Fix pixel alignment and draw2DLine inconsistent offset problems. New test...

Fix pixel alignment and draw2DLine inconsistent offset problems. New test added to make sure that drawPixel and draw2DLine use the same alignment.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4138 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/CBlit.h

@@ -254,7 +254,7 @@ static void RenderLine32_Decal(video::IImage *t,
 	m = dy << 1;
 
 	run = dx;
-	while ( run )
+	do
 	{
 		*dst = argb;
 
@@ -266,7 +266,7 @@ static void RenderLine32_Decal(video::IImage *t,
 			d -= c;
 		}
 		run -= 1;
-	}
+	} while (run>=0);
 
 	t->unlock();
 }
@@ -321,7 +321,7 @@ static void RenderLine32_Blend(video::IImage *t,
 
 	run = dx;
 	const u32 packA = packAlpha ( alpha );
-	while ( run )
+	do
 	{
 		*dst = packA | PixelBlend32( *dst, argb, alpha );
 
@@ -333,7 +333,7 @@ static void RenderLine32_Blend(video::IImage *t,
 			d -= c;
 		}
 		run -= 1;
-	}
+	} while (run>=0);
 
 	t->unlock();
 }
@@ -386,7 +386,7 @@ static void RenderLine16_Decal(video::IImage *t,
 	m = dy << 1;
 
 	run = dx;
-	while ( run )
+	do
 	{
 		*dst = (u16)argb;
 
@@ -398,7 +398,7 @@ static void RenderLine16_Decal(video::IImage *t,
 			d -= c;
 		}
 		run -= 1;
-	}
+	} while (run>=0);
 
 	t->unlock();
 }
@@ -453,7 +453,7 @@ static void RenderLine16_Blend(video::IImage *t,
 
 	run = dx;
 	const u16 packA = alpha ? 0x8000 : 0;
-	while ( run )
+	do
 	{
 		*dst = packA | PixelBlend16( *dst, argb, alpha );
 
@@ -465,7 +465,7 @@ static void RenderLine16_Blend(video::IImage *t,
 			d -= c;
 		}
 		run -= 1;
-	}
+	} 	while (run>=0);
 
 	t->unlock();
 }

source/Irrlicht/CD3D8Driver.cpp

@@ -1259,22 +1259,27 @@ void CD3D8Driver::draw2DLine(const core::position2d<s32>& start,
 					const core::position2d<s32>& end,
 					SColor color)
 {
-	// thanks to Vash TheStampede who sent in his implementation
-	S3DVertex vtx[2];
-	vtx[0] = S3DVertex((f32)start.X, (f32)start.Y, 0.0f,
-					0.0f, 0.0f, 0.0f, // normal
-					color, 0.0f, 0.0f); // texture
+	if (start==end)
+		drawPixel(start.X, start.Y, color);
+	else
+	{
+		// thanks to Vash TheStampede who sent in his implementation
+		S3DVertex vtx[2];
+		vtx[0] = S3DVertex((f32)start.X+0.375f, (f32)start.Y+0.375f, 0.0f,
+						0.0f, 0.0f, 0.0f, // normal
+						color, 0.0f, 0.0f); // texture
 
-	vtx[1] = S3DVertex((f32)end.X, (f32)end.Y, 0.0f,
-					0.0f, 0.0f, 0.0f,
-					color, 0.0f, 0.0f);
+		vtx[1] = S3DVertex((f32)end.X+0.375f, (f32)end.Y+0.375f, 0.0f,
+						0.0f, 0.0f, 0.0f,
+						color, 0.0f, 0.0f);
 
-	setRenderStates2DMode(color.getAlpha() < 255, false, false);
-	setActiveTexture(0,0);
+		setRenderStates2DMode(color.getAlpha() < 255, false, false);
+		setActiveTexture(0,0);
 
-	setVertexShader(EVT_STANDARD);
+		setVertexShader(EVT_STANDARD);
 
-	pID3DDevice->DrawPrimitiveUP(D3DPT_LINELIST, 1, &vtx[0], sizeof(S3DVertex));
+		pID3DDevice->DrawPrimitiveUP(D3DPT_LINELIST, 1, &vtx[0], sizeof(S3DVertex));
+	}
 }
 
 
@@ -1290,7 +1295,7 @@ void CD3D8Driver::drawPixel(u32 x, u32 y, const SColor & color)
 
 	setVertexShader(EVT_STANDARD);
 
