/// <summary>
/// <see cref="PrepareForDraw"/> prepares and updates the Material, ShapeBuilder and VertexBuilder if necessary
/// </summary>
public void PrepareForDraw(out bool vertexBufferHasChanged, out int vertexSize, out int vertexCount)
{
var fieldsList = new ParticlePoolFieldsList(pool);
// User changes to materials might cause vertex layout change
Material.PrepareVertexLayout(fieldsList);
// User changes to shape builders might cause vertex layout change
ShapeBuilder.PrepareVertexLayout(fieldsList);
// Recalculate the required vertex count and stride
VertexBuilder.SetRequiredQuads(ShapeBuilder.QuadsPerParticle, pool.LivingParticles, pool.ParticleCapacity);
vertexBufferHasChanged = (Material.HasVertexLayoutChanged || ShapeBuilder.VertexLayoutHasChanged || VertexBuilder.IsBufferDirty);
// Update the vertex builder and the vertex layout if needed
if (vertexBufferHasChanged)
{
VertexBuilder.ResetVertexElementList();
Material.UpdateVertexBuilder(VertexBuilder);
ShapeBuilder.UpdateVertexBuilder(VertexBuilder);
VertexBuilder.UpdateVertexLayout();
}
vertexSize = VertexBuilder.VertexDeclaration.CalculateSize();
vertexCount = VertexBuilder.VertexCount;
VertexBuilder.SetDirty(false);
}
/// <summary>
/// <see cref="PrepareForDraw"/> prepares and updates the Material, ShapeBuilder and VertexBuilder if necessary
/// </summary>
public void PrepareForDraw()
{
Material.PrepareForDraw(VertexBuilder, ParticleSorter);
ShapeBuilder.PrepareForDraw(VertexBuilder, ParticleSorter);
// Update the vertex builder and the vertex layout if needed
if (Material.HasVertexLayoutChanged || ShapeBuilder.VertexLayoutHasChanged)
{
VertexBuilder.ResetVertexElementList();
Material.UpdateVertexBuilder(VertexBuilder);
ShapeBuilder.UpdateVertexBuilder(VertexBuilder);
VertexBuilder.UpdateVertexLayout();
}
VertexBuilder.SetRequiredQuads(ShapeBuilder.QuadsPerParticle, pool.LivingParticles, pool.ParticleCapacity);
}
/// <summary>
/// Build the vertex buffer from particle data
/// Should come before <see cref="KickVertexBuffer"/>
/// </summary>
/// <param name="device">The graphics device, used to rebuild vertex layouts and shaders if needed</param>
/// <param name="invViewMatrix">The current camera's inverse view matrix</param>
public void BuildVertexBuffer(GraphicsDevice device, ref Matrix invViewMatrix)
{
// Get camera-space X and Y axes for billboard expansion and sort the particles if needed
var unitX = new Vector3(invViewMatrix.M11, invViewMatrix.M12, invViewMatrix.M13);
var unitY = new Vector3(invViewMatrix.M21, invViewMatrix.M22, invViewMatrix.M23);
depthSortVector = Vector3.Cross(unitX, unitY);
ParticleSorter.Sort();
// If the particles are in world space they don't need to be fixed as their coordinates are already in world space
// If the particles are in local space they need to be drawn in world space using the emitter's current location matrix
var posIdentity = new Vector3(0, 0, 0);
var rotIdentity = new Quaternion(0, 0, 0, 1);
var scaleIdentity = 1f;
if (simulationSpace == EmitterSimulationSpace.Local)
{
posIdentity = drawPosition;
rotIdentity = drawRotation;
scaleIdentity = drawScale;
}
PrepareForDraw();
vertexBuilder.SetRequiredQuads(ShapeBuilder.QuadsPerParticle, pool.LivingParticles, pool.ParticleCapacity);
vertexBuilder.MapBuffer(device);
ShapeBuilder.BuildVertexBuffer(vertexBuilder, unitX, unitY, ref posIdentity, ref rotIdentity, scaleIdentity, ParticleSorter);
vertexBuilder.RestartBuffer();
Material.PatchVertexBuffer(vertexBuilder, unitX, unitY, ParticleSorter);
vertexBuilder.UnmapBuffer(device);
}