bgfx/examples/48-drawindirect/drawindirect.cpp
pezcode ba467be036
Add support for indirect draw with indirect count (#2925)
* Add indirect draw with indirect count (BGFX_CAPS_DRAW_INDIRECT_COUNT)

* Update bindings

* VK: Add support for BGFX_CAPS_DRAW_INDIRECT_COUNT

* D3D12: Add support for BGFX_CAPS_DRAW_INDIRECT_COUNT

* GL: Add support for BGFX_CAPS_DRAW_INDIRECT_COUNT

* 48-drawindirect: Use BGFX_CAPS_DRAW_INDIRECT_COUNT if available

* 48-drawindirect: Update shaders
2022-09-17 18:16:19 -07:00

469 lines
13 KiB
C++

/*
* Copyright 2022-2022 Liam Twigger. All rights reserved.
* License: https://github.com/bkaradzic/bgfx/blob/master/LICENSE
*/
// Draw Indirect
// Render multiple different objects with one draw command. This example shows a minimal implementation of indirect drawing
// Reading References:
// https://litasa.github.io/blog/2017/09/04/OpenGL-MultiDrawIndirect-with-Individual-Textures
// https://cpp-rendering.io/indirect-rendering/
#include "common.h"
#include "bgfx_utils.h"
#include "imgui/imgui.h"
namespace
{
struct PosColorVertex
{
float m_x;
float m_y;
float m_z;
uint32_t m_abgr;
static void init()
{
ms_layout
.begin()
.add(bgfx::Attrib::Position, 3, bgfx::AttribType::Float)
.add(bgfx::Attrib::Color0, 4, bgfx::AttribType::Uint8, true)
.end();
};
static bgfx::VertexLayout ms_layout;
};
bgfx::VertexLayout PosColorVertex::ms_layout;
struct ObjectInstance {
float m_vertexOffset;
float m_vertexCount;
float m_indexOffset;
float m_indexCount;
static void init()
{
ms_layout
.begin()
.add(bgfx::Attrib::TexCoord0, 4, bgfx::AttribType::Float)
.end();
};
static bgfx::VertexLayout ms_layout;
};
bgfx::VertexLayout ObjectInstance::ms_layout;
struct RenderInstance {
float m_mtx[16];
float m_color[4];
static void init()
{
ms_layout
.begin()
.add(bgfx::Attrib::TexCoord0, 4, bgfx::AttribType::Float)
.add(bgfx::Attrib::TexCoord1, 4, bgfx::AttribType::Float)
.add(bgfx::Attrib::TexCoord2, 4, bgfx::AttribType::Float)
.add(bgfx::Attrib::TexCoord3, 4, bgfx::AttribType::Float)
.add(bgfx::Attrib::Color0, 4, bgfx::AttribType::Float)
.end();
};
static bgfx::VertexLayout ms_layout;
};
bgfx::VertexLayout RenderInstance::ms_layout;
static PosColorVertex s_multiMeshVertices[12] =
{
// Cube Model
{-1.0f, 1.0f, 1.0f, 0xff000000 },
{ 1.0f, 1.0f, 1.0f, 0xff0000ff },
{-1.0f, -1.0f, 1.0f, 0xff00ff00 },
{ 1.0f, -1.0f, 1.0f, 0xff00ffff },
{-1.0f, 1.0f, -1.0f, 0xffff0000 },
{ 1.0f, 1.0f, -1.0f, 0xffff00ff },
{-1.0f, -1.0f, -1.0f, 0xffffff00 },
{ 1.0f, -1.0f, -1.0f, 0xffffffff },
// Tetrahedron Model (offset = 8)
{ 1.0f, 1.0f, 1.0f, 0xff0000ff },
{ 1.0f, -1.0f, -1.0f, 0xff000000 },
{-1.0f, 1.0f, -1.0f, 0xff00ff00 },
{-1.0f, -1.0f, 1.0f, 0xff00ffff },
};
static const uint16_t s_multiMeshIndices[48] =
{
// Cube Indicies
0, 1, 2, // 0
1, 3, 2,
4, 6, 5, // 2
5, 6, 7,
0, 2, 4, // 4
4, 2, 6,
1, 5, 3, // 6
5, 7, 3,
0, 4, 1, // 8
4, 5, 1,
2, 3, 6, // 10
6, 3, 7,
// Tetrahedron Indices (offset = 36)
0, 2, 1,
1, 2, 3,
0, 3, 2,
1, 3, 0,
};
