include/gpu/GrTypes.h

/*
 * Copyright 2010 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#ifndef GrTypes_DEFINED
#define GrTypes_DEFINED

#include "SkTypes.h"
#include "GrConfig.h"
#include "SkMath.h"

////////////////////////////////////////////////////////////////////////////////

/**
 * Defines overloaded bitwise operators to make it easier to use an enum as a
 * bitfield.
 */
#define GR_MAKE_BITFIELD_OPS(X) \
    inline X operator | (X a, X b) { \
        return (X) (+a | +b); \
    } \
    \
    inline X operator & (X a, X b) { \
        return (X) (+a & +b); \
    } \
    template <typename T> \
    inline X operator & (T a, X b) { \
        return (X) (+a & +b); \
    } \
    template <typename T> \
    inline X operator & (X a, T b) { \
        return (X) (+a & +b); \
    } \

#define GR_DECL_BITFIELD_OPS_FRIENDS(X) \
    friend X operator | (X a, X b); \
    \
    friend X operator & (X a, X b); \
    \
    template <typename T> \
    friend X operator & (T a, X b); \
    \
    template <typename T> \
    friend X operator & (X a, T b); \
////////////////////////////////////////////////////////////////////////////////


/**
 *  Macro to round n up to the next multiple of 4, or return it unchanged if
 *  n is already a multiple of 4
 */
#define GrALIGN4(n)     SkAlign4(n)
#define GrIsALIGN4(n)   SkIsAlign4(n)

template <typename T> const T& GrMin(const T& a, const T& b) {
    return (a < b) ? a : b;
}

template <typename T> const T& GrMax(const T& a, const T& b) {
    return (b < a) ? a : b;
}

// compile time versions of min/max
#define GR_CT_MAX(a, b) (((b) < (a)) ? (a) : (b))
#define GR_CT_MIN(a, b) (((b) < (a)) ? (b) : (a))

/**
 *  divide, rounding up
 */
static inline int32_t GrIDivRoundUp(int x, int y) {
    GrAssert(y > 0);
    return (x + (y-1)) / y;
}
static inline uint32_t GrUIDivRoundUp(uint32_t x, uint32_t y) {
    return (x + (y-1)) / y;
}
static inline size_t GrSizeDivRoundUp(size_t x, size_t y) {
    return (x + (y-1)) / y;
}

// compile time, evaluates Y multiple times
#define GR_CT_DIV_ROUND_UP(X, Y) (((X) + ((Y)-1)) / (Y))

/**
 *  align up
 */
static inline uint32_t GrUIAlignUp(uint32_t x, uint32_t alignment) {
    return GrUIDivRoundUp(x, alignment) * alignment;
}
static inline size_t GrSizeAlignUp(size_t x, size_t alignment) {
    return GrSizeDivRoundUp(x, alignment) * alignment;
}

// compile time, evaluates A multiple times
#define GR_CT_ALIGN_UP(X, A) (GR_CT_DIV_ROUND_UP((X),(A)) * (A))

/**
 * amount of pad needed to align up
 */
static inline uint32_t GrUIAlignUpPad(uint32_t x, uint32_t alignment) {
    return (alignment - x % alignment) % alignment;
}
static inline size_t GrSizeAlignUpPad(size_t x, size_t alignment) {
    return (alignment - x % alignment) % alignment;
}

/**
 *  align down
 */
static inline uint32_t GrUIAlignDown(uint32_t x, uint32_t alignment) {
    return (x / alignment) * alignment;
}
static inline size_t GrSizeAlignDown(size_t x, uint32_t alignment) {
    return (x / alignment) * alignment;
}

/**
 *  Count elements in an array
 */
#define GR_ARRAY_COUNT(array)  SK_ARRAY_COUNT(array)

//!< allocate a block of memory, will never return NULL
extern void* GrMalloc(size_t bytes);

//!< free block allocated by GrMalloc. ptr may be NULL
extern void GrFree(void* ptr);

static inline void Gr_bzero(void* dst, size_t size) {
    memset(dst, 0, size);
}

///////////////////////////////////////////////////////////////////////////////

/**
 *  Return true if n is a power of 2
 */
static inline bool GrIsPow2(unsigned n) {
    return n && 0 == (n & (n - 1));
}