-	S3DVertex vertex((f32)x, (f32)y, 0.f, 0.f, 0.f, 0.f, color, 0.f, 0.f);
+	S3DVertex vertex((f32)x+0.375f, (f32)y+0.375f, 0.f, 0.f, 0.f, 0.f, color, 0.f, 0.f);
 
 	pID3DDevice->DrawPrimitiveUP(D3DPT_POINTLIST, 1, &vertex, sizeof(vertex));
 }

source/Irrlicht/CD3D9Driver.cpp

@@ -1962,23 +1962,28 @@ void CD3D9Driver::draw2DLine(const core::position2d<s32>& start,
 				const core::position2d<s32>& end,
 				SColor color)
 {
-	// thanks to Vash TheStampede who sent in his implementation
-	S3DVertex vtx[2];
-	vtx[0] = S3DVertex((f32)start.X, (f32)start.Y, 0.0f,
-						0.0f, 0.0f, 0.0f, // normal
-						color, 0.0f, 0.0f); // texture
+	if (start==end)
+		drawPixel(start.X, start.Y, color);
+	else
+	{
+		// thanks to Vash TheStampede who sent in his implementation
+		S3DVertex vtx[2];
+		vtx[0] = S3DVertex((f32)start.X+0.375f, (f32)start.Y+0.375f, 0.0f,
+							0.0f, 0.0f, 0.0f, // normal
+							color, 0.0f, 0.0f); // texture
 
-	vtx[1] = S3DVertex((f32)end.X, (f32)end.Y, 0.0f,
-						0.0f, 0.0f, 0.0f,
-						color, 0.0f, 0.0f);
+		vtx[1] = S3DVertex((f32)end.X+0.375f, (f32)end.Y+0.375f, 0.0f,
+							0.0f, 0.0f, 0.0f,
+							color, 0.0f, 0.0f);
 
-	setRenderStates2DMode(color.getAlpha() < 255, false, false);
-	setActiveTexture(0,0);
+		setRenderStates2DMode(color.getAlpha() < 255, false, false);
+		setActiveTexture(0,0);
 
-	setVertexShader(EVT_STANDARD);
+		setVertexShader(EVT_STANDARD);
 
-	pID3DDevice->DrawPrimitiveUP(D3DPT_LINELIST, 1,
-					&vtx[0], sizeof(S3DVertex) );
+		pID3DDevice->DrawPrimitiveUP(D3DPT_LINELIST, 1,
+						&vtx[0], sizeof(S3DVertex) );
+	}
 }
 
 
@@ -1994,7 +1999,7 @@ void CD3D9Driver::drawPixel(u32 x, u32 y, const SColor & color)
 
 	setVertexShader(EVT_STANDARD);
 
-	S3DVertex vertex((f32)x, (f32)y, 0.f, 0.f, 0.f, 0.f, color, 0.f, 0.f);
+	S3DVertex vertex((f32)x+0.375f, (f32)y+0.375f, 0.f, 0.f, 0.f, 0.f, color, 0.f, 0.f);
 
 	pID3DDevice->DrawPrimitiveUP(D3DPT_POINTLIST, 1, &vertex, sizeof(vertex));
 }

source/Irrlicht/COpenGLDriver.cpp

@@ -2377,17 +2377,33 @@ void COpenGLDriver::draw2DRectangle(const core::rect<s32>& position,
 
 //! Draws a 2d line.
 void COpenGLDriver::draw2DLine(const core::position2d<s32>& start,
-				const core::position2d<s32>& end,
-				SColor color)
+				const core::position2d<s32>& end, SColor color)
 {
-	disableTextures();
-	setRenderStates2DMode(color.getAlpha() < 255, false, false);
-
-	glBegin(GL_LINES);
-	glColor4ub(color.getRed(), color.getGreen(), color.getBlue(), color.getAlpha());
-	glVertex2f(GLfloat(start.X), GLfloat(start.Y));
-	glVertex2f(GLfloat(end.X),   GLfloat(end.Y));
-	glEnd();
+	if (start==end)
+		drawPixel(start.X, start.Y, color);
+	else
+	{
+		disableTextures();
+		setRenderStates2DMode(color.getAlpha() < 255, false, false);
+
+		glBegin(GL_LINES);
+		glColor4ub(color.getRed(), color.getGreen(), color.getBlue(), color.getAlpha());
+		GLfloat x=(GLfloat)start.X;
+		GLfloat y=(GLfloat)start.Y;
+		if (x>end.X)
+			x += 0.5f;
+		if (y>end.Y)
+			y += 0.5f;
+		glVertex2f(GLfloat(x), GLfloat(y));
+		x=(GLfloat)end.X;
+		y=(GLfloat)end.Y;
+		if (x>start.X)
+			x += 0.5f;
+		if (y>start.Y)
+			y += 0.5f;
+		glVertex2f(GLfloat(x),   GLfloat(y));
+		glEnd();
+	}
 }
 
