591 lines
20 KiB
C++
591 lines
20 KiB
C++
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////////////////////////////////////////////////////////////
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// Headers
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////////////////////////////////////////////////////////////
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#define STB_PERLIN_IMPLEMENTATION
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#include "stb_perlin.h"
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#include <SFML/Graphics.hpp>
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#include <vector>
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#include <deque>
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#include <sstream>
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#include <algorithm>
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#include <cstring>
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#include <cmath>
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namespace
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{
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// Width and height of the application window
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const unsigned int windowWidth = 800;
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const unsigned int windowHeight = 600;
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// Resolution of the generated terrain
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const unsigned int resolutionX = 800;
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const unsigned int resolutionY = 600;
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// Thread pool parameters
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const unsigned int threadCount = 4;
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const unsigned int blockCount = 32;
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struct WorkItem
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{
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sf::Vertex* targetBuffer;
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unsigned int index;
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};
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std::deque<WorkItem> workQueue;
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std::vector<sf::Thread*> threads;
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int pendingWorkCount = 0;
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bool workPending = true;
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bool bufferUploadPending = false;
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sf::Mutex workQueueMutex;
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struct Setting
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{
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const char* name;
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float* value;
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};
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// Terrain noise parameters
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const int perlinOctaves = 3;
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float perlinFrequency = 7.0f;
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float perlinFrequencyBase = 4.0f;
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// Terrain generation parameters
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float heightBase = 0.0f;
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float edgeFactor = 0.9f;
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float edgeDropoffExponent = 1.5f;
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float snowcapHeight = 0.6f;
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// Terrain lighting parameters
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float heightFactor = windowHeight / 2.0f;
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float heightFlatten = 3.0f;
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float lightFactor = 0.7f;
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}
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// Forward declarations of the functions we define further down
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void threadFunction();
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void generateTerrain(sf::Vertex* vertexBuffer);
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////////////////////////////////////////////////////////////
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/// Entry point of application
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///
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/// \return Application exit code
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///
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////////////////////////////////////////////////////////////
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int main()
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{
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// Create the window of the application
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sf::RenderWindow window(sf::VideoMode(windowWidth, windowHeight), "SFML Island",
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sf::Style::Titlebar | sf::Style::Close);
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window.setVerticalSyncEnabled(true);
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sf::Font font;
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if (!font.loadFromFile("resources/sansation.ttf"))
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return EXIT_FAILURE;
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// Create all of our graphics resources
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sf::Text hudText;
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sf::Text statusText;
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sf::Shader terrainShader;
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sf::RenderStates terrainStates(&terrainShader);
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sf::VertexBuffer terrain(sf::Triangles, sf::VertexBuffer::Static);
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// Set up our text drawables
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statusText.setFont(font);
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statusText.setCharacterSize(28);
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statusText.setFillColor(sf::Color::White);
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statusText.setOutlineColor(sf::Color::Black);
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statusText.setOutlineThickness(2.0f);
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hudText.setFont(font);
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hudText.setCharacterSize(14);
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hudText.setFillColor(sf::Color::White);
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hudText.setOutlineColor(sf::Color::Black);
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hudText.setOutlineThickness(2.0f);
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hudText.setPosition(5.0f, 5.0f);
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// Staging buffer for our terrain data that we will upload to our VertexBuffer
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std::vector<sf::Vertex> terrainStagingBuffer;
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// Check whether the prerequisites are suppprted
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bool prerequisitesSupported = sf::VertexBuffer::isAvailable() && sf::Shader::isAvailable();
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// Set up our graphics resources and set the status text accordingly
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if (!prerequisitesSupported)
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{
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statusText.setString("Shaders and/or Vertex Buffers Unsupported");
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}
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else if (!terrainShader.loadFromFile("resources/terrain.vert", "resources/terrain.frag"))
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{
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prerequisitesSupported = false;
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statusText.setString("Failed to load shader program");
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}
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else
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{
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// Start up our thread pool
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for (unsigned int i = 0; i < threadCount; i++)
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{
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threads.push_back(new sf::Thread(threadFunction));
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threads.back()->launch();
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}
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// Create our VertexBuffer with enough space to hold all the terrain geometry
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terrain.create(resolutionX * resolutionY * 6);
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// Resize the staging buffer to be able to hold all the terrain geometry
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terrainStagingBuffer.resize(resolutionX * resolutionY * 6);
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// Generate the initial terrain
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generateTerrain(&terrainStagingBuffer[0]);
