bgfx/examples/24-nbody/nbody.cpp
2020-12-26 22:46:26 -08:00

467 lines
12 KiB
C++

/*
* Copyright 2014 Stanlo Slasinski. All rights reserved.
* License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
*/
#include "common.h"
#include "bgfx_utils.h"
#include "imgui/imgui.h"
#include "camera.h"
#include <bgfx/bgfx.h>
namespace
{
static const char* s_shapeNames[] =
{
"Point",
"Sphere",
"Box",
"Donut"
};
struct ParamsData
{
float timeStep;
int32_t dispatchSize;
float gravity;
float damping;
float particleIntensity;
float particleSize;
int32_t baseSeed;
float particlePower;
float initialSpeed;
int32_t initialShape;
float maxAccel;
};
void initializeParams(int32_t _mode, ParamsData* _params)
{
switch(_mode)
{
case 0:
_params->timeStep = 0.0067f;
_params->dispatchSize = 32;
_params->gravity = 0.069f;
_params->damping = 0.0f;
_params->particleIntensity = 0.35f;
_params->particleSize = 0.925f;
_params->baseSeed = 0;
_params->particlePower = 5.0f;
_params->initialSpeed = 122.6f;
_params->initialShape = 0;
_params->maxAccel = 30.0;
break;
case 1:
_params->timeStep = 0.0157f;
_params->dispatchSize = 32;
_params->gravity = 0.109f;
_params->damping = 0.25f;
_params->particleIntensity = 0.64f;
_params->particleSize = 0.279f;
_params->baseSeed = 57;
_params->particlePower = 3.5f;
_params->initialSpeed = 3.2f;
_params->initialShape = 1;
_params->maxAccel = 100.0;
break;
case 2:
_params->timeStep = 0.02f;
_params->dispatchSize = 32;
_params->gravity = 0.24f;
_params->damping = 0.12f;
_params->particleIntensity = 1.0f;
_params->particleSize = 1.0f;
_params->baseSeed = 23;
_params->particlePower = 4.0f;
_params->initialSpeed = 31.1f;
_params->initialShape = 2;
_params->maxAccel = 39.29f;
break;
case 3:
_params->timeStep = 0.0118f;
_params->dispatchSize = 32;
_params->gravity = 0.141f;
_params->damping = 1.0f;
_params->particleIntensity = 0.64f;
_params->particleSize = 0.28f;
_params->baseSeed = 60;
_params->particlePower = 1.97f;
_params->initialSpeed = 69.7f;
_params->initialShape = 3;
_params->maxAccel = 3.21f;
break;
}
}
static const float s_quadVertices[] =
{
1.0f, 1.0f,
-1.0f, 1.0f,
-1.0f, -1.0f,
1.0f, -1.0f,
};
static const uint16_t s_quadIndices[] = { 0, 1, 2, 2, 3, 0, };
const uint32_t kThreadGroupUpdateSize = 512;
const uint32_t kMaxParticleCount = 32 * 1024;
class ExampleNbody : public entry::AppI
{
public:
ExampleNbody(const char* _name, const char* _description, const char* _url)
: entry::AppI(_name, _description, _url)
{
}
void init(int32_t _argc, const char* const* _argv, uint32_t _width, uint32_t _height) override
{
Args args(_argc, _argv);
m_width = _width;
m_height = _height;
m_debug = BGFX_DEBUG_NONE;
m_reset = BGFX_RESET_VSYNC;
bgfx::Init init;
init.type = args.m_type;
init.vendorId = args.m_pciId;
init.resolution.width = m_width;
init.resolution.height = m_height;
init.resolution.reset = m_reset;
bgfx::init(init);
// Enable debug text.
bgfx::setDebug(m_debug);
// Set view 0 clear state.
