Added support for automatic texture scaling by backbuffer ratio on backbuffer resize.

examples/09-hdr/hdr.cpp

@@ -216,10 +216,10 @@ int _main_(int /*_argc*/, char** /*_argv*/)
 	lum[4] = bgfx::createFrameBuffer(  1,   1, bgfx::TextureFormat::BGRA8);
 
 	bgfx::FrameBufferHandle bright;
-	bright = bgfx::createFrameBuffer(width/2, height/2, bgfx::TextureFormat::BGRA8);
+	bright = bgfx::createFrameBuffer(bgfx::BackbufferRatio::Half, bgfx::TextureFormat::BGRA8);
 
 	bgfx::FrameBufferHandle blur;
-	blur = bgfx::createFrameBuffer(width/8, height/8, bgfx::TextureFormat::BGRA8);
+	blur = bgfx::createFrameBuffer(bgfx::BackbufferRatio::Eighth, bgfx::TextureFormat::BGRA8);
 
 	// Imgui.
 	imguiCreate();
@@ -256,15 +256,10 @@ int _main_(int /*_argc*/, char** /*_argv*/)
 			uint32_t msaa = (reset&BGFX_RESET_MSAA_MASK)>>BGFX_RESET_MSAA_SHIFT;
 
 			bgfx::destroyFrameBuffer(fbh);
-			bgfx::destroyFrameBuffer(bright);
-			bgfx::destroyFrameBuffer(blur);
 
 			fbtextures[0] = bgfx::createTexture2D(width, height, 1, bgfx::TextureFormat::BGRA8, ( (msaa+1)<<BGFX_TEXTURE_RT_MSAA_SHIFT)|BGFX_TEXTURE_U_CLAMP|BGFX_TEXTURE_V_CLAMP);
 			fbtextures[1] = bgfx::createTexture2D(width, height, 1, bgfx::TextureFormat::D16, BGFX_TEXTURE_RT_BUFFER_ONLY|( (msaa+1)<<BGFX_TEXTURE_RT_MSAA_SHIFT) );
 			fbh = bgfx::createFrameBuffer(BX_COUNTOF(fbtextures), fbtextures, true);
-
-			bright = bgfx::createFrameBuffer(width/2, height/2, bgfx::TextureFormat::BGRA8);
-			blur   = bgfx::createFrameBuffer(width/8, height/8, bgfx::TextureFormat::BGRA8);
 		}
 
 		imguiBeginFrame(mouseState.m_mx

include/bgfx.h

@@ -189,6 +189,20 @@ namespace bgfx
 		};
 	};
 
+	struct BackbufferRatio
+	{
+		enum Enum
+		{
+			None,
+			Equal,
+			Half,
+			Quarter,
+			Eighth,
+			Sixteenth,
+			Double,
+		};
+	};
+
 	static const uint16_t invalidHandle = UINT16_MAX;
 
 	BGFX_HANDLE(DynamicIndexBufferHandle);
@@ -318,10 +332,9 @@ namespace bgfx
 		uint16_t maxTextureSize;   ///< Maximum texture size.
 		uint16_t maxViews;         ///< Maximum views.
 		uint8_t  maxFBAttachments; ///< Maximum frame buffer attachments.
-		uint8_t  numGPUs; ///<
+		uint8_t  numGPUs;          ///< Number of enumerated GPUs.
-
+		uint16_t vendorId;         ///< Selected GPU vendor id.
-		uint16_t vendorId; ///<
+		uint16_t deviceId;         ///< Selected GPU device id.
-		uint16_t deviceId; ///<
 
 		struct GPU
 		{
@@ -329,7 +342,7 @@ namespace bgfx
 			uint16_t deviceId;
 		};
 
-		GPU gpu[4];      ///<
+		GPU gpu[4]; ///< Enumerated GPUs.
 
