urho3d/Engine/Graphics/Batch.h

//
// Urho3D Engine
// Copyright (c) 2008-2011 Lasse Öörni
//
// 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.
//

#pragma once

#include "MathDefs.h"
#include "GraphicsDefs.h"
#include "SharedPtr.h"

class Camera;
class Drawable;
class Geometry;
class Light;
class Material;
class Pass;
class Matrix4x3;
class PixelShader;
class Graphics;
class VertexBuffer;
class VertexShader;

/// Description of a 3D geometry draw call
struct Batch
{
    /// Construct with defaults
    Batch() :
        light_(0),
        shaderData_(0),
        shaderDataSize_(0),
        geometryType_(GEOM_STATIC),
        overrideView_(false),
        hasPriority_(false)
    {
    }
    
    /// Calculate sort key, which consists of priority flag, light, pass and geometry
    void CalculateSortKey();
    /// Prepare for rendering
    void Prepare(Graphics* graphics, bool SetModelTransform = true) const;
    /// Prepare and draw
    void Draw(Graphics* graphics) const;
    
    /// Geometry
    Geometry* geometry_;
    /// Model world transform
    const Matrix4x3* worldTransform_;
    /// Material
    Material* material_;
    /// Material pass
    Pass* pass_;
    /// Vertex shader
    VertexShader* vertexShader_;
    /// Pixel shader
    PixelShader* pixelShader_;
    /// Camera
    Camera* camera_;
    /// Light that affects the geometry, if any
    Light* light_;
    /// Vertex shader data
    const void* shaderData_;
    /// Vertex shader data size in floats
    unsigned shaderDataSize_;
    /// Distance from camera
    float distance_;
    /// Geometry type
    GeometryType geometryType_;
    /// Vertex shader index
    unsigned char vertexShaderIndex_;
    /// Override view transform flag
    bool overrideView_;
    /// Priority flag
    bool hasPriority_;
    /// State sorting key
    unsigned long long sortKey_;
};

/// Data for one geometry instance
struct InstanceData
{
    /// Construct with transform and distance
    InstanceData(const Matrix4x3* worldTransform, float distance) :
        worldTransform_(worldTransform),
        distance_(distance)
    {
    }
    
    /// World transform
    const Matrix4x3* worldTransform_;
    /// Distance from camera
    float distance_;
};

/// Instanced 3D geometry draw call
struct BatchGroup
{
    /// Construct with defaults
    BatchGroup() :
        startIndex_(M_MAX_UNSIGNED)
    {
    }
    
    /// Destruct
    ~BatchGroup()
    {
    }
    
    /// Pre-set the instance transforms. Buffer must be big enough to hold all transforms
    void SetTransforms(void* lockedData, unsigned& freeIndex);
    /// Prepare and draw
    void Draw(Graphics* graphics, VertexBuffer* buffer) const;
    
    /// Geometry
    Geometry* geometry_;
    /// Instance data
    std::vector<InstanceData> instances_;
    /// Material
    Material* material_;
    /// Material pass
    Pass* pass_;
    /// Vertex shader
    VertexShader* vertexShader_;
    /// Pixel shader
    PixelShader* pixelShader_;
    /// Camera
    Camera* camera_;
    /// Light that affects the geometry, if any
    Light* light_;
    /// Vertex shader index
    unsigned char vertexShaderIndex_;
    /// Instance stream start index, or M_MAX_UNSIGNED if transforms not pre-set
    unsigned startIndex_;
};

/// Instanced draw call key
struct BatchGroupKey
{
    /// Light that affects the geometry, if any
    Light* light_;
    /// Material pass
    Pass* pass_;
    /// Material
    Material* material_;
    /// Geometry
    Geometry* geometry_;
    
    /// Test if less than another batch group key
    bool operator < (const BatchGroupKey& rhs) const
    {
        if (light_ == rhs.light_)
        {
            if (pass_ == rhs.pass_)
            {
                if (material_ == rhs.material_)
                    return geometry_ < rhs.geometry_;
                else
                    return material_ < rhs.material_;
            }
            else
                return pass_ < rhs.pass_;
        }
        else
            return light_ < rhs.light_;
    }
    
    /// Test if greater than another batch group key
    bool operator > (const BatchGroupKey& rhs) const
    {
        if (light_ == rhs.light_)
        {
            if (pass_ == rhs.pass_)
            {
                if (material_ == rhs.material_)
                    return geometry_ > rhs.geometry_;
                else
                    return material_ > rhs.material_;
            }
            else
                return pass_ > rhs.pass_;
        }
        else
            return light_ > rhs.light_;
    }
};

/// Queue that contains both instanced and non-instanced draw calls
struct BatchQueue
{
public:
    /// Clear everything
    void Clear();
    /// Add a batch, with instancing if possible
    void AddBatch(const Batch& batch, bool noInstancing = false);
    /// Sort non-instanced draw calls back to front
    void SortBackToFront();
    /// Sort instanced and non-instanced draw calls front to back
    void SortFrontToBack();
    /// Pre-set instance transforms of all groups. The vertex buffer must be big enough to hold all transforms
    void SetTransforms(void* lockedData, unsigned& freeIndex);
    
    /// Return the combined amount of instances
    unsigned GetNumInstances() const;
    
    /// Unsorted non-instanced draw calls
    std::vector<Batch> batches_;
    /// Sorted non-instanced draw calls with priority flag
    std::vector<Batch*> sortedPriorityBatches_;
    /// Sorted non-instanced draw calls
    std::vector<Batch*> sortedBatches_;
    /// Instanced draw calls with priority flag
    std::map<BatchGroupKey, BatchGroup> priorityBatchGroups_;
    /// Instanced draw calls
    std::map<BatchGroupKey, BatchGroup> batchGroups_;
};

/// Queue for light related draw calls
struct LightBatchQueue
{
    /// Light drawable
    Light* light_;
    /// Shadowcaster draw calls
    BatchQueue shadowBatches_;
    /// Lit geometry draw calls
    BatchQueue litBatches_;
    /// Light volume draw calls, should be only one
    std::vector<Batch> volumeBatches_;
    /// Last split flag for clearing the stencil buffer
    bool lastSplit_;
};