internal BackgroundChangeEvent(double TrackPositionDelta, World.Background PreviousBackground, World.Background NextBackground)
{
this.TrackPositionDelta = TrackPositionDelta;
this.DontTriggerAnymore = false;
this.PreviousBackground = PreviousBackground;
this.NextBackground = NextBackground;
}
internal BackgroundChangeEvent(double TrackPositionDelta, World.Background PreviousBackground, World.Background NextBackground)
{
this.TrackPositionDelta = TrackPositionDelta;
this.DontTriggerAnymore = false;
this.PreviousBackground = PreviousBackground;
this.NextBackground = NextBackground;
}
private static void RenderBackground(World.Background Data, float Alpha, float scale)
{
if (Data.Texture != null && Textures.LoadTexture(Data.Texture, Textures.OpenGlTextureWrapMode.RepeatClamp))
{
if (LightingEnabled)
{
GL.Disable(EnableCap.Lighting);
LightingEnabled = false;
}
if (!TexturingEnabled)
{
GL.Enable(EnableCap.Texture2D);
TexturingEnabled = true;
}
if (Alpha == 1.0f)
{
if (BlendEnabled)
{
GL.Disable(EnableCap.Blend);
BlendEnabled = false;
}
}
else if (!BlendEnabled)
{
GL.Enable(EnableCap.Blend);
BlendEnabled = true;
}
GL.BindTexture(TextureTarget.Texture2D, Data.Texture.OpenGlTextures[(int)Textures.OpenGlTextureWrapMode.RepeatClamp].Name);
GL.Color4(1.0f, 1.0f, 1.0f, Alpha);
if (!DisplayListAvailable)
{
BackgroundDisplayList = GL.GenLists(1);
GL.NewList(BackgroundDisplayList, ListMode.Compile);
float y0, y1;
if (Data.KeepAspectRatio)
{
int tw = Data.Texture.Width;
int th = Data.Texture.Height;
double hh = Math.PI * World.BackgroundImageDistance * (double)th /
((double)tw * (double)Data.Repetition);
y0 = (float)(-0.5 * hh);
y1 = (float)(1.5 * hh);
}
else
{
y0 = (float)(-0.125 * World.BackgroundImageDistance);
y1 = (float)(0.375 * World.BackgroundImageDistance);
}
const int n = 32;
Vector3[] bottom = new Vector3[n];
Vector3[] top = new Vector3[n];
double angleValue = 2.61799387799149 - 3.14159265358979 / (double)n;
const double angleIncrement = 6.28318530717958 / (double)n;
/*
* To ensure that the whole background cylinder is rendered inside the viewing frustum,
* the background is rendered before the scene with z-buffer writes disabled. Then,
* the actual distance from the camera is irrelevant as long as it is inside the frustum.
* */
for (int i = 0; i < n; i++)
{
float x = (float)(World.BackgroundImageDistance * Math.Cos(angleValue));
float z = (float)(World.BackgroundImageDistance * Math.Sin(angleValue));
bottom[i] = new Vector3(scale * x, scale * y0, scale * z);
top[i] = new Vector3(scale * x, scale * y1, scale * z);
angleValue += angleIncrement;
}
float textureStart = 0.5f * (float)Data.Repetition / (float)n;
float textureIncrement = -(float)Data.Repetition / (float)n;
double textureX = textureStart;
for (int i = 0; i < n; i++)
{
int j = (i + 1) % n;
// side wall
GL.Begin(PrimitiveType.Quads);
GL.TexCoord2(textureX, 0.005f);
GL.Vertex3(top[i].X, top[i].Y, top[i].Z);
GL.TexCoord2(textureX, 0.995f);
GL.Vertex3(bottom[i].X, bottom[i].Y, bottom[i].Z);
GL.TexCoord2(textureX + textureIncrement, 0.995f);
GL.Vertex3(bottom[j].X, bottom[j].Y, bottom[j].Z);
GL.TexCoord2(textureX + textureIncrement, 0.005f);
GL.Vertex3(top[j].X, top[j].Y, top[j].Z);
GL.End();
// top cap
GL.Begin(PrimitiveType.Triangles);
GL.TexCoord2(textureX, 0.005f);
GL.Vertex3(top[i].X, top[i].Y, top[i].Z);
GL.TexCoord2(textureX + textureIncrement, 0.005f);
GL.Vertex3(top[j].X, top[j].Y, top[j].Z);
GL.TexCoord2(textureX + 0.5 * textureIncrement, 0.1f);
GL.Vertex3(0.0f, top[i].Y, 0.0f);
// bottom cap
GL.TexCoord2(textureX + 0.5 * textureIncrement, 0.9f);
GL.Vertex3(0.0f, bottom[i].Y, 0.0f);
GL.TexCoord2(textureX + textureIncrement, 0.995f);
GL.Vertex3(bottom[j].X, bottom[j].Y, bottom[j].Z);
GL.TexCoord2(textureX, 0.995f);
GL.Vertex3(bottom[i].X, bottom[i].Y, bottom[i].Z);
GL.End();
// finish
textureX += textureIncrement;
}
GL.EndList();
GL.CallList(BackgroundDisplayList);
GL.Disable(EnableCap.Texture2D);
TexturingEnabled = false;
if (!BlendEnabled)
{
GL.Enable(EnableCap.Blend);
BlendEnabled = true;
}
DisplayListAvailable = true;
}
else
{
GL.CallList(BackgroundDisplayList);
GL.Disable(EnableCap.Texture2D);
TexturingEnabled = false;
if (!BlendEnabled)
{
GL.Enable(EnableCap.Blend);
BlendEnabled = true;
}
}
}
}