 		/// Supported texture formats.
 		///   - `BGFX_CAPS_FORMAT_TEXTURE_NONE` - not supported
@@ -549,10 +562,10 @@ namespace bgfx
 	///
 	void shutdown();
 
-	/// Reset graphic settings.
+	/// Reset graphic settings and back-buffer size.
 	///
-	/// @param _width Main window width.
+	/// @param _width Back-buffer width.
-	/// @param _height Main window height.
+	/// @param _height Back-buffer height.
 	/// @param _flags
 	///   - `BGFX_RESET_NONE` - No reset flags.
 	///   - `BGFX_RESET_FULLSCREEN` - Not supported yet.
@@ -560,6 +573,9 @@ namespace bgfx
 	///   - `BGFX_RESET_VSYNC` - Enable V-Sync.
 	///   - `BGFX_RESET_CAPTURE` - Begin screen capture.
 	///
+	/// @attention This call doesn't actually change window size, it just
+	///   resizes back-buffer. Windowing code has to change window size.
+	///
 	/// @attention C99 equivalent is `bgfx_reset`.
 	///
 	void reset(uint32_t _width, uint32_t _height, uint32_t _flags = BGFX_RESET_NONE);
@@ -917,6 +933,9 @@ namespace bgfx
 	///
 	TextureHandle createTexture2D(uint16_t _width, uint16_t _height, uint8_t _numMips, TextureFormat::Enum _format, uint32_t _flags = BGFX_TEXTURE_NONE, const Memory* _mem = NULL);
 
+	///
+	TextureHandle createTexture2D(BackbufferRatio::Enum _ratio, uint8_t _numMips, TextureFormat::Enum _format, uint32_t _flags = BGFX_TEXTURE_NONE);
+
 	/// Create 3D texture.
 	///
 	/// @param _width
@@ -1013,6 +1032,9 @@ namespace bgfx
 	///
 	FrameBufferHandle createFrameBuffer(uint16_t _width, uint16_t _height, TextureFormat::Enum _format, uint32_t _textureFlags = BGFX_TEXTURE_U_CLAMP|BGFX_TEXTURE_V_CLAMP);
 
+	///
+	FrameBufferHandle createFrameBuffer(BackbufferRatio::Enum _ratio, TextureFormat::Enum _format, uint32_t _textureFlags = BGFX_TEXTURE_U_CLAMP|BGFX_TEXTURE_V_CLAMP);
+
 	/// Create frame buffer.
 	///
 	/// @param _num Number of texture attachments.

src/bgfx.cpp

@@ -1830,6 +1830,21 @@ again:
 				}
 				break;
 
+			case CommandBuffer::ResizeTexture:
+				{
+					TextureHandle handle;
+					_cmdbuf.read(handle);
+
+					uint16_t width;
+					_cmdbuf.read(width);
+
+					uint16_t height;
+					_cmdbuf.read(height);
+
+					m_renderCtx->resizeTexture(handle, width, height);
+				}
+				break;
+
 			case CommandBuffer::DestroyTexture:
 				{
 					TextureHandle handle;
@@ -2412,10 +2427,28 @@ again:
 	{
 		BGFX_CHECK_MAIN_THREAD();
 		BX_CHECK(NULL != _mem, "_mem can't be NULL");
-		return s_ctx->createTexture(_mem, _flags, _skip, _info);
+		return s_ctx->createTexture(_mem, _flags, _skip, _info, BackbufferRatio::None);
 	}
 
-	TextureHandle createTexture2D(uint16_t _width, uint16_t _height, uint8_t _numMips, TextureFormat::Enum _format, uint32_t _flags, const Memory* _mem)
+	void getTextureSizeFromRatio(BackbufferRatio::Enum _ratio, uint16_t& _width, uint16_t& _height)
+	{
+		switch (_ratio)
+		{
+		case BackbufferRatio::Half:      _width /=  2; _height /=  2; break;
+		case BackbufferRatio::Quarter:   _width /=  4; _height /=  4; break;
+		case BackbufferRatio::Eighth:    _width /=  8; _height /=  8; break;
+		case BackbufferRatio::Sixteenth: _width /= 16; _height /= 16; break;
+		case BackbufferRatio::Double:    _width *=  2; _height *=  2; break;
+
+		default:
+			break;
+		}
+
+		_width  = bx::uint16_max(1, _width);
+		_height = bx::uint16_max(1, _height);
+	}
+
+	TextureHandle createTexture2D(BackbufferRatio::Enum _ratio, uint16_t _width, uint16_t _height, uint8_t _numMips, TextureFormat::Enum _format, uint32_t _flags, const Memory* _mem)
 	{
 		BGFX_CHECK_MAIN_THREAD();
 
