CODEWITHSUNDEEP
c++structdirectx
RepahidiS
RepahidiS

Reputation: 45

Not a class or struct name _D3DCOLORVALUE

'm coding a image viewer and converter. _D3DCOLORVALUE is defined in d3d8types.h file. I'm using DirectX 8 SDK. If I define a struct with _D3DCOLORVALUE occurred some errors like this :

1. error C2504: '_D3DCOLORVALUE' : base class undefined
2. error C2061: syntax error : identifier '_D3DCOLORVALUE'
3. _D3DCOLORVALUE not a class or struct name

What could be problem?

Note : this project perfectly working on VB6 but I tried build it on VS2012

My3DStruct.h

#include "d3d8types.h"

struct __ColorValue : public _D3DCOLORVALUE //problem is here
{
public:
    void operator = (const D3DCOLORVALUE& cv) { r = cv.r; g = cv.g; b = cv.b; a = cv.a; }
    void operator = (D3DCOLOR cr) { r = ((cr & 0x00ff0000)>>16)/255.0f; g = ((cr & 0x0000ff00)>>8)/255.0f; b = (cr & 0x000000ff)/255.0f; a = ((cr & 0xff000000) >> 24)/255.0f; }
    void Set(float r2, float g2, float b2, float a2) { r = r2; g = g2; b = b2; a = a2; }

    D3DCOLOR ToD3DCOLOR() { return  (((DWORD)(a*255.0f))<<24) | (((DWORD)(r*255.0f))<<16) | (((DWORD)(g*255.0f))<<8) | (((DWORD)(b*255.0f))); }

    __ColorValue() {}
    __ColorValue(D3DCOLOR cr) { *this = cr; }
    __ColorValue(float r2, float g2, float b2, float a2) { this->Set(r2, g2, b2, a2); }

    void operator += (float fDelta) { r += fDelta; g += fDelta; b += fDelta; a += fDelta; }
    void operator -= (float fDelta) { r -= fDelta; g -= fDelta; b -= fDelta; a -= fDelta; }
    void operator *= (float fDelta) { r *= fDelta; g *= fDelta; b *= fDelta; a *= fDelta; }
    void operator /= (float fDelta) { if(0 == fDelta) return; r /= fDelta; g /= fDelta; b /= fDelta; a /= fDelta; }

    D3DCOLORVALUE operator + (float fDelta) { __ColorValue cv = *this; cv.r += fDelta; cv.g += fDelta; cv.b += fDelta; cv.a += fDelta; return cv; }
    D3DCOLORVALUE operator - (float fDelta) { __ColorValue cv = *this; cv.r -= fDelta; cv.g -= fDelta; cv.b -= fDelta; cv.a -= fDelta; return cv; }
    D3DCOLORVALUE operator * (float fDelta) { __ColorValue cv = *this; cv.r *= fDelta; cv.g *= fDelta; cv.b *= fDelta; cv.a *= fDelta; return cv; }
    D3DCOLORVALUE operator / (float fDelta) { __ColorValue cv = *this; cv.r /= fDelta; cv.g /= fDelta; cv.b /= fDelta; cv.a /= fDelta; return cv; }

    void operator += (const D3DCOLORVALUE& cv) { r += cv.r; g += cv.g; b += cv.b; a += cv.a; }
    void operator -= (const D3DCOLORVALUE& cv) { r -= cv.r; g -= cv.g; b -= cv.b; a -= cv.a; }
    void operator *= (const D3DCOLORVALUE& cv) { r *= cv.r; g *= cv.g; b *= cv.b; a *= cv.a; }
    void operator /= (const D3DCOLORVALUE& cv) { r /= cv.r; g /= cv.g; b /= cv.b; a /= cv.a; }

    D3DCOLORVALUE operator + (const D3DCOLORVALUE& cv) { __ColorValue cv2(cv.r, cv.g, cv.b, cv.a); cv2 += cv; return cv2; }
    D3DCOLORVALUE operator - (const D3DCOLORVALUE& cv) { __ColorValue cv2(cv.r, cv.g, cv.b, cv.a); cv2 -= cv; return cv2; }
    D3DCOLORVALUE operator * (const D3DCOLORVALUE& cv) { __ColorValue cv2(cv.r, cv.g, cv.b, cv.a); cv2 *= cv; return cv2; }
    D3DCOLORVALUE operator / (const D3DCOLORVALUE& cv) { __ColorValue cv2(cv.r, cv.g, cv.b, cv.a); cv2 /= cv; return cv2; }
};

d3d8types.h

#ifndef D3DCOLORVALUE_DEFINED
typedef struct _D3DCOLORVALUE {
    float r;
    float g;
    float b;
    float a;
} D3DCOLORVALUE;
#define D3DCOLORVALUE_DEFINED
#endif

Upvotes: 0

Views: 941

Answers (1)

legalize
legalize

Reputation: 2253

All identifiers beginning with two underscores (__) are reserved in C++; you should never use them for your own code anywhere.

You should use D3DCOLORVALUE instead of _D3DCOLORVALUE. The DirectX 8 SDK is pretty old now, but since you're using that old version you can look at my free book The Direct3D Graphics Pipeline that is a mix of DirectX 8/9. Even with the mix in there, that material should be useful to you when using this old a version of DirectX. Chapter 1 discusses D3DCOLOR and D3DCOLORVALUE. Are you using DirectX 8 because you're converting VB6 code and Direct3D 8 was the last API exposed to VB? You're probably better off using Direct3D 9 when doing the port. Direct3D 10, 11 and 12 are significantly different from 9, but 9 is mostly similar to 8 and 8.1.

The idiom typedef struct _X X; is a C-ism because C doesn't recognize the name of a structure as a complete type. In C you have to write struct X all over the place, hence the common idiom to introduce the real structure as the name _X and introduce X as a synonym for struct _X with typedef. All of this is harmless in C++, but also completely unnecessary. In C++, saying struct X means you can use X as the type wherever you need it without forcing you to write struct X or use a typedef.

It looks like you're just trying to provide syntactic sugar for manipulating color values by creating operator+ members on your ColorValue structure. You don't need to derive from D3DCOLORVALUE in order to achieve this; simply define the operators as free functions with appropriate types:

inline D3DCOLORVALUE &operator+(D3DCOLORVALUE &lhs, float delta)
{
    lhs.r += delta;
    lhs.g += delta;
    lhs.b += delta;
    lhs.a += delta;
    return lhs;
}

I believe Microsoft themselves introduced such free functions or member functions on the structures into the SDK at some point. I don't recall which version introduced that, but it was probably after DirectX 8.

Finally, it is generally not a good idea to write your own classes that derive from value types like D3DCOLORVALUE. These are simple structures that don't have virtual destructors and deriving from them leaves you susceptible to object slicing errors. I recommend instead that you prefer aggregation over inheritance.

If your only motivation was to get nice operator+ behavior on D3DCOLORVALUE values, then I suggest the free function approach instead of derivation.

Upvotes: 1

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