BACKENDS: OPENGL: Use a floating point cursor size

When scaler shaders are used, cursor size is adapted to scale on the
game screen texture and not on the back buffer so the size is scaled
twice and is imprecise.
Using a float gives more precision without any performance impact as the
OpenGL code already expects floats.

backends/graphics/opengl/opengl-graphics.cpp

@@ -667,9 +667,9 @@ void OpenGLGraphicsManager::updateScreen() {
 			_backBuffer.enableBlend(Framebuffer::kBlendModePremultipliedTransparency);
 
 			_pipeline->drawTexture(_cursor->getGLTexture(),
-									 _cursorX - _cursorHotspotXScaled + _shakeOffsetScaled.x,
-									 _cursorY - _cursorHotspotYScaled + _shakeOffsetScaled.y,
-									 _cursorWidthScaled, _cursorHeightScaled);
+			                         _cursorX - _cursorHotspotXScaled + _shakeOffsetScaled.x,
+			                         _cursorY - _cursorHotspotYScaled + _shakeOffsetScaled.y,
+			                         _cursorWidthScaled, _cursorHeightScaled);
 			drawCursor = false;
 
 			// Everything we need to clip has been clipped
@@ -1518,11 +1518,14 @@ void OpenGLGraphicsManager::recalculateCursorScaling() {
 		return;
 	}
 
+	uint cursorWidth = _cursor->getWidth();
+	uint cursorHeight = _cursor->getHeight();
+
 	// By default we use the unscaled versions.
 	_cursorHotspotXScaled = _cursorHotspotX;
 	_cursorHotspotYScaled = _cursorHotspotY;
-	_cursorWidthScaled = _cursor->getWidth();
-	_cursorHeightScaled = _cursor->getHeight();
+	_cursorWidthScaled = cursorWidth;
+	_cursorHeightScaled = cursorHeight;
 
 	// In case scaling is actually enabled we will scale the cursor according
 	// to the game screen.
@@ -1531,10 +1534,10 @@ void OpenGLGraphicsManager::recalculateCursorScaling() {
 		const frac_t screenScaleFactorY = intToFrac(_gameDrawRect.height()) / _gameScreen->getHeight();
 
 		_cursorHotspotXScaled = fracToInt(_cursorHotspotXScaled * screenScaleFactorX);
-		_cursorWidthScaled    = fracToInt(_cursorWidthScaled    * screenScaleFactorX);
+		_cursorWidthScaled    = fracToDouble(cursorWidth        * screenScaleFactorX);
 
 		_cursorHotspotYScaled = fracToInt(_cursorHotspotYScaled * screenScaleFactorY);
-		_cursorHeightScaled   = fracToInt(_cursorHeightScaled   * screenScaleFactorY);
+		_cursorHeightScaled   = fracToDouble(cursorHeight       * screenScaleFactorY);
 	}
 }
 

backends/graphics/opengl/opengl-graphics.h

@@ -405,12 +405,12 @@ class OpenGLGraphicsManager : virtual public WindowedGraphicsManager {
 	/**
 	 * The width of the cursor in scaled game display area coordinates.
 	 */
-	uint _cursorWidthScaled;
+	float _cursorWidthScaled;
 
 	/**
 	 * The height of the cursor in scaled game display area coordinates.
 	 */
-	uint _cursorHeightScaled;
+	float _cursorHeightScaled;
 
 	/**
 	 * The key color.