OpenTK. Trouble with mirror reflection - reflection

Question

I have some problems with rendering of mirror reflection in OpenTK. I need to see reflection of objects only from one side from my mirror, but my program also gives reflection from another side and it hides the first one. Could you help me?
private void glControl1_Load(object sender, EventArgs e)
{
loaded = true;
GL.ClearColor(Color.SkyBlue);
initRendering();
Matrix4 p = Matrix4.CreatePerspectiveFieldOfView((float)(80 * Math.PI / 180), 1, 20, 500);
GL.MatrixMode(MatrixMode.Projection);
GL.LoadMatrix(ref p);
Matrix4 modelview = Matrix4.LookAt(70, 70, 70, 0, 0, 0, 0, 1, 0);
GL.MatrixMode(MatrixMode.Modelview);
GL.LoadMatrix(ref modelview);
}
private void glControl1_Paint(object sender, PaintEventArgs e)
{
if (!loaded)
return;
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
drawScene();
/*axes*/
GL.Color3(Color.Black);
GL.Begin(BeginMode.Lines);
GL.Vertex3(0, 0, 0);
GL.Vertex3(70, 0, 0);
GL.Vertex3(0, 0, 0);
GL.Vertex3(0, 70, 0);
GL.Vertex3(0, 0, 0);
GL.Vertex3(0, 0, 70);
GL.End();
glControl1.SwapBuffers();
}
void initRendering()
{
GL.ShadeModel(ShadingModel.Flat);
GL.ClearDepth(1.0f);
GL.ClearStencil(0);
GL.Enable(EnableCap.DepthTest);
GL.DepthFunc(DepthFunction.Lequal);
GL.Hint(HintTarget.PerspectiveCorrectionHint, HintMode.Nicest);
GL.Enable(EnableCap.AutoNormal);
// Setup the drawing area and shading mode
GL.MatrixMode(MatrixMode.Projection);
GL.LoadIdentity();
GL.Enable(EnableCap.PointSmooth);
GL.MatrixMode(MatrixMode.Modelview);
GL.LoadIdentity();
GL.Enable(EnableCap.Lighting);
GL.LightModel(LightModelParameter.LightModelAmbient, ambientLight);
GL.Enable(EnableCap.Normalize);
GL.Enable(EnableCap.ColorMaterial);
}
public class CustomOpenGLControl : GLControl
{
public CustomOpenGLControl()
: base(new OpenTK.Graphics.GraphicsMode(32, 24, 8))
{
}
}
private void drawFrame()
{
GL.Color3(Color.Red);
GL.Begin(BeginMode.Quads);
GL.Normal3(0.0f, -1.0f, 0.0f);
for (int i = 0; i < upWall.Length; i++)
{
GL.Vertex3(upWall[i].x, upWall[i].y, upWall[i].z);
}
GL.End();
GL.Color3(Color.Yellow);
GL.Begin(BeginMode.Quads);
GL.Normal3(0.0f, -1.0f, 0.0f);
for (int i = 0; i < downWall.Length; i++)
{
GL.Vertex3(downWall[i].x, downWall[i].y, downWall[i].z);
}
GL.End();
GL.Color3(Color.Green);
GL.Begin(BeginMode.Quads);
GL.Normal3(0.0f, 0.0f, -1.0f);
for (int i = 0; i < backWall.Length; i++)
{
GL.Vertex3(backWall[i].x, backWall[i].y, backWall[i].z);
}
GL.End();
GL.Color3(Color.Blue);
GL.Begin(BeginMode.Quads);
GL.Normal3(-1.0f, 0.0f, 0.0f);
for (int i = 0; i < rightWall.Length; i++)
{
GL.Vertex3(rightWall[i].x, rightWall[i].y, rightWall[i].z);
}
GL.End();
GL.Color3(Color.Orange);
GL.Begin(BeginMode.Quads);
GL.Normal3(1.0f, 0.0f, 0.0f);
for (int i = 0; i < leftWall.Length; i++)
{
GL.Vertex3(leftWall[i].x, leftWall[i].y, leftWall[i].z);
}
GL.End();
}
private void drawMirror()
{
GL.PushMatrix();
GL.Begin(BeginMode.Quads);
GL.Normal3(0.0f, -1.0f, 0.0f);
for (int i = 0; i < mirror.Length; i++)
{
GL.Vertex3(mirror[i].x, mirror[i].y, mirror[i].z);
}
GL.End();
GL.PopMatrix();
}
private void drawScene()
{
GL.Clear(ClearBufferMask.AccumBufferBit | ClearBufferMask.DepthBufferBit | ClearBufferMask.StencilBufferBit | ClearBufferMask.ColorBufferBit);
double[] eqr = { 0f, y0 + height / 6f, 0f, 0.0f };
GL.PushMatrix();
GL.ColorMask(false, false, false, false);
GL.Enable(EnableCap.StencilTest);
GL.StencilFunc(StencilFunction.Always, 1, 1);
GL.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Replace);
GL.Disable(EnableCap.DepthTest);
drawMirror();
GL.Enable(EnableCap.DepthTest);
GL.ColorMask(true, true, true, true);
GL.StencilFunc(StencilFunction.Equal, 1, 1);
GL.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Keep);
GL.Enable(EnableCap.ClipPlane0);
GL.ClipPlane(ClipPlaneName.ClipPlane0, eqr);
GL.PushMatrix();
GL.Scale(1, -1, 1);
drawFrame();
GL.PopMatrix();
GL.Disable(EnableCap.ClipPlane0);
GL.Disable(EnableCap.StencilTest);
GL.Enable(EnableCap.Blend);
GL.Disable(EnableCap.Lighting);
GL.Color4(1, 1, 1, 0.3f);
GL.BlendFunc(BlendingFactorSrc.SrcAlpha, BlendingFactorDest.OneMinusSrcAlpha);
drawMirror();
GL.Enable(EnableCap.Lighting);
GL.Disable(EnableCap.Blend);
drawFrame();
GL.PopMatrix();
}
}

Answer 1

Sorry, I cant help too much with this. I would run your code, but unfortunately I am not at my programming computer right now, and I don't have any experience with opentk.