149 lines
3.3 KiB
C++
149 lines
3.3 KiB
C++
#include <iostream>
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#include <sstream>
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#include <vector>
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#define OLC_PGE_APPLICATION
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#include "olcPixelGameEngine.h"
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const float GRAVITY = 5.81f;
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const float DRAG = 0.99f;
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struct Link;
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struct Vec2f {
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float x, y;
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};
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struct MassPoint {
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Vec2f sPosition;
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bool bLocked = false; // If true, the point will not be able to move
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float fMass;
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std::vector<Link*> sLinks;
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MassPoint(Vec2f sPos, float fMass)
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: sPosition(sPos),
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sLastPosition(sPos),
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fMass(fMass) { }
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void step() {
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if (bLocked) return;
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// Inertia
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Vec2f sVelocity;
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sVelocity.x = sPosition.x - sLastPosition.x * DRAG;
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sVelocity.y = sPosition.y - sLastPosition.y * DRAG;
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sPosition.x += sVelocity.x;
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sPosition.y += sVelocity.y + GRAVITY;
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sLastPosition.x = sPosition.x;
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sLastPosition.y = sPosition.y;
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}
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void solve() {
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}
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private:
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Vec2f sLastPosition;
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};
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struct Link {
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float fRestingDistance;
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float fStiffness;
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float fTear;
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MassPoint* p0;
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MassPoint* p1;
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void solve() {
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float diffX = p0->sPosition.x - p1->sPosition.x;
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float diffY = p0->sPosition.y - p1->sPosition.y;
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float d = sqrt(diffX * diffX + diffY * diffY);
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float difference = (fRestingDistance - d) / d;
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float im1 = 1 / p0->fMass;
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float im2 = 1 / p1->fMass;
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float scalarP1 = (im1 / (im1 + im2)) * fStiffness;
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float scalarP2 = fStiffness - scalarP1;
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p0->sPosition.x += diffX * scalarP1 * difference;
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p0->sPosition.y += diffY * scalarP1 * difference;
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p1->sPosition.x -= diffX * scalarP2 * difference;
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p1->sPosition.y -= diffY * scalarP2 * difference;
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}
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};
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class VerletCloth : public olc::PixelGameEngine {
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public:
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std::vector<MassPoint> sPoints;
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int iConstraintAccuracy;
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VerletCloth() {
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sAppName = "Verlet Cloth Simulation";
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}
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bool OnUserCreate() override {
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sPoints.push_back({{ 1.0f, 1.0f }, 1.0f});
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iConstraintAccuracy = 5;
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return true;
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}
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bool OnUserUpdate(float fElapsedTime) override {
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m_fTimeCounter += fElapsedTime;
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if (m_fTimeCounter >= 0.016f) {
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Clear(olc::WHITE);
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m_fTimeCounter = 0.0f;
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for (int x = 0; x < iConstraintAccuracy; x++) {
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for (int i = 0; i < sPoints.size(); i++) {
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MassPoint pointmass = sPoints[i];
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pointmass.solve();
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}
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}
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for (auto& sPoint : sPoints){
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std::stringstream str;
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str << "Pos: X:" << sPoint.sPosition.x << ":Y:" << sPoint.sPosition.y;
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DrawString(0, 0, str.str(), olc::BLACK);
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sPoint.step();
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FillRect(sPoint.sPosition.x, sPoint.sPosition.y, 4, 4, olc::BLACK);
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}
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}
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if (GetKey(olc::ESCAPE).bPressed)
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exit(0);
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return true;
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}
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void DrawLink(Link& link) {
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DrawLine(link.p0->sPosition.x, link.p0->sPosition.y,
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link.p1->sPosition.x, link.p1->sPosition.y,
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olc::RED);
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}
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private:
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float m_fTimeCounter = 0.0f;
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};
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int main(int argc, char** argv) {
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VerletCloth app;
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app.Construct(1000, 600, 1, 1);
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app.Start();
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return 0;
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}
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