/**
 *  Return the next power of 2 >= n.
 */
static inline uint32_t GrNextPow2(uint32_t n) {
    return n ? (1 << (32 - SkCLZ(n - 1))) : 1;
}

static inline int GrNextPow2(int n) {
    GrAssert(n >= 0); // this impl only works for non-neg.
    return n ? (1 << (32 - SkCLZ(n - 1))) : 1;
}

///////////////////////////////////////////////////////////////////////////////

/**
 *  16.16 fixed point type
 */
typedef int32_t GrFixed;

#if GR_DEBUG

static inline int16_t GrToS16(intptr_t x) {
    GrAssert((int16_t)x == x);
    return (int16_t)x;
}

#else

#define GrToS16(x)  x

#endif


///////////////////////////////////////////////////////////////////////////////

/**
 * Possible 3D APIs that may be used by Ganesh.
 */
enum GrBackend {
    kOpenGL_GrBackend,
};

/**
 * Backend-specific 3D context handle
 *      GrGLInterface* for OpenGL. If NULL will use the default GL interface.
 */
typedef intptr_t GrBackendContext;

///////////////////////////////////////////////////////////////////////////////

/**
 * Type used to describe format of vertices in arrays
 * Values are defined in GrDrawTarget
 */
typedef int GrVertexLayout;

/**
* Geometric primitives used for drawing.
*/
enum GrPrimitiveType {
    kTriangles_GrPrimitiveType,
    kTriangleStrip_GrPrimitiveType,
    kTriangleFan_GrPrimitiveType,
    kPoints_GrPrimitiveType,
    kLines_GrPrimitiveType,     // 1 pix wide only
    kLineStrip_GrPrimitiveType  // 1 pix wide only
};

static inline bool GrIsPrimTypeLines(GrPrimitiveType type) {
    return kLines_GrPrimitiveType == type || kLineStrip_GrPrimitiveType == type;
}

static inline bool GrIsPrimTypeTris(GrPrimitiveType type) {
    return kTriangles_GrPrimitiveType == type     ||
           kTriangleStrip_GrPrimitiveType == type ||
           kTriangleFan_GrPrimitiveType == type;
}

/**
 * Coeffecients for alpha-blending.
 */
enum GrBlendCoeff {
    kInvalid_GrBlendCoeff = -1,

    kZero_GrBlendCoeff,    //<! 0
    kOne_GrBlendCoeff,     //<! 1
    kSC_GrBlendCoeff,      //<! src color
    kISC_GrBlendCoeff,     //<! one minus src color
    kDC_GrBlendCoeff,      //<! dst color
    kIDC_GrBlendCoeff,     //<! one minus dst color
    kSA_GrBlendCoeff,      //<! src alpha
    kISA_GrBlendCoeff,     //<! one minus src alpha
    kDA_GrBlendCoeff,      //<! dst alpha
    kIDA_GrBlendCoeff,     //<! one minus dst alpha
    kConstC_GrBlendCoeff,  //<! constant color
    kIConstC_GrBlendCoeff, //<! one minus constant color
    kConstA_GrBlendCoeff,  //<! constant color alpha
    kIConstA_GrBlendCoeff, //<! one minus constant color alpha

    kPublicGrBlendCoeffCount
};

/**
 *  Formats for masks, used by the font cache.
 *  Important that these are 0-based.
 */
enum GrMaskFormat {
    kA8_GrMaskFormat,    //!< 1-byte per pixel
    kA565_GrMaskFormat,  //!< 2-bytes per pixel
    kA888_GrMaskFormat,  //!< 4-bytes per pixel

    kCount_GrMaskFormats //!< used to allocate arrays sized for mask formats
};

/**
 *  Return the number of bytes-per-pixel for the specified mask format.
 */
static inline int GrMaskFormatBytesPerPixel(GrMaskFormat format) {
    GrAssert((unsigned)format <= 2);
    // kA8   (0) -> 1
    // kA565 (1) -> 2
    // kA888 (2) -> 4
    return 1 << (int)format;
}

/**
 * Pixel configurations.
 */
enum GrPixelConfig {
    kUnknown_GrPixelConfig,
    kAlpha_8_GrPixelConfig,
    kIndex_8_GrPixelConfig,
    kRGB_565_GrPixelConfig,
    /**
     * Premultiplied
     */
    kRGBA_4444_GrPixelConfig,
    /**
     * Premultiplied. Byte order is r,g,b,a.
     */
    kRGBA_8888_GrPixelConfig,
    /**
     * Premultiplied. Byte order is b,g,r,a.
     */
    kBGRA_8888_GrPixelConfig,

    kGrPixelConfigCount
};

