public AtmosphereVisualComponent(Path ShaderPath, AtmosphereOptions Options, AtmosphereQualityOptions QualityOptions)
{
Shader.PrecompilerInput pci = Shader.CreatePrecompilerInput();
this._Atmosphere = Atmosphere.Generate(Options, QualityOptions, pci, ShaderPath);
Path atmosphere = ShaderPath["Atmosphere"];
Atmosphere.DefineConstants(Options, QualityOptions, pci);
this._Main = Shader.Load(atmosphere["Planet.glsl"], pci);
this._Radius = Options.RadiusGround;
}
/// <summary>
/// Creates a precomputed atmosphere using shaders and the graphics card.
/// </summary>
public static PrecomputedAtmosphere Generate(
AtmosphereOptions Options,
AtmosphereQualityOptions QualityOptions,
Shader.PrecompilerInput PrecompilerInitial,
Path ShaderPath)
{
PrecomputedAtmosphere pa = new PrecomputedAtmosphere();
Shader.PrecompilerInput pci = PrecompilerInitial.Copy();
DefineConstants(Options, QualityOptions, pci);
Path atmosphere = ShaderPath["Atmosphere"];
Path precompute = atmosphere["Precompute"];
// Load shaders.
Shader.PrecompilerInput transmittancepci = pci.Copy();
Shader transmittance = Shader.Load(precompute["Transmittance.glsl"], transmittancepci);
Shader.PrecompilerInput irradianceinitialdeltapci = pci.Copy();
irradianceinitialdeltapci.Define("INITIAL");
irradianceinitialdeltapci.Define("DELTA");
Shader irradianceinitialdelta = Shader.Load(precompute["Irradiance.glsl"], irradianceinitialdeltapci);
Shader.PrecompilerInput irradianceinitialpci = pci.Copy();
irradianceinitialpci.Define("INITIAL");
Shader irradianceinitial = Shader.Load(precompute["Irradiance.glsl"], irradianceinitialpci);
Shader.PrecompilerInput irradiancedeltapci = pci.Copy();
irradiancedeltapci.Define("DELTA");
Shader irradiancedelta = Shader.Load(precompute["Irradiance.glsl"], irradiancedeltapci);
Shader.PrecompilerInput irradiancepci = pci.Copy();
Shader irradiance = Shader.Load(precompute["Irradiance.glsl"], irradiancepci);
Shader.PrecompilerInput inscatterinitialdeltapci = pci.Copy();
inscatterinitialdeltapci.Define("INITIAL");
inscatterinitialdeltapci.Define("DELTA");
Shader inscatterinitialdelta = Shader.Load(precompute["Inscatter.glsl"], inscatterinitialdeltapci);
Shader.PrecompilerInput inscatterinitialpci = pci.Copy();
inscatterinitialpci.Define("INITIAL");
Shader inscatterinitial = Shader.Load(precompute["Inscatter.glsl"], inscatterinitialpci);
Shader.PrecompilerInput inscatterdeltapci = pci.Copy();
inscatterdeltapci.Define("DELTA");
Shader inscatterdelta = Shader.Load(precompute["Inscatter.glsl"], inscatterdeltapci);
Shader.PrecompilerInput inscatterpci = pci.Copy();
Shader inscatter = Shader.Load(precompute["Inscatter.glsl"], inscatterpci);
Shader.PrecompilerInput pointscatterpci = pci.Copy();
Shader pointscatter = Shader.Load(precompute["PointScatter.glsl"], pointscatterpci);
// Initialize textures
int transwidth = QualityOptions.TransmittanceResMu;
int transheight = QualityOptions.TransmittanceResR;
int irrwidth = QualityOptions.IrradianceResMu;
int irrheight = QualityOptions.IrradianceResR;
int atwidth = QualityOptions.AtmosphereResMuS * QualityOptions.AtmosphereResNu;
int atheight = QualityOptions.AtmosphereResMu;
int atdepth = QualityOptions.AtmosphereResR;
pa.Transmittance = Texture.Initialize2D(transwidth, transheight, Texture.RGB16Float);
pa.Irradiance = Texture.Initialize2D(irrwidth, irrheight, Texture.RGB16Float);
pa.Inscatter = Texture.Initialize3D(atwidth, atheight, atdepth, Texture.RGBA16Float);
Texture irrdelta = Texture.Initialize2D(irrwidth, irrheight, Texture.RGB16Float);
Texture insdelta = Texture.Initialize3D(atwidth, atheight, atdepth, Texture.RGB16Float);
Texture ptsdelta = Texture.Initialize3D(atwidth, atheight, atdepth, Texture.RGB16Float);
pa.Transmittance.SetUnit(TextureTarget.Texture2D, TextureUnit.Texture0);
pa.Inscatter.SetUnit(TextureTarget.Texture3D, TextureUnit.Texture2);
irrdelta.SetUnit(TextureTarget.Texture2D, TextureUnit.Texture3);
insdelta.SetUnit(TextureTarget.Texture3D, TextureUnit.Texture4);
ptsdelta.SetUnit(TextureTarget.Texture3D, TextureUnit.Texture5);
uint fbo;
GL.GenFramebuffers(1, out fbo);
GL.BindFramebuffer(FramebufferTarget.FramebufferExt, fbo);
GL.ReadBuffer(ReadBufferMode.ColorAttachment0);
GL.DrawBuffer(DrawBufferMode.ColorAttachment0);
// Create transmittance texture (information about how light is filtered through the atmosphere).
