// SwiftShader Software Renderer
//
// Copyright(c) 2005-2013 TransGaming Inc.
//
// All rights reserved. No part of this software may be copied, distributed, transmitted,
// transcribed, stored in a retrieval system, translated into any human or computer
// language by any means, or disclosed to third parties without the explicit written
// agreement of TransGaming Inc. Without such an agreement, no rights or licenses, express
// or implied, including but not limited to any patent rights, are granted to you.
//

// Context.h: Defines the Context class, managing all GL state and performing
// rendering operations. It is the GLES2 specific implementation of EGLContext.

#ifndef LIBGLESV2_CONTEXT_H_
#define LIBGLESV2_CONTEXT_H_

#include "Context.hpp"
#include "Image.hpp"
#include "Renderer/Sampler.hpp"

#define GL_APICALL
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#define EGLAPI
#include <EGL/egl.h>

#include <map>
#include <string>

namespace egl
{
class Display;
class Surface;
class Config;
}

namespace es2
{
class Device;
class Shader;
class Program;
class Texture;
class Texture2D;
class TextureCubeMap;
class TextureExternal;
class Fence;

enum
{
    MAX_VERTEX_ATTRIBS = 16,
	MAX_UNIFORM_VECTORS = 256,   // Device limit
    MAX_VERTEX_UNIFORM_VECTORS = 256 - 3,   // Reserve space for gl_DepthRange
    MAX_VARYING_VECTORS = 10,
    MAX_TEXTURE_IMAGE_UNITS = 16,
    MAX_VERTEX_TEXTURE_IMAGE_UNITS = 4,
    MAX_COMBINED_TEXTURE_IMAGE_UNITS = MAX_TEXTURE_IMAGE_UNITS + MAX_VERTEX_TEXTURE_IMAGE_UNITS,
    MAX_FRAGMENT_UNIFORM_VECTORS = 224 - 3,    // Reserve space for gl_DepthRange
    MAX_DRAW_BUFFERS = 1,

    IMPLEMENTATION_COLOR_READ_FORMAT = GL_RGB,
    IMPLEMENTATION_COLOR_READ_TYPE = GL_UNSIGNED_SHORT_5_6_5
};

const float ALIASED_LINE_WIDTH_RANGE_MIN = 1.0f;
const float ALIASED_LINE_WIDTH_RANGE_MAX = 1.0f;
const float ALIASED_POINT_SIZE_RANGE_MIN = 0.125f;
const float ALIASED_POINT_SIZE_RANGE_MAX = 8192.0f;
const float MAX_TEXTURE_MAX_ANISOTROPY = 16.0f;

struct Color
{
    float red;
    float green;
    float blue;
    float alpha;
};

// Helper structure describing a single vertex attribute
class VertexAttribute
{
  public:
    VertexAttribute() : mType(GL_FLOAT), mSize(0), mNormalized(false), mStride(0), mOffset(0), mArrayEnabled(false)
    {
    }

    int typeSize() const;

    GLsizei stride() const
    {
        return mStride ? mStride : typeSize();
    }

    // From glVertexAttribPointer
    GLenum mType;
    GLint mSize;
    bool mNormalized;
    GLsizei mStride;   // 0 means natural stride
    intptr_t mOffset;

    sw::Resource *buffer;

    bool mArrayEnabled;   // From glEnable/DisableVertexAttribArray
};

typedef VertexAttribute VertexAttributeArray[MAX_VERTEX_ATTRIBS];

// Helper structure to store all raw state
struct State
{
    Color colorClearValue;
    GLclampf depthClearValue;
    int stencilClearValue;

    bool cullFace;
    GLenum cullMode;
    GLenum frontFace;
    bool depthTest;
    GLenum depthFunc;
    bool blend;
    GLenum sourceBlendRGB;
    GLenum destBlendRGB;
    GLenum sourceBlendAlpha;
    GLenum destBlendAlpha;
    GLenum blendEquationRGB;
    GLenum blendEquationAlpha;
    Color blendColor;
    bool stencilTest;
    GLenum stencilFunc;
    GLint stencilRef;
    GLuint stencilMask;
    GLenum stencilFail;
    GLenum stencilPassDepthFail;
    GLenum stencilPassDepthPass;
    GLuint stencilWritemask;
    GLenum stencilBackFunc;
    GLint stencilBackRef;
    GLuint stencilBackMask;
    GLenum stencilBackFail;
    GLenum stencilBackPassDepthFail;
    GLenum stencilBackPassDepthPass;
    GLuint stencilBackWritemask;
    bool polygonOffsetFill;
    GLfloat polygonOffsetFactor;
    GLfloat polygonOffsetUnits;
    bool sampleAlphaToCoverage;
    bool sampleCoverage;
    GLclampf sampleCoverageValue;
    bool sampleCoverageInvert;
    bool scissorTest;
    bool dither;

    GLfloat lineWidth;

    GLenum generateMipmapHint;
    GLenum fragmentShaderDerivativeHint;

    GLint viewportX;
    GLint viewportY;
    GLsizei viewportWidth;
    GLsizei viewportHeight;
    float zNear;
    float zFar;

    GLint scissorX;
    GLint scissorY;
    GLsizei scissorWidth;
    GLsizei scissorHeight;

    bool colorMaskRed;
    bool colorMaskGreen;
    bool colorMaskBlue;
    bool colorMaskAlpha;
    bool depthMask;

    unsigned int activeSampler;   // Active texture unit selector - GL_TEXTURE0
    sw::Resource *elementArrayBuffer;
    GLuint readFramebuffer;
    GLuint drawFramebuffer;
	
