gx: add get texture filters (#175)

* gx: avoid data duplication in texture filter map

* gx: add GX_GetTexObjFilterMode()

Without this function there is no way to retrieve the texture
minification and magnification filters.

Author: mardy

gc/ogc/gx.h

@@ -4110,6 +4110,21 @@ u16 GX_GetTexObjWidth(const GXTexObj* obj);
  */
 void GX_GetTexObjLOD(const GXTexObj* obj, f32 *minlod, f32 *maxlod);
 
+/*!
+ * \fn void GX_GetTexObjFilterMode(const GXTexObj* obj, u8 *minfilt, u8 *magfilt)
+ * \brief Returns the filter mode for the texture object \a obj.
+ *
+ * \note Use GX_InitTexObjLOD() or GX_InitTexObjFilterMode() to initialize the
+ * texture filter mode.
+ *
+ * \param[in] obj ptr to a texture object
+ * \param[out] minfilt minification filter mode; will be one of \ref texfilter
+ * \param[out] maxfilt magnification filter mode; will be \a GX_NEAR or \a GX_LINEAR
+ *
+ * \return none
+ */
+void GX_GetTexObjFilterMode(const GXTexObj *obj, u8 *minfilt, u8 *magfilt);
+
 /*!
  * \fn void GX_GetTexObjAll(const GXTexObj* obj, void** image_ptr, u16* width, u16* height, u8* format, u8* wrap_s, u8* wrap_t, u8* mipmap);
  * \brief Returns the parameters described by a texture object. Texture objects are used to describe all the parameters associated with a texture, including size, format, wrap modes, filter modes, etc. Texture objects are initialized using either GX_InitTexObj() or, for color index format textures, GX_InitTexObjCI().

libogc/gx.c

@@ -105,6 +105,7 @@ static const u8 _gxteximg1ids[8] = {0x8C,0x8D,0x8E,0x8F,0xAC,0xAD,0xAE,0xAF};
 static const u8 _gxteximg2ids[8] = {0x90,0x91,0x92,0x93,0xB0,0xB1,0xB2,0xB3};
 static const u8 _gxteximg3ids[8] = {0x94,0x95,0x96,0x97,0xB4,0xB5,0xB6,0xB7};
 static const u8 _gxtextlutids[8] = {0x98,0x99,0x9A,0x9B,0xB8,0xB9,0xBA,0xBB};
+static const u8 _gx2HWFiltConv[] = {0x00,0x04,0x01,0x05,0x02,0x06,0x00,0x00};
 
 #if defined(HW_RVL)
 
@@ -3034,6 +3035,22 @@ void GX_GetTexObjLOD(const GXTexObj *obj, f32 *minlod, f32 *maxlod)
 	*maxlod = _SHIFTR(ptr->tex_lod, 8, 8) / 16.0f;
 }
 
+void GX_GetTexObjFilterMode(const GXTexObj *obj, u8 *minfilt, u8 *magfilt)
+{
+	const struct __gx_texobj *ptr = (const struct __gx_texobj*)obj;
+	u8 hw_filt, i;
+
+	*magfilt = ptr->tex_filt & 0x10 ? GX_LINEAR : GX_NEAR;
+	hw_filt = _SHIFTR(ptr->tex_filt, 5, 3);
+	for (i = 0; i < sizeof(_gx2HWFiltConv); i++)
+		if (_gx2HWFiltConv[i] == hw_filt) {
+			*minfilt = i;
+			break;
+		}
+	if (i == sizeof(_gx2HWFiltConv)) /* we didn't find it */
+		*minfilt = GX_NEAR;
+}
+
 void GX_GetTexObjAll(const GXTexObj *obj, void** image_ptr, u16* width, u16* height,
                      u8* format, u8* wrap_s, u8* wrap_t, u8* mipmap)
 {
@@ -3290,15 +3307,13 @@ void GX_InitTexObjCI(GXTexObj *obj,void *img_ptr,u16 wd,u16 ht,u8 fmt,u8 wrap_s,
 void GX_InitTexObjLOD(GXTexObj *obj,u8 minfilt,u8 magfilt,f32 minlod,f32 maxlod,f32 lodbias,u8 biasclamp,u8 edgelod,u8 maxaniso)
 {
 	struct __gx_texobj *ptr = (struct __gx_texobj*)obj;
-	static const u8 GX2HWFiltConv[] = {0x00,0x04,0x01,0x05,0x02,0x06,0x00,0x00};
-	//static const u8 HW2GXFiltConv[] = {0x00,0x02,0x04,0x00,0x01,0x03,0x05,0x00};
 
 	if(lodbias<-4.0f) lodbias = -4.0f;
 	else if(lodbias==4.0f) lodbias = 3.99f;
 
 	ptr->tex_filt = (ptr->tex_filt&~0x1fe00)|(_SHIFTL(((u32)(32.0f*lodbias)),9,8));
 	ptr->tex_filt = (ptr->tex_filt&~0x10)|(_SHIFTL((magfilt==GX_LINEAR?1:0),4,1));
-	ptr->tex_filt = (ptr->tex_filt&~0xe0)|(_SHIFTL(GX2HWFiltConv[minfilt],5,3));
+	ptr->tex_filt = (ptr->tex_filt&~0xe0)|(_SHIFTL(_gx2HWFiltConv[minfilt],5,3));
 	ptr->tex_filt = (ptr->tex_filt&~0x100)|(_SHIFTL(!(edgelod&0xff),8,1));
 	ptr->tex_filt = (ptr->tex_filt&~0x180000)|(_SHIFTL(maxaniso,19,2));
 	ptr->tex_filt = (ptr->tex_filt&~0x200000)|(_SHIFTL(biasclamp,21,1));
@@ -3335,10 +3350,9 @@ void GX_InitTexObjWrapMode(GXTexObj *obj,u8 wrap_s,u8 wrap_t)
 void GX_InitTexObjFilterMode(GXTexObj *obj,u8 minfilt,u8 magfilt)
 {
 	struct __gx_texobj *ptr = (struct __gx_texobj*)obj;
-	static const u8 GX2HWFiltConv[] = {0x00,0x04,0x01,0x05,0x02,0x06,0x00,0x00};
 
 	ptr->tex_filt = (ptr->tex_filt&~0x10)|(_SHIFTL((magfilt==GX_LINEAR?1:0),4,1));
-	ptr->tex_filt = (ptr->tex_filt&~0xe0)|(_SHIFTL(GX2HWFiltConv[minfilt],5,3));
+	ptr->tex_filt = (ptr->tex_filt&~0xe0)|(_SHIFTL(_gx2HWFiltConv[minfilt],5,3));
 }
 
 void GX_InitTexObjMinLOD(GXTexObj *obj,f32 minlod)