static const uint32_t s_maxSideSize = 81;
class DrawIndirect : public entry::AppI
{
public:
DrawIndirect(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_TEXT;
m_reset = BGFX_RESET_VSYNC;
m_sideSize = 11;
m_nDrawElements = s_maxSideSize*s_maxSideSize;
m_useIndirectCount = false;
bgfx::Init init;
init.type = args.m_type;
init.vendorId = args.m_pciId;
init.platformData.nwh = entry::getNativeWindowHandle(entry::kDefaultWindowHandle);
init.platformData.ndt = entry::getNativeDisplayHandle();
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
);
// Create vertex stream declaration.
PosColorVertex::init();
ObjectInstance::init();
RenderInstance::init();
// Create static vertex buffer.
m_vbh = bgfx::createVertexBuffer(
bgfx::makeRef(s_multiMeshVertices, sizeof(s_multiMeshVertices) )
, PosColorVertex::ms_layout
);
// Create static index buffer.
m_ibh = bgfx::createIndexBuffer(
bgfx::makeRef(s_multiMeshIndices, sizeof(s_multiMeshIndices) )
);
// Create program from shaders.
m_program = loadProgram("vs_instancing", "fs_instancing"); // These are reused from 05-instancing
m_indirect_program = BGFX_INVALID_HANDLE;
m_indirect_count_program = BGFX_INVALID_HANDLE;
m_indirect_buffer_handle = BGFX_INVALID_HANDLE;
m_indirect_count_buffer_handle = BGFX_INVALID_HANDLE;
m_object_list_buffer = BGFX_INVALID_HANDLE;
u_drawParams = bgfx::createUniform("u_drawParams", bgfx::UniformType::Vec4);
const bool computeSupported = !!(BGFX_CAPS_COMPUTE & bgfx::getCaps()->supported);
const bool indirectSupported = !!(BGFX_CAPS_DRAW_INDIRECT & bgfx::getCaps()->supported);
const bool instancingSupported = !!(BGFX_CAPS_INSTANCING & bgfx::getCaps()->supported);
if (computeSupported && indirectSupported && instancingSupported)
{
// Set up indirect program
// This is a barebones program that populates the indirect buffer handle with draw requests
m_indirect_program = bgfx::createProgram(loadShader("cs_drawindirect"), true);
m_indirect_buffer_handle = bgfx::createIndirectBuffer(m_nDrawElements);
const bool indirectCountSupported = !!(BGFX_CAPS_DRAW_INDIRECT_COUNT & bgfx::getCaps()->supported);
if (indirectCountSupported)
{
m_useIndirectCount = true;
m_indirect_count_program = bgfx::createProgram(loadShader("cs_drawindirect_count"), true);
const bgfx::Memory * mem = bgfx::alloc(sizeof(uint32_t));
*(uint32_t *)mem->data = 0;
m_indirect_count_buffer_handle = bgfx::createIndexBuffer(mem, BGFX_BUFFER_INDEX32 | BGFX_BUFFER_COMPUTE_WRITE | BGFX_BUFFER_DRAW_INDIRECT);
}
const bgfx::Memory * mem = bgfx::alloc(sizeof(ObjectInstance) * m_nDrawElements);
ObjectInstance* objs = (ObjectInstance*) mem->data;
for (uint32_t ii = 0; ii < m_nDrawElements; ++ii)
{
if (ii % 2)
{
// Tetrahedron
objs[ii].m_vertexOffset = 8;
objs[ii].m_vertexCount = 4; // m_vertexCount is unused in compute shader, its only here for completeness
objs[ii].m_indexOffset = 36;
objs[ii].m_indexCount = 12;
}
else
{
// Cube
objs[ii].m_vertexOffset = 0;
objs[ii].m_vertexCount = 8;
objs[ii].m_indexOffset = 0;
