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/* Copyright (C) 2015 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* 0 A.D. is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
#include "precompiled.h"
#include "ParticleEmitter.h"
#include "graphics/LightEnv.h"
#include "graphics/LOSTexture.h"
#include "graphics/ParticleEmitterType.h"
#include "graphics/ParticleManager.h"
#include "graphics/ShaderProgram.h"
#include "graphics/TextureManager.h"
#include "renderer/Renderer.h"
CParticleEmitter::CParticleEmitter(const CParticleEmitterTypePtr& type) :
m_Type(type), m_Active(true), m_NextParticleIdx(0), m_EmissionRoundingError(0.f),
m_LastUpdateTime(type->m_Manager.GetCurrentTime()),
m_IndexArray(GL_STATIC_DRAW),
m_VertexArray(GL_DYNAMIC_DRAW),
m_LastFrameNumber(-1)
{
// If we should start with particles fully emitted, pretend that we
// were created in the past so the first update will produce lots of
// particles.
// TODO: instead of this, maybe it would make more sense to do a full
// lifetime-length update of all emitters when the game first starts
// (so that e.g. buildings constructed later on won't have fully-started
// emitters, but those at the start will)?
if (m_Type->m_StartFull)
m_LastUpdateTime -= m_Type->m_MaxLifetime;
m_Particles.reserve(m_Type->m_MaxParticles);
m_AttributePos.type = GL_FLOAT;
m_AttributePos.elems = 3;
m_VertexArray.AddAttribute(&m_AttributePos);
m_AttributeAxis.type = GL_FLOAT;
m_AttributeAxis.elems = 2;
m_VertexArray.AddAttribute(&m_AttributeAxis);
m_AttributeUV.type = GL_FLOAT;
m_AttributeUV.elems = 2;
m_VertexArray.AddAttribute(&m_AttributeUV);
m_AttributeColor.type = GL_UNSIGNED_BYTE;
m_AttributeColor.elems = 4;
m_VertexArray.AddAttribute(&m_AttributeColor);
m_VertexArray.SetNumVertices(m_Type->m_MaxParticles * 4);
m_VertexArray.Layout();
m_IndexArray.SetNumVertices(m_Type->m_MaxParticles * 6);
m_IndexArray.Layout();
VertexArrayIterator<u16> index = m_IndexArray.GetIterator();
for (size_t i = 0; i < m_Type->m_MaxParticles; ++i)
{
*index++ = i*4 + 0;
*index++ = i*4 + 1;
*index++ = i*4 + 2;
*index++ = i*4 + 2;
*index++ = i*4 + 3;
*index++ = i*4 + 0;
}
m_IndexArray.Upload();
m_IndexArray.FreeBackingStore();
}
void CParticleEmitter::UpdateArrayData(int frameNumber)
{
if (m_LastFrameNumber == frameNumber)
return;
m_LastFrameNumber = frameNumber;
// Update m_Particles
m_Type->UpdateEmitter(*this, m_Type->m_Manager.GetCurrentTime() - m_LastUpdateTime);
m_LastUpdateTime = m_Type->m_Manager.GetCurrentTime();
// Regenerate the vertex array data:
VertexArrayIterator<CVector3D> attrPos = m_AttributePos.GetIterator<CVector3D>();
VertexArrayIterator<float[2]> attrAxis = m_AttributeAxis.GetIterator<float[2]>();
VertexArrayIterator<float[2]> attrUV = m_AttributeUV.GetIterator<float[2]>();
VertexArrayIterator<SColor4ub> attrColor = m_AttributeColor.GetIterator<SColor4ub>();
ENSURE(m_Particles.size() <= m_Type->m_MaxParticles);
CBoundingBoxAligned bounds;
for (size_t i = 0; i < m_Particles.size(); ++i)
{
// TODO: for more efficient rendering, maybe we should replace this with
// a degenerate quad if alpha is 0
bounds += m_Particles[i].pos;
*attrPos++ = m_Particles[i].pos;
*attrPos++ = m_Particles[i].pos;
*attrPos++ = m_Particles[i].pos;
*attrPos++ = m_Particles[i].pos;
// Compute corner offsets, split into sin/cos components so the vertex
// shader can multiply by the camera-right (or left?) and camera-up vectors
// to get rotating billboards:
float s = sin(m_Particles[i].angle) * m_Particles[i].size/2.f;
float c = cos(m_Particles[i].angle) * m_Particles[i].size/2.f;
(*attrAxis)[0] = c;
(*attrAxis)[1] = s;
++attrAxis;
(*attrAxis)[0] = s;
(*attrAxis)[1] = -c;
++attrAxis;
(*attrAxis)[0] = -c;
(*attrAxis)[1] = -s;
++attrAxis;
(*attrAxis)[0] = -s;
(*attrAxis)[1] = c;
++attrAxis;
(*attrUV)[0] = 1;
(*attrUV)[1] = 0;
++attrUV;
(*attrUV)[0] = 0;
(*attrUV)[1] = 0;
++attrUV;
(*attrUV)[0] = 0;
(*attrUV)[1] = 1;
++attrUV;
(*attrUV)[0] = 1;
(*attrUV)[1] = 1;
++attrUV;
SColor4ub color = m_Particles[i].color;
// Special case: If the blending depends on the source color, not the source alpha,
// then pre-multiply by the alpha. (This is kind of a hack.)