transmittance.Call();
transmittance.Draw2DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
pa.Transmittance.ID, transwidth, transheight);
// Create delta irradiance texture (ground lighting cause by sun).
irradianceinitialdelta.Call();
irradianceinitialdelta.SetUniform("Transmittance", TextureUnit.Texture0);
irradianceinitialdelta.Draw2DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
irrdelta.ID, irrwidth, irrheight);
// Create initial inscatter texture (light from atmosphere from sun, rayleigh and mie parts seperated for precision).
inscatterinitial.Call();
inscatterinitial.SetUniform("Transmittance", TextureUnit.Texture0);
inscatterinitial.Draw3DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
pa.Inscatter.ID, atwidth, atheight, atdepth);
// Initialize irradiance to zero (ground lighting caused by atmosphere).
irradianceinitial.Call();
irradianceinitial.Draw2DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
pa.Irradiance.ID, irrwidth, irrheight);
// Copy inscatter to delta inscatter, combining rayleigh and mie parts.
inscatterinitialdelta.Call();
inscatterinitialdelta.SetUniform("Inscatter", TextureUnit.Texture2);
inscatterinitialdelta.Draw3DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
insdelta.ID, atwidth, atheight, atdepth);
for (int t = 2; t <= QualityOptions.MultipleScatteringOrder; t++)
{
// Generate point scattering information
// Note that this texture will likely be very dark because it contains data for a single point, as opposed to a long line.
pointscatter.Call();
pointscatter.SetUniform("IrradianceDelta", TextureUnit.Texture3);
pointscatter.SetUniform("InscatterDelta", TextureUnit.Texture4);
pointscatter.Draw3DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
ptsdelta.ID, atwidth, atheight, atdepth);
// Compute new irradiance delta using current inscatter delta.
irradiancedelta.Call();
irradiancedelta.SetUniform("InscatterDelta", TextureUnit.Texture4);
irradiancedelta.Draw2DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
irrdelta.ID, irrwidth, irrheight);
// Compute new inscatter delta using pointscatter data.
inscatterdelta.Call();
inscatterdelta.SetUniform("Transmittance", TextureUnit.Texture0);
inscatterdelta.SetUniform("PointScatter", TextureUnit.Texture5);
inscatterdelta.Draw3DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
insdelta.ID, atwidth, atheight, atdepth);
GL.Enable(EnableCap.Blend);
GL.BlendEquation(BlendEquationMode.FuncAdd);
GL.BlendFunc(BlendingFactorSrc.One, BlendingFactorDest.One);
// Add irradiance delta to irradiance.
irradiance.Call();
irradiance.SetUniform("IrradianceDelta", TextureUnit.Texture3);
irradiance.Draw2DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
pa.Irradiance.ID, irrwidth, irrheight);
// Add inscatter delta to inscatter.
inscatter.Call();
inscatter.SetUniform("InscatterDelta", TextureUnit.Texture4);
inscatter.Draw3DFrame(FramebufferTarget.FramebufferExt, FramebufferAttachment.ColorAttachment0Ext,
pa.Inscatter.ID, atwidth, atheight, atdepth);
GL.Disable(EnableCap.Blend);
}
insdelta.Delete();
irrdelta.Delete();
ptsdelta.Delete();
GL.BindFramebuffer(FramebufferTarget.FramebufferExt, 0);
GL.Finish();
GL.DeleteFramebuffers(1, ref fbo);
return pa;
}
/// <summary>
/// Makes an entity that displays an atmosphere.
/// </summary>
public static Entity MakeEntity(Path ShaderPath, AtmosphereOptions Options, AtmosphereQualityOptions QualityOptions)
{
return Entity.WithComponent(new AtmosphereVisualComponent(ShaderPath, Options, QualityOptions));
}
/// <summary>
/// Defines precompiler constants for atmosphere shaders based on options.
/// </summary>
public static void DefineConstants(
AtmosphereOptions Options,
AtmosphereQualityOptions QualityOptions,
Shader.PrecompilerInput PrecompilerInput)
{
PrecompilerInput.Define("ATMOSPHERE_RES_R", QualityOptions.AtmosphereResR.ToString());
PrecompilerInput.Define("ATMOSPHERE_RES_MU", QualityOptions.AtmosphereResMu.ToString());
PrecompilerInput.Define("ATMOSPHERE_RES_MU_S", QualityOptions.AtmosphereResMuS.ToString());
PrecompilerInput.Define("ATMOSPHERE_RES_NU", QualityOptions.AtmosphereResNu.ToString());
PrecompilerInput.Define("IRRADIANCE_RES_R", QualityOptions.IrradianceResR.ToString());
PrecompilerInput.Define("IRRADIANCE_RES_MU", QualityOptions.IrradianceResMu.ToString());
PrecompilerInput.Define("TRANSMITTANCE_RES_R", QualityOptions.TransmittanceResR.ToString());
PrecompilerInput.Define("TRANSMITTANCE_RES_MU", QualityOptions.TransmittanceResMu.ToString());
PrecompilerInput.Define("RADIUS_GROUND", Options.RadiusGround.ToString());
PrecompilerInput.Define("RADIUS_BOUND", Options.RadiusBound.ToString());
PrecompilerInput.Define("AVERAGE_GROUND_REFLECTANCE", Options.AverageGroundReflectance.ToString());
PrecompilerInput.Define("RAYLEIGH_AVERAGE_HEIGHT", Options.RayleighAverageHeight.ToString());
PrecompilerInput.Define("MIE_AVERAGE_HEIGHT", Options.MieAverageHeight.ToString());
}