@@ -2440,19 +2473,36 @@ again:
 		uint32_t magic = BGFX_CHUNK_MAGIC_TEX;
 		bx::write(&writer, magic);
 
+		if (BackbufferRatio::None != _ratio)
+		{
+			_width  = uint16_t(s_ctx->m_frame->m_resolution.m_width);
+			_height = uint16_t(s_ctx->m_frame->m_resolution.m_height);
+			getTextureSizeFromRatio(_ratio, _width, _height);
+		}
+
 		TextureCreate tc;
-		tc.m_flags = _flags;
+		tc.m_flags   = _flags;
-		tc.m_width = _width;
+		tc.m_width   = _width;
-		tc.m_height = _height;
+		tc.m_height  = _height;
-		tc.m_sides = 0;
+		tc.m_sides   = 0;
-		tc.m_depth = 0;
+		tc.m_depth   = 0;
 		tc.m_numMips = _numMips;
-		tc.m_format = uint8_t(_format);
+		tc.m_format  = uint8_t(_format);
 		tc.m_cubeMap = false;
-		tc.m_mem = _mem;
+		tc.m_mem     = _mem;
 		bx::write(&writer, tc);
 
-		return s_ctx->createTexture(mem, _flags, 0, NULL);
+		return s_ctx->createTexture(mem, _flags, 0, NULL, _ratio);
+	}
+
+	TextureHandle createTexture2D(uint16_t _width, uint16_t _height, uint8_t _numMips, TextureFormat::Enum _format, uint32_t _flags, const Memory* _mem)
+	{
+		return createTexture2D(BackbufferRatio::None, _width, _height, _numMips, _format, _flags, _mem);
+	}
+
+	TextureHandle createTexture2D(BackbufferRatio::Enum _ratio, uint8_t _numMips, TextureFormat::Enum _format, uint32_t _flags)
+	{
+		return createTexture2D(_ratio, 0, 0, _numMips, _format, _flags, NULL);
 	}
 
 	TextureHandle createTexture3D(uint16_t _width, uint16_t _height, uint16_t _depth, uint8_t _numMips, TextureFormat::Enum _format, uint32_t _flags, const Memory* _mem)
@@ -2493,7 +2543,7 @@ again:
 		tc.m_mem = _mem;
 		bx::write(&writer, tc);
 
-		return s_ctx->createTexture(mem, _flags, 0, NULL);
+		return s_ctx->createTexture(mem, _flags, 0, NULL, BackbufferRatio::None);
 	}
 
 	TextureHandle createTextureCube(uint16_t _size, uint8_t _numMips, TextureFormat::Enum _format, uint32_t _flags, const Memory* _mem)
@@ -2533,7 +2583,7 @@ again:
 		tc.m_mem     = _mem;
 		bx::write(&writer, tc);
 
-		return s_ctx->createTexture(mem, _flags, 0, NULL);
+		return s_ctx->createTexture(mem, _flags, 0, NULL, BackbufferRatio::None);
 	}
 
 	void destroyTexture(TextureHandle _handle)
@@ -2596,6 +2646,13 @@ again:
 		return createFrameBuffer(1, &th, true);
 	}
 
+	FrameBufferHandle createFrameBuffer(BackbufferRatio::Enum _ratio, TextureFormat::Enum _format, uint32_t _textureFlags)
+	{
+		_textureFlags |= _textureFlags&BGFX_TEXTURE_RT_MSAA_MASK ? 0 : BGFX_TEXTURE_RT;
+		TextureHandle th = createTexture2D(_ratio, 1, _format, _textureFlags);
+		return createFrameBuffer(1, &th, true);
+	}
+
 	FrameBufferHandle createFrameBuffer(uint8_t _num, TextureHandle* _handles, bool _destroyTextures)
 	{
 		BGFX_CHECK_MAIN_THREAD();

src/bgfx_p.h

@@ -305,6 +305,7 @@ namespace bgfx
 	bool isGraphicsDebuggerPresent();
 	void release(const Memory* _mem);
 	const char* getAttribName(Attrib::Enum _attr);
+	void getTextureSizeFromRatio(BackbufferRatio::Enum _ratio, uint16_t& _width, uint16_t& _height);
 
