gfx_opengl_texture.hh

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/*
 * LEGAL:   COPYRIGHT (C) 2007 JIM E. BROOKS
 *          THIS SOURCE CODE IS RELEASED UNDER THE TERMS
 *          OF THE GNU GENERAL PUBLIC LICENSE VERSION 2 (GPL 2).
 ******************************************************************************/

#ifndef GFX_OPENGL_TEXTURE_HH
#define GFX_OPENGL_TEXTURE_HH 1

namespace gfx {

// Compile BGRA8 or RGBA8 texels.  BGRA8 is faster on Nvidia.
#if 1
#define COMPILE_TEXEL32_BGRA8 1
#else
#define COMPILE_TEXEL32_RGBA8 1
#endif

class TexCoord
{
public:
            TexCoord( void ) : x(0), y(0) { }
            TexCoord( fp X, fp Y ) : x(X), y(Y) { }
    void    Set( fp X, fp Y ) { x = X; y = Y; }

    friend bool operator<( const TexCoord& a, const TexCoord& b )
    {
        RETURN_LT_TRUE_GT_FALSE( a.x, b.x )
        RETURN_LT_TRUE_GT_FALSE( a.y, b.y )
        return false;  // equal
    }

public:
    fp  x;
    fp  y;
};
typedef TexCoord TexCoord2;

INLINE ostream&
operator<<( ostream& strm, const TexCoord& texCoord )
{
    strm << '(' << texCoord.x << ',' << texCoord.y << ')';
    return strm;
}

class TextureModes
{
PREVENT_INSTANTIATING(TextureModes)
public:
    enum
    {
        TEXTURE_ID_INVALID = 0  // OpenGL defines 0 to mean no texture
    };

    enum eMipmap
    {
        eMipmap_OFF,  // bool
        eMipmap_ON
    };

    enum eMinFilter
    {
        eMinFilter_DEFAULT                  = GL_NEAREST,
        eMinFilter_NEAREST                  = GL_NEAREST,
        eMinFilter_LINEAR                   = GL_LINEAR,
        eMinFilter_NEAREST_MIPMAP_NEAREST   = GL_NEAREST_MIPMAP_NEAREST,
        eMinFilter_NEAREST_MIPMAP_LINEAR    = GL_NEAREST_MIPMAP_LINEAR,
        eMinFilter_LINEAR_MIPMAP_NEAREST    = GL_LINEAR_MIPMAP_NEAREST,
        eMinFilter_LINEAR_MIPMAP_LINEAR     = GL_LINEAR_MIPMAP_LINEAR,
    };

    enum eMagFilter
    {
        eMagFilter_DEFAULT          = GL_NEAREST,
        eMagFilter_NEAREST          = GL_NEAREST,
        eMagFilter_LINEAR           = GL_LINEAR,
        // Magnfication filter doesn't apply to mipmaps.
    };

    enum eWrap
    {
        eWrap_DEFAULT               = GL_REPEAT,
        eWrap_REPEAT                = GL_REPEAT,
        eWrap_CLAMP                 = GL_CLAMP,       // -- use CLAMP_TO_EDGE (else black border/seam will appear) --
        eWrap_CLAMP_TO_EDGE         = GL_CLAMP_TO_EDGE,
        eWrap_CLAMP_TO_BORDER       = GL_CLAMP_TO_BORDER,
    };

    enum eFunc
    {
        eFunc_DEFAULT               = GL_MODULATE,
        eFunc_MODULATE              = GL_MODULATE,
        eFunc_DECAL                 = GL_DECAL,
        eFunc_REPLACE               = GL_REPLACE,
        eFunc_BLEND                 = GL_BLEND,
    };
};

class TexelDefs
{
PREVENT_INSTANTIATING(TexelDefs)
public:
    typedef uint32 Texel32;  

    enum
    {
        #if COMPILE_TEXEL32_RGBA8
        TEXEL32_RR = 0,     // byte indexs
        TEXEL32_GG = 1,
        TEXEL32_BB = 2,
        TEXEL32_AA = 3,
        #else  // default BGRA8
        TEXEL32_BB = 0,
        TEXEL32_GG = 1,
        TEXEL32_RR = 2,
        TEXEL32_AA = 3,
        #endif
    };

