plumbing direct framebuffer access through the libretro way

common.h

@@ -91,12 +91,12 @@
 
 #define GBA_SCREEN_WIDTH  (240)
 #define GBA_SCREEN_HEIGHT (160)
-#define GBA_SCREEN_PITCH  (240)
+//#define GBA_SCREEN_PITCH  (240)
 
 // The buffer is 16 bit color depth.
 // We reserve extra memory at the end for extra effects (winobj rendering).
 #define GBA_SCREEN_BUFFER_SIZE  \
-  (GBA_SCREEN_PITCH * (GBA_SCREEN_HEIGHT + 1) * sizeof(uint16_t))
+  (gba_screen_pitch * (GBA_SCREEN_HEIGHT + 1) * sizeof(uint16_t))
 
 
 typedef u32 fixed16_16;

libretro/libretro.c

@@ -136,6 +136,24 @@ static void show_warning_message(const char* text, unsigned durationms) {
   }
 }
 
+static void set_screen_pixels() {
+   struct retro_framebuffer fbufr;
+   fbufr.width = GBA_SCREEN_WIDTH;
+   fbufr.height = GBA_SCREEN_HEIGHT;
+   fbufr.access_flags = RETRO_MEMORY_ACCESS_WRITE | RETRO_MEMORY_ACCESS_READ;
+   if (environ_cb(RETRO_ENVIRONMENT_GET_CURRENT_SOFTWARE_FRAMEBUFFER, &fbufr)) {
+      gba_screen_pixels = fbufr.data;
+      gba_screen_pitch = fbufr.pitch / sizeof(uint16_t);
+   } else if (!gba_screen_pixels) {
+      gba_screen_pitch = GBA_SCREEN_WIDTH;
+#ifdef _3DS
+      gba_screen_pixels = (uint16_t*)linearMemAlign(GBA_SCREEN_BUFFER_SIZE, 128);
+#else
+      gba_screen_pixels = (uint16_t*)malloc(GBA_SCREEN_BUFFER_SIZE);
+#endif
+   }
+}
+
 /* Frameskip START */
 
 static void audio_buff_status_cb(
@@ -214,7 +232,7 @@ static void video_post_process_cc(void)
 
    for (y = 0; y < GBA_SCREEN_HEIGHT; y++)
    {
-      for (x = 0; x < GBA_SCREEN_PITCH; x++)
+      for (x = 0; x < gba_screen_pitch; x++)
       {
          u16 src_color = *(src + x);
 
@@ -222,8 +240,8 @@ static void video_post_process_cc(void)
          *(dst + x) = *(gba_cc_lut + (((src_color & 0xFFC0) >> 1) | (src_color & 0x1F)));
       }
 
-      src += GBA_SCREEN_PITCH;
+      src += gba_screen_pitch;
-      dst += GBA_SCREEN_PITCH;
+      dst += gba_screen_pitch;
    }
 }
 
@@ -236,7 +254,7 @@ static void video_post_process_mix(void)
 
    for (y = 0; y < GBA_SCREEN_HEIGHT; y++)
    {
-      for (x = 0; x < GBA_SCREEN_PITCH; x++)
+      for (x = 0; x < gba_screen_pitch; x++)
       {
          /* Get colours from current + previous frames (RGB565) */
          uint16_t rgb_curr = *(src_curr + x);
@@ -251,9 +269,9 @@ static void video_post_process_mix(void)
          *(dst + x)        = (rgb_curr + rgb_prev + ((rgb_curr ^ rgb_prev) & 0x821)) >> 1;
       }
 
-      src_curr += GBA_SCREEN_PITCH;
+      src_curr += gba_screen_pitch;
-      src_prev += GBA_SCREEN_PITCH;
+      src_prev += gba_screen_pitch;
-      dst      += GBA_SCREEN_PITCH;
+      dst      += gba_screen_pitch;
    }
 }
 
@@ -266,7 +284,7 @@ static void video_post_process_cc_mix(void)
 
    for (y = 0; y < GBA_SCREEN_HEIGHT; y++)
    {
-      for (x = 0; x < GBA_SCREEN_PITCH; x++)
+      for (x = 0; x < gba_screen_pitch; x++)
       {
          /* Get colours from current + previous frames (RGB565) */
          uint16_t rgb_curr = *(src_curr + x);
@@ -284,9 +302,9 @@ static void video_post_process_cc_mix(void)
          *(dst + x) = *(gba_cc_lut + (((rgb_mix & 0xFFC0) >> 1) | (rgb_mix & 0x1F)));
       }
 
-      src_curr += GBA_SCREEN_PITCH;
+      src_curr += gba_screen_pitch;
-      src_prev += GBA_SCREEN_PITCH;
+      src_prev += gba_screen_pitch;
-      dst      += GBA_SCREEN_PITCH;
+      dst      += gba_screen_pitch;
    }
 }
 
@@ -409,7 +427,7 @@ static void video_run(void)
    if (skip_next_frame)
    {
       video_cb(NULL, GBA_SCREEN_WIDTH, GBA_SCREEN_HEIGHT,
-            GBA_SCREEN_PITCH * 2);
+            gba_screen_pitch * 2);
       return;
    }
 
@@ -420,7 +438,8 @@ static void video_run(void)
    }
 
    video_cb(gba_screen_pixels_buf, GBA_SCREEN_WIDTH, GBA_SCREEN_HEIGHT,
-            GBA_SCREEN_PITCH * 2);
+            gba_screen_pitch * 2);
+   set_screen_pixels();
 }
 
 #ifdef PERF_TEST
@@ -532,12 +551,7 @@ void retro_init(void)
    init_gamepak_buffer();
    init_sound();
 
-   if(!gba_screen_pixels)
+   set_screen_pixels();
-#ifdef _3DS
-      gba_screen_pixels = (uint16_t*)linearMemAlign(GBA_SCREEN_BUFFER_SIZE, 128);
-#else
-      gba_screen_pixels = (uint16_t*)malloc(GBA_SCREEN_BUFFER_SIZE);
-#endif
 
    libretro_supports_bitmasks = false;
    if (environ_cb(RETRO_ENVIRONMENT_GET_INPUT_BITMASKS, NULL))

video.cc

@@ -23,9 +23,10 @@ extern "C" {
 }
 
 u16* gba_screen_pixels = NULL;
+u32 gba_screen_pitch = GBA_SCREEN_WIDTH;
 
 #define get_screen_pixels()   gba_screen_pixels
-#define get_screen_pitch()    GBA_SCREEN_PITCH
+#define get_screen_pitch()    gba_screen_pitch
 
 typedef struct {
   u16 attr0, attr1, attr2, attr3;
@@ -1471,7 +1472,7 @@ void render_scanline_objs(
       u32 obj_enable = read_ioreg(REG_WINOUT) >> 8;
 
       // Render at the next scanline!
-      u16 *tmp_ptr = (u16*)&scanline[GBA_SCREEN_PITCH];
+      u16 *tmp_ptr = (u16*)&scanline[get_screen_pitch()];
       render_scanline_conditional(sec_start, sec_end, tmp_ptr, obj_enable);
     }
 

video.h

@@ -27,5 +27,6 @@ extern s32 affine_reference_x[2];
 extern s32 affine_reference_y[2];
 
 extern u16* gba_screen_pixels;
+extern u32 gba_screen_pitch;
 
 #endif