bgfx/examples/24-nbody/nbody.cpp

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/*
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* Copyright 2014 Stanlo Slasinski. All rights reserved.
* License: http://www.opensource.org/licenses/BSD-2-Clause
*/
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#include "common.h"
#include "bgfx_utils.h"
#include "imgui/imgui.h"
#include "camera.h"
#include <bgfx/bgfx.h>
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struct u_paramsDataStruct
{
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;
};
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void InitializeParams(int32_t _mode, u_paramsDataStruct* _params)
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{
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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;
}
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}
static const float s_quadVertices[] =
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{
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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, };
int _main_(int /*_argc*/, char** /*_argv*/)
{
uint32_t width = 1280;
uint32_t height = 720;
uint32_t debug = BGFX_DEBUG_TEXT;
uint32_t reset = BGFX_RESET_VSYNC;
bgfx::init();
bgfx::reset(width, height, reset);
// Enable debug text.
bgfx::setDebug(debug);
// Set view 0 clear state.
bgfx::setViewClear(0
, BGFX_CLEAR_COLOR|BGFX_CLEAR_DEPTH
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, 0x303030ff
, 1.0f
, 0
);
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const bgfx::Caps* caps = bgfx::getCaps();
const bool computeSupported = !!(caps->supported & BGFX_CAPS_COMPUTE);
const bool indirectSupported = !!(caps->supported & BGFX_CAPS_DRAW_INDIRECT);
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if (computeSupported)
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{
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// Imgui.
imguiCreate();
bgfx::VertexDecl quadVertexDecl;
quadVertexDecl.begin()
.add(bgfx::Attrib::Position, 2, bgfx::AttribType::Float)
.end();
// Create static vertex buffer.
bgfx::VertexBufferHandle vbh = bgfx::createVertexBuffer(
// Static data can be passed with bgfx::makeRef
bgfx::makeRef(s_quadVertices, sizeof(s_quadVertices) )
, quadVertexDecl
);
// Create static index buffer.
bgfx::IndexBufferHandle ibh = bgfx::createIndexBuffer(
// Static data can be passed with bgfx::makeRef
bgfx::makeRef(s_quadIndices, sizeof(s_quadIndices) )
);
// Create particle program from shaders.
bgfx::ProgramHandle particleProgram = loadProgram("vs_particle", "fs_particle");
// Setup compute buffers
bgfx::VertexDecl computeVertexDecl;
computeVertexDecl.begin()
.add(bgfx::Attrib::TexCoord0, 4, bgfx::AttribType::Float)
.end();
const uint32_t threadGroupUpdateSize = 512;
const uint32_t maxParticleCount = 32 * 1024;
bgfx::DynamicVertexBufferHandle currPositionBuffer0 = bgfx::createDynamicVertexBuffer(1 << 15, computeVertexDecl, BGFX_BUFFER_COMPUTE_READ_WRITE);
bgfx::DynamicVertexBufferHandle currPositionBuffer1 = bgfx::createDynamicVertexBuffer(1 << 15, computeVertexDecl, BGFX_BUFFER_COMPUTE_READ_WRITE);
bgfx::DynamicVertexBufferHandle prevPositionBuffer0 = bgfx::createDynamicVertexBuffer(1 << 15, computeVertexDecl, BGFX_BUFFER_COMPUTE_READ_WRITE);
bgfx::DynamicVertexBufferHandle prevPositionBuffer1 = bgfx::createDynamicVertexBuffer(1 << 15, computeVertexDecl, BGFX_BUFFER_COMPUTE_READ_WRITE);
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bgfx::UniformHandle u_params = bgfx::createUniform("u_params", bgfx::UniformType::Vec4, 3);
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bgfx::ProgramHandle initInstancesProgram = bgfx::createProgram(loadShader("cs_init_instances"), true);
bgfx::ProgramHandle updateInstancesProgram = bgfx::createProgram(loadShader("cs_update_instances"), true);
bgfx::ProgramHandle indirectProgram = BGFX_INVALID_HANDLE;
bgfx::IndirectBufferHandle indirectBuffer = BGFX_INVALID_HANDLE;
if (indirectSupported)
{
indirectProgram = bgfx::createProgram(loadShader("cs_indirect"), true);
indirectBuffer = bgfx::createIndirectBuffer(2);
}
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u_paramsDataStruct u_paramsData;
InitializeParams(0, &u_paramsData);
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bgfx::setUniform(u_params, &u_paramsData, 3);
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bgfx::setBuffer(0, prevPositionBuffer0, bgfx::Access::Write);
bgfx::setBuffer(1, currPositionBuffer0, bgfx::Access::Write);
bgfx::dispatch(0, initInstancesProgram, maxParticleCount / threadGroupUpdateSize, 1, 1);
float view[16];
float initialPos[3] = { 0.0f, 0.0f, -45.0f };
cameraCreate();
cameraSetPosition(initialPos);
cameraSetVerticalAngle(0.0f);
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cameraGetViewMtx(view);
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int32_t scrollArea = 0;
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bool useIndirect = false;
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entry::MouseState mouseState;
while (!entry::processEvents(width, height, debug, reset, &mouseState) )
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{
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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);
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if (deltaTime > 1000.0)
{
abort();
}
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// Set view 0 default viewport.
