/// <summary>
/// numberOfBuffers is the amount of vertex buffers used by the particle system for multi buffering.
/// Multi buffering can avoid stalling of the GPU but will also increases it's memory consumption.
/// If you want to avoid stalling create the same amount of buffers as your maximum rendered emitters at the
/// same time.
/// For example allocating one buffer with 16383 particles takes up 2048KB(2MB) GPU memory.
/// This call requires that there is a GL context
/// </summary>
/// <param name="numberOfBuffers">the amount of vertex buffers used by the particle system for multi buffering.</param>
/// <param name="maxParticlesPerBuffer">Maximum number of particles that you will be able to display.</param>
public static void Init(int numberOfBuffers = 2, int maxParticlesPerBuffer = MaxPossibleParticles)
{
_numberOfVertexBuffers = numberOfBuffers;
if (maxParticlesPerBuffer > MaxPossibleParticles)
{
maxParticlesPerBuffer = MaxPossibleParticles;
Debug.WriteLine("StardustStarlingRenderer WARNING: Tried to render than possible particles, setting value to max");
}
_maxParticles = maxParticlesPerBuffer;
SparrowParticleBuffers.CreateBuffers(maxParticlesPerBuffer, numberOfBuffers);
if (!_initCalled)
{
for (int i = 0; i < 0x800; ++i)
{
SCosLut[i & 0x7FF] = (float)Math.Cos(i * 0.00306796157577128245943617517898); // 0.003067 = 2PI/2048
SSinLut[i & 0x7FF] = (float)Math.Sin(i * 0.00306796157577128245943617517898);
}
// handle a lost device context
SparrowSharp.ContextCreated += SparrowSharpOnContextCreated;
_initCalled = true;
}
}
private static void SparrowSharpOnContextCreated()
{
SparrowParticleBuffers.CreateBuffers(_maxParticles, _numberOfVertexBuffers);
}
private void RenderCustom(Painter painter, int mNumBatchedParticles, float parentAlpha)
{
if (_mNumParticles == 0 || SparrowParticleBuffers.BuffersCreated == false)
{
return;
}
if (mNumBatchedParticles > _maxParticles)
{
Debug.WriteLine("Over " + _maxParticles + " particles! Aborting rendering");
return;
}
SparrowParticleBuffers.SwitchVertexBuffer();
painter.FinishMeshBatch();
painter.DrawCount += 1;
painter.PrepareToDraw();
global::Sparrow.Display.BlendMode.Get(BlendMode).Activate();
RenderAlpha[0] = RenderAlpha[1] = RenderAlpha[2] = PremultiplyAlpha ? parentAlpha : 1;
RenderAlpha[3] = parentAlpha;
var program = ParticleProgram.GetProgram();
program.Activate();
int uAlpha = program.Uniforms["uAlpha"];
Gl.Uniform4(uAlpha, RenderAlpha[0], RenderAlpha[1], RenderAlpha[2], RenderAlpha[3]);
int uMvpMatrix = program.Uniforms["uMvpMatrix"];
Gl.UniformMatrix4(uMvpMatrix, false, painter.State.MvpMatrix3D.RawData);
//context.setTextureAt(0, mTexture.Base);
Gl.BindBuffer(BufferTarget.ArrayBuffer, SparrowParticleBuffers.VertexBuffer);
Gl.BufferData(BufferTarget.ArrayBuffer, (uint)(_vertexes.Length * sizeof(float)), _vertexes, BufferUsage.DynamicDraw);
uint attribPosition = (uint)program.Attributes["aPosition"];
Gl.EnableVertexAttribArray(attribPosition);
Gl.VertexAttribPointer(attribPosition, 2, VertexAttribType.Float, false, 32, (IntPtr)0);
uint attribColor = (uint)program.Attributes["aColor"];
Gl.EnableVertexAttribArray(attribColor);
Gl.VertexAttribPointer(attribColor, 4, VertexAttribType.Float, false, 32, (IntPtr)8);
uint aTexCoords = (uint)program.Attributes["aTexCoords"];
Gl.EnableVertexAttribArray(aTexCoords);
Gl.VertexAttribPointer(aTexCoords, 2, VertexAttribType.Float, false, 32, (IntPtr)24);
Gl.ActiveTexture(TextureUnit.Texture0);
RenderUtil.SetSamplerStateAt(_mTexture.Base, _mTexture.NumMipMaps > 0, TexSmoothing);
Gl.BindBuffer(BufferTarget.ElementArrayBuffer, SparrowParticleBuffers.IndexBuffer);
// TODO limit max number of particles
Gl.DrawElements(PrimitiveType.Triangles, (_mNumParticles + mNumBatchedParticles) * 6, DrawElementsType.UnsignedShort, IntPtr.Zero);
Gl.DisableVertexAttribArray(attribPosition);
Gl.DisableVertexAttribArray(attribColor);
Gl.DisableVertexAttribArray(aTexCoords);
Gl.BindTexture(TextureTarget.Texture2d, 0);
}