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statusText.setString("Generating Terrain...");
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}
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// Center the status text
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statusText.setPosition((windowWidth - statusText.getLocalBounds().width) / 2.f, (windowHeight - statusText.getLocalBounds().height) / 2.f);
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// Set up an array of pointers to our settings for arrow navigation
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Setting settings[] =
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{
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{"perlinFrequency", &perlinFrequency},
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{"perlinFrequencyBase", &perlinFrequencyBase},
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{"heightBase", &heightBase},
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{"edgeFactor", &edgeFactor},
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{"edgeDropoffExponent", &edgeDropoffExponent},
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{"snowcapHeight", &snowcapHeight},
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{"heightFactor", &heightFactor},
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{"heightFlatten", &heightFlatten},
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{"lightFactor", &lightFactor}
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};
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const int settingCount = 9;
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int currentSetting = 0;
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std::ostringstream osstr;
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sf::Clock clock;
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while (window.isOpen())
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{
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// Handle events
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sf::Event event;
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while (window.pollEvent(event))
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{
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// Window closed or escape key pressed: exit
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if ((event.type == sf::Event::Closed) ||
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((event.type == sf::Event::KeyPressed) && (event.key.code == sf::Keyboard::Escape)))
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{
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window.close();
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break;
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}
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// Arrow key pressed:
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if (prerequisitesSupported && (event.type == sf::Event::KeyPressed))
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{
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switch (event.key.code)
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{
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case sf::Keyboard::Return: generateTerrain(&terrainStagingBuffer[0]); break;
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case sf::Keyboard::Down: currentSetting = (currentSetting + 1) % settingCount; break;
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case sf::Keyboard::Up: currentSetting = (currentSetting + settingCount - 1) % settingCount; break;
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case sf::Keyboard::Left: *(settings[currentSetting].value) -= 0.1f; break;
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case sf::Keyboard::Right: *(settings[currentSetting].value) += 0.1f; break;
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default: break;
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}
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}
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}
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// Clear, draw graphics objects and display
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window.clear();
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window.draw(statusText);
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if (prerequisitesSupported)
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{
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{
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sf::Lock lock(workQueueMutex);
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// Don't bother updating/drawing the VertexBuffer while terrain is being regenerated
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if (!pendingWorkCount)
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{
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// If there is new data pending to be uploaded to the VertexBuffer, do it now
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if (bufferUploadPending)
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{
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terrain.update(&terrainStagingBuffer[0]);
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bufferUploadPending = false;
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}
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terrainShader.setUniform("lightFactor", lightFactor);
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window.draw(terrain, terrainStates);
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}
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}
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// Update and draw the HUD text
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osstr.str("");
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osstr << "Frame: " << clock.restart().asMilliseconds() << "ms\n"
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<< "perlinOctaves: " << perlinOctaves << "\n\n"
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<< "Use the arrow keys to change the values.\nUse the return key to regenerate the terrain.\n\n";
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for (int i = 0; i < settingCount; ++i)
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osstr << ((i == currentSetting) ? ">> " : " ") << settings[i].name << ": " << *(settings[i].value) << "\n";
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hudText.setString(osstr.str());
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window.draw(hudText);
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}
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// Display things on screen
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window.display();
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}
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// Shut down our thread pool
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{
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sf::Lock lock(workQueueMutex);
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workPending = false;
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}
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while (!threads.empty())
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{
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threads.back()->wait();
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delete threads.back();
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threads.pop_back();
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}
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return EXIT_SUCCESS;
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}
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////////////////////////////////////////////////////////////
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/// Get the terrain elevation at the given coordinates.
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///
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////////////////////////////////////////////////////////////
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float getElevation(float x, float y)
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{
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x = x / resolutionX - 0.5f;
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y = y / resolutionY - 0.5f;
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float elevation = 0.0f;
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for (int i = 0; i < perlinOctaves; i++)
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{
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elevation += stb_perlin_noise3(
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x * perlinFrequency * std::pow(perlinFrequencyBase, i),
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y * perlinFrequency * std::pow(perlinFrequencyBase, i),
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0, 0, 0, 0
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) * std::pow(perlinFrequencyBase, -i);
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}
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elevation = (elevation + 1.f) / 2.f;
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float distance = 2.0f * std::sqrt(x * x + y * y);
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elevation = (elevation + heightBase) * (1.0f - edgeFactor * std::pow(distance, edgeDropoffExponent));
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elevation = std::min(std::max(elevation, 0.0f), 1.0f);
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return elevation;
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}
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////////////////////////////////////////////////////////////
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/// Get the terrain moisture at the given coordinates.
