/// <summary> Called before Render (normally by RenderList::Render) to set up data for the render.
/// currentstate may be null, meaning, don't apply
/// RenderState may be null, meaning don't change</summary>
public void Bind(GLRenderState currentstate, IGLProgramShader shader, GLMatrixCalc matrixcalc)
{
if (currentstate != null && RenderState != null) // if either null, it means the last render state applied is the same as our render state, so no need to apply
{
currentstate.ApplyState(RenderState); // else go to this state
}
VertexArray?.Bind(); // give the VA a chance to bind to GL
RenderData?.Bind(this, shader, matrixcalc); // optional render data supplied by the user to bind
ElementBuffer?.BindElement(); // if we have an element buffer, give it a chance to bind
IndirectBuffer?.BindIndirect(); // if we have an indirect buffer, give it a chance to bind
ParameterBuffer?.BindParameter(); // if we have a parameter buffer, give it a chance to bind
}
static unsafe void RunCompute(Sample sample, bool indirectSupported)
{
// build vertex layouts
var quadLayout = new VertexLayout();
quadLayout.Begin()
.Add(VertexAttributeUsage.Position, 2, VertexAttributeType.Float)
.End();
var computeLayout = new VertexLayout();
computeLayout.Begin()
.Add(VertexAttributeUsage.TexCoord0, 4, VertexAttributeType.Float)
.End();
// static quad data
var vb = new VertexBuffer(MemoryBlock.FromArray(QuadVertices), quadLayout);
var ib = new IndexBuffer(MemoryBlock.FromArray(QuadIndices));
// create compute buffers
var currPositionBuffer0 = new DynamicVertexBuffer(1 << 15, computeLayout, BufferFlags.ComputeReadWrite);
var currPositionBuffer1 = new DynamicVertexBuffer(1 << 15, computeLayout, BufferFlags.ComputeReadWrite);
var prevPositionBuffer0 = new DynamicVertexBuffer(1 << 15, computeLayout, BufferFlags.ComputeReadWrite);
var prevPositionBuffer1 = new DynamicVertexBuffer(1 << 15, computeLayout, BufferFlags.ComputeReadWrite);
// load shaders
var particleProgram = ResourceLoader.LoadProgram("vs_particle", "fs_particle");
var initInstancesProgram = ResourceLoader.LoadProgram("cs_init_instances");
var updateInstancesProgram = ResourceLoader.LoadProgram("cs_update_instances");
// indirect rendering support
var indirectProgram = SharpBgfx.Program.Invalid;
var indirectBuffer = IndirectBuffer.Invalid;
bool useIndirect = false;
if (indirectSupported)
{
indirectProgram = ResourceLoader.LoadProgram("cs_indirect");
indirectBuffer = new IndirectBuffer(2);
useIndirect = true;
}
// setup params uniforms
var paramData = new ParamsData {
TimeStep = 0.0157f,
DispatchSize = 32,
Gravity = 0.109f,
Damping = 0.25f,
ParticleIntensity = 0.64f,
ParticleSize = 0.279f,
BaseSeed = 57,
ParticlePower = 3.5f,
InitialSpeed = 3.2f,
InitialShape = 1,
MaxAccel = 100.0f
};
// have the compute shader run initialization
var u_params = new Uniform("u_params", UniformType.Vector4, 3);
Bgfx.SetUniform(u_params, ¶mData, 3);
Bgfx.SetComputeBuffer(0, prevPositionBuffer0, ComputeBufferAccess.Write);
Bgfx.SetComputeBuffer(1, currPositionBuffer0, ComputeBufferAccess.Write);
Bgfx.Dispatch(0, initInstancesProgram, MaxParticleCount / ThreadGroupUpdateSize);
// start the frame clock
var clock = new Clock();
clock.Start();
// main loop
while (sample.ProcessEvents(ResetFlags.Vsync))
{
// tick the clock
var elapsed = clock.Frame();
var time = clock.TotalTime();
// write some debug text
Bgfx.DebugTextClear();
Bgfx.DebugTextWrite(0, 1, DebugColor.White, DebugColor.Blue, "SharpBgfx/Samples/24-NBody");
Bgfx.DebugTextWrite(0, 2, DebugColor.White, DebugColor.Cyan, "Description: N-body simulation with compute shaders using buffers.");
Bgfx.DebugTextWrite(0, 3, DebugColor.White, DebugColor.Cyan, "Frame: {0:F3} ms", elapsed * 1000);
// fill the indirect buffer if we're using it
if (useIndirect)
{
Bgfx.SetUniform(u_params, ¶mData, 3);
Bgfx.SetComputeBuffer(0, indirectBuffer, ComputeBufferAccess.Write);
