| private ReadPixels ( int x, int y, int width, int height, uint format, uint type, IntPtr pixels ) : void | ||
| x | int | |
| y | int | |
| width | int | |
| height | int | |
| format | uint | |
| type | uint | |
| pixels | IntPtr | |
| return | void | |
/// <summary>
/// Read pixels in specified rect and get the VertexIds they represent.
/// </summary>
/// <param name="target"></param>
/// <returns></returns>
private static unsafe List <Tuple <Point, uint> > ReadPixels(Rectangle target)
{
var result = new List <Tuple <Point, uint> >();
// get coded color.
using (var codedColor = new UnmanagedArray <Pixel>(target.Width * target.Height))
{
OpenGL.ReadPixels(target.X, target.Y, target.Width, target.Height,
OpenGL.GL_RGBA, OpenGL.GL_UNSIGNED_BYTE, codedColor.Header);
var array = (Pixel *)codedColor.Header.ToPointer();
int index = 0;
var vertexIdList = new List <uint>();
for (int yOffset = target.Height - 1; yOffset >= 0; yOffset--)
{
for (int xOffset = 0; xOffset < target.Width; xOffset++)
{
Pixel pixel = array[index++];
// This is when (x, y) is not on background and some primitive is picked.
if (!pixel.IsWhite())
{
uint stageVertexId = pixel.ToStageVertexId();
if (!vertexIdList.Contains(stageVertexId))
{
result.Add(new Tuple <Point, uint>(
new Point(target.X + xOffset, target.Y + yOffset), stageVertexId));
vertexIdList.Add(stageVertexId);
}
}
}
}
}
return(result);
}
private static unsafe bool PickedSomething(Rectangle rect, Rectangle rectangle)
{
if (rect.Width <= 0 || rect.Height <= 0)
{
return(false);
}
bool result = false;
using (var codedColor = new UnmanagedArray <byte>(rect.Width * rect.Height))
{
OpenGL.ReadPixels(rect.X, rectangle.Height - rect.Y - 1, rect.Width, rect.Height,
OpenGL.GL_DEPTH_COMPONENT, OpenGL.GL_UNSIGNED_BYTE, codedColor.Header);
var array = (byte *)codedColor.Header.ToPointer();
for (int i = 0; i < codedColor.Length; i++)
{
if (array[i] < byte.MaxValue)
{
result = true;
break;
}
}
}
return(result);
}
/// <summary>
/// <para>Read pixels in specified rect and get the VertexIds they represent.</para>
/// </summary>
/// <param name="rect"></param>
/// <param name="canvasHeight"></param>
/// <returns></returns>
public static unsafe List <Tuple <Point, uint> > ReadPixels(
Rectangle rect, int canvasHeight)
{
var result = new List <Tuple <Point, uint> >();
if (rect.Width <= 0 || rect.Height <= 0)
{
return(result);
}
// get coded color.
using (var codedColor = new UnmanagedArray <Pixel>(rect.Width * rect.Height))
{
OpenGL.ReadPixels(rect.X, canvasHeight - rect.Y - 1, rect.Width, rect.Height,
OpenGL.GL_RGBA, OpenGL.GL_UNSIGNED_BYTE, codedColor.Header);
var array = (Pixel *)codedColor.Header.ToPointer();
int index = 0;
var vertexIdList = new List <uint>();
for (int yOffset = rect.Height - 1; yOffset >= 0; yOffset--)
{
for (int xOffset = 0; xOffset < rect.Width; xOffset++)
{
Pixel pixel = array[index++];
if (!
// This is when (x, y) is on background and no primitive is picked.
(pixel.r == byte.MaxValue && pixel.g == byte.MaxValue &&
pixel.b == byte.MaxValue && pixel.a == byte.MaxValue))
{
/* // This is how is vertexID coded into color in vertex shader.
* int objectID = gl_VertexID;
* codedColor = vec4(
* float(objectID & 0xFF),
* float((objectID >> 8) & 0xFF),
* float((objectID >> 16) & 0xFF),
* float((objectID >> 24) & 0xFF));
*/
// get vertexID from coded color.