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///
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////////////////////////////////////////////////////////////
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float getMoisture(float x, float y)
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{
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x = x / resolutionX - 0.5f;
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y = y / resolutionY - 0.5f;
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float moisture = stb_perlin_noise3(
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x * 4.f + 0.5f,
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y * 4.f + 0.5f,
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0, 0, 0, 0
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);
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return (moisture + 1.f) / 2.f;
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}
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////////////////////////////////////////////////////////////
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/// Get the lowlands terrain color for the given moisture.
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///
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////////////////////////////////////////////////////////////
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sf::Color getLowlandsTerrainColor(float moisture)
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{
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sf::Color color =
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moisture < 0.27f ? sf::Color(240, 240, 180) :
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moisture < 0.3f ? sf::Color(240 - 240 * (moisture - 0.27f) / 0.03f, 240 - 40 * (moisture - 0.27f) / 0.03f, 180 - 180 * (moisture - 0.27f) / 0.03f) :
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moisture < 0.4f ? sf::Color(0, 200, 0) :
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moisture < 0.48f ? sf::Color(0, 200 - 40 * (moisture - 0.4f) / 0.08f, 0) :
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moisture < 0.6f ? sf::Color(0, 160, 0) :
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moisture < 0.7f ? sf::Color(34 * (moisture - 0.6f) / 0.1f, 160 - 60 * (moisture - 0.6f) / 0.1f, 34 * (moisture - 0.6f) / 0.1f) :
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sf::Color(34, 100, 34);
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return color;
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}
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////////////////////////////////////////////////////////////
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/// Get the highlands terrain color for the given elevation
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/// and moisture.
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///
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////////////////////////////////////////////////////////////
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sf::Color getHighlandsTerrainColor(float elevation, float moisture)
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{
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sf::Color lowlandsColor = getLowlandsTerrainColor(moisture);
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sf::Color color =
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moisture < 0.6f ? sf::Color(112, 128, 144) :
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sf::Color(112 + 110 * (moisture - 0.6f) / 0.4f, 128 + 56 * (moisture - 0.6f) / 0.4f, 144 - 9 * (moisture - 0.6f) / 0.4f);
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float factor = std::min((elevation - 0.4f) / 0.1f, 1.f);
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color.r = lowlandsColor.r * (1.f - factor) + color.r * factor;
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color.g = lowlandsColor.g * (1.f - factor) + color.g * factor;
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color.b = lowlandsColor.b * (1.f - factor) + color.b * factor;
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return color;
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}
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////////////////////////////////////////////////////////////
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/// Get the snowcap terrain color for the given elevation
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/// and moisture.
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///
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////////////////////////////////////////////////////////////
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sf::Color getSnowcapTerrainColor(float elevation, float moisture)
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{
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sf::Color highlandsColor = getHighlandsTerrainColor(elevation, moisture);
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sf::Color color = sf::Color::White;
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float factor = std::min((elevation - snowcapHeight) / 0.05f, 1.f);
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color.r = highlandsColor.r * (1.f - factor) + color.r * factor;
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color.g = highlandsColor.g * (1.f - factor) + color.g * factor;
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color.b = highlandsColor.b * (1.f - factor) + color.b * factor;
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return color;
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}
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////////////////////////////////////////////////////////////
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/// Get the terrain color for the given elevation and
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/// moisture.
