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618 lines
20 KiB
C++
618 lines
20 KiB
C++
////////////////////////////////////////////////////////////
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// Headers
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////////////////////////////////////////////////////////////
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#include <SFML/Graphics.hpp>
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#define STB_PERLIN_IMPLEMENTATION
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#include <stb_perlin.h>
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#include <algorithm>
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#include <array>
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#include <deque>
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#include <iostream>
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#include <mutex>
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#include <sstream>
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#include <thread>
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#include <vector>
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#include <cmath>
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#include <cstdint>
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#include <cstdlib>
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#include <cstring>
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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 sf::Vector2u windowSize(800, 600);
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// Resolution of the generated terrain
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const sf::Vector2u resolution(800, 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<std::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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std::recursive_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 = static_cast<float>(windowSize.y) / 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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/// Get the terrain elevation at the given coordinates.
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///
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////////////////////////////////////////////////////////////
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float getElevation(sf::Vector2u position)
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{
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const sf::Vector2f normalized = sf::Vector2f(position).componentWiseDiv(sf::Vector2f(resolution)) -
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sf::Vector2f(0.5f, 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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const sf::Vector2f scaled = normalized * perlinFrequency * static_cast<float>(std::pow(perlinFrequencyBase, i));
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elevation += stb_perlin_noise3(scaled.x, scaled.y, 0, 0, 0, 0) *
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static_cast<float>(std::pow(perlinFrequencyBase, -i));
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}
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elevation = (elevation + 1.f) / 2.f;
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const float distance = 2.0f * normalized.length();
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elevation = (elevation + heightBase) * (1.0f - edgeFactor * std::pow(distance, edgeDropoffExponent));
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elevation = std::clamp(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(sf::Vector2u position)
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{
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const sf::Vector2f normalized = sf::Vector2f(position).componentWiseDiv(sf::Vector2f(resolution)) -
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sf::Vector2f(0.5f, 0.5f);
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const sf::Vector2f transformed = normalized * 4.f + sf::Vector2f(0.5f, 0.5f);
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const float moisture = stb_perlin_noise3(transformed.x, transformed.y, 0, 0, 0, 0);
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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 colorFromFloats(float r, float g, float b)
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{
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return {static_cast<std::uint8_t>(r), static_cast<std::uint8_t>(g), static_cast<std::uint8_t>(b)};
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}
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sf::Color getLowlandsTerrainColor(float moisture)
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{
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if (moisture < 0.27f)
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return colorFromFloats(240, 240, 180);
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if (moisture < 0.3f)
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return colorFromFloats(240 - (240 * (moisture - 0.27f) / 0.03f),
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240 - (40 * (moisture - 0.27f) / 0.03f),
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180 - (180 * (moisture - 0.27f) / 0.03f));
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if (moisture < 0.4f)
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return colorFromFloats(0, 200, 0);
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if (moisture < 0.48f)
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return colorFromFloats(0, 200 - (40 * (moisture - 0.4f) / 0.08f), 0);
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if (moisture < 0.6f)
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return colorFromFloats(0, 160, 0);
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if (moisture < 0.7f)
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return colorFromFloats((34 * (moisture - 0.6f) / 0.1f),
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160 - (60 * (moisture - 0.6f) / 0.1f),
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(34 * (moisture - 0.6f) / 0.1f));
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return colorFromFloats(34, 100, 34);
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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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const sf::Color lowlandsColor = getLowlandsTerrainColor(moisture);
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const sf::Color color = moisture < 0.6f ? sf::Color(112, 128, 144)
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: colorFromFloats(112 + (110 * (moisture - 0.6f) / 0.4f),
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128 + (56 * (moisture - 0.6f) / 0.4f),
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144 - (9 * (moisture - 0.6f) / 0.4f));
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const float factor = std::min((elevation - 0.4f) / 0.1f, 1.f);
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return colorFromFloats(lowlandsColor.r * (1.f - factor) + color.r * factor,
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lowlandsColor.g * (1.f - factor) + color.g * factor,
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lowlandsColor.b * (1.f - factor) + color.b * factor);
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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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const sf::Color highlandsColor = getHighlandsTerrainColor(elevation, moisture);
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const sf::Color color = sf::Color::White;
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const float factor = std::min((elevation - snowcapHeight) / 0.05f, 1.f);
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return colorFromFloats(highlandsColor.r * (1.f - factor) + color.r * factor,
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highlandsColor.g * (1.f - factor) + color.g * factor,
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highlandsColor.b * (1.f - factor) + color.b * factor);
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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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if (elevation < 0.11f)
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return {0, 0, static_cast<std::uint8_t>(elevation / 0.11f * 74.f + 181.0f)};
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if (elevation < 0.14f)
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return {static_cast<std::uint8_t>(std::pow((elevation - 0.11f) / 0.03f, 0.3f) * 48.f),
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static_cast<std::uint8_t>(std::pow((elevation - 0.11f) / 0.03f, 0.3f) * 48.f),
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255};
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if (elevation < 0.16f)
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return {static_cast<std::uint8_t>((elevation - 0.14f) * 128.f / 0.02f + 48.f),
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static_cast<std::uint8_t>((elevation - 0.14f) * 128.f / 0.02f + 48.f),
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static_cast<std::uint8_t>(127.0f + (0.16f - elevation) * 128.f / 0.02f)};
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if (elevation < 0.17f)
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return {240, 230, 140};
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if (elevation < 0.4f)
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return getLowlandsTerrainColor(moisture);
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if (elevation < snowcapHeight)
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return getHighlandsTerrainColor(elevation, moisture);
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return getSnowcapTerrainColor(elevation, moisture);
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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(float left, float right, float bottom, float top)
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{
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const sf::Vector3f deltaX(1, 0, (std::pow(right, heightFlatten) - std::pow(left, heightFlatten)) * heightFactor);
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const sf::Vector3f deltaY(0, 1, (std::pow(top, heightFlatten) - std::pow(bottom, heightFlatten)) * heightFactor);
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sf::Vector3f crossProduct = deltaX.cross(deltaY);
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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 {crossProduct.x, crossProduct.y};
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}
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////////////////////////////////////////////////////////////
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/// Compute the vertex representing the terrain at the given
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/// coordinates.