	Program *program;
	egl::Image *colorBuffer;
	egl::Image *depthBuffer;
	egl::Image *stencilBuffer;

    VertexAttribute vertexAttribute[MAX_VERTEX_ATTRIBS];

    GLint unpackAlignment;
    GLint packAlignment;
};

class Context : public egl::Context
{
public:
    Context(const egl::Config *config, const Context *shareContext);

	virtual void makeCurrent(egl::Surface *surface);
	virtual void destroy();
	virtual int getClientVersion();

    void markAllStateDirty();

    // State manipulation
    void setClearColor(float red, float green, float blue, float alpha);
    void setClearDepth(float depth);
    void setClearStencil(int stencil);

    void setCullFace(bool enabled);
    bool isCullFaceEnabled() const;
    void setCullMode(GLenum mode);
    void setFrontFace(GLenum front);

    void setDepthTest(bool enabled);
    bool isDepthTestEnabled() const;
    void setDepthFunc(GLenum depthFunc);
    void setDepthRange(float zNear, float zFar);
    
    void setBlend(bool enabled);
    bool isBlendEnabled() const;
    void setBlendFactors(GLenum sourceRGB, GLenum destRGB, GLenum sourceAlpha, GLenum destAlpha);
    void setBlendColor(float red, float green, float blue, float alpha);
    void setBlendEquation(GLenum rgbEquation, GLenum alphaEquation);

    void setStencilTest(bool enabled);
    bool isStencilTestEnabled() const;
    void setStencilParams(GLenum stencilFunc, GLint stencilRef, GLuint stencilMask);
    void setStencilBackParams(GLenum stencilBackFunc, GLint stencilBackRef, GLuint stencilBackMask);
    void setStencilWritemask(GLuint stencilWritemask);
    void setStencilBackWritemask(GLuint stencilBackWritemask);
    void setStencilOperations(GLenum stencilFail, GLenum stencilPassDepthFail, GLenum stencilPassDepthPass);
    void setStencilBackOperations(GLenum stencilBackFail, GLenum stencilBackPassDepthFail, GLenum stencilBackPassDepthPass);

    void setPolygonOffsetFill(bool enabled);
    bool isPolygonOffsetFillEnabled() const;
    void setPolygonOffsetParams(GLfloat factor, GLfloat units);

    void setSampleAlphaToCoverage(bool enabled);
    bool isSampleAlphaToCoverageEnabled() const;
    void setSampleCoverage(bool enabled);
    bool isSampleCoverageEnabled() const;
    void setSampleCoverageParams(GLclampf value, bool invert);

    void setDither(bool enabled);
    bool isDitherEnabled() const;

    void setLineWidth(GLfloat width);

    void setGenerateMipmapHint(GLenum hint);
    void setFragmentShaderDerivativeHint(GLenum hint);

    void setViewportParams(GLint x, GLint y, GLsizei width, GLsizei height);

	void setScissorTest(bool enabled);
    bool isScissorTestEnabled() const;
    void setScissorParams(GLint x, GLint y, GLsizei width, GLsizei height);

    void setColorMask(bool red, bool green, bool blue, bool alpha);
    void setDepthMask(bool mask);

    void setActiveSampler(unsigned int active);

    void setEnableVertexAttribArray(unsigned int attribNum, bool enabled);
    const VertexAttribute &getVertexAttribState(unsigned int attribNum);
    void setVertexAttribState(unsigned int attribNum, sw::Resource *buffer, GLint size, GLenum type,
                              bool normalized, GLsizei stride, intptr_t offset);
    
    void setUnpackAlignment(GLint alignment);
    GLint getUnpackAlignment() const;

    void setPackAlignment(GLint alignment);
    GLint getPackAlignment() const;
	
    void drawArrays(GLenum mode, GLint first, GLsizei count);
    void drawElements(GLenum mode, GLsizei count, GLenum type, intptr_t offset);
    void finish();
    void flush();

    void recordInvalidEnum();
    void recordInvalidValue();
    void recordInvalidOperation();
    void recordOutOfMemory();
    void recordInvalidFramebufferOperation();

    GLenum getError();

    static int getSupportedMultiSampleDepth(sw::Format format, int requested);
    	
	Device *getDevice();

public:
	virtual ~Context();

    bool applyRenderTarget();
    void applyState(GLenum drawMode);
    GLenum applyVertexBuffer(GLint base, GLint first);
    void applyIndexBuffer();
    void applyShaders();
	void applyTexture(sw::SamplerType type, int sampler, Texture *texture);

    bool cullSkipsDraw(GLenum drawMode);
    bool isTriangleMode(GLenum drawMode);

    const egl::Config *const mConfig;

    State mState;

    // Recorded errors
    bool mInvalidEnum;
    bool mInvalidValue;
    bool mInvalidOperation;
    bool mOutOfMemory;
    bool mInvalidFramebufferOperation;

    bool mHasBeenCurrent;

    unsigned int mAppliedProgramSerial;
    
    // state caching flags
    bool mDepthStateDirty;
    bool mMaskStateDirty;
    bool mPixelPackingStateDirty;
    bool mBlendStateDirty;
    bool mStencilStateDirty;
    bool mPolygonOffsetStateDirty;
    bool mSampleStateDirty;
    bool mFrontFaceDirty;
    bool mDitherStateDirty;
	
	Device *device;
};
}

#endif   // INCLUDE_CONTEXT_H_