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///
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////////////////////////////////////////////////////////////
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sf::Color getTerrainColor(float elevation, float moisture)
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{
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sf::Color color =
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elevation < 0.11f ? sf::Color(0, 0, elevation / 0.11f * 74.f + 181.0f) :
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elevation < 0.14f ? sf::Color(std::pow((elevation - 0.11f) / 0.03f, 0.3f) * 48.f, std::pow((elevation - 0.11f) / 0.03f, 0.3f) * 48.f, 255) :
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elevation < 0.16f ? sf::Color((elevation - 0.14f) * 128.f / 0.02f + 48.f, (elevation - 0.14f) * 128.f / 0.02f + 48.f, 127.0f + (0.16f - elevation) * 128.f / 0.02f) :
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elevation < 0.17f ? sf::Color(240, 230, 140) :
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elevation < 0.4f ? getLowlandsTerrainColor(moisture) :
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elevation < snowcapHeight ? getHighlandsTerrainColor(elevation, moisture) :
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getSnowcapTerrainColor(elevation, moisture);
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return color;
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}
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////////////////////////////////////////////////////////////
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/// Compute a compressed representation of the surface
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/// normal based on the given coordinates, and the elevation
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/// of the 4 adjacent neighbours.
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///
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////////////////////////////////////////////////////////////
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sf::Vector2f computeNormal(int x, int y, float left, float right, float bottom, float top)
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{
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sf::Vector3f deltaX(1, 0, (std::pow(right, heightFlatten) - std::pow(left, heightFlatten)) * heightFactor);
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sf::Vector3f deltaY(0, 1, (std::pow(top, heightFlatten) - std::pow(bottom, heightFlatten)) * heightFactor);
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sf::Vector3f crossProduct(
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deltaX.y * deltaY.z - deltaX.z * deltaY.y,
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deltaX.z * deltaY.x - deltaX.x * deltaY.z,
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deltaX.x * deltaY.y - deltaX.y * deltaY.x
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);
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// Scale cross product to make z component 1.0f so we can drop it
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crossProduct /= crossProduct.z;
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// Return "compressed" normal
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return sf::Vector2f(crossProduct.x, crossProduct.y);
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}
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////////////////////////////////////////////////////////////
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/// Process a terrain generation work item. Use the vector
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/// of vertices as scratch memory and upload the data to
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/// the vertex buffer when done.
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///
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////////////////////////////////////////////////////////////
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void processWorkItem(std::vector<sf::Vertex>& vertices, const WorkItem& workItem)
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{
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unsigned int rowBlockSize = (resolutionY / blockCount) + 1;
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unsigned int rowStart = rowBlockSize * workItem.index;
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if (rowStart >= resolutionY)
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return;
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unsigned int rowEnd = std::min(rowStart + rowBlockSize, resolutionY);
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unsigned int rowCount = rowEnd - rowStart;
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const float scalingFactorX = static_cast<float>(windowWidth) / static_cast<float>(resolutionX);
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const float scalingFactorY = static_cast<float>(windowHeight) / static_cast<float>(resolutionY);
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for (unsigned int y = rowStart; y < rowEnd; y++)
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{
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for (int x = 0; x < resolutionX; x++)
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{
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int arrayIndexBase = ((y - rowStart) * resolutionX + x) * 6;
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// Top left corner (first triangle)
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if (x > 0)
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{
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vertices[arrayIndexBase + 0] = vertices[arrayIndexBase - 6 + 5];
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}
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else if (y > rowStart)
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{
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vertices[arrayIndexBase + 0] = vertices[arrayIndexBase - resolutionX * 6 + 1];
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}
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else