// the vertexID is the last vertex that constructs the primitive.
// see http://www.cnblogs.com/bitzhuwei/p/modern-opengl-picking-primitive-in-VBO-2.html
uint shiftedR = (uint)pixel.r;
uint shiftedG = (uint)pixel.g << 8;
uint shiftedB = (uint)pixel.b << 16;
uint shiftedA = (uint)pixel.a << 24;
var vertexId = shiftedR + shiftedG + shiftedB + shiftedA;
if (!vertexIdList.Contains(vertexId))
{
result.Add(new Tuple <Point, uint>(
new Point(rect.X + xOffset, rect.Y + yOffset), vertexId));
vertexIdList.Add(vertexId);
}
}
}
}
}
return(result);
}
/// <summary>
/// Screen shot of OpenGL canvas.
/// </summary>
/// <param name="x">左下角坐标为(0, 0)</param>
/// <param name="y">左下角坐标为(0, 0)</param>
/// <param name="width">宽度</param>
/// <param name="height">高度</param>
public static Bitmap ScreenShot(int x, int y, int width, int height)
{
var format = System.Drawing.Imaging.PixelFormat.Format32bppArgb;
var bitmap = new Bitmap(width, height, format);
var bitmapRect = new Rectangle(0, 0, bitmap.Width, bitmap.Height);
var lockMode = System.Drawing.Imaging.ImageLockMode.WriteOnly;
System.Drawing.Imaging.BitmapData bmpData = bitmap.LockBits(bitmapRect, lockMode, format);
OpenGL.ReadPixels(x, y, width, height, OpenGL.GL_BGRA, OpenGL.GL_UNSIGNED_BYTE, bmpData.Scan0);
bitmap.UnlockBits(bmpData);
bitmap.RotateFlip(RotateFlipType.Rotate180FlipX);
return(bitmap);
}
/// <summary>
///
/// </summary>
/// <param name="deviceContext"></param>
public override void Blit(IntPtr deviceContext)
{
if (this.DeviceContextHandle != IntPtr.Zero)
{
// Set the read buffer.
OpenGL.ReadBuffer(OpenGL.GL_COLOR_ATTACHMENT0);
// Read the pixels into the DIB section.
OpenGL.ReadPixels(0, 0, this.Width, this.Height, OpenGL.GL_BGRA,
OpenGL.GL_UNSIGNED_BYTE, this.dibSection.Bits);
// Blit the DC (containing the DIB section) to the target DC.
Win32.BitBlt(deviceContext, 0, 0, this.Width, this.Height,
this.dibSection.MemoryDeviceContext, 0, 0, Win32.SRCCOPY);
}
}
/// <summary>
/// 把OpenGL渲染的内容保存到图片文件。
/// </summary>
/// <param name="x">左下角坐标为(0, 0)</param>
/// <param name="y">左下角坐标为(0, 0)</param>
/// <param name="width">宽度</param>
/// <param name="height">高度</param>
/// <param name="filename"></param>
public static void Save2Picture(int x, int y, int width, int height, string filename)
{
var format = System.Drawing.Imaging.PixelFormat.Format32bppArgb;
using (var bitmap = new Bitmap(width, height, format))
{
var bitmapRect = new Rectangle(0, 0, bitmap.Width, bitmap.Height);
var lockMode = System.Drawing.Imaging.ImageLockMode.WriteOnly;
System.Drawing.Imaging.BitmapData bmpData = bitmap.LockBits(bitmapRect, lockMode, format);
OpenGL.ReadPixels(x, y, width, height, OpenGL.GL_BGRA, OpenGL.GL_UNSIGNED_BYTE, bmpData.Scan0);
bitmap.UnlockBits(bmpData);
bitmap.RotateFlip(RotateFlipType.Rotate180FlipX);
bitmap.Save(filename);
}
}
/// <summary>
/// Gets stage vertex id by color coded picking machanism.
/// Note: left bottom is(0, 0). This is different from Winform's left top being (0, 0).
