embedded_libs/box2d-2.4.1/testbed/tests/ray_cast.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 "settings.h"
#include "test.h"
#include "imgui/imgui.h"
enum
{
e_maxBodies = 256
};
// This test demonstrates how to use the world ray-cast feature.
// NOTE: we are intentionally filtering one of the polygons, therefore
// the ray will always miss one type of polygon.
// This callback finds the closest hit. Polygon 0 is filtered.
class RayCastClosestCallback : public b2RayCastCallback
{
public:
RayCastClosestCallback()
{
m_hit = false;
}
float ReportFixture(b2Fixture* fixture, const b2Vec2& point, const b2Vec2& normal, float fraction) override
{
uintptr_t index = fixture->GetUserData().pointer;
if (index == 1)
{
// By returning -1, we instruct the calling code to ignore this fixture and
// continue the ray-cast to the next fixture.
return -1.0f;
}
m_hit = true;
m_point = point;
m_normal = normal;
// By returning the current fraction, we instruct the calling code to clip the ray and
// continue the ray-cast to the next fixture. WARNING: do not assume that fixtures
// are reported in order. However, by clipping, we can always get the closest fixture.
return fraction;
}
bool m_hit;
b2Vec2 m_point;
b2Vec2 m_normal;
};
// This callback finds any hit. Polygon 0 is filtered. For this type of query we are usually
// just checking for obstruction, so the actual fixture and hit point are irrelevant.
class RayCastAnyCallback : public b2RayCastCallback
{
public:
RayCastAnyCallback()
{
m_hit = false;
}
float ReportFixture(b2Fixture* fixture, const b2Vec2& point, const b2Vec2& normal, float) override
{
uintptr_t index = fixture->GetUserData().pointer;
if (index == 1)
{
// By returning -1, we instruct the calling code to ignore this fixture and
// continue the ray-cast to the next fixture.
return -1.0f;
}
m_hit = true;
m_point = point;
m_normal = normal;
// At this point we have a hit, so we know the ray is obstructed.
// By returning 0, we instruct the calling code to terminate the ray-cast.
return 0.0f;
}
bool m_hit;
b2Vec2 m_point;
b2Vec2 m_normal;
};
// This ray cast collects multiple hits along the ray. Polygon 0 is filtered.
// The fixtures are not necessary reported in order, so we might not capture
// the closest fixture.
class RayCastMultipleCallback : public b2RayCastCallback
{
public:
enum
{
e_maxCount = 3
};
RayCastMultipleCallback()
{
m_count = 0;
}
float ReportFixture(b2Fixture* fixture, const b2Vec2& point, const b2Vec2& normal, float) override
{
uintptr_t index = fixture->GetUserData().pointer;
if (index == 1)
{
// By returning -1, we instruct the calling code to ignore this fixture and
// continue the ray-cast to the next fixture.
return -1.0f;
}
b2Assert(m_count < e_maxCount);
m_points[m_count] = point;
m_normals[m_count] = normal;
++m_count;
if (m_count == e_maxCount)
{
// At this point the buffer is full.
// By returning 0, we instruct the calling code to terminate the ray-cast.
return 0.0f;
}
// By returning 1, we instruct the caller to continue without clipping the ray.