// Aliases for pixel configs that match skia's byte order.
#ifndef SK_CPU_LENDIAN
    #error "Skia gpu currently assumes little endian"
#endif
#if 24 == SK_A32_SHIFT && 16 == SK_R32_SHIFT && \
     8 == SK_G32_SHIFT &&  0 == SK_B32_SHIFT
    static const GrPixelConfig kSkia8888_GrPixelConfig = kBGRA_8888_GrPixelConfig;
#elif 24 == SK_A32_SHIFT && 16 == SK_B32_SHIFT && \
       8 == SK_G32_SHIFT &&  0 == SK_R32_SHIFT
    static const GrPixelConfig kSkia8888_GrPixelConfig = kRGBA_8888_GrPixelConfig;
#else
    #error "SK_*32_SHIFT values must correspond to GL_BGRA or GL_RGBA format."
#endif

// This alias is deprecated and will be removed.
static const GrPixelConfig kSkia8888_PM_GrPixelConfig = kSkia8888_GrPixelConfig;

// Returns true if the pixel config has 8bit r,g,b,a components in that byte
// order
static inline bool GrPixelConfigIsRGBA8888(GrPixelConfig config) {
    switch (config) {
        case kRGBA_8888_GrPixelConfig:
            return true;
        default:
            return false;
    }
}

// Returns true if the pixel config has 8bit b,g,r,a components in that byte
// order
static inline bool GrPixelConfigIsBGRA8888(GrPixelConfig config) {
    switch (config) {
        case kBGRA_8888_GrPixelConfig:
            return true;
        default:
            return false;
    }
}

// Returns true if the pixel config is 32 bits per pixel
static inline bool GrPixelConfigIs32Bit(GrPixelConfig config) {
    switch (config) {
        case kRGBA_8888_GrPixelConfig:
        case kBGRA_8888_GrPixelConfig:
            return true;
        default:
            return false;
    }
}

// Takes a config and returns the equivalent config with the R and B order
// swapped if such a config exists. Otherwise, kUnknown_GrPixelConfig
static inline GrPixelConfig GrPixelConfigSwapRAndB(GrPixelConfig config) {
    switch (config) {
        case kBGRA_8888_GrPixelConfig:
            return kRGBA_8888_GrPixelConfig;
        case kRGBA_8888_GrPixelConfig:
            return kBGRA_8888_GrPixelConfig;
        default:
            return kUnknown_GrPixelConfig;
    }
}

static inline size_t GrBytesPerPixel(GrPixelConfig config) {
    switch (config) {
        case kAlpha_8_GrPixelConfig:
        case kIndex_8_GrPixelConfig:
            return 1;
        case kRGB_565_GrPixelConfig:
        case kRGBA_4444_GrPixelConfig:
            return 2;
        case kRGBA_8888_GrPixelConfig:
        case kBGRA_8888_GrPixelConfig:
            return 4;
        default:
            return 0;
    }
}

static inline bool GrPixelConfigIsOpaque(GrPixelConfig config) {
    switch (config) {
        case kRGB_565_GrPixelConfig:
            return true;
        default:
            return false;
    }
}

static inline bool GrPixelConfigIsAlphaOnly(GrPixelConfig config) {
    switch (config) {
        case kAlpha_8_GrPixelConfig:
            return true;
        default:
            return false;
    }
}

/**
 * Optional bitfield flags that can be passed to createTexture.
 */
enum GrTextureFlags {
    kNone_GrTextureFlags            = 0x0,
    /**
     * Creates a texture that can be rendered to as a GrRenderTarget. Use
     * GrTexture::asRenderTarget() to access.
     */
    kRenderTarget_GrTextureFlagBit  = 0x1,
    /**
     * By default all render targets have an associated stencil buffer that
     * may be required for path filling. This flag overrides stencil buffer
     * creation.
     * MAKE THIS PRIVATE?
     */
    kNoStencil_GrTextureFlagBit     = 0x2,
    /**
     * Hint that the CPU may modify this texture after creation.
     */
    kDynamicUpdate_GrTextureFlagBit = 0x4,

    kDummy_GrTextureFlagBit,
    kLastPublic_GrTextureFlagBit = kDummy_GrTextureFlagBit-1,
};