 	inline uint32_t castfu(float _value)
 	{
@@ -568,6 +569,7 @@ namespace bgfx
 			CreateProgram,
 			CreateTexture,
 			UpdateTexture,
+			ResizeTexture,
 			CreateFrameBuffer,
 			CreateUniform,
 			UpdateViewName,
@@ -1849,6 +1851,7 @@ namespace bgfx
 		virtual void updateTextureBegin(TextureHandle _handle, uint8_t _side, uint8_t _mip) = 0;
 		virtual void updateTexture(TextureHandle _handle, uint8_t _side, uint8_t _mip, const Rect& _rect, uint16_t _z, uint16_t _depth, uint16_t _pitch, const Memory* _mem) = 0;
 		virtual void updateTextureEnd() = 0;
+		virtual void resizeTexture(TextureHandle _handle, uint16_t _width, uint16_t _height) = 0;
 		virtual void destroyTexture(TextureHandle _handle) = 0;
 		virtual void createFrameBuffer(FrameBufferHandle _handle, uint8_t _num, const TextureHandle* _textureHandles) = 0;
 		virtual void createFrameBuffer(FrameBufferHandle _handle, void* _nwh, uint32_t _width, uint32_t _height, TextureFormat::Enum _depthFormat) = 0;
@@ -1925,6 +1928,17 @@ namespace bgfx
 			m_resolution.m_flags  = _flags;
 
 			memset(m_fb, 0xff, sizeof(m_fb) );
+
+			for (uint16_t ii = 0, num = m_textureHandle.getNumHandles(); ii < num; ++ii)
+			{
+				uint16_t textureIdx = m_textureHandle.getHandleAt(ii);
+				const TextureRef& textureRef = m_textureRef[textureIdx];
+				if (BackbufferRatio::None != textureRef.m_bbRatio)
+				{
+					TextureHandle handle = { textureIdx };
+					resizeTexture(handle, uint16_t(m_resolution.m_width), uint16_t(m_resolution.m_height) );
+				}
+			}
 		}
 
 		BGFX_API_FUNC(void setDebug(uint32_t _debug) )
@@ -2723,7 +2737,7 @@ namespace bgfx
 			}
 		}
 
-		BGFX_API_FUNC(TextureHandle createTexture(const Memory* _mem, uint32_t _flags, uint8_t _skip, TextureInfo* _info) )
+		BGFX_API_FUNC(TextureHandle createTexture(const Memory* _mem, uint32_t _flags, uint8_t _skip, TextureInfo* _info, BackbufferRatio::Enum _ratio) )
 		{
 			TextureInfo ti;
 			if (NULL == _info)
@@ -2761,6 +2775,7 @@ namespace bgfx
 			{
 				TextureRef& ref = m_textureRef[handle.idx];
 				ref.m_refCount = 1;
+				ref.m_bbRatio  = uint8_t(_ratio);
 				ref.m_format   = uint8_t(_info->format);
 
 				CommandBuffer& cmdbuf = getCommandBuffer(CommandBuffer::CreateTexture);
@@ -2786,6 +2801,26 @@ namespace bgfx
 			textureDecRef(_handle);
 		}
 
+		void resizeTexture(TextureHandle _handle, uint16_t _width, uint16_t _height)
+		{
+			const TextureRef& textureRef = m_textureRef[_handle.idx];
+			BX_CHECK(BackbufferRatio::None != textureRef.m_bbRatio, "");
+
+			getTextureSizeFromRatio(BackbufferRatio::Enum(textureRef.m_bbRatio), _width, _height);
+
+			BX_TRACE("Resize %3d: %4dx%d %s"
+				, _handle.idx
+				, _width
+				, _height
+				, getName(TextureFormat::Enum(textureRef.m_format) )
+				);
+
+			CommandBuffer& cmdbuf = getCommandBuffer(CommandBuffer::ResizeTexture);
+			cmdbuf.write(_handle);
+			cmdbuf.write(_width);
+			cmdbuf.write(_height);
+		}
+
 		void textureIncRef(TextureHandle _handle)
 		{
 			TextureRef& ref = m_textureRef[_handle.idx];
@@ -3437,6 +3472,7 @@ namespace bgfx
 		struct TextureRef
 		{
 			int16_t m_refCount;
+			uint8_t m_bbRatio;
 			uint8_t m_format;
 		};
 

