Update for N-Gage - Audio is now double buffered (#15516)

[N-Gage] Audio is now double buffered to avoid stuttering and glitches. Some audio platform specific variables were exposed through SDL_Hints. Same method was used to display FPS. N-gage functions to obtain the current buffer and screen pitch were added to the render.

Adds hints:

SDL_AUDIO_NGAGE_LATENCY
SDL_AUDIO_NGAGE_SCHEDULER_TICK
SDL_AUDIO_NGAGE_PROCESS_TICK
SDL_AUDIO_NGAGE_PROCESS_PRIORITY
SDL_RENDER_SHOW_FPS

Adds functions to get current buffer address and pitch:

void *NGAGE_GetBackbufferAddress(void);
int NGAGE_GetBackbufferPitch(void);

---------
Co-authored-by: Michael Fitzmayer <mail@michael-fitzmayer.de>
Co-authored-by: Eddy Jansson <eloj@users.noreply.github.com>

src/render/ngage/SDL_render_ngage.cpp

@@ -149,6 +149,23 @@ void NGAGE_SetRenderTargetInternal(NGAGE_TextureData *target)
     }
 }
 
+static void SDLCALL NGAGE_ShowFPSChanged(void *userdata, const char *name, const char *oldValue, const char *newValue)
+{
+    CRenderer *renderer = (CRenderer *)userdata;
+    renderer->SetShowFPS(SDL_GetStringBoolean(newValue, false));
+}
+
+
+void *NGAGE_GetBackbufferAddress(void)
+{
+    return gRenderer->GetCurrentBitmap()->DataAddress();
+}
+
+int NGAGE_GetBackbufferPitch(void)
+{
+    return CFbsBitmap::ScanLineLength(NGAGE_SCREEN_WIDTH, EColor4K) / 2;
+}
+
 #ifdef __cplusplus
 }
 #endif
@@ -166,6 +183,8 @@ CRenderer::CRenderer() : iRenderer(0), iDirectScreen(0), iScreenGc(0), iWsSessio
 
 CRenderer::~CRenderer()
 {
+    SDL_RemoveHintCallback(SDL_HINT_RENDER_NGAGE_SHOW_FPS, NGAGE_ShowFPSChanged, this);
+
     delete iRenderer;
     iRenderer = 0;
 
@@ -266,6 +285,8 @@ void CRenderer::ConstructL()
         }
         iDirectScreen->ScreenDevice()->SetAutoUpdate(ETrue);
     }
+
+    SDL_AddHintCallback(SDL_HINT_RENDER_NGAGE_SHOW_FPS, NGAGE_ShowFPSChanged, this);
 }
 
 void CRenderer::Restart(RDirectScreenAccess::TTerminationReasons aReason)
@@ -336,6 +357,8 @@ bool CRenderer::Copy(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_Rec
         return false;
     }
 
+   
+
     NGAGE_TextureData *phdata = (NGAGE_TextureData *)texture->internal;
     if (!phdata || !phdata->bitmap) {
         return false;
@@ -346,7 +369,7 @@ bool CRenderer::Copy(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_Rec
 
     int sw = srcrect->w;
     int sh = srcrect->h;
-
+   
     // Fast path: render target texture with no color mod.
     // BitBlt directly from its bitmap — DataAddress() is unreliable
     // for bitmaps that have been drawn into via a CFbsBitGc.
@@ -359,7 +382,8 @@ bool CRenderer::Copy(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_Rec
     SDL_GetTextureBlendMode(texture, &blend);
     bool no_color_key = (blend != SDL_BLENDMODE_BLEND);
 
-    if (phdata->gc && no_color_mod && no_scale && no_color_key) {
+    if (phdata->gc && no_color_mod && no_scale && no_color_key)
+    {
         CFbsBitGc *gc = GetCurrentGc();
         if (gc) {
             TRect aSource(TPoint(srcrect->x, srcrect->y), TSize(sw, sh));
@@ -369,6 +393,7 @@ bool CRenderer::Copy(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_Rec
         return true;
     }
 
+
     // Fast path: color-key with no color mod and no scale.
     // Blit directly from the source bitmap into the destination, skipping transparent pixels.
     if (no_color_mod && no_scale && !no_color_key && phdata->has_color_key) {
@@ -414,6 +439,7 @@ bool CRenderer::Copy(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_Rec
             return false;
         }
     }
+
     TSize scratch_size = iScratchBitmap->SizeInPixels();
     if (scratch_size.iWidth < sw || scratch_size.iHeight < sh) {
         iScratchBitmap->Reset();
@@ -438,6 +464,7 @@ bool CRenderer::Copy(SDL_Renderer *renderer, SDL_Texture *texture, const SDL_Rec
     void *source = iPixelBufferA;
     void *dest = iPixelBufferB;
 
+
     if (!no_color_mod) {
         ApplyColorMod(dest, source, src_pitch, sw, sh, texture->color);
         void *tmp = source;
@@ -934,13 +961,15 @@ void CRenderer::HandleEvent(const TWsEvent &aWsEvent)
         timestamp = SDL_GetPerformanceCounter();
         SDL_SendKeyboardKey(timestamp, 1, aWsEvent.Key()->iCode, ConvertScancode(aWsEvent.Key()->iScanCode), true);
 
+        /*
+        commented out so it works with hints
         if (aWsEvent.Key()->iScanCode == EStdKeyHash) {
             if (iShowFPS) {
                 iShowFPS = EFalse;
             } else {
                 iShowFPS = ETrue;
             }
-        }
+        }*/
 
         break;
     case EEventKeyUp: /* Key events */

src/render/ngage/SDL_render_ngage_c.h

@@ -25,6 +25,10 @@
 #define NGAGE_SCREEN_WIDTH  176
 #define NGAGE_SCREEN_HEIGHT 208
 
+#ifndef SDL_HINT_RENDER_NGAGE_SHOW_FPS
+#define SDL_HINT_RENDER_NGAGE_SHOW_FPS "SDL_RENDER_NGAGE_SHOW_FPS"
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -108,6 +112,8 @@ void NGAGE_SetDrawColor(const Uint32 color);
 void NGAGE_PumpEventsInternal(void);
 void NGAGE_SuspendScreenSaverInternal(bool suspend);
 void NGAGE_SetRenderTargetInternal(NGAGE_TextureData *target);
+void *NGAGE_GetBackbufferAddress(void);
+int NGAGE_GetBackbufferPitch(void);
 
 #ifdef __cplusplus
 }

src/render/ngage/SDL_render_ngage_c.hpp

@@ -46,6 +46,7 @@ class CRenderer : public MDirectScreenAccess
     void SetClipRect(TInt aX, TInt aY, TInt aWidth, TInt aHeight);
     void UpdateFPS();
     void SuspendScreenSaver(TBool aSuspend);
+    void SetShowFPS(TBool aShow) { iShowFPS = aShow; }
 
     // Render target management.
     void SetRenderTarget(NGAGE_TextureData *aTarget);