/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/

#ifndef GrGLSLProgramDesc_DEFINED
#define GrGLSLProgramDesc_DEFINED

#include "GrColor.h"
#include "GrProgramDesc.h"
#include "GrGpu.h"
#include "GrTypesPriv.h"

class GrGLSLProgramDescBuilder;

class GrGLSLProgramDesc : public GrProgramDesc {
    friend class GrGLSLProgramDescBuilder;
};

/**
* This class can be used to build a GrProgramDesc.  It also provides helpers for accessing
* GL specific info in the header.
*/
class GrGLSLProgramDescBuilder {
public:
    typedef GrProgramDesc::KeyHeader KeyHeader;
    // The key, stored in fKey, is composed of five parts(first 2 are defined in the key itself):
    // 1. uint32_t for total key length.
    // 2. uint32_t for a checksum.
    // 3. Header struct defined above.
    // 4. Backend-specific information including per-processor keys and their key lengths.
    //    Each processor's key is a variable length array of uint32_t.
    enum {
        // Part 3.
        kHeaderOffset = GrGLSLProgramDesc::kHeaderOffset,
        kHeaderSize = SkAlign4(sizeof(KeyHeader)),
        // Part 4.
        // This is the offset into the backenend specific part of the key, which includes
        // per-processor keys.
        kProcessorKeysOffset = kHeaderOffset + kHeaderSize,
    };

    /**
    * Builds a GLSL specific program descriptor
    *
    * @param GrPrimitiveProcessor The geometry
    * @param GrPipeline  The optimized drawstate.  The descriptor will represent a program
    *                        which this optstate can use to draw with.  The optstate contains
    *                        general draw information, as well as the specific color, geometry,
    *                        and coverage stages which will be used to generate the GL Program for
    *                        this optstate.
    * @param GrGLSLCaps     Capabilities of the GLSL backend.
    * @param GrProgramDesc  The built and finalized descriptor
    **/
    static bool Build(GrProgramDesc*,
                      const GrPrimitiveProcessor&,
                      const GrPipeline&,
                      const GrGLSLCaps&);
};

#endif