Bgfx.Dispatch(0, indirectProgram);
}
// update particle positions
Bgfx.SetComputeBuffer(0, prevPositionBuffer0, ComputeBufferAccess.Read);
Bgfx.SetComputeBuffer(1, currPositionBuffer0, ComputeBufferAccess.Read);
Bgfx.SetComputeBuffer(2, prevPositionBuffer1, ComputeBufferAccess.Write);
Bgfx.SetComputeBuffer(3, currPositionBuffer1, ComputeBufferAccess.Write);
Bgfx.SetUniform(u_params, ¶mData, 3);
if (useIndirect)
{
Bgfx.Dispatch(0, updateInstancesProgram, indirectBuffer, 1);
}
else
{
Bgfx.Dispatch(0, updateInstancesProgram, paramData.DispatchSize);
}
// ping-pong the buffers for next frame
Swap(ref currPositionBuffer0, ref currPositionBuffer1);
Swap(ref prevPositionBuffer0, ref prevPositionBuffer1);
// view transforms for particle rendering
var viewMatrix = Matrix4x4.CreateLookAt(new Vector3(0.0f, 0.0f, -45.0f), -Vector3.UnitZ, Vector3.UnitY);
var projMatrix = Matrix4x4.CreatePerspectiveFieldOfView((float)Math.PI / 4, (float)sample.WindowWidth / sample.WindowHeight, 0.1f, 10000.0f);
Bgfx.SetViewTransform(0, &viewMatrix.M11, &projMatrix.M11);
Bgfx.SetViewRect(0, 0, 0, sample.WindowWidth, sample.WindowHeight);
// draw the particles
Bgfx.SetVertexBuffer(vb);
Bgfx.SetIndexBuffer(ib);
Bgfx.SetInstanceDataBuffer(currPositionBuffer0, 0, paramData.DispatchSize * ThreadGroupUpdateSize);
Bgfx.SetRenderState(RenderState.ColorWrite | RenderState.BlendAdd | RenderState.DepthTestAlways);
if (useIndirect)
{
Bgfx.Submit(0, particleProgram, indirectBuffer);
}
else
{
Bgfx.Submit(0, particleProgram);
}
// done with frame
Bgfx.Frame();
}
// cleanup
if (indirectSupported)
{
indirectProgram.Dispose();
indirectBuffer.Dispose();
}
u_params.Dispose();
currPositionBuffer0.Dispose();
currPositionBuffer1.Dispose();
prevPositionBuffer0.Dispose();
prevPositionBuffer1.Dispose();
updateInstancesProgram.Dispose();
initInstancesProgram.Dispose();
particleProgram.Dispose();
ib.Dispose();
vb.Dispose();
}
/// <summary>
/// Submits an indirect batch of drawing commands to be used for rendering.
/// </summary>
/// <param name="id">The index of the view to submit.</param>
/// <param name="program">The program with which to render.</param>
/// <param name="indirectBuffer">The buffer containing drawing commands.</param>
/// <param name="startIndex">The index of the first command to process.</param>
/// <param name="count">The number of commands to process from the buffer.</param>
/// <param name="depth">A depth value to use for sorting the batch.</param>
/// <returns>The number of draw calls.</returns>
public static int Submit(byte id, Program program, IndirectBuffer indirectBuffer, int startIndex = 0, int count = 1, int depth = 0)
{
return NativeMethods.bgfx_submit_indirect(id, program.handle, indirectBuffer.handle, (ushort)startIndex, (ushort)count, depth);
}
/// <summary>
/// Sets an indirect buffer as a compute resource.
/// </summary>
/// <param name="stage">The resource stage to set.</param>
/// <param name="buffer">The buffer to set.</param>
/// <param name="access">Access control flags.</param>
public static void SetComputeBuffer(byte stage, IndirectBuffer buffer, ComputeBufferAccess access)
{
NativeMethods.bgfx_set_compute_indirect_buffer(stage, buffer.handle, access);
}
/// <summary>
/// Dispatches an indirect compute job.
/// </summary>
/// <param name="id">The index of the view to dispatch.</param>
/// <param name="program">The shader program to use.</param>
/// <param name="indirectBuffer">The buffer containing drawing commands.</param>
/// <param name="startIndex">The index of the first command to process.</param>
/// <param name="count">The number of commands to process from the buffer.</param>
public static void Dispatch(byte id, Program program, IndirectBuffer indirectBuffer, int startIndex = 0, int count = 1)
{
// TODO: unused
byte unused = 0;
NativeMethods.bgfx_dispatch_indirect(id, program.handle, indirectBuffer.handle, (ushort)startIndex, (ushort)count, unused);
}