bgfx::setViewClear(0
, BGFX_CLEAR_COLOR|BGFX_CLEAR_DEPTH
, 0x303030ff
, 1.0f
, 0
);
const bgfx::Caps* caps = bgfx::getCaps();
m_computeSupported = !!(caps->supported & BGFX_CAPS_COMPUTE);
m_indirectSupported = !!(caps->supported & BGFX_CAPS_DRAW_INDIRECT);
imguiCreate();
if (m_computeSupported)
{
bgfx::VertexLayout quadVertexLayout;
quadVertexLayout.begin()
.add(bgfx::Attrib::Position, 2, bgfx::AttribType::Float)
.end();
// Create static vertex buffer.
m_vbh = bgfx::createVertexBuffer(
// Static data can be passed with bgfx::makeRef
bgfx::makeRef(s_quadVertices, sizeof(s_quadVertices) )
, quadVertexLayout
);
// Create static index buffer.
m_ibh = bgfx::createIndexBuffer(
// Static data can be passed with bgfx::makeRef
bgfx::makeRef(s_quadIndices, sizeof(s_quadIndices) )
);
// Create particle program from shaders.
m_particleProgram = loadProgram("vs_particle", "fs_particle");
// Setup compute buffers
bgfx::VertexLayout computeVertexLayout;
computeVertexLayout.begin()
.add(bgfx::Attrib::TexCoord0, 4, bgfx::AttribType::Float)
.end();
m_currPositionBuffer0 = bgfx::createDynamicVertexBuffer(1 << 15, computeVertexLayout, BGFX_BUFFER_COMPUTE_READ_WRITE);
m_currPositionBuffer1 = bgfx::createDynamicVertexBuffer(1 << 15, computeVertexLayout, BGFX_BUFFER_COMPUTE_READ_WRITE);
m_prevPositionBuffer0 = bgfx::createDynamicVertexBuffer(1 << 15, computeVertexLayout, BGFX_BUFFER_COMPUTE_READ_WRITE);
m_prevPositionBuffer1 = bgfx::createDynamicVertexBuffer(1 << 15, computeVertexLayout, BGFX_BUFFER_COMPUTE_READ_WRITE);
u_params = bgfx::createUniform("u_params", bgfx::UniformType::Vec4, 3);
m_initInstancesProgram = bgfx::createProgram(loadShader("cs_init_instances"), true);
m_updateInstancesProgram = bgfx::createProgram(loadShader("cs_update_instances"), true);
m_indirectProgram = BGFX_INVALID_HANDLE;
m_indirectBuffer = BGFX_INVALID_HANDLE;
if (m_indirectSupported)
{
m_indirectProgram = bgfx::createProgram(loadShader("cs_indirect"), true);
m_indirectBuffer = bgfx::createIndirectBuffer(2);
}
initializeParams(0, &m_paramsData);
bgfx::setUniform(u_params, &m_paramsData, 3);
bgfx::setBuffer(0, m_prevPositionBuffer0, bgfx::Access::Write);
bgfx::setBuffer(1, m_currPositionBuffer0, bgfx::Access::Write);
bgfx::dispatch(0, m_initInstancesProgram, kMaxParticleCount / kThreadGroupUpdateSize, 1, 1);
cameraCreate();
cameraSetPosition({ 0.0f, 0.0f, -45.0f });
cameraSetVerticalAngle(0.0f);
m_useIndirect = false;
m_timeOffset = bx::getHPCounter();
}
}
virtual int shutdown() override
{
// Cleanup.
cameraDestroy();
imguiDestroy();
if (m_computeSupported)
{
if (m_indirectSupported)
{
bgfx::destroy(m_indirectProgram);
bgfx::destroy(m_indirectBuffer);
}
bgfx::destroy(u_params);
bgfx::destroy(m_currPositionBuffer0);
bgfx::destroy(m_currPositionBuffer1);
bgfx::destroy(m_prevPositionBuffer0);
bgfx::destroy(m_prevPositionBuffer1);
bgfx::destroy(m_updateInstancesProgram);
bgfx::destroy(m_initInstancesProgram);
bgfx::destroy(m_ibh);
bgfx::destroy(m_vbh);
bgfx::destroy(m_particleProgram);
}
// Shutdown bgfx.
