viktorljung
66 lines
2.4 KiB
C++
66 lines
2.4 KiB
C++
/*
|
|
* Copyright (c) 2013 Google, Inc.
|
|
*
|
|
* This software is provided 'as-is', without any express or implied
|
|
* warranty. In no event will the authors be held liable for any damages
|
|
* arising from the use of this software.
|
|
* Permission is granted to anyone to use this software for any purpose,
|
|
* including commercial applications, and to alter it and redistribute it
|
|
* freely, subject to the following restrictions:
|
|
* 1. The origin of this software must not be misrepresented; you must not
|
|
* claim that you wrote the original software. If you use this software
|
|
* in a product, an acknowledgment in the product documentation would be
|
|
* appreciated but is not required.
|
|
* 2. Altered source versions must be plainly marked as such, and must not be
|
|
* misrepresented as being the original software.
|
|
* 3. This notice may not be removed or altered from any source distribution.
|
|
*/
|
|
#include <Box2D/Particle/b2Particle.h>
|
|
#include <Box2D/Common/b2Draw.h>
|
|
|
|
#define B2PARTICLECOLOR_BITS_PER_COMPONENT (sizeof(uint8) << 3)
|
|
// Maximum value of a b2ParticleColor component.
|
|
#define B2PARTICLECOLOR_MAX_VALUE \
|
|
((1U << B2PARTICLECOLOR_BITS_PER_COMPONENT) - 1)
|
|
|
|
/// Number of bits used to store each b2ParticleColor component.
|
|
const uint8 b2ParticleColor::k_bitsPerComponent =
|
|
B2PARTICLECOLOR_BITS_PER_COMPONENT;
|
|
const float32 b2ParticleColor::k_maxValue = (float)B2PARTICLECOLOR_MAX_VALUE;
|
|
const float32 b2ParticleColor::k_inverseMaxValue =
|
|
1.0f / (float)B2PARTICLECOLOR_MAX_VALUE;
|
|
|
|
b2ParticleColor b2ParticleColor_zero(0, 0, 0, 0);
|
|
|
|
b2ParticleColor::b2ParticleColor(const b2Color& color)
|
|
{
|
|
Set(color);
|
|
}
|
|
|
|
b2Color b2ParticleColor::GetColor() const
|
|
{
|
|
return b2Color(k_inverseMaxValue * r,
|
|
k_inverseMaxValue * g,
|
|
k_inverseMaxValue * b);
|
|
}
|
|
|
|
void b2ParticleColor::Set(const b2Color& color)
|
|
{
|
|
Set((uint8)(k_maxValue * color.r),
|
|
(uint8)(k_maxValue * color.g),
|
|
(uint8)(k_maxValue * color.b),
|
|
B2PARTICLECOLOR_MAX_VALUE);
|
|
}
|
|
|
|
int32 b2CalculateParticleIterations(
|
|
float32 gravity, float32 radius, float32 timeStep)
|
|
{
|
|
// In some situations you may want more particle iterations than this,
|
|
// but to avoid excessive cycle cost, don't recommend more than this.
|
|
const int32 B2_MAX_RECOMMENDED_PARTICLE_ITERATIONS = 8;
|
|
const float32 B2_RADIUS_THRESHOLD = 0.01f;
|
|
int32 iterations =
|
|
(int32) ceilf(b2Sqrt(gravity / (B2_RADIUS_THRESHOLD * radius)) * timeStep);
|
|
return b2Clamp(iterations, 1, B2_MAX_RECOMMENDED_PARTICLE_ITERATIONS);
|
|
}
|