470 lines
13 KiB
C++
470 lines
13 KiB
C++
/*
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* Copyright 2022-2022 Liam Twigger. All rights reserved.
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* License: https://github.com/bkaradzic/bgfx/blob/master/LICENSE
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*/
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// Draw Indirect
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// Render multiple different objects with one draw command. This example shows a minimal implementation of indirect drawing
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// Reading References:
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// https://litasa.github.io/blog/2017/09/04/OpenGL-MultiDrawIndirect-with-Individual-Textures
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// https://cpp-rendering.io/indirect-rendering/
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#include "common.h"
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#include "bgfx_utils.h"
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#include "imgui/imgui.h"
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namespace
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{
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struct PosColorVertex
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{
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float m_x;
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float m_y;
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float m_z;
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uint32_t m_abgr;
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static void init()
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{
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ms_layout
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.begin()
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.add(bgfx::Attrib::Position, 3, bgfx::AttribType::Float)
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.add(bgfx::Attrib::Color0, 4, bgfx::AttribType::Uint8, true)
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.end();
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};
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static bgfx::VertexLayout ms_layout;
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};
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bgfx::VertexLayout PosColorVertex::ms_layout;
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struct ObjectInstance {
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float m_vertexOffset;
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float m_vertexCount;
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float m_indexOffset;
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float m_indexCount;
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static void init()
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{
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ms_layout
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.begin()
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.add(bgfx::Attrib::TexCoord0, 4, bgfx::AttribType::Float)
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.end();
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};
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static bgfx::VertexLayout ms_layout;
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};
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bgfx::VertexLayout ObjectInstance::ms_layout;
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struct RenderInstance {
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float m_mtx[16];
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float m_color[4];
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static void init()
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{
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ms_layout
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.begin()
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.add(bgfx::Attrib::TexCoord0, 4, bgfx::AttribType::Float)
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.add(bgfx::Attrib::TexCoord1, 4, bgfx::AttribType::Float)
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.add(bgfx::Attrib::TexCoord2, 4, bgfx::AttribType::Float)
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.add(bgfx::Attrib::TexCoord3, 4, bgfx::AttribType::Float)
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.add(bgfx::Attrib::Color0, 4, bgfx::AttribType::Float)
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.end();
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};
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static bgfx::VertexLayout ms_layout;
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};
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bgfx::VertexLayout RenderInstance::ms_layout;
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static PosColorVertex s_multiMeshVertices[12] =
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{
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// Cube Model
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{-1.0f, 1.0f, 1.0f, 0xff000000 },
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{ 1.0f, 1.0f, 1.0f, 0xff0000ff },
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{-1.0f, -1.0f, 1.0f, 0xff00ff00 },
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{ 1.0f, -1.0f, 1.0f, 0xff00ffff },
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{-1.0f, 1.0f, -1.0f, 0xffff0000 },
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{ 1.0f, 1.0f, -1.0f, 0xffff00ff },
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{-1.0f, -1.0f, -1.0f, 0xffffff00 },
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{ 1.0f, -1.0f, -1.0f, 0xffffffff },
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// Tetrahedron Model (offset = 8)
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{ 1.0f, 1.0f, 1.0f, 0xff0000ff },
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{ 1.0f, -1.0f, -1.0f, 0xff000000 },
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{-1.0f, 1.0f, -1.0f, 0xff00ff00 },
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{-1.0f, -1.0f, 1.0f, 0xff00ffff },
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};
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static const uint16_t s_multiMeshIndices[48] =
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{
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// Cube Indicies
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0, 1, 2, // 0
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1, 3, 2,
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4, 6, 5, // 2
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5, 6, 7,
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0, 2, 4, // 4
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4, 2, 6,
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1, 5, 3, // 6
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5, 7, 3,
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0, 4, 1, // 8
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4, 5, 1,
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2, 3, 6, // 10
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6, 3, 7,
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// Tetrahedron Indices (offset = 36)
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0, 2, 1,
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1, 2, 3,
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0, 3, 2,
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1, 3, 0,
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};
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static const uint32_t s_maxSideSize = 81;
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class DrawIndirect : public entry::AppI
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{
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public:
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DrawIndirect(const char* _name, const char* _description, const char* _url)
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: entry::AppI(_name, _description, _url)
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{
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}
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void init(int32_t _argc, const char* const* _argv, uint32_t _width, uint32_t _height) override
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{
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Args args(_argc, _argv);
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m_width = _width;
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m_height = _height;
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m_debug = BGFX_DEBUG_TEXT;
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m_reset = BGFX_RESET_VSYNC;
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m_sideSize = 11;
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m_nDrawElements = s_maxSideSize*s_maxSideSize;
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m_useIndirectCount = false;
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bgfx::Init init;
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init.type = args.m_type;
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init.vendorId = args.m_pciId;
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init.platformData.nwh = entry::getNativeWindowHandle(entry::kDefaultWindowHandle);
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init.platformData.ndt = entry::getNativeDisplayHandle();
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init.platformData.type = entry::getNativeWindowHandleType();
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init.resolution.width = m_width;
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init.resolution.height = m_height;
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init.resolution.reset = m_reset;
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bgfx::init(init);
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// Enable debug text.