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///
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////////////////////////////////////////////////////////////
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const auto scalingFactors = sf::Vector2f(windowSize).componentWiseDiv(sf::Vector2f(resolution));
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sf::Vertex computeVertex(sf::Vector2u position)
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{
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sf::Vertex vertex;
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vertex.position = sf::Vector2f(position).componentWiseMul(scalingFactors);
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vertex.color = getTerrainColor(getElevation(position), getMoisture(position));
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vertex.texCoords = computeNormal(getElevation(position - sf::Vector2u(1, 0)),
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getElevation(position + sf::Vector2u(1, 0)),
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getElevation(position + sf::Vector2u(0, 1)),
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getElevation(position - sf::Vector2u(0, 1)));
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return vertex;
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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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const unsigned int rowBlockSize = (resolution.y / blockCount) + 1;
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const unsigned int rowStart = rowBlockSize * workItem.index;
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if (rowStart >= resolution.y)
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return;
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const unsigned int rowEnd = std::min(rowStart + rowBlockSize, resolution.y);
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const unsigned int rowCount = rowEnd - rowStart;
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for (unsigned int y = rowStart; y < rowEnd; ++y)
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{
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for (unsigned int x = 0; x < resolution.x; ++x)
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{
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const unsigned int arrayIndexBase = ((y - rowStart) * resolution.x + 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 - resolution.x * 6 + 1];
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}
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else
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{
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vertices[arrayIndexBase + 0] = computeVertex({x, y});
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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] = computeVertex({x, y + 1});
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}
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// Bottom right corner (first triangle)
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vertices[arrayIndexBase + 2] = computeVertex({x + 1, y + 1});
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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 - resolution.x * 6 + 2];
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}
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else
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{
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vertices[arrayIndexBase + 5] = computeVertex({x + 1, y});
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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 + (resolution.x * rowStart * 6),
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vertices.data(),
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sizeof(sf::Vertex) * resolution.x * rowCount * 6);
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}
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////////////////////////////////////////////////////////////
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/// Worker thread entry point. We use a thread pool to avoid
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/// the heavy cost of constantly recreating and starting
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/// new threads whenever we need to regenerate the terrain.
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///
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////////////////////////////////////////////////////////////
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void threadFunction()
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{
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const unsigned int rowBlockSize = (resolution.y / blockCount) + 1;
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std::vector<sf::Vertex> vertices(resolution.x * rowBlockSize * 6);
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WorkItem workItem = {nullptr, 0};
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// Loop until the application exits
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for (;;)
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{
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workItem.targetBuffer = nullptr;
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// Check if there are new work items in the queue
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{
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const std::lock_guard lock(workQueueMutex);
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if (!workPending)
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return;
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if (!workQueue.empty())
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{
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workItem = workQueue.front();
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workQueue.pop_front();
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}
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}
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// If we didn't receive a new work item, keep looping
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if (!workItem.targetBuffer)
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{
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sf::sleep(sf::milliseconds(10));
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continue;
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}
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processWorkItem(vertices, workItem);
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{
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const std::lock_guard lock(workQueueMutex);
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--pendingWorkCount;
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}
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}
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}
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////////////////////////////////////////////////////////////
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/// Terrain generation entry point. This queues up the
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/// generation work items which the worker threads dequeue
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/// and process.