return 1.0f;
}
b2Vec2 m_points[e_maxCount];
b2Vec2 m_normals[e_maxCount];
int32 m_count;
};
class RayCast : public Test
{
public:
enum Mode
{
e_any = 0,
e_closest = 1,
e_multiple = 2
};
RayCast()
{
// Ground body
{
b2BodyDef bd;
b2Body* ground = m_world->CreateBody(&bd);
b2EdgeShape shape;
shape.SetTwoSided(b2Vec2(-40.0f, 0.0f), b2Vec2(40.0f, 0.0f));
ground->CreateFixture(&shape, 0.0f);
}
{
b2Vec2 vertices[3];
vertices[0].Set(-0.5f, 0.0f);
vertices[1].Set(0.5f, 0.0f);
vertices[2].Set(0.0f, 1.5f);
m_polygons[0].Set(vertices, 3);
}
{
b2Vec2 vertices[3];
vertices[0].Set(-0.1f, 0.0f);
vertices[1].Set(0.1f, 0.0f);
vertices[2].Set(0.0f, 1.5f);
m_polygons[1].Set(vertices, 3);
}
{
float w = 1.0f;
float b = w / (2.0f + b2Sqrt(2.0f));
float s = b2Sqrt(2.0f) * b;
b2Vec2 vertices[8];
vertices[0].Set(0.5f * s, 0.0f);
vertices[1].Set(0.5f * w, b);
vertices[2].Set(0.5f * w, b + s);
vertices[3].Set(0.5f * s, w);
vertices[4].Set(-0.5f * s, w);
vertices[5].Set(-0.5f * w, b + s);
vertices[6].Set(-0.5f * w, b);
vertices[7].Set(-0.5f * s, 0.0f);
m_polygons[2].Set(vertices, 8);
}
{
m_polygons[3].SetAsBox(0.5f, 0.5f);
}
{
m_circle.m_radius = 0.5f;
}
{
m_edge.SetTwoSided(b2Vec2(-1.0f, 0.0f), b2Vec2(1.0f, 0.0f));
}
m_bodyIndex = 0;
memset(m_bodies, 0, sizeof(m_bodies));
m_degrees = 0.0f;
m_mode = e_closest;
}
void Create(int32 index)
{
if (m_bodies[m_bodyIndex] != NULL)
{
m_world->DestroyBody(m_bodies[m_bodyIndex]);
m_bodies[m_bodyIndex] = NULL;
}
b2BodyDef bd;
float x = RandomFloat(-10.0f, 10.0f);
float y = RandomFloat(0.0f, 20.0f);
bd.position.Set(x, y);
bd.angle = RandomFloat(-b2_pi, b2_pi);
if (index == 4)
{
bd.angularDamping = 0.02f;
}
m_bodies[m_bodyIndex] = m_world->CreateBody(&bd);
if (index < 4)
{
b2FixtureDef fd;
fd.shape = m_polygons + index;
fd.friction = 0.3f;
fd.userData.pointer = index + 1;
m_bodies[m_bodyIndex]->CreateFixture(&fd);
}
else if (index < 5)
{
b2FixtureDef fd;
fd.shape = &m_circle;
fd.friction = 0.3f;
fd.userData.pointer = index + 1;
m_bodies[m_bodyIndex]->CreateFixture(&fd);
}
else
{
b2FixtureDef fd;
fd.shape = &m_edge;
fd.friction = 0.3f;
fd.userData.pointer = index + 1;
m_bodies[m_bodyIndex]->CreateFixture(&fd);
}
m_bodyIndex = (m_bodyIndex + 1) % e_maxBodies;
}
void DestroyBody()
{
for (int32 i = 0; i < e_maxBodies; ++i)
{
if (m_bodies[i] != NULL)
{
m_world->DestroyBody(m_bodies[i]);
m_bodies[i] = NULL;
return;
}
}
}
void UpdateUI() override
{
ImGui::SetNextWindowPos(ImVec2(10.0f, 100.0f));
ImGui::SetNextWindowSize(ImVec2(210.0f, 285.0f));
ImGui::Begin("Ray-cast Controls", nullptr, ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize);
if (ImGui::Button("Shape 1"))
{
Create(0);
}
if (ImGui::Button("Shape 2"))
{
Create(1);
}
if (ImGui::Button("Shape 3"))
{
Create(2);
}
if (ImGui::Button("Shape 4"))
{
Create(3);
}
if (ImGui::Button("Shape 5"))
{
Create(4);
}
if (ImGui::Button("Shape 6"))
{
Create(5);
}
if (ImGui::Button("Destroy Shape"))
{
DestroyBody();
}
ImGui::RadioButton("Any", &m_mode, e_any);
ImGui::RadioButton("Closest", &m_mode, e_closest);
ImGui::RadioButton("Multiple", &m_mode, e_multiple);
ImGui::SliderFloat("Angle", &m_degrees, 0.0f, 360.0f, "%.0f");
ImGui::End();
}
void Step(Settings& settings) override
{
Test::Step(settings);
