/**
* Called once when OpenGL is ready.
* */
public void Init()
{
// Stencil test
GL.Enable(EnableCap.StencilTest);
// Depth test
GL.Enable(EnableCap.DepthTest);
// Blending
GL.Enable(EnableCap.Blend);
GL.BlendFunc(BlendingFactorSrc.SrcAlpha, BlendingFactorDest.OneMinusSrcAlpha);
// Culling
GL.Enable(EnableCap.CullFace);
GL.CullFace(CullFaceMode.Back);
GL.FrontFace(FrontFaceDirection.Ccw);
Shader.CheckError();
// OpenGL-Information
string version_string = GL.GetString(StringName.Version);
Console.WriteLine("OpenGL-Version: " + version_string);
Shader.CheckError();
Console.WriteLine("Stencil buffer bits: " + GL.GetInteger(GetPName.StencilBits));
Shader.CheckError();
Console.WriteLine("Depth buffer bits: " + GL.GetInteger(GetPName.DepthBits));
Shader.CheckError();
// For OpenGL 2.1 and lower
Dictionary <string, bool> extensions =
new Dictionary <string, bool>();
string extension_string = GL.GetString(StringName.Extensions);
foreach (string extension in extension_string.Split(' '))
{
extensions.Add(extension, true);
}
GL.ClearColor(rootNode.BackgroundColor.X,
rootNode.BackgroundColor.Y,
rootNode.BackgroundColor.Z, 1);
// Setup shader
shader.CompileAndLink();
shader.Use();
ShaderAttributes.GetInstance().GetAttributes(shader.ProgramId);
// Start timer
timer.Start();
InitContent();
}
/**
* Draw the scene graph content - regular mode.
* */
private void DrawRegular()
{
ShaderAttributes.GetInstance().SetCameraEyeParameter(camera.Eye);
ShaderAttributes.GetInstance().SetShaderModeParameter(GetRoot().Shader.Mode);
ShaderAttributes.GetInstance().SetLightPositionParameter(rootNode.LightPosition);
// No change in stencil buffer
GL.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Keep);
// Draw if stencil value is > 0
GL.StencilFunc(StencilFunction.Always, 0, 255);
rootNode.Traverse(RenderMode.REGULAR, Matrix4.Identity);
}
/**
* Draw using the VBO
* */
public void Draw()
{
if (vertexBufferId < 0 || normalBufferId < 0 || colorBufferId < 0 || indexBufferId < 0 || texCoordBufferId < 0)
{
Init();
}
GL.EnableVertexAttribArray(
ShaderAttributes.GetInstance().LocationPosition);
GL.EnableVertexAttribArray(
ShaderAttributes.GetInstance().LocationNormal);
GL.EnableVertexAttribArray(
ShaderAttributes.GetInstance().LocationColor);
GL.EnableVertexAttribArray(
ShaderAttributes.GetInstance().LocationTexCoords);
GL.BindBuffer(BufferTarget.ArrayBuffer, vertexBufferId);
GL.VertexAttribPointer(ShaderAttributes.GetInstance().LocationPosition,
3, VertexAttribPointerType.Float, false, 0, IntPtr.Zero);
GL.BindBuffer(BufferTarget.ArrayBuffer, normalBufferId);
GL.VertexAttribPointer(ShaderAttributes.GetInstance().LocationNormal,
3, VertexAttribPointerType.Float, false, 0, IntPtr.Zero);
GL.BindBuffer(BufferTarget.ArrayBuffer, colorBufferId);
GL.VertexAttribPointer(ShaderAttributes.GetInstance().LocationColor,
4, VertexAttribPointerType.Float, false, 0, IntPtr.Zero);
GL.BindBuffer(BufferTarget.ArrayBuffer, texCoordBufferId);
GL.VertexAttribPointer(ShaderAttributes.GetInstance().LocationTexCoords,
2, VertexAttribPointerType.Float, false, 0, IntPtr.Zero);
GL.DrawArrays(primitiveType, 0, renderVertices.Count);
Shader.CheckError();
}
public override void Traverse(RenderMode mode, Matrix4 modelMatrix)
{
ShaderAttributes.GetInstance().SetModelMatrixParameter(modelMatrix);
ShaderAttributes.GetInstance().SetViewMatrixParameter(GetRootNode().Camera.GetViewMatrix());
DrawGL(mode, modelMatrix);
}
private void DrawShadowVolume()
{
GL.ClearStencil(0);
GL.Clear(ClearBufferMask.StencilBufferBit);
// ************* ORIGINAL SCENE - NO LIGHTING *************
// Stencil buffer never changed
GL.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Keep);
// Stencil test always passed
GL.StencilFunc(StencilFunction.Always, 0, 255);
// Setup shader
shader.Mode = Shader.ShaderMode.AMBIENT_ONLY;
ShaderAttributes.GetInstance().SetCameraEyeParameter(camera.Eye);
ShaderAttributes.GetInstance().SetShaderModeParameter(GetRoot().Shader.Mode);
ShaderAttributes.GetInstance().SetLightPositionParameter(rootNode.LightPosition);
// Render scene w/o lighting
rootNode.Traverse(RenderMode.REGULAR, Matrix4.Identity);
// ************* SHADOW VOLUMS BACK FACES *************
// Disable writes to the depth and color buffers.
GL.DepthMask(false);
GL.ColorMask(false, false, false, false);
// Use back-face culling.
GL.CullFace(CullFaceMode.Back);
// Stencil buffer always inc
GL.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Incr);
// Stencil test always passed
GL.StencilFunc(StencilFunction.Always, 0, 255);
// Render the shadow volumes (because of culling, only their front faces are rendered).
rootNode.Traverse(RenderMode.SHADOW_VOLUME, Matrix4.Identity);
// ************* SHADOW VOLUMS FRONT FACES *************
// GL.Begin (PrimitiveType.Quads);
// GL.Vertex3 (-0.5f, 0.5, -0.5f);
// GL.Vertex3 (-0.5f, 0.5, 0.5f);
// GL.Vertex3 (0.5f, 0.5, 0.5f);
// GL.Vertex3 (0.5f, 0.5, -0.5f);
// GL.End ();
//
// Use front-face culling.
GL.CullFace(CullFaceMode.Front);
// Set the stencil operation to decrement on depth pass.
GL.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Decr);
// Render the shadow volumes (only their back faces are rendered).
rootNode.Traverse(RenderMode.SHADOW_VOLUME, Matrix4.Identity);
// ************* ORIGINAL SCENE *************
// No change in stencil buffer
GL.StencilOp(StencilOp.Keep, StencilOp.Keep, StencilOp.Keep);
// Draw if stencil value is > 0
GL.StencilFunc(StencilFunction.Equal, 0, 255);
GL.DepthMask(true);
GL.ColorMask(true, true, true, true);
GL.CullFace(CullFaceMode.Back);
GL.Clear(ClearBufferMask.DepthBufferBit);
shader.Mode = Shader.ShaderMode.PHONG;
ShaderAttributes.GetInstance().SetShaderModeParameter(GetRoot().Shader.Mode);
rootNode.Traverse(RenderMode.REGULAR, Matrix4.Identity);
}