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///
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////////////////////////////////////////////////////////////
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void generateTerrain(sf::Vertex* buffer)
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{
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bufferUploadPending = true;
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// Make sure the work queue is empty before queuing new work
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for (;;)
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{
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{
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const std::lock_guard lock(workQueueMutex);
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if (pendingWorkCount == 0u)
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break;
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}
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sf::sleep(sf::milliseconds(10));
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}
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// Queue all the new work items
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{
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const std::lock_guard lock(workQueueMutex);
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for (unsigned int i = 0; i < blockCount; ++i)
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{
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const WorkItem workItem = {buffer, i};
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workQueue.push_back(workItem);
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}
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pendingWorkCount = blockCount;
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}
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}
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} // namespace
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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(windowSize), "SFML Island", sf::Style::Titlebar | sf::Style::Close);
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window.setVerticalSyncEnabled(true);
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const sf::Font font("resources/tuffy.ttf");
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// Create all of our graphics resources
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sf::Text hudText(font);
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sf::Text statusText(font);
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sf::Shader terrainShader;
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sf::RenderStates terrainStates;
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sf::VertexBuffer terrain(sf::PrimitiveType::Triangles, sf::VertexBuffer::Usage::Static);
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// Set up our text drawables
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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.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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// Set up our graphics resources and set the status text accordingly
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if (!sf::VertexBuffer::isAvailable() || !sf::Shader::isAvailable())
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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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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.emplace_back(threadFunction);
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}
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// Create our VertexBuffer with enough space to hold all the terrain geometry
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if (!terrain.create(resolution.x * resolution.y * 6))
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{
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std::cerr << "Failed to create vertex buffer" << std::endl;
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return EXIT_FAILURE;
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}
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// Resize the staging buffer to be able to hold all the terrain geometry
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terrainStagingBuffer.resize(resolution.x * resolution.y * 6);
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// Generate the initial terrain
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generateTerrain(terrainStagingBuffer.data());
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statusText.setString("Generating Terrain...");
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// Set up the render states
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terrainStates = sf::RenderStates(&terrainShader);
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}
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// Center the status text
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statusText.setPosition((sf::Vector2f(windowSize) - statusText.getLocalBounds().size) / 2.f);
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// Set up an array of pointers to our settings for arrow navigation
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constexpr std::array<Setting, 9> settings = {
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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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std::size_t 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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while (const std::optional event = window.pollEvent())
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{
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// Window closed or escape key pressed: exit
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if (event->is<sf::Event::Closed>() ||
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(event->is<sf::Event::KeyPressed>() &&
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event->getIf<sf::Event::KeyPressed>()->code == sf::Keyboard::Key::Escape))
|
|
{
|
|
window.close();
|
|
break;
|
|
}
|
|
|
|
// Arrow key pressed:
|
|
// TODO Replace use of getNativeHandle() when validity function is added
|
|
if (terrainShader.getNativeHandle() != 0 && event->is<sf::Event::KeyPressed>())
|
|
{
|
|
switch (event->getIf<sf::Event::KeyPressed>()->code)
|
|
{
|
|
case sf::Keyboard::Key::Enter:
|
|
generateTerrain(terrainStagingBuffer.data());
|
|
break;
|
|
case sf::Keyboard::Key::Down:
|
|
currentSetting = (currentSetting + 1) % settings.size();
|
|
break;
|
|
case sf::Keyboard::Key::Up:
|
|
currentSetting = (currentSetting + settings.size() - 1) % settings.size();
|
|
break;
|
|
case sf::Keyboard::Key::Left:
|
|
*(settings[currentSetting].value) -= 0.1f;
|
|
break;
|
|
case sf::Keyboard::Key::Right:
|
|
*(settings[currentSetting].value) += 0.1f;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Clear, draw graphics objects and display
|
|
window.clear();
|
|
|
|
window.draw(statusText);
|
|
|
|
if (terrainShader.getNativeHandle() != 0)
|
|
{
|
|
{
|
|
const std::lock_guard lock(workQueueMutex);
|
|
|
|
// Don't bother updating/drawing the VertexBuffer while terrain is being regenerated
|
|
if (!pendingWorkCount)
|
|
{
|
|
// If there is new data pending to be uploaded to the VertexBuffer, do it now
|
|
if (bufferUploadPending)
|
|
{
|
|
if (!terrain.update(terrainStagingBuffer.data()))
|
|
{
|
|
std::cerr << "Failed to update vertex buffer" << std::endl;
|
|
return EXIT_FAILURE;
|
|
}
|
|
|
|
bufferUploadPending = false;
|
|
}
|
|
|
|
terrainShader.setUniform("lightFactor", lightFactor);
|
|
window.draw(terrain, terrainStates);
|
|
}
|
|
}
|
|
|
|
// Update and draw the HUD text
|
|
osstr.str("");
|
|
osstr << "Frame: " << clock.restart().asMilliseconds() << "ms\n"
|
|
<< "perlinOctaves: " << perlinOctaves << "\n\n"
|
|
<< "Use the arrow keys to change the values.\nUse the return key to regenerate the terrain.\n\n";
|
|
|
|
for (std::size_t i = 0; i < settings.size(); ++i)
|
|
osstr << ((i == currentSetting) ? ">> " : " ") << settings[i].name << ": "
|
|
<< *(settings[i].value) << '\n';
|
|
|
|
hudText.setString(osstr.str());
|
|
|
|
window.draw(hudText);
|
|
}
|
|
|
|
// Display things on screen
|
|
window.display();
|
|
}
|
|
|
|
// Shut down our thread pool
|
|
{
|
|
const std::lock_guard lock(workQueueMutex);
|
|
workPending = false;
|
|
}
|
|
|
|
while (!threads.empty())
|
|
{
|
|
threads.back().join();
|
|
threads.pop_back();
|
|
}
|
|
}
|