GR_MAKE_BITFIELD_OPS(GrTextureFlags)

enum {
   /**
    *  For Index8 pixel config, the colortable must be 256 entries
    */
    kGrColorTableSize = 256 * 4 //sizeof(GrColor)
};

/**
 * Some textures will be stored such that the upper and left edges of the content meet at the
 * the origin (in texture coord space) and for other textures the lower and left edges meet at
 * the origin. Render-targets are always consistent with the convention of the underlying
 * backend API to make it easier to mix native backend rendering with Skia rendering.
 */

enum GrSurfaceOrigin {
    kBottomLeft_GrSurfaceOrigin,
    kTopLeft_GrSurfaceOrigin,
};

/**
 * Describes a texture to be created.
 */
struct GrTextureDesc {
    GrTextureDesc()
    : fFlags(kNone_GrTextureFlags)
    , fWidth(0)
    , fHeight(0)
    , fConfig(kUnknown_GrPixelConfig)
    , fSampleCnt(0) {
    }

    GrTextureFlags         fFlags;  //!< bitfield of TextureFlags
    int                    fWidth;  //!< Width of the texture
    int                    fHeight; //!< Height of the texture

    /**
     * Format of source data of the texture. Not guaranteed to be the same as
     * internal format used by 3D API.
     */
    GrPixelConfig          fConfig;

    /**
     * The number of samples per pixel or 0 to disable full scene AA. This only
     * applies if the kRenderTarget_GrTextureFlagBit is set. The actual number
     * of samples may not exactly match the request. The request will be rounded
     * up to the next supported sample count, or down if it is larger than the
     * max supported count.
     */
    int                    fSampleCnt;
};

/**
 * GrCacheID is used create and find cached GrResources (e.g. GrTextures). The ID has two parts:
 * the domain and the key. Domains simply allow multiple clients to use 0-based indices as their
 * cache key without colliding. The key uniquely identifies a GrResource within the domain.
 * Users of the cache must obtain a domain via GenerateDomain().
 */
struct GrCacheID {
public:
    typedef uint8_t  Domain;

    struct Key {
        union {
            uint8_t  fData8[16];
            uint32_t fData32[4];
            uint64_t fData64[2];
        };
    };

    /**
     * A default cache ID is invalid; a set method must be called before the object is used.
     */
    GrCacheID() { fDomain = kInvalid_Domain; }

    /**
     * Initialize the cache ID to a domain and key.
     */
    GrCacheID(Domain domain, const Key& key) {
        GrAssert(kInvalid_Domain != domain);
        this->reset(domain, key);
    }

    void reset(Domain domain, const Key& key) {
        fDomain = domain;
        memcpy(&fKey, &key, sizeof(Key));
    }

    /** Has this been initialized to a valid domain */
    bool isValid() const { return kInvalid_Domain != fDomain; }

    const Key& getKey() const { GrAssert(this->isValid()); return fKey; }
    Domain getDomain() const { GrAssert(this->isValid()); return fDomain; }

    /** Creates a new unique ID domain. */
    static Domain GenerateDomain();

private:
    Key             fKey;
    Domain          fDomain;

    static const Domain kInvalid_Domain = 0;
};

/**
 * Clips are composed from these objects.
 */
enum GrClipType {
    kRect_ClipType,
    kPath_ClipType
};

/**
 * Commands used to describe a path. Each command
 * is accompanied by some number of points.
 */
enum GrPathCmd {
    kMove_PathCmd,      //!< Starts a new subpath at
                        //   at the returned point
                        // 1 point
    kLine_PathCmd,      //!< Adds a line segment
                        // 2 points
    kQuadratic_PathCmd, //!< Adds a quadratic segment
                        // 3 points
    kCubic_PathCmd,     //!< Adds a cubic segment
                        // 4 points
    kClose_PathCmd,     //!< Closes the current subpath
                        //   by connecting a line to the
                        //   starting point.
                        // 0 points
    kEnd_PathCmd        //!< Indicates the end of the last subpath
                        //   when iterating
                        // 0 points.
};

/**
 * Gets the number of points associated with a path command.
 */
static int inline NumPathCmdPoints(GrPathCmd cmd) {
    static const int gNumPoints[] = {
        1, 2, 3, 4, 0, 0
    };
    return gNumPoints[cmd];
}