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bgfx::setDebug(m_debug);
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// Set view 0 clear state.
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bgfx::setViewClear(0
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, BGFX_CLEAR_COLOR|BGFX_CLEAR_DEPTH
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, 0x303030ff
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, 1.0f
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, 0
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);
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// Create vertex stream declaration.
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PosColorVertex::init();
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ObjectInstance::init();
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RenderInstance::init();
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// Create static vertex buffer.
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m_vbh = bgfx::createVertexBuffer(
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bgfx::makeRef(s_multiMeshVertices, sizeof(s_multiMeshVertices) )
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, PosColorVertex::ms_layout
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);
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// Create static index buffer.
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m_ibh = bgfx::createIndexBuffer(
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bgfx::makeRef(s_multiMeshIndices, sizeof(s_multiMeshIndices) )
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);
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// Create program from shaders.
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m_program = loadProgram("vs_instancing", "fs_instancing"); // These are reused from 05-instancing
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m_indirect_program = BGFX_INVALID_HANDLE;
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m_indirect_count_program = BGFX_INVALID_HANDLE;
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m_indirect_buffer_handle = BGFX_INVALID_HANDLE;
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m_indirect_count_buffer_handle = BGFX_INVALID_HANDLE;
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m_object_list_buffer = BGFX_INVALID_HANDLE;
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u_drawParams = bgfx::createUniform("u_drawParams", bgfx::UniformType::Vec4);
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const bool computeSupported = !!(BGFX_CAPS_COMPUTE & bgfx::getCaps()->supported);
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const bool indirectSupported = !!(BGFX_CAPS_DRAW_INDIRECT & bgfx::getCaps()->supported);
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const bool instancingSupported = !!(BGFX_CAPS_INSTANCING & bgfx::getCaps()->supported);
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if (computeSupported && indirectSupported && instancingSupported)
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{
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// Set up indirect program
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// This is a barebones program that populates the indirect buffer handle with draw requests
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m_indirect_program = bgfx::createProgram(loadShader("cs_drawindirect"), true);
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m_indirect_buffer_handle = bgfx::createIndirectBuffer(m_nDrawElements);
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const bool indirectCountSupported = !!(BGFX_CAPS_DRAW_INDIRECT_COUNT & bgfx::getCaps()->supported);
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if (indirectCountSupported)
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{
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m_useIndirectCount = true;
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m_indirect_count_program = bgfx::createProgram(loadShader("cs_drawindirect_count"), true);
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const bgfx::Memory * mem = bgfx::alloc(sizeof(uint32_t));
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*(uint32_t *)mem->data = 0;
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m_indirect_count_buffer_handle = bgfx::createIndexBuffer(mem, BGFX_BUFFER_INDEX32 | BGFX_BUFFER_COMPUTE_WRITE | BGFX_BUFFER_DRAW_INDIRECT);
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}
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const bgfx::Memory * mem = bgfx::alloc(sizeof(ObjectInstance) * m_nDrawElements);
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ObjectInstance* objs = (ObjectInstance*) mem->data;
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for (uint32_t ii = 0; ii < m_nDrawElements; ++ii)
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{
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if (ii % 2)
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{
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// Tetrahedron
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objs[ii].m_vertexOffset = 8;
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objs[ii].m_vertexCount = 4; // m_vertexCount is unused in compute shader, its only here for completeness
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objs[ii].m_indexOffset = 36;
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objs[ii].m_indexCount = 12;
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}
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else
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{
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// Cube
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objs[ii].m_vertexOffset = 0;
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objs[ii].m_vertexCount = 8;
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objs[ii].m_indexOffset = 0;
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objs[ii].m_indexCount = 36;
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}
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}
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// This is a list of objects to be rendered via the indirect program
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m_object_list_buffer = bgfx::createVertexBuffer(mem, ObjectInstance::ms_layout, BGFX_BUFFER_COMPUTE_READ);
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// This is the instance buffer used for rendering.