    enum
    {
    #if BASE_LITTLE_ENDIAN
        #if COMPILE_TEXEL32_RGBA8
        TEXEL32_RR_BIT_SHIFT = 0,       // RGBA
        TEXEL32_GG_BIT_SHIFT = 8,
        TEXEL32_BB_BIT_SHIFT = 16,
        TEXEL32_AA_BIT_SHIFT = 24,
        #else // default COMPILE_TEXEL32_BGRA8
        TEXEL32_BB_BIT_SHIFT = 0,       // BGRA
        TEXEL32_GG_BIT_SHIFT = 8,
        TEXEL32_RR_BIT_SHIFT = 16,
        TEXEL32_AA_BIT_SHIFT = 24,
        #endif
    #elif BASE_BIG_ENDIAN
        #if COMPILE_TEXEL32_RGBA8       // RGBA
        TEXEL32_RR_BIT_SHIFT = 24,
        TEXEL32_GG_BIT_SHIFT = 16,
        TEXEL32_BB_BIT_SHIFT = 8,
        TEXEL32_AA_BIT_SHIFT = 0,
        #else // default COMPILE_TEXEL32_BGRA8
        TEXEL32_BB_BIT_SHIFT = 24,      // BGRA
        TEXEL32_GG_BIT_SHIFT = 16,
        TEXEL32_RR_BIT_SHIFT = 8,
        TEXEL32_AA_BIT_SHIFT = 0,
        #endif
    #endif
    };

    enum
    {
        TEXEL32_LEN         = 4,
        TEXEL32_BGRA8_LEN   = 4,
        TEXEL32_RGBA8_LEN   = 4,
        TEXEL_DEFAULT_LEN   = 4,
    };

    enum eTexelType
    {
        // --- REMINDER: Update TexelTypeToTexelLen() ---
        eTexelType_BGR8     = GL_BGR,
        eTexelType_RGB8     = GL_RGB,
        eTexelType_BGRA8    = GL_BGRA,  // GL_BGRA8 doesn't exist (RGBA8 does though)
        eTexelType_RGBA8    = GL_RGBA,
        eTexelType_Texel32  = GL_BGRA,
        eTexelType_DEFAULT  = GL_BGRA,  // faster than RGBA8
    };

    enum eTexEnv
    {
        eTexEnv_MODULATE    = GL_MODULATE,
        eTexEnv_DECAL       = GL_DECAL,
        eTexEnv_REPLACE     = GL_REPLACE,
    };
};

class TextureMethods
{
PREVENT_INSTANTIATING(TextureMethods)
public:
    CLASS_METHOD
    TexelDefs::Texel32
    MakeTexel32( uint b, uint g, uint r, uint a )  // -- BGRA args --
    {
        return (b << TexelDefs::TEXEL32_BB_BIT_SHIFT)
             | (g << TexelDefs::TEXEL32_GG_BIT_SHIFT)
             | (r << TexelDefs::TEXEL32_RR_BIT_SHIFT)
             | (a << TexelDefs::TEXEL32_AA_BIT_SHIFT);
    }

    CLASS_METHOD
    TexelDefs::Texel32
    MakeTexel32( const RGBA color )
    {
        // Cast to uint or RGBA::operator[], which returns uint8, will cause truncation.
        return (uint(color[BB]) << TexelDefs::TEXEL32_BB_BIT_SHIFT)
             | (uint(color[GG]) << TexelDefs::TEXEL32_GG_BIT_SHIFT)
             | (uint(color[RR]) << TexelDefs::TEXEL32_RR_BIT_SHIFT)
             | (uint(color[AA]) << TexelDefs::TEXEL32_AA_BIT_SHIFT);
    }

    CLASS_METHOD
    uint
    TexelTypeToTexelLen( TexelDefs::eTexelType texelType )
    {
        switch ( texelType )
        {
            case TexelDefs::eTexelType_BGR8:  // no Alpha
            case TexelDefs::eTexelType_RGB8:
                return 3;
            break;

            case TexelDefs::eTexelType_BGRA8:  // has Alpha
            case TexelDefs::eTexelType_RGBA8:
          //case TexelDefs::eTexelType_Texel32:  // dup
          //case TexelDefs::eTexelType_DEFAULT:  // dup
                return 4;
            break;

            default:
                ASSERT(0); return 4;  // guess 4 in RELEASE
            break;
        }

        return 4;  // (shutup old gcc)
    }
};

class TextureBase
:   public TextureModes, public TexelDefs, public TextureMethods,
    public Shared
{
    // empty
};

} // namespace gfx

#endif // GFX_OPENGL_TEXTURE_HH

Palomino 3D Engine documents generated by doxygen 1.5.3 on Fri Nov 23 11:26:11 2007