///////////////////////////////////////////////////////////////////////////////

// opaque type for 3D API object handles
typedef intptr_t GrBackendObject;

/**
 * Gr can wrap an existing texture created by the client with a GrTexture
 * object. The client is responsible for ensuring that the texture lives at
 * least as long as the GrTexture object wrapping it. We require the client to
 * explicitly provide information about the texture, such as width, height,
 * and pixel config, rather than querying the 3D APIfor these values. We expect
 * these to be immutable even if the 3D API doesn't require this (OpenGL).
 *
 * Textures that are also render targets are supported as well. Gr will manage
 * any ancillary 3D API (stencil buffer, FBO id, etc) objects necessary for
 * Gr to draw into the render target. To access the render target object
 * call GrTexture::asRenderTarget().
 *
 * If in addition to the render target flag, the caller also specifies a sample
 * count Gr will create an MSAA buffer that resolves into the texture. Gr auto-
 * resolves when it reads from the texture. The client can explictly resolve
 * using the GrRenderTarget interface.
 *
 * Note: These flags currently form a subset of GrTexture's flags.
 */

enum GrBackendTextureFlags {
    /**
     * No flags enabled
     */
    kNone_GrBackendTextureFlag             = kNone_GrTextureFlags,
    /**
     * Indicates that the texture is also a render target, and thus should have
     * a GrRenderTarget object.
     *
     * D3D (future): client must have created the texture with flags that allow
     * it to be used as a render target.
     */
    kRenderTarget_GrBackendTextureFlag     = kRenderTarget_GrTextureFlagBit,
};
GR_MAKE_BITFIELD_OPS(GrBackendTextureFlags)

struct GrBackendTextureDesc {
    GrBackendTextureDesc() { memset(this, 0, sizeof(*this)); }
    GrBackendTextureFlags           fFlags;
    GrSurfaceOrigin                 fOrigin;
    int                             fWidth;         //<! width in pixels
    int                             fHeight;        //<! height in pixels
    GrPixelConfig                   fConfig;        //<! color format
    /**
     * If the render target flag is set and sample count is greater than 0
     * then Gr will create an MSAA buffer that resolves to the texture.
     */
    int                             fSampleCnt;
    /**
     * Handle to the 3D API object.
     * OpenGL: Texture ID.
     */
    GrBackendObject                 fTextureHandle;
};

///////////////////////////////////////////////////////////////////////////////

/**
 * Gr can wrap an existing render target created by the client in the 3D API
 * with a GrRenderTarget object. The client is responsible for ensuring that the
 * underlying 3D API object lives at least as long as the GrRenderTarget object
 * wrapping it. We require the client to explicitly provide information about
 * the target, such as width, height, and pixel config rather than querying the
 * 3D API for these values. We expect these properties to be immutable even if
 * the 3D API doesn't require this (OpenGL).
 */

struct GrBackendRenderTargetDesc {
    GrBackendRenderTargetDesc() { memset(this, 0, sizeof(*this)); }
    int                             fWidth;         //<! width in pixels
    int                             fHeight;        //<! height in pixels
    GrPixelConfig                   fConfig;        //<! color format
    /**
     * The number of samples per pixel. Gr uses this to influence decisions
     * about applying other forms of anti-aliasing.
     */
    int                             fSampleCnt;
    /**
     * Number of bits of stencil per-pixel.
     */
    int                             fStencilBits;
    /**
     * Handle to the 3D API object.
     * OpenGL: FBO ID
     */
    GrBackendObject                 fRenderTargetHandle;
};

///////////////////////////////////////////////////////////////////////////////
// Legacy names that will be kept until WebKit can be updated.

typedef GrBackend GrEngine;
static const GrBackend kOpenGL_Shaders_GrEngine = kOpenGL_GrBackend;

typedef GrBackendContext GrPlatform3DContext;

typedef GrBackendObject GrPlatform3DObject;

typedef GrBackendTextureFlags GrPlatformTextureFlags;
static const GrBackendTextureFlags kNone_GrPlatformTextureFlag = kNone_GrBackendTextureFlag;
static const GrBackendTextureFlags kRenderTarget_GrPlatformTextureFlag = kRenderTarget_GrBackendTextureFlag;

typedef GrBackendTextureDesc GrPlatformTextureDesc;

typedef GrBackendRenderTargetDesc GrPlatformRenderTargetDesc;

///////////////////////////////////////////////////////////////////////////////

#endif