Fix font rendering (#2653)

* Fix subpixel font rendering

* remove const

examples/10-font/font.cpp

@@ -266,7 +266,10 @@ public:
 			float view[16];
 			bx::mtxLookAt(view, eye, at);
 
-			const float centering = 0.5f;
+			float centering = 0.0f;
+			if (bgfx::getRendererType() == bgfx::RendererType::Direct3D9) {
+				centering = -0.5f;
+			}
 
 			// Setup a top-left ortho matrix for screen space drawing.
 			const bgfx::Caps* caps = bgfx::getCaps();

examples/11-fontsdf/fontsdf.cpp

@@ -253,7 +253,10 @@ public:
 			float view[16];
 			bx::mtxLookAt(view, eye, at);
 
-			const float centering = 0.5f;
+			float centering = 0.0f;
+			if (bgfx::getRendererType() == bgfx::RendererType::Direct3D9) {
+				centering = -0.5f;
+			}
 
 			// Setup a top-left ortho matrix for screen space drawing.
 			const bgfx::Caps* caps = bgfx::getCaps();

examples/common/cube_atlas.cpp

@@ -259,7 +259,7 @@ Atlas::Atlas(uint16_t _textureSize, uint16_t _maxRegionsCount)
 	BX_ASSERT(_textureSize >= 64 && _textureSize <= 4096, "Invalid _textureSize %d.", _textureSize);
 	BX_ASSERT(_maxRegionsCount >= 64 && _maxRegionsCount <= 32000, "Invalid _maxRegionsCount %d.", _maxRegionsCount);
 
-	init();
+	m_texelSize = float(UINT16_MAX) / float(m_textureSize);
 
 	m_layers = new PackedLayer[6];
 	for (int ii = 0; ii < 6; ++ii)
@@ -287,7 +287,7 @@ Atlas::Atlas(uint16_t _textureSize, const uint8_t* _textureBuffer, uint16_t _reg
 {
 	BX_ASSERT(_regionCount <= 64 && _maxRegionsCount <= 4096, "_regionCount %d, _maxRegionsCount %d", _regionCount, _maxRegionsCount);
 
-	init();
+	m_texelSize = float(UINT16_MAX) / float(m_textureSize);
 
 	m_regions = new AtlasRegion[_regionCount];
 	m_textureBuffer = new uint8_t[getTextureBufferSize()];
@@ -313,30 +313,6 @@ Atlas::~Atlas()
 	delete [] m_textureBuffer;
 }
 
-void Atlas::init()
-{
-	m_texelSize = float(UINT16_MAX) / float(m_textureSize);
-	float texelHalf = m_texelSize/2.0f;
-	switch (bgfx::getRendererType() )
-	{
-	case bgfx::RendererType::Direct3D9:
-		m_texelOffset[0] = 0.0f;
-		m_texelOffset[1] = 0.0f;
-		break;
-
-	case bgfx::RendererType::Direct3D11:
-	case bgfx::RendererType::Direct3D12:
-		m_texelOffset[0] = texelHalf;
-		m_texelOffset[1] = texelHalf;
-		break;
-
-	default:
-		m_texelOffset[0] = texelHalf;
-		m_texelOffset[1] = -texelHalf;
-		break;
-	}
-}
-
 uint16_t Atlas::addRegion(uint16_t _width, uint16_t _height, const uint8_t* _bitmapBuffer, AtlasRegion::Type _type, uint16_t outline)
 {
 	if (m_regionCount >= m_maxRegionCount)
@@ -469,10 +445,10 @@ static void writeUV(uint8_t* _vertexBuffer, int16_t _x, int16_t _y, int16_t _z,
 
 void Atlas::packUV(const AtlasRegion& _region, uint8_t* _vertexBuffer, uint32_t _offset, uint32_t _stride) const
 {
-	int16_t x0 = (int16_t)( ( (float)_region.x * m_texelSize + m_texelOffset[0]) - float(INT16_MAX) );
-	int16_t y0 = (int16_t)( ( (float)_region.y * m_texelSize + m_texelOffset[1]) - float(INT16_MAX) );
-	int16_t x1 = (int16_t)( ( ( (float)_region.x + _region.width) * m_texelSize + m_texelOffset[0]) - float(INT16_MAX) );
-	int16_t y1 = (int16_t)( ( ( (float)_region.y + _region.height) * m_texelSize + m_texelOffset[1]) - float(INT16_MAX) );
+	int16_t x0 = (int16_t)( ( (float)_region.x * m_texelSize) - float(INT16_MAX) );
+	int16_t y0 = (int16_t)( ( (float)_region.y * m_texelSize) - float(INT16_MAX) );
+	int16_t x1 = (int16_t)( ( ( (float)_region.x + _region.width) * m_texelSize) - float(INT16_MAX) );
+	int16_t y1 = (int16_t)( ( ( (float)_region.y + _region.height) * m_texelSize) - float(INT16_MAX) );
 	int16_t ww = (int16_t)( (float(INT16_MAX) / 4.0f) * (float)_region.getComponentIndex() );
 
 	_vertexBuffer += _offset;

examples/common/cube_atlas.h

@@ -135,8 +135,6 @@ public:
 	}
 
 private:
-	void init();
-
 	struct PackedLayer;
 	PackedLayer* m_layers;
 	AtlasRegion* m_regions;
@@ -148,7 +146,6 @@ private:
 	bgfx::TextureHandle m_textureHandle;
 	uint16_t m_textureSize;
 	float m_texelSize;
-	float m_texelOffset[2];
 
 	uint16_t m_regionCount;
 	uint16_t m_maxRegionCount;