if (m_Type->m_BlendFuncDst == GL_ONE_MINUS_SRC_COLOR)
{
color.R = (color.R * color.A) / 255;
color.G = (color.G * color.A) / 255;
color.B = (color.B * color.A) / 255;
}
*attrColor++ = color;
*attrColor++ = color;
*attrColor++ = color;
*attrColor++ = color;
}
m_ParticleBounds = bounds;
m_VertexArray.Upload();
}
void CParticleEmitter::PrepareForRendering()
{
m_VertexArray.PrepareForRendering();
}
void CParticleEmitter::Bind(const CShaderProgramPtr& shader)
{
CLOSTexture& los = g_Renderer.GetScene().GetLOSTexture();
shader->BindTexture(str_losTex, los.GetTextureSmooth());
shader->Uniform(str_losTransform, los.GetTextureMatrix()[0], los.GetTextureMatrix()[12], 0.f, 0.f);
const CLightEnv& lightEnv = g_Renderer.GetLightEnv();
shader->Uniform(str_sunColor, lightEnv.m_SunColor);
shader->Uniform(str_fogColor, lightEnv.m_FogColor);
shader->Uniform(str_fogParams, lightEnv.m_FogFactor, lightEnv.m_FogMax, 0.f, 0.f);
shader->BindTexture(str_baseTex, m_Type->m_Texture);
pglBlendEquationEXT(m_Type->m_BlendEquation);
glBlendFunc(m_Type->m_BlendFuncSrc, m_Type->m_BlendFuncDst);
}
void CParticleEmitter::RenderArray(const CShaderProgramPtr& shader)
{
// Some drivers apparently don't like count=0 in glDrawArrays here,
// so skip all drawing in that case
if (m_Particles.empty())
return;
u8* indexBase = m_IndexArray.Bind();
u8* base = m_VertexArray.Bind();
GLsizei stride = (GLsizei)m_VertexArray.GetStride();
shader->VertexPointer(3, GL_FLOAT, stride, base + m_AttributePos.offset);
// Pass the sin/cos axis components as texcoords for no particular reason
// other than that they fit. (Maybe this should be glVertexAttrib* instead?)
shader->TexCoordPointer(GL_TEXTURE0, 2, GL_FLOAT, stride, base + m_AttributeUV.offset);
shader->TexCoordPointer(GL_TEXTURE1, 2, GL_FLOAT, stride, base + m_AttributeAxis.offset);
shader->ColorPointer(4, GL_UNSIGNED_BYTE, stride, base + m_AttributeColor.offset);
shader->AssertPointersBound();
glDrawElements(GL_TRIANGLES, (GLsizei)(m_Particles.size() * 6), GL_UNSIGNED_SHORT, indexBase);
g_Renderer.GetStats().m_DrawCalls++;
g_Renderer.GetStats().m_Particles += m_Particles.size();
}
void CParticleEmitter::Unattach(const CParticleEmitterPtr& self)
{
m_Active = false;
m_Type->m_Manager.AddUnattachedEmitter(self);
}
void CParticleEmitter::AddParticle(const SParticle& particle)
{
if (m_NextParticleIdx >= m_Particles.size())
m_Particles.push_back(particle);
else
m_Particles[m_NextParticleIdx] = particle;
m_NextParticleIdx = (m_NextParticleIdx + 1) % m_Type->m_MaxParticles;
}
void CParticleEmitter::SetEntityVariable(const std::string& name, float value)
{
m_EntityVariables[name] = value;
}
CModelParticleEmitter::CModelParticleEmitter(const CParticleEmitterTypePtr& type) :
m_Type(type)
{
m_Emitter = CParticleEmitterPtr(new CParticleEmitter(m_Type));
}
CModelParticleEmitter::~CModelParticleEmitter()
{
m_Emitter->Unattach(m_Emitter);
}
void CModelParticleEmitter::SetEntityVariable(const std::string& name, float value)
{
m_Emitter->SetEntityVariable(name, value);
}
CModelAbstract* CModelParticleEmitter::Clone() const
{
return new CModelParticleEmitter(m_Type);
}
void CModelParticleEmitter::CalcBounds()
{
// TODO: we ought to compute sensible bounds here, probably based on the
// current computed particle positions plus the emitter type's largest
// potential bounding box at the current position
m_WorldBounds = m_Type->CalculateBounds(m_Emitter->GetPosition(), m_Emitter->GetParticleBounds());
}
void CModelParticleEmitter::ValidatePosition()
{
// TODO: do we need to do anything here?
// This is a convenient (though possibly not particularly appropriate) place
// to invalidate bounds so they'll be recomputed from the recent particle data
InvalidateBounds();
}
void CModelParticleEmitter::InvalidatePosition()
{
}
void CModelParticleEmitter::SetTransform(const CMatrix3D& transform)
{
if (m_Transform == transform)
return;
m_Emitter->SetPosition(transform.GetTranslation());
m_Emitter->SetRotation(transform.GetRotation());
// call base class to set transform on this object
CRenderableObject::SetTransform(transform);
}
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