[client/obs] improve frambuffer_read functions to support copy pitch

Fixes #244

common/include/common/framebuffer.h

@@ -40,12 +40,14 @@ void framebuffer_wait(const FrameBuffer * frame, size_t size);
 /**
  * Read data from the KVMFRFrame into the dst buffer
  */
-bool framebuffer_read(const FrameBuffer * frame, void * dst, size_t size);
+bool framebuffer_read(const FrameBuffer * frame, void * dst, size_t dstpitch,
+    size_t height, size_t width, size_t bpp, size_t pitch);
 
 /**
  * Read data from the KVMFRFrame using a callback
  */
-bool framebuffer_read_fn(const FrameBuffer * frame, FrameBufferReadFn fn, size_t size, void * opaque);
+bool framebuffer_read_fn(const FrameBuffer * frame, size_t height, size_t width,
+    size_t bpp, size_t pitch, FrameBufferReadFn fn, void * opaque);
 
 /**
  * Prepare the framebuffer for writing

common/src/framebuffer.c

@@ -38,53 +38,55 @@ void framebuffer_wait(const FrameBuffer * frame, size_t size)
   while(atomic_load_explicit(&frame->wp, memory_order_relaxed) != size) {}
 }
 
-bool framebuffer_read(const FrameBuffer * frame, void * dst, size_t size)
+
+bool framebuffer_read(const FrameBuffer * frame, void * dst, size_t dstpitch,
+    size_t height, size_t width, size_t bpp, size_t pitch)
 {
-  uint8_t *d  = (uint8_t*)dst;
-  uint64_t rp = 0;
-  while(rp < size)
+  uint8_t       *d         = (uint8_t*)dst;
+  uint_least32_t rp        = 0;
+  size_t         y         = 0;
+  const size_t   linewidth = width * bpp;
+
+  while(y < height)
   {
     uint_least32_t wp;
 
     /* spinlock */
     do
       wp = atomic_load_explicit(&frame->wp, memory_order_relaxed);
-    while(rp == wp);
+    while(wp - rp < pitch);
 
-    /* copy what we can */
-    uint64_t avail = wp - rp;
-    avail = avail > size ? size : avail;
+    memcpy(d, frame->data + rp, linewidth);
 
-    memcpy(d, frame->data + rp, avail);
-
-    rp   += avail;
-    d    += avail;
-    size -= avail;
+    rp += pitch;
+    d  += dstpitch;
+    ++y;
   }
+
   return true;
 }
 
-bool framebuffer_read_fn(const FrameBuffer * frame, FrameBufferReadFn fn, size_t size, void * opaque)
+bool framebuffer_read_fn(const FrameBuffer * frame, size_t height, size_t width,
+    size_t bpp, size_t pitch, FrameBufferReadFn fn, void * opaque)
 {
-  uint64_t rp = 0;
-  while(rp < size)
+  uint_least32_t rp        = 0;
+  size_t         y         = 0;
+  const size_t   linewidth = width * bpp;
+
+  while(y < height)
   {
     uint_least32_t wp;
 
     /* spinlock */
     do
       wp = atomic_load_explicit(&frame->wp, memory_order_relaxed);
-    while(rp == wp);
+    while(wp - rp < pitch);
 
-    /* copy what we can */
-    uint64_t avail = wp - rp;
-    avail = avail > size ? size : avail;
-
-    if (!fn(opaque, frame->data + rp, avail))
+    if (!fn(opaque, frame->data + rp, linewidth))
       return false;
 
-    rp   += avail;
-    size -= avail;
+    rp += pitch;
+    ++y;
   }
 
   return true;