Added usb video example

examples/usb-video/arm9/source/main.cpp

@@ -0,0 +1,86 @@
+#include "common.h"
+#include <nds.h>
+#include <stdio.h>
+#include <libtwl/gfx/gfx.h>
+#include <libtwl/dma/dmaTwl.h>
+#include <libtwl/gfx/gfxStatus.h>
+#include <libtwl/mem/memVram.h>
+#include <libtwl/mem/memExtern.h>
+#include <libtwl/rtos/rtosIrq.h>
+#include <libtwl/rtos/rtosThread.h>
+#include <libtwl/rtos/rtosEvent.h>
+#include <libtwl/ipc/ipcSync.h>
+#include <libtwl/ipc/ipcFifoSystem.h>
+#include "Camera.h"
+#include "IpcChannels.h"
+
+#define FRAME_SIZE                  (256 * 192 * 2)
+#define NUMBER_OF_FRAME_BUFFERS     3
+
+static rtos_event_t sVblankEvent;
+static rtos_event_t sCaptureEvent;
+
+static u32 sCurrentFrame = 0;
+static vu32 sRequestedFrame = 0;
+
+static void vblankIrq(u32 irqMask)
+{
+    rtos_signalEvent(&sVblankEvent);
+}
+
+static void captureIpcMessageHandler(u32 channel, u32 data, void* arg)
+{
+    sRequestedFrame++;
+    rtos_signalEvent(&sCaptureEvent);
+}
+
+int main(int argc, char* argv[])
+{
+    *(vu32*)0x04000000 = 0x10000;
+    *(vu16*)0x05000000 = 31 << 5;
+    *(vu16*)0x0400006C = 0;
+
+    mem_setDsCartridgeCpu(EXMEMCNT_SLOT1_CPU_ARM7);
+    mem_setMainMemoryPriority(EXMEMCNT_MAIN_MEM_PRIO_ARM7);
+
+    rtos_initIrq();
+    rtos_startMainThread();
+    ipc_initFifoSystem();
+
+    rtos_createEvent(&sVblankEvent);
+
+    while (ipc_getArm7SyncBits() != 7);
+
+    *(vu16*)0x05000000 = 31 << 10;
+    cam_init(false);
+    *(vu16*)0x05000000 = 31;
+
+    rtos_createEvent(&sCaptureEvent);
+    ipc_setChannelHandler(IPC_CHANNEL_CAPTURE, captureIpcMessageHandler, nullptr);
+
+    ipc_setArm9SyncBits(6);
+
+    rtos_setIrqFunc(RTOS_IRQ_VBLANK, vblankIrq);
+    rtos_enableIrqMask(RTOS_IRQ_VBLANK);
+    gfx_setVBlankIrqEnabled(true);
+
+	mem_setVramAMapping(MEM_VRAM_AB_LCDC);
+    REG_DISPCNT = 0x20000;
+
+    u8* frameBuffer = new(std::align_val_t(32)) u8[FRAME_SIZE * NUMBER_OF_FRAME_BUFFERS];
+    ipc_sendFifoMessage(IPC_CHANNEL_CAPTURE, (u32)frameBuffer >> 5);
+
+    while (true)
+    {
+        rtos_waitEvent(&sCaptureEvent, false, true);
+        while (sCurrentFrame != sRequestedFrame)
+        {
+            cam_dmaStart(1, frameBuffer + FRAME_SIZE * (sCurrentFrame % 3));
+            dma_twlWait(1);
+            sCurrentFrame++;
+            ipc_sendFifoMessage(IPC_CHANNEL_CAPTURE, 0);
+        }
+    }
+
+    return 0;
+}