g_debugDraw.DrawString(5, m_textLine, "Shape 1 is intentionally ignored by the ray");
m_textLine += m_textIncrement;
switch (m_mode)
{
case e_closest:
g_debugDraw.DrawString(5, m_textLine, "Ray-cast mode: closest - find closest fixture along the ray");
break;
case e_any:
g_debugDraw.DrawString(5, m_textLine, "Ray-cast mode: any - check for obstruction");
break;
case e_multiple:
g_debugDraw.DrawString(5, m_textLine, "Ray-cast mode: multiple - gather multiple fixtures");
break;
}
m_textLine += m_textIncrement;
float angle = b2_pi * m_degrees / 180.0f;
float L = 11.0f;
b2Vec2 point1(0.0f, 10.0f);
b2Vec2 d(L * cosf(angle), L * sinf(angle));
b2Vec2 point2 = point1 + d;
if (m_mode == e_closest)
{
RayCastClosestCallback callback;
m_world->RayCast(&callback, point1, point2);
if (callback.m_hit)
{
g_debugDraw.DrawPoint(callback.m_point, 5.0f, b2Color(0.4f, 0.9f, 0.4f));
g_debugDraw.DrawSegment(point1, callback.m_point, b2Color(0.8f, 0.8f, 0.8f));
b2Vec2 head = callback.m_point + 0.5f * callback.m_normal;
g_debugDraw.DrawSegment(callback.m_point, head, b2Color(0.9f, 0.9f, 0.4f));
}
else
{
g_debugDraw.DrawSegment(point1, point2, b2Color(0.8f, 0.8f, 0.8f));
}
}
else if (m_mode == e_any)
{
RayCastAnyCallback callback;
m_world->RayCast(&callback, point1, point2);
if (callback.m_hit)
{
g_debugDraw.DrawPoint(callback.m_point, 5.0f, b2Color(0.4f, 0.9f, 0.4f));
g_debugDraw.DrawSegment(point1, callback.m_point, b2Color(0.8f, 0.8f, 0.8f));
b2Vec2 head = callback.m_point + 0.5f * callback.m_normal;
g_debugDraw.DrawSegment(callback.m_point, head, b2Color(0.9f, 0.9f, 0.4f));
}
else
{
g_debugDraw.DrawSegment(point1, point2, b2Color(0.8f, 0.8f, 0.8f));
}
}
else if (m_mode == e_multiple)
{
RayCastMultipleCallback callback;
m_world->RayCast(&callback, point1, point2);
g_debugDraw.DrawSegment(point1, point2, b2Color(0.8f, 0.8f, 0.8f));
for (int32 i = 0; i < callback.m_count; ++i)
{
b2Vec2 p = callback.m_points[i];
b2Vec2 n = callback.m_normals[i];
g_debugDraw.DrawPoint(p, 5.0f, b2Color(0.4f, 0.9f, 0.4f));
g_debugDraw.DrawSegment(point1, p, b2Color(0.8f, 0.8f, 0.8f));
b2Vec2 head = p + 0.5f * n;
g_debugDraw.DrawSegment(p, head, b2Color(0.9f, 0.9f, 0.4f));
}
}
#if 0
// This case was failing.
{
b2Vec2 vertices[4];
//vertices[0].Set(-22.875f, -3.0f);
//vertices[1].Set(22.875f, -3.0f);
//vertices[2].Set(22.875f, 3.0f);
//vertices[3].Set(-22.875f, 3.0f);
b2PolygonShape shape;
//shape.Set(vertices, 4);
shape.SetAsBox(22.875f, 3.0f);
b2RayCastInput input;
input.p1.Set(10.2725f,1.71372f);
input.p2.Set(10.2353f,2.21807f);
//input.maxFraction = 0.567623f;
input.maxFraction = 0.56762173f;
b2Transform xf;
xf.SetIdentity();
xf.position.Set(23.0f, 5.0f);
b2RayCastOutput output;
bool hit;
hit = shape.RayCast(&output, input, xf);
hit = false;
b2Color color(1.0f, 1.0f, 1.0f);
b2Vec2 vs[4];
for (int32 i = 0; i < 4; ++i)
{
vs[i] = b2Mul(xf, shape.m_vertices[i]);
}
g_debugDraw.DrawPolygon(vs, 4, color);
g_debugDraw.DrawSegment(input.p1, input.p2, color);
}
#endif
}
static Test* Create()
{
return new RayCast;
}
int32 m_bodyIndex;
b2Body* m_bodies[e_maxBodies];
b2PolygonShape m_polygons[4];
b2CircleShape m_circle;
b2EdgeShape m_edge;
float m_degrees;
int32 m_mode;
};
static int testIndex = RegisterTest("Collision", "Ray Cast", RayCast::Create);