DecalRData.cpp

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/* Copyright (C) 2012 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 "DecalRData.h"

#include "graphics/Decal.h"
#include "graphics/LightEnv.h"
#include "graphics/Model.h"
#include "graphics/ShaderManager.h"
#include "graphics/Terrain.h"
#include "graphics/TextureManager.h"
#include "ps/CLogger.h"
#include "ps/Game.h"
#include "ps/Profile.h"
#include "renderer/Renderer.h"
#include "renderer/TerrainRenderer.h"
#include "simulation2/Simulation2.h"
#include "simulation2/components/ICmpWaterManager.h"

// TODO: Currently each decal is a separate CDecalRData. We might want to use
// lots of decals for special effects like shadows, footprints, etc, in which
// case we should probably redesign this to batch them all together for more
// efficient rendering.

CDecalRData::CDecalRData(CModelDecal* decal, CSimulation2* simulation)
    : m_Decal(decal), m_IndexArray(GL_STATIC_DRAW), m_Array(GL_STATIC_DRAW), m_Simulation(simulation)
{
    m_Position.type = GL_FLOAT;
    m_Position.elems = 3;
    m_Array.AddAttribute(&m_Position);

    m_DiffuseColor.type = GL_UNSIGNED_BYTE;
    m_DiffuseColor.elems = 4;
    m_Array.AddAttribute(&m_DiffuseColor);

    m_UV.type = GL_FLOAT;
    m_UV.elems = 2;
    m_Array.AddAttribute(&m_UV);

    BuildArrays();
}

CDecalRData::~CDecalRData()
{
}

void CDecalRData::Update(CSimulation2* simulation)
{
    m_Simulation = simulation;
    if (m_UpdateFlags != 0)
    {
        BuildArrays();
        m_UpdateFlags = 0;
    }
}

void CDecalRData::RenderDecals(std::vector<CDecalRData*>& decals, const CShaderDefines& context, 
                   ShadowMap* shadow, bool isDummyShader, const CShaderProgramPtr& dummy)
{
    CShaderDefines contextDecal = context;
    contextDecal.Add(str_DECAL, str_1);

    for (size_t i = 0; i < decals.size(); ++i)
    {
        CDecalRData *decal = decals[i];
        
        CMaterial &material = decal->m_Decal->m_Decal.m_Material;
        
        if (material.GetShaderEffect().length() == 0)
        {
            LOGERROR(L"Terrain renderer failed to load shader effect.\n");
            continue;
        }
        
        int numPasses = 1;
        CShaderTechniquePtr techBase; 
        
        if (!isDummyShader)
        {
            techBase = g_Renderer.GetShaderManager().LoadEffect(
                material.GetShaderEffect(), contextDecal, material.GetShaderDefines(0));
            
            if (!techBase)
            {
                LOGERROR(L"Terrain renderer failed to load shader effect (%hs)\n",          
                        material.GetShaderEffect().string().c_str());
                continue;
            }
            
            numPasses = techBase->GetNumPasses();
        }
        
        for (int pass = 0; pass < numPasses; ++pass)
        {
            if (!isDummyShader)
            {
                techBase->BeginPass(pass);
                TerrainRenderer::PrepareShader(techBase->GetShader(), shadow);
                
                glEnable(GL_BLEND);
                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
            }
            
            const CShaderProgramPtr& shader = isDummyShader ? dummy : techBase->GetShader(pass);
                
            if (material.GetSamplers().size() != 0)
            {
                const CMaterial::SamplersVector& samplers = material.GetSamplers();
                size_t samplersNum = samplers.size();
                
                for (size_t s = 0; s < samplersNum; ++s)
                {
                    const CMaterial::TextureSampler& samp = samplers[s];
                    shader->BindTexture(samp.Name, samp.Sampler);
                }
                
                material.GetStaticUniforms().BindUniforms(shader);

                // TODO: Need to handle floating decals correctly. In particular, we need
                // to render non-floating before water and floating after water (to get
                // the blending right), and we also need to apply the correct lighting in
                // each case, which doesn't really seem possible with the current
                // TerrainRenderer.
                // Also, need to mark the decals as dirty when water height changes.

                //  glDisable(GL_TEXTURE_2D);
                //  m_Decal->GetBounds().Render();
                //  glEnable(GL_TEXTURE_2D);

                u8* base = decal->m_Array.Bind();
                GLsizei stride = (GLsizei)decal->m_Array.GetStride();

                u8* indexBase = decal->m_IndexArray.Bind();