bgfx::shutdown();
return 0;
}
bool update() override
{
if (!entry::processEvents(m_width, m_height, m_debug, m_reset, &m_mouseState) )
{
imguiBeginFrame(
m_mouseState.m_mx
, m_mouseState.m_my
, (m_mouseState.m_buttons[entry::MouseButton::Left ] ? IMGUI_MBUT_LEFT : 0)
| (m_mouseState.m_buttons[entry::MouseButton::Right ] ? IMGUI_MBUT_RIGHT : 0)
| (m_mouseState.m_buttons[entry::MouseButton::Middle] ? IMGUI_MBUT_MIDDLE : 0)
, m_mouseState.m_mz
, uint16_t(m_width)
, uint16_t(m_height)
);
showExampleDialog(this
, !m_computeSupported
? "Compute is not supported."
: NULL
);
int64_t now = bx::getHPCounter();
static int64_t last = now;
const int64_t frameTime = now - last;
last = now;
const double freq = double(bx::getHPFrequency() );
const float deltaTime = float(frameTime/freq);
// Set view 0 default viewport.
bgfx::setViewRect(0, 0, 0, uint16_t(m_width), uint16_t(m_height) );
if (m_computeSupported)
{
ImGui::SetNextWindowPos(
ImVec2(m_width - m_width / 5.0f - 10.0f, 10.0f)
, ImGuiCond_FirstUseEver
);
ImGui::SetNextWindowSize(
ImVec2(m_width / 5.0f, m_height / 1.5f)
, ImGuiCond_FirstUseEver
);
ImGui::Begin("Settings"
, NULL
, 0
);
bool reset = false;
int32_t shape = m_paramsData.initialShape;
if (ImGui::Combo("Initial shape", &shape, s_shapeNames, BX_COUNTOF(s_shapeNames) ) )
{
// Modify parameters and reset if shape is changed
initializeParams(shape, &m_paramsData);
reset = true;
}
ImGui::SliderInt("Random seed", &m_paramsData.baseSeed, 0, 100);
if (ImGui::Button("Reset") )
{
reset = true;
}
ImGui::Separator();
ImGui::SliderInt("Particle count (x512)", &m_paramsData.dispatchSize, 1, 64);
ImGui::SliderFloat("Gravity", &m_paramsData.gravity, 0.0f, 0.3f);
ImGui::SliderFloat("Damping", &m_paramsData.damping, 0.0f, 1.0f);
ImGui::SliderFloat("Max acceleration", &m_paramsData.maxAccel, 0.0f, 100.0f);
ImGui::SliderFloat("Time step", &m_paramsData.timeStep, 0.0f, 0.02f);
ImGui::Separator();
ImGui::SliderFloat("Particle intensity", &m_paramsData.particleIntensity, 0.0f, 1.0f);
ImGui::SliderFloat("Particle size", &m_paramsData.particleSize, 0.0f, 1.0f);
ImGui::SliderFloat("Particle power", &m_paramsData.particlePower, 0.001f, 16.0f);
ImGui::Separator();
if (m_indirectSupported)
{
ImGui::Checkbox("Use draw/dispatch indirect", &m_useIndirect);
}
ImGui::End();
if (reset)
{
bgfx::setBuffer(0, m_prevPositionBuffer0, bgfx::Access::Write);
bgfx::setBuffer(1, m_currPositionBuffer0, bgfx::Access::Write);
bgfx::setUniform(u_params, &m_paramsData, 3);
bgfx::dispatch(0, m_initInstancesProgram, kMaxParticleCount / kThreadGroupUpdateSize, 1, 1);
}
if (m_useIndirect)
{
bgfx::setUniform(u_params, &m_paramsData, 3);
bgfx::setBuffer(0, m_indirectBuffer, bgfx::Access::Write);
bgfx::dispatch(0, m_indirectProgram);
}
bgfx::setBuffer(0, m_prevPositionBuffer0, bgfx::Access::Read);
bgfx::setBuffer(1, m_currPositionBuffer0, bgfx::Access::Read);
bgfx::setBuffer(2, m_prevPositionBuffer1, bgfx::Access::Write);
bgfx::setBuffer(3, m_currPositionBuffer1, bgfx::Access::Write);
bgfx::setUniform(u_params, &m_paramsData, 3);
if (m_useIndirect)
{
bgfx::dispatch(0, m_updateInstancesProgram, m_indirectBuffer, 1);
}
else
{
bgfx::dispatch(0, m_updateInstancesProgram, uint16_t(m_paramsData.dispatchSize), 1, 1);
}
bx::swap(m_currPositionBuffer0, m_currPositionBuffer1);
bx::swap(m_prevPositionBuffer0, m_prevPositionBuffer1);
// Update camera.