objs[ii].m_indexCount = 36;
}
}
// This is a list of objects to be rendered via the indirect program
m_object_list_buffer = bgfx::createVertexBuffer(mem, ObjectInstance::ms_layout, BGFX_BUFFER_COMPUTE_READ);
// This is the instance buffer used for rendering.
// You could instead use a dynamic instance buffer when rendering (use bgfx::allocInstanceDataBuffer in draw loop)
m_instance_buffer = bgfx::createDynamicVertexBuffer(m_nDrawElements, RenderInstance::ms_layout, BGFX_BUFFER_COMPUTE_WRITE);
}
m_timeOffset = bx::getHPCounter();
imguiCreate();
}
int shutdown() override
{
imguiDestroy();
// Cleanup.
bgfx::destroy(m_ibh);
bgfx::destroy(m_vbh);
bgfx::destroy(m_program);
if (bgfx::isValid(m_indirect_program))
{
bgfx::destroy(m_indirect_program);
}
if (bgfx::isValid(m_indirect_count_program))
{
bgfx::destroy(m_indirect_count_program);
}
if (bgfx::isValid(m_indirect_buffer_handle))
{
bgfx::destroy(m_indirect_buffer_handle);
}
if (bgfx::isValid(m_indirect_count_buffer_handle))
{
bgfx::destroy(m_indirect_count_buffer_handle);
}
if (bgfx::isValid(m_object_list_buffer))
{
bgfx::destroy(m_object_list_buffer);
}
if (bgfx::isValid(m_instance_buffer))
{
bgfx::destroy(m_instance_buffer);
}
bgfx::destroy(u_drawParams);
// Shutdown bgfx.
bgfx::shutdown();
return 0;
}
bool update() override
{
if (!entry::processEvents(m_width, m_height, m_debug, m_reset, &m_mouseState) )
{
// Get renderer capabilities info.
const bool computeSupported = !!(BGFX_CAPS_COMPUTE & bgfx::getCaps()->supported);
const bool indirectSupported = !!(BGFX_CAPS_DRAW_INDIRECT & bgfx::getCaps()->supported);
const bool indirectCountSupported = !!(BGFX_CAPS_DRAW_INDIRECT_COUNT & bgfx::getCaps()->supported);
const bool instancingSupported = !!(BGFX_CAPS_INSTANCING & bgfx::getCaps()->supported);
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);
ImGui::SetNextWindowPos(
ImVec2(m_width - m_width / 5.0f - 10.0f, 10.0f)
, ImGuiCond_FirstUseEver
);
ImGui::SetNextWindowSize(
ImVec2(m_width / 5.0f, m_height / 2.0f)
, ImGuiCond_FirstUseEver
);
ImGui::Begin("Settings"
, NULL
, 0
);
ImGui::Text("%d draw calls", bgfx::getStats()->numDraw);
ImGui::Text("%d objects drawn", m_sideSize*m_sideSize);
ImGui::Text("Grid Side Size:");
ImGui::SliderInt("##size", (int*)&m_sideSize, 1, s_maxSideSize);
ImGui::BeginDisabled(!indirectCountSupported);
ImGui::Checkbox("Indirect Count", &m_useIndirectCount);
ImGui::EndDisabled();
if (!indirectCountSupported && ImGui::IsItemHovered(ImGuiHoveredFlags_AllowWhenDisabled) )
{
ImGui::SetTooltip("Indirect Count is not supported by GPU.");
}
ImGui::End();
imguiEndFrame();
// Set view 0 default viewport.
bgfx::setViewRect(0, 0, 0, uint16_t(m_width), uint16_t(m_height) );
// This dummy draw call is here to make sure that view 0 is cleared
// if no other draw calls are submitted to view 0.
bgfx::touch(0);
const bx::Vec3 at = { 0.0f, 0.0f, 0.0f };
const bx::Vec3 eye = { 0.0f, 0.0f, -35.0f };
// Set view and projection matrix for view 0.
{
float view[16];
bx::mtxLookAt(view, eye, at);
