//
// Urho3D Engine
// Copyright (c) 2008-2012 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 "GPUObject.h"
#include "GraphicsDefs.h"
#include "HashSet.h"
#include "RefCounted.h"
#include "ArrayPtr.h"

class Shader;

/// %Shader parameter definition.
struct ShaderParameter
{
    /// Construct with defaults.
    ShaderParameter() :
        type_(VS),
        register_(M_MAX_UNSIGNED),
        regCount_(0),
        lastSource_((void*)M_MAX_UNSIGNED)
    {
    }
    
    /// Construct with parameters.
    ShaderParameter(ShaderType type, unsigned reg, unsigned regCount) :
        type_(type),
        register_(reg),
        regCount_(regCount),
        lastSource_((void*)M_MAX_UNSIGNED)
    {
    }
    
    /// %Shader type.
    ShaderType type_;
    /// Hardware register.
    unsigned register_;
    /// Number of registers.
    unsigned regCount_;
    /// Last data source.
    const void* lastSource_;
};

/// Vertex or pixel shader on the GPU.
class ShaderVariation : public RefCounted, public GPUObject
{
public:
    /// Construct.
    ShaderVariation(Shader* owner, ShaderType type, bool isSM3);
    /// Destruct.
    virtual ~ShaderVariation();
    
    /// Create the shader program. Return true if successful.
    bool Create();
    /// Release shader.
    virtual void Release();
    
    /// %Set name.
    void SetName(const String& name);
    /// %Set bytecode.
    void SetByteCode(const SharedArrayPtr<unsigned char>& byteCode);
    /// Add a parameter.
    void AddParameter(StringHash param, const ShaderParameter& definition);
    /// Add a texture unit.
    void AddTextureUnit(TextureUnit unit);
    /// Clear parameters and texture unit use flags.
    void ClearParameters();
    /// Optimize the parameter map for optimal query speed
    void OptimizeParameters();
    
    /// Return shader type.
    ShaderType GetShaderType() const { return shaderType_; }
    /// Return full shader name.
    const String& GetName() const { return name_; }
    /// Return whether created successfully.
    bool IsCreated() const;
    /// Return whether compile failed.
    bool IsFailed() const { return failed_; }
    /// Return whether requires Shader Model 3.
    bool IsSM3() const { return isSM3_; }
    /// Return whether uses a parameter.
    bool HasParameter(StringHash param) const { return parameters_.Contains(param); }
    /// Return whether uses a texture unit (only for pixel shaders.)
    bool HasTextureUnit(TextureUnit unit) const { return useTextureUnit_[unit]; }
    /// Return all parameter definitions.
    const HashMap<StringHash, ShaderParameter>& GetParameters() const { return parameters_; }
    
private:
    /// Shader type.
    ShaderType shaderType_;
    /// Full shader name.
    String name_;
    /// Shader bytecode.
    SharedArrayPtr<unsigned char> byteCode_;
    /// Shader Model 3 flag.
    bool isSM3_;
    /// Compile failed flag.
    bool failed_;
    /// Shader parameters.
    HashMap<StringHash, ShaderParameter> parameters_;
    /// Texture unit use flags.
    bool useTextureUnit_[MAX_TEXTURE_UNITS];
};