/// <summary>
/// Lazily recomputes the world inverse transpose matrix and
/// eye position based on the current effect parameter settings.
/// </summary>
internal static BlEffectDirtyFlags SetLightingMatrices(BlEffectDirtyFlags dirtyFlags, ref Matrix world, ref Matrix view,
EffectParameter worldParam, EffectParameter worldInverseTransposeParam, EffectParameter eyePositionParam)
{
// Set the world and world inverse transpose matrices.
if ((dirtyFlags & BlEffectDirtyFlags.World) != 0)
{
Matrix worldTranspose;
Matrix worldInverseTranspose;
Matrix.Invert(ref world, out worldTranspose);
Matrix.Transpose(ref worldTranspose, out worldInverseTranspose);
worldParam.SetValue(world);
worldInverseTransposeParam.SetValue(worldInverseTranspose);
dirtyFlags &= ~BlEffectDirtyFlags.World;
}
// Set the eye position.
if ((dirtyFlags & BlEffectDirtyFlags.EyePosition) != 0)
{
Matrix viewInverse;
Matrix.Invert(ref view, out viewInverse);
eyePositionParam.SetValue(viewInverse.Translation);
dirtyFlags &= ~BlEffectDirtyFlags.EyePosition;
}
return(dirtyFlags);
}
/// <summary>
/// Lazily recomputes the world+view+projection matrix and
/// fog vector based on the current effect parameter settings.
/// </summary>
internal static BlEffectDirtyFlags SetWorldViewProjAndFog(BlEffectDirtyFlags dirtyFlags,
ref Matrix world, ref Matrix view, ref Matrix projection, ref Matrix worldView,
bool fogEnabled, float fogStart, float fogEnd,
EffectParameter worldViewProjParam, EffectParameter fogVectorParam)
{
// Recompute the world+view+projection matrix?
if ((dirtyFlags & BlEffectDirtyFlags.WorldViewProj) != 0)
{
Matrix worldViewProj;
Matrix.Multiply(ref world, ref view, out worldView);
Matrix.Multiply(ref worldView, ref projection, out worldViewProj);
worldViewProjParam.SetValue(worldViewProj);
dirtyFlags &= ~BlEffectDirtyFlags.WorldViewProj;
}
if (fogEnabled)
{
// Recompute the fog vector?
if ((dirtyFlags & (BlEffectDirtyFlags.Fog | BlEffectDirtyFlags.FogEnable)) != 0)
{
SetFogVector(ref worldView, fogStart, fogEnd, fogVectorParam);
dirtyFlags &= ~(BlEffectDirtyFlags.Fog | BlEffectDirtyFlags.FogEnable);
}
}
else
{
// When fog is disabled, make sure the fog vector is reset to zero.
if ((dirtyFlags & BlEffectDirtyFlags.FogEnable) != 0)
{
fogVectorParam.SetValue(Vector4.Zero);
dirtyFlags &= ~BlEffectDirtyFlags.FogEnable;
}
}
return(dirtyFlags);
}
/// <summary>
/// Lazily computes derived parameter values immediately before applying the effect.
/// </summary>
protected override void OnApply()
{
// Recompute the world+view+projection matrix or fog vector?
dirtyFlags = BlEffectHelpers.SetWorldViewProjAndFog(dirtyFlags, ref world, ref view, ref projection, ref worldView, fogEnabled, fogStart, fogEnd, worldViewProjParam, fogVectorParam);
// Recompute the diffuse/emissive/alpha material color parameters?
if ((dirtyFlags & BlEffectDirtyFlags.MaterialColor) != 0)
{
BlEffectHelpers.SetMaterialColor(lightingEnabled, alpha, ref diffuseColor, ref emissiveColor, ref ambientLightColor, diffuseColorParam, emissiveColorParam);
dirtyFlags &= ~BlEffectDirtyFlags.MaterialColor;
}
if (lightingEnabled)
{
// Recompute the world inverse transpose and eye position?
dirtyFlags = BlEffectHelpers.SetLightingMatrices(dirtyFlags, ref world, ref view, worldParam, worldInverseTransposeParam, eyePositionParam);
// Check if we can use the only-bother-with-the-first-light shader optimization.
bool newOneLight = !light1.Enabled && !light2.Enabled;
if (oneLight != newOneLight)
{
oneLight = newOneLight;
dirtyFlags |= BlEffectDirtyFlags.ShaderIndex;
}
}
// Recompute the shader index?
if ((dirtyFlags & BlEffectDirtyFlags.ShaderIndex) != 0)
{
int shaderIndex = 0;
if (!fogEnabled)
{
shaderIndex += 1;
}
if (vertexColorEnabled)
{
shaderIndex += 2;
}
if (textureEnabled)
{
shaderIndex += 4;
}
if (lightingEnabled)
{
if (preferPerPixelLighting)
{
shaderIndex += 24;
}
else if (oneLight)
{
shaderIndex += 16;
}
else
{
shaderIndex += 8;
}
}
dirtyFlags &= ~BlEffectDirtyFlags.ShaderIndex;
CurrentTechnique = Techniques[shaderIndex];
}
}