/// </summary>
/// <param name="x">target pixel position(Left Down is (0, 0)).</param>
/// <param name="y">target pixel position(Left Down is (0, 0)).</param>
/// <returns></returns>
internal static unsafe uint ReadStageVertexId(int x, int y)
{
var array = new Pixel[1];
GCHandle pinned = GCHandle.Alloc(array, GCHandleType.Pinned);
IntPtr header = Marshal.UnsafeAddrOfPinnedArrayElement(array, 0);
// get coded color.
OpenGL.ReadPixels(x, y, 1, 1, OpenGL.GL_RGBA, OpenGL.GL_UNSIGNED_BYTE, header);
pinned.Free();
Pixel pixel = array[0];
uint stageVertexId = pixel.IsWhite() ?
uint.MaxValue :
// This is when (x, y) is not on background and some primitive is picked.
pixel.ToStageVertexId();
return(stageVertexId);
}
/// <summary>
/// Read pixels in specified rect and get the VertexIds they represent.
/// </summary>
/// <param name="target"></param>
/// <returns></returns>
private static unsafe List <Tuple <Point, uint> > ReadPixels(Rectangle target)
{
// get coded color.
var codedColor = new Pixel[target.Width * target.Height];
{
GCHandle pinned = GCHandle.Alloc(codedColor, GCHandleType.Pinned);
IntPtr header = Marshal.UnsafeAddrOfPinnedArrayElement(codedColor, 0);
OpenGL.ReadPixels(target.X, target.Y, target.Width, target.Height,
OpenGL.GL_RGBA, OpenGL.GL_UNSIGNED_BYTE, header);
pinned.Free();
}
var result = new List <Tuple <Point, uint> >();
int index = 0;
var vertexIdList = new List <uint>();
for (int yOffset = target.Height - 1; yOffset >= 0; yOffset--)
{
for (int xOffset = 0; xOffset < target.Width; xOffset++)
{
Pixel pixel = codedColor[index++];
// This is when (x, y) is not on background and some primitive is picked.
if (!pixel.IsWhite())
{
uint stageVertexId = pixel.ToStageVertexId();
if (!vertexIdList.Contains(stageVertexId))
{
result.Add(new Tuple <Point, uint>(
new Point(target.X + xOffset, target.Y + yOffset), stageVertexId));
vertexIdList.Add(stageVertexId);
}
}
}
}
return(result);
}
public static unsafe uint ReadPixel(
int x, int y, int canvasHeight)
{
uint stageVertexId = uint.MaxValue;
// get coded color.
using (var codedColor = new UnmanagedArray <byte>(4))
{
OpenGL.ReadPixels(x, canvasHeight - y - 1, 1, 1, OpenGL.GL_RGBA, OpenGL.GL_UNSIGNED_BYTE, codedColor.Header);
var array = (Pixel *)codedColor.Header.ToPointer();
Pixel pixel = array[0];
if (!
// This is when (x, y) is on background and no primitive is picked.
(pixel.r == byte.MaxValue && pixel.g == byte.MaxValue &&
pixel.b == byte.MaxValue && pixel.a == byte.MaxValue))
{
/* // This is how is vertexID coded into color in vertex shader.
* int objectID = gl_VertexID;
* codedColor = vec4(
* float(objectID & 0xFF),
* float((objectID >> 8) & 0xFF),
* float((objectID >> 16) & 0xFF),
* float((objectID >> 24) & 0xFF));
*/
// get vertexID from coded color.
// the vertexID is the last vertex that constructs the primitive.
// see http://www.cnblogs.com/bitzhuwei/p/modern-opengl-picking-primitive-in-VBO-2.html
uint shiftedR = (uint)pixel.r;
uint shiftedG = (uint)pixel.g << 8;
uint shiftedB = (uint)pixel.b << 16;
uint shiftedA = (uint)pixel.a << 24;
stageVertexId = shiftedR + shiftedG + shiftedB + shiftedA;
}
}
return(stageVertexId);
}