 //! Draws a pixel

tests/drawPixel.cpp

@@ -110,12 +110,76 @@ static bool pixelAccuracy(E_DRIVER_TYPE driverType)
 	return result;
 }
 
+// this test draws lines of different lengths and compares
+// them with pixel placement
+// grey pixels denote start and end of the white drawn lines
+// black pixels only make those grey points better visible
+// yellow and magenta lines should start and end next toa black pixel,
+// yellow one right to the last black pixel down, magenta below the last
+// black pixel to the right
+// white lines are always double drawn, lines back and forth.
+static bool drawLine(E_DRIVER_TYPE driverType)
+{
+	IrrlichtDevice *device = createDevice( driverType, dimension2d<u32>(160, 120), 32);
+	if (!device)
+		return true; // Treat a failure to create a driver as benign; this saves a lot of #ifdefs
+
+	IVideoDriver* driver = device->getVideoDriver();
+
+	logTestString("Testing driver %ls\n", driver->getName());
+
+	device->getSceneManager()->addCameraSceneNode();
+
+	driver->beginScene(true, true, SColor(255,100,101,140));
+	// horizontal lines
+	for (u32 i=0; i<20; ++i)
+	{
+		driver->draw2DLine(core::vector2di(10,10+3*i), core::vector2di(10+2*i,10+3*i));
+		// mark start point
+		driver->drawPixel(9,10+3*i+1, video::SColor(0xff000000));
+		driver->drawPixel(10,10+3*i+1, video::SColor(0xff888888));
+		driver->drawPixel(11,10+3*i+1, video::SColor(0xff000000));
+		// mark end point
+		driver->drawPixel(9+2*i,10+3*i+1, video::SColor(0xff000000));
+		driver->drawPixel(10+2*i,10+3*i+1, video::SColor(0xff888888));
+		driver->drawPixel(11+2*i,10+3*i+1, video::SColor(0xff000000));
+		driver->draw2DLine(core::vector2di(10+2*i,10+3*i+2), core::vector2di(10,10+3*i+2));
+	}
+	// vertical lines
+	for (u32 i=0; i<20; ++i)
+	{
+		driver->draw2DLine(core::vector2di(11+3*i,10), core::vector2di(11+3*i,10+2*i));
+		// mark start point
+		driver->drawPixel(11+3*i+1,9, video::SColor(0xff000000));
+		driver->drawPixel(11+3*i+1,10, video::SColor(0xff888888));
+		driver->drawPixel(11+3*i+1,11, video::SColor(0xff000000));
+		// mark end point
+		driver->drawPixel(11+3*i+1,9+2*i, video::SColor(0xff000000));
+		driver->drawPixel(11+3*i+1,10+2*i, video::SColor(0xff888888));
+		driver->drawPixel(11+3*i+1,11+2*i, video::SColor(0xff000000));
+		driver->draw2DLine(core::vector2di(11+3*i+2,10+2*i), core::vector2di(11+3*i+2, 10));
+	}
+	// diagonal lines
+	driver->draw2DLine(core::vector2di(14,14),core::vector2di(50,68), video::SColor(0xffffff00));
+	driver->draw2DLine(core::vector2di(15,14),core::vector2di(69,50), video::SColor(0xffff00ff));
+	driver->endScene();
+
+	bool result = takeScreenshotAndCompareAgainstReference(driver, "-drawLine.png");
+
+	device->closeDevice();
+	device->run();
+	device->drop();
+
+	return result;
+}
+
 bool drawPixel(void)
 {
 	bool result = true;
 
 	TestWithAllDrivers(lineRender);
 	TestWithAllDrivers(pixelAccuracy);
+	TestWithAllDrivers(drawLine);
 
 	return result;
 }