src/renderer_d3d11.cpp

@@ -978,6 +978,35 @@ BX_PRAGMA_DIAGNOSTIC_POP();
 		{
 		}
 
+		void resizeTexture(TextureHandle _handle, uint16_t _width, uint16_t _height) BX_OVERRIDE
+		{
+			TextureD3D11& texture = m_textures[_handle.idx];
+
+			uint32_t size = sizeof(uint32_t) + sizeof(TextureCreate);
+			const Memory* mem = alloc(size);
+
+			bx::StaticMemoryBlockWriter writer(mem->data, mem->size);
+			uint32_t magic = BGFX_CHUNK_MAGIC_TEX;
+			bx::write(&writer, magic);
+
+			TextureCreate tc;
+			tc.m_flags   = texture.m_flags;
+			tc.m_width   = _width;
+			tc.m_height  = _height;
+			tc.m_sides   = 0;
+			tc.m_depth   = 0;
+			tc.m_numMips = 1;
+			tc.m_format  = texture.m_requestedFormat;
+			tc.m_cubeMap = false;
+			tc.m_mem     = NULL;
+			bx::write(&writer, tc);
+
+			texture.destroy();
+			texture.create(mem, tc.m_flags, 0);
+
+			release(mem);
+		}
+
 		void destroyTexture(TextureHandle _handle) BX_OVERRIDE
 		{
 			m_textures[_handle.idx].destroy();
@@ -2462,7 +2491,7 @@ BX_PRAGMA_DIAGNOSTIC_POP();
 		ID3D11DeviceContext* deviceCtx = s_renderD3D11->m_deviceCtx;
 		BX_CHECK(m_dynamic, "Must be dynamic!");
 
-#if 1
+#if 0
 		BX_UNUSED(_discard);
 		ID3D11Device* device = s_renderD3D11->m_device;
 

src/renderer_d3d9.cpp

@@ -774,6 +774,13 @@ namespace bgfx { namespace d3d9
 			m_updateTexture = NULL;
 		}
 
+		void resizeTexture(TextureHandle _handle, uint16_t _width, uint16_t _height) BX_OVERRIDE
+		{
+			TextureD3D9& texture = m_textures[_handle.idx];
+			texture.m_width  = _width;
+			texture.m_height = _height;
+		}
+
 		void destroyTexture(TextureHandle _handle) BX_OVERRIDE
 		{
 			m_textures[_handle.idx].destroy();

src/renderer_gl.cpp

@@ -1717,6 +1717,35 @@ namespace bgfx { namespace gl
 		{
 		}
 
+		void resizeTexture(TextureHandle _handle, uint16_t _width, uint16_t _height) BX_OVERRIDE
+		{
+			TextureGL& texture = m_textures[_handle.idx];
+
+			uint32_t size = sizeof(uint32_t) + sizeof(TextureCreate);
+			const Memory* mem = alloc(size);
+
+			bx::StaticMemoryBlockWriter writer(mem->data, mem->size);
+			uint32_t magic = BGFX_CHUNK_MAGIC_TEX;
+			bx::write(&writer, magic);
+
+			TextureCreate tc;
+			tc.m_flags   = texture.m_flags;
+			tc.m_width   = _width;
+			tc.m_height  = _height;
+			tc.m_sides   = 0;
+			tc.m_depth   = 0;
+			tc.m_numMips = 1;
+			tc.m_format  = texture.m_requestedFormat;
+			tc.m_cubeMap = false;
+			tc.m_mem     = NULL;
+			bx::write(&writer, tc);
+
+			texture.destroy();
+			texture.create(mem, tc.m_flags, 0);
+
+			release(mem);
+		}
+
 		void destroyTexture(TextureHandle _handle) BX_OVERRIDE
 		{
 			m_textures[_handle.idx].destroy();

src/renderer_null.cpp

@@ -113,6 +113,10 @@ namespace bgfx { namespace noop
 		{
 		}
 
+		void resizeTexture(TextureHandle /*_handle*/, uint16_t /*_width*/, uint16_t /*_height*/) BX_OVERRIDE
+		{
+		}
+
 		void destroyTexture(TextureHandle /*_handle*/) BX_OVERRIDE
 		{
 		}