- GLfixed fog[MAX_WIDTH];
- _mesa_win_fog_coords_from_z( ctx, n, z, fog );
- _mesa_fog_rgba_pixels( ctx, n, fog, rgba );
+ const SWcontext *swrast = SWRAST_CONTEXT(ctx);
+ const GLuint n = span->end;
+ GLchan (*rgba)[4] = (GLchan (*)[4]) span->color.rgba;
+ GLchan rFog, gFog, bFog;
+
+ ASSERT(ctx->Fog.Enabled);
+ ASSERT((span->interpMask | span->arrayMask) & SPAN_FOG);
+ ASSERT(span->arrayMask & SPAN_RGBA);
+
+ UNCLAMPED_FLOAT_TO_CHAN(rFog, ctx->Fog.Color[RCOMP]);
+ UNCLAMPED_FLOAT_TO_CHAN(gFog, ctx->Fog.Color[GCOMP]);
+ UNCLAMPED_FLOAT_TO_CHAN(bFog, ctx->Fog.Color[BCOMP]);
+
+ if (swrast->_PreferPixelFog) {
+ /* compute fog factor from each fragment's Z value */
+ if ((span->interpMask & SPAN_Z) && (span->arrayMask & SPAN_Z) == 0)
+ _mesa_span_interpolate_z(ctx, span);
+ compute_fog_factors_from_z(ctx, n, span->zArray, span->fogArray);
+ span->arrayMask |= SPAN_FOG;
+ }
+
+ if (span->arrayMask & SPAN_FOG) {
+ GLuint i;
+ for (i = 0; i < n; i++) {
+ const GLfloat fog = span->fogArray[i];
+ const GLfloat oneMinusFog = 1.0F - fog;
+ rgba[i][RCOMP] = (GLchan) (fog * rgba[i][RCOMP] + oneMinusFog * rFog);
+ rgba[i][GCOMP] = (GLchan) (fog * rgba[i][GCOMP] + oneMinusFog * gFog);
+ rgba[i][BCOMP] = (GLchan) (fog * rgba[i][BCOMP] + oneMinusFog * bFog);
+ }
+ }
+ else {
+ GLfloat fog = span->fog, dFog = span->fogStep;
+ GLuint i;
+ for (i = 0; i < n; i++) {
+ const GLfloat oneMinusFog = 1.0F - fog;
+ rgba[i][RCOMP] = (GLchan) (fog * rgba[i][RCOMP] + oneMinusFog * rFog);
+ rgba[i][GCOMP] = (GLchan) (fog * rgba[i][GCOMP] + oneMinusFog * gFog);
+ rgba[i][BCOMP] = (GLchan) (fog * rgba[i][BCOMP] + oneMinusFog * bFog);
+ fog += dFog;
+ }
+ }