#if !CONFIG2_GLES
                if (isDummyShader)
                {
                    glColor3fv(decal->m_Decal->GetShadingColor().FloatArray());
                }
                else
#endif
                {
                    
                    shader->Uniform(str_shadingColor, decal->m_Decal->GetShadingColor());
                }

                shader->VertexPointer(3, GL_FLOAT, stride, base + decal->m_Position.offset);
                shader->ColorPointer(4, GL_UNSIGNED_BYTE, stride, base + decal->m_DiffuseColor.offset);
                shader->TexCoordPointer(GL_TEXTURE0, 2, GL_FLOAT, stride, base + decal->m_UV.offset);

                shader->AssertPointersBound();

                if (!g_Renderer.m_SkipSubmit)
                {
                    glDrawElements(GL_TRIANGLES, (GLsizei)decal->m_IndexArray.GetNumVertices(), GL_UNSIGNED_SHORT, indexBase);
                }

                // bump stats
                g_Renderer.m_Stats.m_DrawCalls++;
                g_Renderer.m_Stats.m_TerrainTris += decal->m_IndexArray.GetNumVertices() / 3;

                CVertexBuffer::Unbind();
            }
            
            if (!isDummyShader)
            {
                glDisable(GL_BLEND);
                techBase->EndPass();
            }
        }
    }
}

void CDecalRData::BuildArrays()
{
    PROFILE("decal build");

    const SDecal& decal = m_Decal->m_Decal;

    // TODO: Currently this constructs an axis-aligned bounding rectangle around
    // the decal. It would be more efficient for rendering if we excluded tiles
    // that are outside the (non-axis-aligned) decal rectangle.

    ssize_t i0, j0, i1, j1;
    m_Decal->CalcVertexExtents(i0, j0, i1, j1);

    // Construct vertex data arrays

    CmpPtr<ICmpWaterManager> cmpWaterManager(*m_Simulation, SYSTEM_ENTITY);

    m_Array.SetNumVertices((i1-i0+1)*(j1-j0+1));
    m_Array.Layout();
    VertexArrayIterator<CVector3D> Position = m_Position.GetIterator<CVector3D>();
    VertexArrayIterator<SColor4ub> DiffuseColor = m_DiffuseColor.GetIterator<SColor4ub>();
    VertexArrayIterator<float[2]> UV = m_UV.GetIterator<float[2]>();

    const CLightEnv& lightEnv = g_Renderer.GetLightEnv();
    bool cpuLighting = (g_Renderer.GetRenderPath() == CRenderer::RP_FIXED);

    for (ssize_t j = j0; j <= j1; ++j)
    {
        for (ssize_t i = i0; i <= i1; ++i)
        {
            CVector3D pos;
            m_Decal->m_Terrain->CalcPosition(i, j, pos);

            if (decal.m_Floating && cmpWaterManager)
                pos.Y = std::max(pos.Y, cmpWaterManager->GetExactWaterLevel(pos.X, pos.Z));

            *Position = pos;
            ++Position;

            CVector3D normal;
            m_Decal->m_Terrain->CalcNormal(i, j, normal);
            *DiffuseColor = cpuLighting ? lightEnv.EvaluateTerrainDiffuseScaled(normal) : lightEnv.EvaluateTerrainDiffuseFactor(normal);
            ++DiffuseColor;

            // Map from world space back into decal texture space
            CVector3D inv = m_Decal->GetInvTransform().Transform(pos);
            (*UV)[0] = 0.5f + (inv.X - decal.m_OffsetX) / decal.m_SizeX;
            (*UV)[1] = 0.5f - (inv.Z - decal.m_OffsetZ) / decal.m_SizeZ; // flip V to match our texture convention
            ++UV;
        }
    }

    m_Array.Upload();
    m_Array.FreeBackingStore();

    // Construct index arrays for each terrain tile

    m_IndexArray.SetNumVertices((i1-i0)*(j1-j0)*6);
    m_IndexArray.Layout();
    VertexArrayIterator<u16> Index = m_IndexArray.GetIterator();

    u16 base = 0;
    ssize_t w = i1-i0+1;
    for (ssize_t dj = 0; dj < j1-j0; ++dj)
    {
        for (ssize_t di = 0; di < i1-i0; ++di)
        {
            bool dir = m_Decal->m_Terrain->GetTriangulationDir(i0+di, j0+dj);
            if (dir)
            {
                *Index++ = u16(((dj+0)*w+(di+0))+base);
                *Index++ = u16(((dj+0)*w+(di+1))+base);
                *Index++ = u16(((dj+1)*w+(di+0))+base);

                *Index++ = u16(((dj+0)*w+(di+1))+base);
                *Index++ = u16(((dj+1)*w+(di+1))+base);
                *Index++ = u16(((dj+1)*w+(di+0))+base);
            }
            else
            {
                *Index++ = u16(((dj+0)*w+(di+0))+base);
                *Index++ = u16(((dj+0)*w+(di+1))+base);
                *Index++ = u16(((dj+1)*w+(di+1))+base);

                *Index++ = u16(((dj+1)*w+(di+1))+base);
                *Index++ = u16(((dj+1)*w+(di+0))+base);
                *Index++ = u16(((dj+0)*w+(di+0))+base);
            }
        }
    }

    m_IndexArray.Upload();
    m_IndexArray.FreeBackingStore();
}