readtexture mip / gl metal noop support

src/renderer_gl.cpp

@@ -2383,7 +2383,6 @@ namespace bgfx { namespace gl
 		{
 			if (m_readBackSupported)
 			{
-				_mip;
 				const TextureGL& texture = m_textures[_handle.idx];
 				const bool compressed    = isCompressed(TextureFormat::Enum(texture.m_textureFormat) );
 
@@ -2392,14 +2391,14 @@ namespace bgfx { namespace gl
 				if (compressed)
 				{
 					GL_CHECK(glGetCompressedTexImage(texture.m_target
-						, 0
+						, _mip
 						, _data
 						) );
 				}
 				else
 				{
 					GL_CHECK(glGetTexImage(texture.m_target
-						, 0
+						, _mip
 						, texture.m_fmt
 						, texture.m_type
 						, _data

src/renderer_mtl.mm

@@ -796,7 +796,7 @@ namespace bgfx { namespace mtl
 		{
 		}
 
-		void readTexture(TextureHandle _handle, void* _data) BX_OVERRIDE
+		void readTexture(TextureHandle _handle, void* _data, uint8_t _mip) BX_OVERRIDE
 		{
 			m_commandBuffer.commit();
 			m_commandBuffer.waitUntilCompleted();
@@ -804,13 +804,15 @@ namespace bgfx { namespace mtl
 
 			const TextureMtl& texture = m_textures[_handle.idx];
 
-			uint32_t width  = texture.m_ptr.width();
-			uint32_t height = texture.m_ptr.height();
+			BX_CHECK(_mip<texture.m_numMips,"Invalid mip: %d num mips:",_mip,texture.m_numMips);
+
+			uint32_t width  = texture.m_ptr.width() >> _mip;
+			uint32_t height = texture.m_ptr.height() >> _mip;
 			const uint8_t bpp = getBitsPerPixel(TextureFormat::Enum(texture.m_textureFormat) );
 
 			MTLRegion region = { { 0, 0, 0 }, { width, height, 1 } };
 
-			texture.m_ptr.getBytes(_data, width*bpp/8, 0, region, 0, 0);
+			texture.m_ptr.getBytes(_data, width*bpp/8, 0, region, _mip, 0);
 
 			m_commandBuffer = m_commandQueue.commandBuffer();
 			retain(m_commandBuffer); //NOTE: keep alive to be useable at 'flip'

src/renderer_noop.cpp

@@ -136,7 +136,7 @@ namespace bgfx { namespace noop
 		{
 		}
 
-		void readTexture(TextureHandle /*_handle*/, void* /*_data*/) BX_OVERRIDE
+		void readTexture(TextureHandle /*_handle*/, void* /*_data*/, uint8_t /*_mip*/) BX_OVERRIDE
 		{
 		}