re-add mipmapping, support it in OpenGL (D3D unimplemented)

stepmania/src/RageTextureID.cpp

@@ -3,40 +3,14 @@
 
 void RageTextureID::Init()
 {
-	/* Maximum size of the texture, per dimension. */
 	iMaxSize = 2048;
-
-	/* Number of mipmaps. (unimplemented) */
-	iMipMaps = 4;
-
-	/* Maximum number of bits for alpha.  In 16-bit modes, lowering
-	 * this gives more bits for color values. (0, 1 or 4) */
+	bMipMaps = false;	// Most sprites (especially text) look worse with mip maps
 	iAlphaBits = 4;
-
-	/* If this is greater than -1, then the image will be loaded as a luma/alpha
-	 * map, eg. I4A4.  At most 8 bits per pixel will be used  This only actually happens
-	 * when paletted textures are supported.
-	 *
-	 * If the sum of alpha and grayscale bits is <= 4, and the system supports 4-bit
-	 * palettes, then the image will be loaded with 4bpp.
-	 *
-	 * This may be set to 0, resulting in an alpha map with all pixels white. */
 	iGrayscaleBits = -1;
-
-	/* If true and color precision is being lost, dither. (slow) */
 	bDither = false;
-	/* If true, resize the image to fill the internal texture. (slow) */
 	bStretch = false;
-
-	/* Preferred color depth of the image.  (This is overridden for
-	 * paletted images and transparencies.) */
    	iColorDepth = -1; /* default */
-
-	/* If true, enable HOT PINK color keying. (deprecated but needed for
-	 * banners) */
 	bHotPinkColorKey = false;
-
-	/* These hints will be used in addition to any in the filename. */
 	AdditionalTextureHints = "";
 }
 
@@ -45,7 +19,7 @@ bool RageTextureID::operator<(const RageTextureID &rhs) const
 #define COMP(a) if(a<rhs.a) return true; if(a>rhs.a) return false;
 	COMP(filename);
 	COMP(iMaxSize);
-	COMP(iMipMaps);
+	COMP(bMipMaps);
 	COMP(iAlphaBits);
 	COMP(iGrayscaleBits);
 	COMP(iColorDepth);
@@ -63,7 +37,7 @@ bool RageTextureID::operator==(const RageTextureID &rhs) const
 	return 
 		EQUAL(filename) &&
 		EQUAL(iMaxSize) &&
-		EQUAL(iMipMaps) &&
+		EQUAL(bMipMaps) &&
 		EQUAL(iAlphaBits) &&
 		EQUAL(iGrayscaleBits) &&
 		EQUAL(iColorDepth) &&