bgfx::setViewRect(0, 0, 0, width, height);
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// Use debug font to print information about this example.
bgfx::dbgTextClear();
bgfx::dbgTextPrintf(0, 1, 0x4f, "bgfx/examples/24-nbody");
bgfx::dbgTextPrintf(0, 2, 0x6f, "Description: N-body simulation with compute shaders using buffers.");
imguiBeginFrame(mouseState.m_mx
, mouseState.m_my
, (mouseState.m_buttons[entry::MouseButton::Left ] ? IMGUI_MBUT_LEFT : 0)
| (mouseState.m_buttons[entry::MouseButton::Right ] ? IMGUI_MBUT_RIGHT : 0)
| (mouseState.m_buttons[entry::MouseButton::Middle] ? IMGUI_MBUT_MIDDLE : 0)
, mouseState.m_mz
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, width
, height
);
imguiBeginScrollArea("Settings", width - width / 4 - 10, 10, width / 4, 500, &scrollArea);
imguiSlider("Random seed", u_paramsData.baseSeed, 0, 100);
int32_t shape = imguiChoose(u_paramsData.initialShape, "Point", "Sphere", "Box", "Donut");
imguiSlider("Initial speed", u_paramsData.initialSpeed, 0.0f, 300.0f, 0.1f);
bool defaults = imguiButton("Reset");
imguiSeparatorLine();
imguiSlider("Particle count (x512)", u_paramsData.dispatchSize, 1, 64);
imguiSlider("Gravity", u_paramsData.gravity, 0.0f, 0.3f, 0.001f);
imguiSlider("Damping", u_paramsData.damping, 0.0f, 1.0f, 0.01f);
imguiSlider("Max acceleration", u_paramsData.maxAccel, 0.0f, 100.0f, 0.01f);
imguiSlider("Time step", u_paramsData.timeStep, 0.0f, 0.02f, 0.0001f);
imguiSeparatorLine();
imguiSlider("Particle intensity", u_paramsData.particleIntensity, 0.0f, 1.0f, 0.001f);
imguiSlider("Particle size", u_paramsData.particleSize, 0.0f, 1.0f, 0.001f);
imguiSlider("Particle power", u_paramsData.particlePower, 0.001f, 16.0f, 0.01f);
imguiSeparatorLine();
if (imguiCheck("Use draw/dispatch indirect", useIndirect, indirectSupported) )
{
useIndirect = !useIndirect;
}
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imguiEndScrollArea();
imguiEndFrame();
// Modify parameters and reset if shape is changed
if (shape != u_paramsData.initialShape)
{
defaults = true;
InitializeParams(shape, &u_paramsData);
}
if (defaults)
{
bgfx::setBuffer(0, prevPositionBuffer0, bgfx::Access::Write);
bgfx::setBuffer(1, currPositionBuffer0, bgfx::Access::Write);
bgfx::setUniform(u_params, &u_paramsData, 3);
bgfx::dispatch(0, initInstancesProgram, maxParticleCount / threadGroupUpdateSize, 1, 1);
}
if (useIndirect)
{
bgfx::setUniform(u_params, &u_paramsData, 3);
bgfx::setBuffer(0, indirectBuffer, bgfx::Access::Write);
bgfx::dispatch(0, indirectProgram);
}
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bgfx::setBuffer(0, prevPositionBuffer0, bgfx::Access::Read);
bgfx::setBuffer(1, currPositionBuffer0, bgfx::Access::Read);
bgfx::setBuffer(2, prevPositionBuffer1, bgfx::Access::Write);
bgfx::setBuffer(3, currPositionBuffer1, bgfx::Access::Write);
bgfx::setUniform(u_params, &u_paramsData, 3);
if (useIndirect)
{
bgfx::dispatch(0, updateInstancesProgram, indirectBuffer, 1);
}
else
{
bgfx::dispatch(0, updateInstancesProgram, u_paramsData.dispatchSize, 1, 1);
}
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bx::xchg(currPositionBuffer0, currPositionBuffer1);
bx::xchg(prevPositionBuffer0, prevPositionBuffer1);
// Update camera.