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// You could instead use a dynamic instance buffer when rendering (use bgfx::allocInstanceDataBuffer in draw loop)
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m_instance_buffer = bgfx::createDynamicVertexBuffer(m_nDrawElements, RenderInstance::ms_layout, BGFX_BUFFER_COMPUTE_WRITE);
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}
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m_timeOffset = bx::getHPCounter();
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imguiCreate();
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}
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int shutdown() override
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{
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imguiDestroy();
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// Cleanup.
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bgfx::destroy(m_ibh);
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bgfx::destroy(m_vbh);
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bgfx::destroy(m_program);
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if (bgfx::isValid(m_indirect_program))
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{
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bgfx::destroy(m_indirect_program);
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}
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if (bgfx::isValid(m_indirect_count_program))
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{
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bgfx::destroy(m_indirect_count_program);
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}
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if (bgfx::isValid(m_indirect_buffer_handle))
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{
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bgfx::destroy(m_indirect_buffer_handle);
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}
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if (bgfx::isValid(m_indirect_count_buffer_handle))
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{
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bgfx::destroy(m_indirect_count_buffer_handle);
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}
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if (bgfx::isValid(m_object_list_buffer))
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{
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bgfx::destroy(m_object_list_buffer);
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}
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if (bgfx::isValid(m_instance_buffer))
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{
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bgfx::destroy(m_instance_buffer);
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}
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bgfx::destroy(u_drawParams);
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// Shutdown bgfx.
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bgfx::shutdown();
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return 0;
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}
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bool update() override
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{
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if (!entry::processEvents(m_width, m_height, m_debug, m_reset, &m_mouseState) )
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{
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// Get renderer capabilities info.
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const bool computeSupported = !!(BGFX_CAPS_COMPUTE & bgfx::getCaps()->supported);
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const bool indirectSupported = !!(BGFX_CAPS_DRAW_INDIRECT & bgfx::getCaps()->supported);
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const bool indirectCountSupported = !!(BGFX_CAPS_DRAW_INDIRECT_COUNT & bgfx::getCaps()->supported);
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const bool instancingSupported = !!(BGFX_CAPS_INSTANCING & bgfx::getCaps()->supported);
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imguiBeginFrame(m_mouseState.m_mx
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, m_mouseState.m_my
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, (m_mouseState.m_buttons[entry::MouseButton::Left ] ? IMGUI_MBUT_LEFT : 0)
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| (m_mouseState.m_buttons[entry::MouseButton::Right ] ? IMGUI_MBUT_RIGHT : 0)
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| (m_mouseState.m_buttons[entry::MouseButton::Middle] ? IMGUI_MBUT_MIDDLE : 0)
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, m_mouseState.m_mz
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, uint16_t(m_width)
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, uint16_t(m_height)
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);
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showExampleDialog(this);
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ImGui::SetNextWindowPos(
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ImVec2(m_width - m_width / 5.0f - 10.0f, 10.0f)
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, ImGuiCond_FirstUseEver
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);
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ImGui::SetNextWindowSize(
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ImVec2(m_width / 5.0f, m_height / 2.0f)
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, ImGuiCond_FirstUseEver
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);
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ImGui::Begin("Settings"
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, NULL
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, 0
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);
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ImGui::Text("%d draw calls", bgfx::getStats()->numDraw);
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ImGui::Text("%d objects drawn", m_sideSize*m_sideSize);
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ImGui::Text("Grid Side Size:");
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ImGui::SliderInt("##size", (int*)&m_sideSize, 1, s_maxSideSize);
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ImGui::BeginDisabled(!indirectCountSupported);
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ImGui::Checkbox("Indirect Count", &m_useIndirectCount);
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ImGui::EndDisabled();
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if (!indirectCountSupported && ImGui::IsItemHovered(ImGuiHoveredFlags_AllowWhenDisabled) )
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{
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ImGui::SetTooltip("Indirect Count is not supported by GPU.");
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}
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ImGui::End();
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imguiEndFrame();
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// Set view 0 default viewport.
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bgfx::setViewRect(0, 0, 0, uint16_t(m_width), uint16_t(m_height) );
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// This dummy draw call is here to make sure that view 0 is cleared
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// if no other draw calls are submitted to view 0.
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bgfx::touch(0);
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const bx::Vec3 at = { 0.0f, 0.0f, 0.0f };
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const bx::Vec3 eye = { 0.0f, 0.0f, -35.0f };
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// Set view and projection matrix for view 0.