cameraUpdate(deltaTime, m_mouseState, ImGui::MouseOverArea() );
float view[16];
cameraGetViewMtx(view);
// Set view and projection matrix for view 0.
{
float proj[16];
bx::mtxProj(
proj
, 90.0f
, float(m_width)/float(m_height)
, 0.1f
, 10000.0f
, bgfx::getCaps()->homogeneousDepth
);
bgfx::setViewTransform(0, view, proj);
// Set view 0 default viewport.
bgfx::setViewRect(0, 0, 0, uint16_t(m_width), uint16_t(m_height) );
}
// Set vertex and index buffer.
bgfx::setVertexBuffer(0, m_vbh);
bgfx::setIndexBuffer(m_ibh);
bgfx::setInstanceDataBuffer(m_currPositionBuffer0
, 0
, m_paramsData.dispatchSize * kThreadGroupUpdateSize
);
// Set render states.
bgfx::setState(0
| BGFX_STATE_WRITE_RGB
| BGFX_STATE_BLEND_ADD
| BGFX_STATE_DEPTH_TEST_ALWAYS
);
// Submit primitive for rendering to view 0.
if (m_useIndirect)
{
bgfx::submit(0, m_particleProgram, m_indirectBuffer, 0);
}
else
{
bgfx::submit(0, m_particleProgram);
}
}
imguiEndFrame();
// Advance to next frame. Rendering thread will be kicked to
// process submitted rendering primitives.
bgfx::frame();
return true;
}
return false;
}
entry::MouseState m_mouseState;
uint32_t m_width;
uint32_t m_height;
uint32_t m_debug;
uint32_t m_reset;
bool m_useIndirect;
bool m_computeSupported;
bool m_indirectSupported;
ParamsData m_paramsData;
bgfx::VertexBufferHandle m_vbh;
bgfx::IndexBufferHandle m_ibh;
bgfx::ProgramHandle m_particleProgram;
bgfx::ProgramHandle m_indirectProgram;
bgfx::ProgramHandle m_initInstancesProgram;
bgfx::ProgramHandle m_updateInstancesProgram;
bgfx::IndirectBufferHandle m_indirectBuffer;
bgfx::DynamicVertexBufferHandle m_currPositionBuffer0;
bgfx::DynamicVertexBufferHandle m_currPositionBuffer1;
bgfx::DynamicVertexBufferHandle m_prevPositionBuffer0;
bgfx::DynamicVertexBufferHandle m_prevPositionBuffer1;
bgfx::UniformHandle u_params;
int64_t m_timeOffset;
};
} // namespace
ENTRY_IMPLEMENT_MAIN(
ExampleNbody
, "24-nbody"
, "N-body simulation with compute shaders using buffers."
, "https://bkaradzic.github.io/bgfx/examples.html#nbody"
);