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{
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vertices[arrayIndexBase + 0].position = sf::Vector2f(x * scalingFactorX, y * scalingFactorY);
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vertices[arrayIndexBase + 0].color = getTerrainColor(getElevation(x, y), getMoisture(x, y));
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vertices[arrayIndexBase + 0].texCoords = computeNormal(x, y, getElevation(x - 1, y), getElevation(x + 1, y), getElevation(x, y + 1), getElevation(x, y - 1));
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}
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// Bottom left corner (first triangle)
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if (x > 0)
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{
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vertices[arrayIndexBase + 1] = vertices[arrayIndexBase - 6 + 2];
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}
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else
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{
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vertices[arrayIndexBase + 1].position = sf::Vector2f(x * scalingFactorX, (y + 1) * scalingFactorY);
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vertices[arrayIndexBase + 1].color = getTerrainColor(getElevation(x, y + 1), getMoisture(x, y + 1));
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vertices[arrayIndexBase + 1].texCoords = computeNormal(x, y + 1, getElevation(x - 1, y + 1), getElevation(x + 1, y + 1), getElevation(x, y + 2), getElevation(x, y));
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}
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// Bottom right corner (first triangle)
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vertices[arrayIndexBase + 2].position = sf::Vector2f((x + 1) * scalingFactorX, (y + 1) * scalingFactorY);
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vertices[arrayIndexBase + 2].color = getTerrainColor(getElevation(x + 1, y + 1), getMoisture(x + 1, y + 1));
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vertices[arrayIndexBase + 2].texCoords = computeNormal(x + 1, y + 1, getElevation(x, y + 1), getElevation(x + 2, y + 1), getElevation(x + 1, y + 2), getElevation(x + 1, y));
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// Top left corner (second triangle)
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vertices[arrayIndexBase + 3] = vertices[arrayIndexBase + 0];
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// Bottom right corner (second triangle)
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vertices[arrayIndexBase + 4] = vertices[arrayIndexBase + 2];
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// Top right corner (second triangle)
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if (y > rowStart)
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{
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vertices[arrayIndexBase + 5] = vertices[arrayIndexBase - resolutionX * 6 + 2];
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}
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else
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{
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vertices[arrayIndexBase + 5].position = sf::Vector2f((x + 1) * scalingFactorX, y * scalingFactorY);
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vertices[arrayIndexBase + 5].color = getTerrainColor(getElevation(x + 1, y), getMoisture(x + 1, y));
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vertices[arrayIndexBase + 5].texCoords = computeNormal(x + 1, y, getElevation(x, y), getElevation(x + 2, y), getElevation(x + 1, y + 1), getElevation(x + 1, y - 1));
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}
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}
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}
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// Copy the resulting geometry from our thread-local buffer into the target buffer
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|
std::memcpy(workItem.targetBuffer + (resolutionX * rowStart * 6), &vertices[0], sizeof(sf::Vertex) * resolutionX * rowCount * 6);
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////////
|
|
/// Worker thread entry point. We use a thread pool to avoid
|
|
/// the heavy cost of constantly recreating and starting
|
|
/// new threads whenever we need to regenerate the terrain.
|
|
///
|
|
////////////////////////////////////////////////////////////
|
|
void threadFunction()
|
|
{
|
|
unsigned int rowBlockSize = (resolutionY / blockCount) + 1;
|
|
|
|
std::vector<sf::Vertex> vertices(resolutionX * rowBlockSize * 6);
|
|
|
|
WorkItem workItem = {0, 0};
|
|
|
|
// Loop until the application exits
|
|
for (;;)
|
|
{
|
|
workItem.targetBuffer = 0;
|
|
|
|
// Check if there are new work items in the queue
|
|
{
|
|
sf::Lock lock(workQueueMutex);
|
|
|
|
if (!workPending)
|
|
return;
|
|
|
|
if (!workQueue.empty())
|
|
{
|
|
workItem = workQueue.front();
|
|
workQueue.pop_front();
|
|
}
|
|
}
|
|
|
|
// If we didn't receive a new work item, keep looping
|
|
if (!workItem.targetBuffer)
|
|
{
|
|
sf::sleep(sf::milliseconds(10));
|
|
|
|
continue;
|
|
}
|
|
|
|
processWorkItem(vertices, workItem);
|
|
|
|
{
|
|
sf::Lock lock(workQueueMutex);
|
|
|
|
--pendingWorkCount;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
////////////////////////////////////////////////////////////
|
|
/// Terrain generation entry point. This queues up the
|
|
/// generation work items which the worker threads dequeue
|
|
/// and process.
|
|
///
|
|
////////////////////////////////////////////////////////////
|
|
void generateTerrain(sf::Vertex* buffer)
|
|
{
|
|
bufferUploadPending = true;
|
|
|
|
// Make sure the work queue is empty before queuing new work
|
|
for (;;)
|
|
{
|
|
{
|
|
sf::Lock lock(workQueueMutex);
|
|
|
|
if (workQueue.empty())
|
|
break;
|
|
}
|
|
|
|
sf::sleep(sf::milliseconds(10));
|
|
}
|
|
|
|
// Queue all the new work items
|
|
{
|
|
sf::Lock lock(workQueueMutex);
|
|
|
|
for (unsigned int i = 0; i < blockCount; i++)
|
|
{
|
|
WorkItem workItem = {buffer, i};
|
|
workQueue.push_back(workItem);
|
|
}
|
|
|
|
pendingWorkCount = blockCount;
|
|
}
|
|
}
|