+#define LINEAR_FOG(f, coord) f = (fogEnd - coord) * fogScale
+
+#define EXP_FOG(f, coord) f = EXPF(density * coord)
+
+#define EXP2_FOG(f, coord) \
+do { \
+ GLfloat tmp = negDensitySquared * coord * coord; \
+ if (tmp < FLT_MIN_10_EXP) \
+ tmp = FLT_MIN_10_EXP; \
+ f = EXPF(tmp); \
+ } while(0)
+
+
+#define BLEND_FOG(f, coord) f = coord
+
+
+
+/**
+ * Template code for computing fog blend factor and applying it to colors.
+ * \param TYPE either GLubyte, GLushort or GLfloat.
+ * \param COMPUTE_F code to compute the fog blend factor, f.
+ */
+#define FOG_LOOP(TYPE, FOG_FUNC) \
+if (span->arrayAttribs & FRAG_BIT_FOGC) { \
+ GLuint i; \
+ for (i = 0; i < span->end; i++) { \
+ const GLfloat fogCoord = span->array->attribs[FRAG_ATTRIB_FOGC][i][0]; \
+ const GLfloat c = FABSF(fogCoord); \
+ GLfloat f, oneMinusF; \
+ FOG_FUNC(f, c); \
+ f = CLAMP(f, 0.0F, 1.0F); \
+ oneMinusF = 1.0F - f; \
+ rgba[i][RCOMP] = (TYPE) (f * rgba[i][RCOMP] + oneMinusF * rFog); \
+ rgba[i][GCOMP] = (TYPE) (f * rgba[i][GCOMP] + oneMinusF * gFog); \
+ rgba[i][BCOMP] = (TYPE) (f * rgba[i][BCOMP] + oneMinusF * bFog); \
+ } \
+} \
+else { \
+ const GLfloat fogStep = span->attrStepX[FRAG_ATTRIB_FOGC][0]; \
+ GLfloat fogCoord = span->attrStart[FRAG_ATTRIB_FOGC][0]; \
+ const GLfloat wStep = span->attrStepX[FRAG_ATTRIB_WPOS][3]; \
+ GLfloat w = span->attrStart[FRAG_ATTRIB_WPOS][3]; \
+ GLuint i; \
+ for (i = 0; i < span->end; i++) { \
+ const GLfloat c = FABSF(fogCoord) / w; \
+ GLfloat f, oneMinusF; \
+ FOG_FUNC(f, c); \
+ f = CLAMP(f, 0.0F, 1.0F); \
+ oneMinusF = 1.0F - f; \
+ rgba[i][RCOMP] = (TYPE) (f * rgba[i][RCOMP] + oneMinusF * rFog); \
+ rgba[i][GCOMP] = (TYPE) (f * rgba[i][GCOMP] + oneMinusF * gFog); \
+ rgba[i][BCOMP] = (TYPE) (f * rgba[i][BCOMP] + oneMinusF * bFog); \
+ fogCoord += fogStep; \
+ w += wStep; \
+ } \
+}
+
+/* As above, but CI mode (XXX try to merge someday) */
+#define FOG_LOOP_CI(FOG_FUNC) \
+if (span->arrayAttribs & FRAG_BIT_FOGC) { \
+ GLuint i; \
+ for (i = 0; i < span->end; i++) { \
+ const GLfloat fogCoord = span->array->attribs[FRAG_ATTRIB_FOGC][i][0]; \
+ const GLfloat c = FABSF(fogCoord); \
+ GLfloat f; \
+ FOG_FUNC(f, c); \
+ f = CLAMP(f, 0.0F, 1.0F); \
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex); \
+ } \
+} \
+else { \
+ const GLfloat fogStep = span->attrStepX[FRAG_ATTRIB_FOGC][0]; \
+ GLfloat fogCoord = span->attrStart[FRAG_ATTRIB_FOGC][0]; \
+ const GLfloat wStep = span->attrStepX[FRAG_ATTRIB_WPOS][3]; \
+ GLfloat w = span->attrStart[FRAG_ATTRIB_WPOS][3]; \
+ GLuint i; \
+ for (i = 0; i < span->end; i++) { \
+ const GLfloat c = FABSF(fogCoord) / w; \
+ GLfloat f; \
+ FOG_FUNC(f, c); \
+ f = CLAMP(f, 0.0F, 1.0F); \
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex); \
+ fogCoord += fogStep; \
+ w += wStep; \
+ } \
+}
+
+
+