cameraUpdate(deltaTime, mouseState);
cameraGetViewMtx(view);
// Set view and projection matrix for view 0.
const bgfx::HMD* hmd = bgfx::getHMD();
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if (NULL != hmd && 0 != (hmd->flags & BGFX_HMD_RENDERING) )
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{
float viewHead[16];
float eye[3] = {};
bx::mtxQuatTranslationHMD(viewHead, hmd->eye[0].rotation, eye);
float tmp[16];
bx::mtxMul(tmp, view, viewHead);
float proj[16];
bx::mtxProj(proj, hmd->eye[0].fov, 0.1f, 10000.0f);
bgfx::setViewTransform(0, tmp, proj);
// Set view 0 default viewport.
//
// Use HMD's width/height since HMD's internal frame buffer size
// might be much larger than window size.
bgfx::setViewRect(0, 0, 0, hmd->width, hmd->height);
}
else
{
float proj[16];
bx::mtxProj(proj, 90.0f, float(width)/float(height), 0.1f, 10000.0f);
bgfx::setViewTransform(0, view, proj);
// Set view 0 default viewport.
bgfx::setViewRect(0, 0, 0, width, height);
}
// Set vertex and index buffer.
bgfx::setVertexBuffer(vbh);
bgfx::setIndexBuffer(ibh);
bgfx::setInstanceDataBuffer(currPositionBuffer0, 0, u_paramsData.dispatchSize * threadGroupUpdateSize);
// Set render states.
bgfx::setState(0
| BGFX_STATE_RGB_WRITE
| BGFX_STATE_BLEND_ADD
| BGFX_STATE_DEPTH_TEST_ALWAYS
);
// Submit primitive for rendering to view 0.
if (useIndirect)
{
bgfx::submit(0, particleProgram, indirectBuffer, 0);
}
else
{
bgfx::submit(0, particleProgram);
}
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// Advance to next frame. Rendering thread will be kicked to
// process submitted rendering primitives.
bgfx::frame();
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}
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// Cleanup.
cameraDestroy();
imguiDestroy();
if (indirectSupported)
{
bgfx::destroyProgram(indirectProgram);
bgfx::destroyIndirectBuffer(indirectBuffer);
}
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bgfx::destroyUniform(u_params);
bgfx::destroyDynamicVertexBuffer(currPositionBuffer0);
bgfx::destroyDynamicVertexBuffer(currPositionBuffer1);
bgfx::destroyDynamicVertexBuffer(prevPositionBuffer0);
bgfx::destroyDynamicVertexBuffer(prevPositionBuffer1);
bgfx::destroyProgram(updateInstancesProgram);
bgfx::destroyProgram(initInstancesProgram);
bgfx::destroyIndexBuffer(ibh);
bgfx::destroyVertexBuffer(vbh);
bgfx::destroyProgram(particleProgram);
}
else
{
int64_t timeOffset = bx::getHPCounter();
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entry::MouseState mouseState;
while (!entry::processEvents(width, height, debug, reset, &mouseState) )
{
int64_t now = bx::getHPCounter();
float time = (float)( (now - timeOffset)/double(bx::getHPFrequency() ) );
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bgfx::setViewRect(0, 0, 0, width, height);
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bgfx::dbgTextClear();
bgfx::dbgTextPrintf(0, 1, 0x4f, "bgfx/examples/24-nbody");
bgfx::dbgTextPrintf(0, 2, 0x6f, "Description: N-body simulation with compute shaders using buffers.");
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bool blink = uint32_t(time*3.0f)&1;
bgfx::dbgTextPrintf(0, 5, blink ? 0x1f : 0x01, " Compute is not supported by GPU. ");
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bgfx::touch(0);
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bgfx::frame();
}
}
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// Shutdown bgfx.
bgfx::shutdown();
return 0;
}