_sync(pipe);
 }
 
+void usb_fxlink_screenshot(bool onscreen)
+{
+	capture_vram(onscreen, "image");
+}
+
 void usb_fxlink_text(char const *text, int size)
 {
 	if(size == 0) size = strlen(text);
@@ -130,3 +135,8 @@ void usb_fxlink_text(char const *text, int size)
 	usb_write_sync(pipe, text, size, unit_size, false);
 	usb_commit_sync(pipe);
 }
+
+void usb_fxlink_videocapture(bool onscreen)
+{
+	capture_vram(onscreen, "video");
+}