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{
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float view[16];
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bx::mtxLookAt(view, eye, at);
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float proj[16];
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bx::mtxProj(proj, 60.0f, float(m_width)/float(m_height), 0.1f, 500.0f, bgfx::getCaps()->homogeneousDepth);
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bgfx::setViewTransform(0, view, proj);
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// Set view 0 default viewport.
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bgfx::setViewRect(0, 0, 0, uint16_t(m_width), uint16_t(m_height) );
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}
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float time = (float)( (bx::getHPCounter() - m_timeOffset)/double(bx::getHPFrequency() ) );
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if (computeSupported && indirectSupported && instancingSupported)
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{
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// Build indirect buffer & prepare instance buffer
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// NOTE: IF you are rendering static data then
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// this could be done once on startup and results stored
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// This is done here for demonstration purposes
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// The model matrix for each instance is also set on compute
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// you could modify this to, eg, do frustrum culling on the GPU
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float ud[4] = { float(m_nDrawElements), float(m_sideSize), float(time), 0 };
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uint32_t numToDraw = (m_sideSize*m_sideSize);
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bgfx::setUniform(u_drawParams, ud);
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bgfx::setBuffer(0, m_object_list_buffer, bgfx::Access::Read);
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bgfx::setBuffer(1, m_indirect_buffer_handle, bgfx::Access::Write);
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bgfx::setBuffer(2, m_instance_buffer, bgfx::Access::Write);
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// Dispatch the call. We are using 64 local threads on the GPU to process the object list
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// So lets dispatch ceil(numToDraw/64) workgroups of 64 local threads
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if (m_useIndirectCount)
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{
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bgfx::setBuffer(3, m_indirect_count_buffer_handle, bgfx::Access::Write);
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bgfx::dispatch(0, m_indirect_count_program, uint32_t(numToDraw/64 + 1), 1, 1);
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}
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else
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{
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bgfx::dispatch(0, m_indirect_program, uint32_t(numToDraw/64 + 1), 1, 1);
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}
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// Submit our 1 draw call
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// Set vertex and index buffer.
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bgfx::setIndexBuffer(m_ibh);
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bgfx::setVertexBuffer(0, m_vbh);
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bgfx::setInstanceDataBuffer(m_instance_buffer, 0, numToDraw);
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// Set render states.
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bgfx::setState(BGFX_STATE_DEFAULT);
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// Submit primitive for rendering to view 0.
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if (m_useIndirectCount)
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{
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// With indirect count, the number of draws is read from a buffer
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bgfx::submit(0, m_program, m_indirect_buffer_handle, 0, m_indirect_count_buffer_handle);
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}
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else
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{
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bgfx::submit(0, m_program, m_indirect_buffer_handle, 0, numToDraw);
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}
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}
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else
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{
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// Compute/Indirect/Instancing is not supported
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bool blink = uint32_t(time*3.0f)&1;
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bgfx::dbgTextPrintf(0, 0, blink ? 0x4f : 0x04, " Compute/Indirect/Instancing is not supported by GPU. ");
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}
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// Advance to next frame. Rendering thread will be kicked to
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// process submitted rendering primitives.
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bgfx::frame();
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return true;
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}
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return false;
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}
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entry::MouseState m_mouseState;
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uint32_t m_width;
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uint32_t m_height;
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uint32_t m_debug;
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uint32_t m_reset;
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uint32_t m_sideSize;
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uint32_t m_nDrawElements;
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bool m_useIndirectCount;
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bgfx::VertexBufferHandle m_vbh;
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bgfx::IndexBufferHandle m_ibh;
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bgfx::ProgramHandle m_program;
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bgfx::IndirectBufferHandle m_indirect_buffer_handle;
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bgfx::IndexBufferHandle m_indirect_count_buffer_handle;
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bgfx::ProgramHandle m_indirect_program;
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bgfx::ProgramHandle m_indirect_count_program;
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bgfx::VertexBufferHandle m_object_list_buffer;
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bgfx::DynamicVertexBufferHandle m_instance_buffer;
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bgfx::UniformHandle u_drawParams;
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int64_t m_timeOffset;
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};
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} // namespace
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ENTRY_IMPLEMENT_MAIN(
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DrawIndirect
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, "48-drawindirect"
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, "Simple example of indirect rendering to render multiple different meshes with 1 draw call"
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, "https://bkaradzic.github.io/bgfx/examples.html#drawindirect"
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);
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