pixelformat: added convenience functions for determining the format equivalent with and without an alpha channel

app/render/pixelformat.cpp

@@ -164,6 +164,52 @@ PixelFormat::Format PixelFormat::OIIOFormatToOliveFormat(OIIO::TypeDesc desc, bo
   return PixelFormat::PIX_FMT_INVALID;
 }
 
+PixelFormat::Format PixelFormat::GetFormatWithAlphaChannel(PixelFormat::Format f)
+{
+  switch (f) {
+  case PIX_FMT_INVALID:
+  case PIX_FMT_COUNT:
+    break;
+  case PIX_FMT_RGB8:
+  case PIX_FMT_RGBA8:
+    return PIX_FMT_RGBA8;
+  case PIX_FMT_RGB16U:
+  case PIX_FMT_RGBA16U:
+    return PIX_FMT_RGBA16U;
+  case PIX_FMT_RGB16F:
+  case PIX_FMT_RGBA16F:
+    return PIX_FMT_RGBA16F;
+  case PIX_FMT_RGB32F:
+  case PIX_FMT_RGBA32F:
+    return PIX_FMT_RGBA32F;
+  }
+
+  return PIX_FMT_INVALID;
+}
+
+PixelFormat::Format PixelFormat::GetFormatWithoutAlphaChannel(PixelFormat::Format f)
+{
+  switch (f) {
+  case PIX_FMT_INVALID:
+  case PIX_FMT_COUNT:
+    break;
+  case PIX_FMT_RGB8:
+  case PIX_FMT_RGBA8:
+    return PIX_FMT_RGB8;
+  case PIX_FMT_RGB16U:
+  case PIX_FMT_RGBA16U:
+    return PIX_FMT_RGB16U;
+  case PIX_FMT_RGB16F:
+  case PIX_FMT_RGBA16F:
+    return PIX_FMT_RGB16F;
+  case PIX_FMT_RGB32F:
+  case PIX_FMT_RGBA32F:
+    return PIX_FMT_RGB32F;
+  }
+
+  return PIX_FMT_INVALID;
+}
+
 int PixelFormat::GetBufferSize(const PixelFormat::Format &format, const int &width, const int &height)
 {
   return BytesPerPixel(format) * width * height;

app/render/pixelformat.h

@@ -68,6 +68,9 @@ public:
 
   static Format OIIOFormatToOliveFormat(OIIO::TypeDesc desc, bool has_alpha);
 
+  static Format GetFormatWithAlphaChannel(Format f);
+  static Format GetFormatWithoutAlphaChannel(Format f);
+
   /**
    * @brief Returns the minimum buffer size (in bytes) necessary for a given format, width, and height.
    *