Source/platform/graphics/filters/custom/CustomFilterValidatedProgram.h

/*
 * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * SUCH DAMAGE.
 */

#ifndef CustomFilterValidatedProgram_h
#define CustomFilterValidatedProgram_h

#include "platform/graphics/filters/custom/CustomFilterCompiledProgram.h"
#include "platform/graphics/filters/custom/CustomFilterProgramInfo.h"
#include "wtf/PassRefPtr.h"
#include "wtf/RefCounted.h"
#include "wtf/RefPtr.h"
#include "wtf/text/WTFString.h"

// PlatformCompiledProgram defines a type that is compatible with the framework used to implement accelerated compositing on a particular platform.
namespace WebCore {

struct ANGLEShaderSymbol;
class CustomFilterCompiledProgram;
class CustomFilterGlobalContext;

//
// A unique combination of vertex shader and fragment shader is only validated and compiled once.
// All shaders are validated through ANGLE in CustomFilterValidatedProgram before being compiled by the GraphicsContext3D in CustomFilterCompiledProgram.
// For shaders that use the CSS mix function, CustomFilterValidatedProgram adds shader code to perform DOM texture access, blending, and compositing.
//
// The CustomFilterGlobalContext caches the validated programs.
// CustomFilterValidatedProgram owns a CustomFilterCompiledProgram if validation and compilation succeeds.
// Thus, compiled programs are cached via their validated program owners.
//
// CustomFilterGlobalContext has a weak reference to the CustomFilterValidatedProgram.
// Thus, the CustomFilterValidatedProgram destructor needs to notify the CustomFilterGlobalContext to remove the program from the cache.
// FECustomFilter is the reference owner of the CustomFilterValidatedProgram.
// Thus, a validated and compiled shader is only kept alive as long as there is at least one visible layer that applies the shader.
//
class PLATFORM_EXPORT CustomFilterValidatedProgram : public RefCounted<CustomFilterValidatedProgram> {
public:
    static PassRefPtr<CustomFilterValidatedProgram> create(CustomFilterGlobalContext* globalContext, const CustomFilterProgramInfo& programInfo)
    {
        return adoptRef(new CustomFilterValidatedProgram(globalContext, programInfo));
    }

    ~CustomFilterValidatedProgram();

    const CustomFilterProgramInfo& programInfo() const { return m_programInfo; }
    CustomFilterProgramInfo validatedProgramInfo() const;

    PassRefPtr<CustomFilterCompiledProgram> compiledProgram();

    const String& validatedVertexShader() const
    {
        ASSERT(m_isInitialized);
        return m_validatedVertexShader;
    }

    const String& validatedFragmentShader() const
    {
        ASSERT(m_isInitialized);
        return m_validatedFragmentShader;
    }

    bool isInitialized() const { return m_isInitialized; }

    // 'detachFromGlobalContext' is called when the CustomFilterGlobalContext is deleted, and there's no need for the callback anymore.
    // Note that CustomFilterGlobalContext does not keep a strong reference to the CustomFilterValidatedProgram.
    void detachFromGlobalContext() { m_globalContext = 0; }
private:
    CustomFilterValidatedProgram(CustomFilterGlobalContext*, const CustomFilterProgramInfo&);

    void platformInit();
    void platformDestroy();

    static String defaultVertexShaderString();
    static String defaultFragmentShaderString();

    static String blendFunctionString(blink::WebBlendMode);
    static String compositeFunctionString(CompositeOperator);

    void rewriteMixVertexShader(const Vector<ANGLEShaderSymbol>& symbols);
    void rewriteMixFragmentShader();

    bool needsInputTexture() const;

    CustomFilterGlobalContext* m_globalContext;
    CustomFilterProgramInfo m_programInfo;

    String m_validatedVertexShader;
    String m_validatedFragmentShader;

    RefPtr<CustomFilterCompiledProgram> m_compiledProgram;

    bool m_isInitialized;
};

}


#endif