embedded_libs/box2d-2.4.1/testbed/tests/character_collision.cpp
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// MIT License
// Copyright (c) 2019 Erin Catto
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#include "test.h"
/// This is a test of typical character collision scenarios. This does not
/// show how you should implement a character in your application.
/// Instead this is used to test smooth collision on edge chains.
class CharacterCollision : public Test
{
public:
CharacterCollision()
{
// Ground body
{
b2BodyDef bd;
b2Body* ground = m_world->CreateBody(&bd);
b2EdgeShape shape;
shape.SetTwoSided(b2Vec2(-20.0f, 0.0f), b2Vec2(20.0f, 0.0f));
ground->CreateFixture(&shape, 0.0f);
}
// Collinear edges with no adjacency information.
// This shows the problematic case where a box shape can hit
// an internal vertex.
{
b2BodyDef bd;
b2Body* ground = m_world->CreateBody(&bd);
b2EdgeShape shape;
shape.SetTwoSided(b2Vec2(-8.0f, 1.0f), b2Vec2(-6.0f, 1.0f));
ground->CreateFixture(&shape, 0.0f);
shape.SetTwoSided(b2Vec2(-6.0f, 1.0f), b2Vec2(-4.0f, 1.0f));
ground->CreateFixture(&shape, 0.0f);
shape.SetTwoSided(b2Vec2(-4.0f, 1.0f), b2Vec2(-2.0f, 1.0f));
ground->CreateFixture(&shape, 0.0f);
}
// Chain shape
{
b2BodyDef bd;
bd.angle = 0.25f * b2_pi;
b2Body* ground = m_world->CreateBody(&bd);
b2Vec2 vs[4];
vs[0].Set(5.0f, 7.0f);
vs[1].Set(6.0f, 8.0f);
vs[2].Set(7.0f, 8.0f);
vs[3].Set(8.0f, 7.0f);
b2ChainShape shape;
shape.CreateLoop(vs, 4);
ground->CreateFixture(&shape, 0.0f);
}
// Square tiles. This shows that adjacency shapes may
// have non-smooth collision. There is no solution
// to this problem.
{
b2BodyDef bd;
b2Body* ground = m_world->CreateBody(&bd);
b2PolygonShape shape;
shape.SetAsBox(1.0f, 1.0f, b2Vec2(4.0f, 3.0f), 0.0f);
ground->CreateFixture(&shape, 0.0f);
shape.SetAsBox(1.0f, 1.0f, b2Vec2(6.0f, 3.0f), 0.0f);
ground->CreateFixture(&shape, 0.0f);
shape.SetAsBox(1.0f, 1.0f, b2Vec2(8.0f, 3.0f), 0.0f);
ground->CreateFixture(&shape, 0.0f);
}
// Square made from an edge loop. Collision should be smooth.
{
b2BodyDef bd;
b2Body* ground = m_world->CreateBody(&bd);
b2Vec2 vs[4];
vs[0].Set(-1.0f, 3.0f);
vs[1].Set(1.0f, 3.0f);
vs[2].Set(1.0f, 5.0f);
vs[3].Set(-1.0f, 5.0f);
b2ChainShape shape;
shape.CreateLoop(vs, 4);
ground->CreateFixture(&shape, 0.0f);
}
// Edge loop. Collision should be smooth.
{
b2BodyDef bd;
bd.position.Set(-10.0f, 4.0f);
b2Body* ground = m_world->CreateBody(&bd);
b2Vec2 vs[10];
vs[0].Set(0.0f, 0.0f);
vs[1].Set(6.0f, 0.0f);
vs[2].Set(6.0f, 2.0f);
vs[3].Set(4.0f, 1.0f);
vs[4].Set(2.0f, 2.0f);
vs[5].Set(0.0f, 2.0f);
vs[6].Set(-2.0f, 2.0f);
vs[7].Set(-4.0f, 3.0f);
vs[8].Set(-6.0f, 2.0f);
vs[9].Set(-6.0f, 0.0f);
b2ChainShape shape;
shape.CreateLoop(vs, 10);
ground->CreateFixture(&shape, 0.0f);
}
// Square character 1
{
b2BodyDef bd;
bd.position.Set(-3.0f, 8.0f);
bd.type = b2_dynamicBody;
bd.fixedRotation = true;
bd.allowSleep = false;
b2Body* body = m_world->CreateBody(&bd);
b2PolygonShape shape;
shape.SetAsBox(0.5f, 0.5f);
b2FixtureDef fd;
fd.shape = &shape;
fd.density = 20.0f;
body->CreateFixture(&fd);
}
// Square character 2
{
b2BodyDef bd;
bd.position.Set(-5.0f, 5.0f);
bd.type = b2_dynamicBody;
bd.fixedRotation = true;
bd.allowSleep = false;
b2Body* body = m_world->CreateBody(&bd);
b2PolygonShape shape;
shape.SetAsBox(0.25f, 0.25f);
b2FixtureDef fd;
fd.shape = &shape;
fd.density = 20.0f;
body->CreateFixture(&fd);
}
// Hexagon character
{
b2BodyDef bd;
bd.position.Set(-5.0f, 8.0f);
bd.type = b2_dynamicBody;
bd.fixedRotation = true;
bd.allowSleep = false;
b2Body* body = m_world->CreateBody(&bd);
float angle = 0.0f;
float delta = b2_pi / 3.0f;
b2Vec2 vertices[6];
for (int32 i = 0; i < 6; ++i)
{
vertices[i].Set(0.5f * cosf(angle), 0.5f * sinf(angle));
angle += delta;
}
b2PolygonShape shape;
shape.Set(vertices, 6);
b2FixtureDef fd;
fd.shape = &shape;
fd.density = 20.0f;
body->CreateFixture(&fd);
}
// Circle character
{
b2BodyDef bd;
bd.position.Set(3.0f, 5.0f);
bd.type = b2_dynamicBody;
bd.fixedRotation = true;
bd.allowSleep = false;
b2Body* body = m_world->CreateBody(&bd);
b2CircleShape shape;
shape.m_radius = 0.5f;
b2FixtureDef fd;
fd.shape = &shape;
fd.density = 20.0f;
body->CreateFixture(&fd);
}
// Circle character
{
b2BodyDef bd;
bd.position.Set(-7.0f, 6.0f);
bd.type = b2_dynamicBody;
bd.allowSleep = false;
m_character = m_world->CreateBody(&bd);
b2CircleShape shape;
shape.m_radius = 0.25f;
b2FixtureDef fd;
fd.shape = &shape;
fd.density = 20.0f;
fd.friction = 1.0f;
m_character->CreateFixture(&fd);
}
}
void Step(Settings& settings) override
{
b2Vec2 v = m_character->GetLinearVelocity();
v.x = -5.0f;
m_character->SetLinearVelocity(v);
Test::Step(settings);
g_debugDraw.DrawString(5, m_textLine, "This tests various character collision shapes.");
m_textLine += m_textIncrement;
g_debugDraw.DrawString(5, m_textLine, "Limitation: square and hexagon can snag on aligned boxes.");
m_textLine += m_textIncrement;
g_debugDraw.DrawString(5, m_textLine, "Feature: edge chains have smooth collision inside and out.");
m_textLine += m_textIncrement;
}
static Test* Create()
{
return new CharacterCollision;
}
b2Body* m_character;
};
static int testIndex = RegisterTest("Examples", "Character Collision", CharacterCollision::Create);