float proj[16];
bx::mtxProj(proj, 60.0f, float(m_width)/float(m_height), 0.1f, 500.0f, 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) );
}
float time = (float)( (bx::getHPCounter() - m_timeOffset)/double(bx::getHPFrequency() ) );
if (computeSupported && indirectSupported && instancingSupported)
{
// Build indirect buffer & prepare instance buffer
// NOTE: IF you are rendering static data then
// this could be done once on startup and results stored
// This is done here for demonstration purposes
// The model matrix for each instance is also set on compute
// you could modify this to, eg, do frustrum culling on the GPU
float ud[4] = { float(m_nDrawElements), float(m_sideSize), float(time), 0 };
uint32_t numToDraw = (m_sideSize*m_sideSize);
bgfx::setUniform(u_drawParams, ud);
bgfx::setBuffer(0, m_object_list_buffer, bgfx::Access::Read);
bgfx::setBuffer(1, m_indirect_buffer_handle, bgfx::Access::Write);
bgfx::setBuffer(2, m_instance_buffer, bgfx::Access::Write);
// Dispatch the call. We are using 64 local threads on the GPU to process the object list
// So lets dispatch ceil(numToDraw/64) workgroups of 64 local threads
if (m_useIndirectCount)
{
bgfx::setBuffer(3, m_indirect_count_buffer_handle, bgfx::Access::Write);
bgfx::dispatch(0, m_indirect_count_program, uint32_t(numToDraw/64 + 1), 1, 1);
}
else
{
bgfx::dispatch(0, m_indirect_program, uint32_t(numToDraw/64 + 1), 1, 1);
}
// Submit our 1 draw call
// Set vertex and index buffer.
bgfx::setIndexBuffer(m_ibh);
bgfx::setVertexBuffer(0, m_vbh);
bgfx::setInstanceDataBuffer(m_instance_buffer, 0, numToDraw);
// Set render states.
bgfx::setState(BGFX_STATE_DEFAULT);
// Submit primitive for rendering to view 0.
if (m_useIndirectCount)
{
// With indirect count, the number of draws is read from a buffer
bgfx::submit(0, m_program, m_indirect_buffer_handle, 0, m_indirect_count_buffer_handle);
}
else
{
bgfx::submit(0, m_program, m_indirect_buffer_handle, 0, uint16_t(numToDraw));
}
}
else
{
// Compute/Indirect/Instancing is not supported
bool blink = uint32_t(time*3.0f)&1;
bgfx::dbgTextPrintf(0, 0, blink ? 0x4f : 0x04, " Compute/Indirect/Instancing is not supported by GPU. ");
}
// 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;
uint32_t m_sideSize;
uint32_t m_nDrawElements;
bool m_useIndirectCount;
bgfx::VertexBufferHandle m_vbh;
bgfx::IndexBufferHandle m_ibh;
bgfx::ProgramHandle m_program;
bgfx::IndirectBufferHandle m_indirect_buffer_handle;
bgfx::IndexBufferHandle m_indirect_count_buffer_handle;
bgfx::ProgramHandle m_indirect_program;
bgfx::ProgramHandle m_indirect_count_program;
bgfx::VertexBufferHandle m_object_list_buffer;
bgfx::DynamicVertexBufferHandle m_instance_buffer;
bgfx::UniformHandle u_drawParams;
int64_t m_timeOffset;
};
} // namespace
ENTRY_IMPLEMENT_MAIN(
DrawIndirect
, "48-drawindirect"
, "Simple example of indirect rendering to render multiple different meshes with 1 draw call"
, "https://bkaradzic.github.io/bgfx/examples.html#drawindirect"
);