/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrGLVertexShader_DEFINED
#define GrGLVertexShader_DEFINED

#include "GrGLShaderBuilder.h"

class GrGLVarying;

class GrGLVertexBuilder : public GrGLShaderBuilder {
public:
    GrGLVertexBuilder(GrGLProgramBuilder* program);

    /**
     * Are explicit local coordinates provided as input to the vertex shader.
     */
    bool hasLocalCoords() const { return (fLocalCoordsVar != fPositionVar); }

    /** Returns a vertex attribute that represents the local coords in the VS. This may be the same
        as positionAttribute() or it may not be. It depends upon whether the rendering code
        specified explicit local coords or not in the GrDrawState. */
    const GrGLShaderVar& localCoordsAttribute() const { return *fLocalCoordsVar; }

    /** Returns a vertex attribute that represents the vertex position in the VS. This is the
        pre-matrix position and is commonly used by effects to compute texture coords via a matrix.
      */
    const GrGLShaderVar& positionAttribute() const { return *fPositionVar; }

    /** returns the expected position output */
    const char* glPosition() const { return "pos3"; }

    /** returns the expected uviewM matrix */
    // TODO all of this fixed function stuff can live on the GP/PP
    const char* uViewM() const { return "uViewM"; }
    const char* inPosition() const { return "inPosition"; }


private:
    /*
     * Internal call for GrGLProgramBuilder.addVarying
     */
    void addVarying(const char* name, GrGLVarying*);

    /*
     * private helpers for compilation by GrGLProgramBuilder
     */
    void transformToNormalizedDeviceSpace();
    //TODO GP itself should setup the uniform view matrix
    void setupUniformViewMatrix();
    void setupPositionAndLocalCoords();
    void setupBuiltinVertexAttribute(const char* inName, GrGLSLExpr1* out);
    void setupBuiltinVertexAttribute(const char* inName, GrGLSLExpr4* out);
    void emitAttributes(const GrGeometryProcessor& gp);
    void bindVertexAttributes(GrGLuint programID);
    bool compileAndAttachShaders(GrGLuint programId, SkTDArray<GrGLuint>* shaderIds) const;

    // an internal call which checks for uniquness of a var before adding it to the list of inputs
    bool addAttribute(const GrShaderVar& var);
    struct AttributePair {
        void set(int index, const SkString& name) {
            fIndex = index; fName = name;
        }
        int      fIndex;
        SkString fName;
    };

    GrGLShaderVar*                      fPositionVar;
    GrGLShaderVar*                      fLocalCoordsVar;
    const char*                         fRtAdjustName;
    int                                 fEffectAttribOffset;

    friend class GrGLProgramBuilder;

    typedef GrGLShaderBuilder INHERITED;
};

#endif