- GLcontext *ctx = VB->ctx;
-
- /* If full eye coords weren't required, just calculate the eye Z
- * values.
- */
- if (!ctx->NeedEyeCoords) {
- GLfloat *m = ctx->ModelView.m;
- GLfloat plane[4];
-
- plane[0] = m[2];
- plane[1] = m[6];
- plane[2] = m[10];
- plane[3] = m[14];
-
- gl_dotprod_tab[0][VB->ObjPtr->size](&VB->Eye,
- 2, /* fill z coordinates */
- VB->ObjPtr,
- plane,
- 0 );
-
- make_fog_coord_tab[0]( VB, &VB->Eye, 0 );
- }
- else
- {
- make_fog_coord_tab[0]( VB, VB->EyePtr, 0 );
- }
-}
-
-
-/* Drivers that want fog coordinates in VB->Spec[0] alpha, can substitute this
- * stage for the default PIPE_OP_FOG pipeline stage.
- */
-struct gl_pipeline_stage gl_fog_coord_stage = {
- "build fog coordinates",
- PIPE_OP_FOG,
- PIPE_PRECALC|PIPE_IMMEDIATE,
- 0,
- NEW_FOG,
- NEW_LIGHTING|NEW_RASTER_OPS|NEW_FOG|NEW_MODELVIEW,
- 0, 0,
- 0, 0, 0,
- check_fog_coords,
- gl_make_fog_coords
-};
-
-
-
-
-
-/*
- * Apply fog to an array of RGBA pixels.
- * Input: n - number of pixels
- * z - array of integer depth values
- * red, green, blue, alpha - pixel colors
- * Output: red, green, blue, alpha - fogged pixel colors
- */
-void
-_mesa_fog_rgba_pixels( const GLcontext *ctx,
- GLuint n, const GLdepth z[], GLubyte rgba[][4] )
-{
- GLfloat c = ctx->ProjectionMatrix.m[10];
- GLfloat d = ctx->ProjectionMatrix.m[14];
- GLuint i;
-
- GLfloat rFog = ctx->Fog.Color[0] * 255.0F;
- GLfloat gFog = ctx->Fog.Color[1] * 255.0F;
- GLfloat bFog = ctx->Fog.Color[2] * 255.0F;
-
- GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ];
- GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ];
-
- switch (ctx->Fog.Mode) {
- case GL_LINEAR:
- {
- GLfloat fogEnd = ctx->Fog.End;
- GLfloat fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = -d / (c+ndcz);
- GLfloat f, g;
- if (eyez < 0.0) eyez = -eyez;
- f = (fogEnd - eyez) * fogScale;
- f = CLAMP( f, 0.0F, 1.0F );
- g = 1.0F - f;
- rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
- rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
- rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
- }
- }
- break;
- case GL_EXP:
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = d / (c+ndcz);
- GLfloat f, g;
- if (eyez < 0.0)
- eyez = -eyez;
- f = exp( -ctx->Fog.Density * eyez );
- g = 1.0F - f;
- rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
- rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
- rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
- }
- break;
- case GL_EXP2:
- {
- GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = d / (c+ndcz);
- GLfloat f, g;
- GLfloat tmp = negDensitySquared * eyez * eyez;
-#ifdef __alpha__
- /* XXX this underflow check may be needed for other systems */
- if (tmp < FLT_MIN_10_EXP)
- f = exp( FLT_MIN_10_EXP );
- else
-#endif
- f = exp( tmp );
- g = 1.0F - f;
- rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog);
- rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog);
- rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog);
- }
- }
- break;
- default:
- gl_problem(ctx, "Bad fog mode in _mesa_fog_rgba_pixels");
- return;
- }
-}
-
-
-
-
-/*
- * Apply fog to an array of color index pixels.
- * Input: n - number of pixels
- * z - array of integer depth values
- * index - pixel color indexes
- * Output: index - fogged pixel color indexes
- */
-void
-_mesa_fog_ci_pixels( const GLcontext *ctx,
- GLuint n, const GLdepth z[], GLuint index[] )
-{
- GLfloat c = ctx->ProjectionMatrix.m[10];
- GLfloat d = ctx->ProjectionMatrix.m[14];
- GLuint i;
-
- GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ];
- GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ];
-
- switch (ctx->Fog.Mode) {
- case GL_LINEAR:
- {
- GLfloat fogEnd = ctx->Fog.End;
- GLfloat fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = -d / (c+ndcz);
- GLfloat f;
- if (eyez < 0.0) eyez = -eyez;
- f = (fogEnd - eyez) * fogScale;
- f = CLAMP( f, 0.0F, 1.0F );
- index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
- }
- }
- break;
- case GL_EXP:
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = -d / (c+ndcz);
- GLfloat f;
- if (eyez < 0.0)
- eyez = -eyez;
- f = exp( -ctx->Fog.Density * eyez );
- f = CLAMP( f, 0.0F, 1.0F );
- index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
- }
- break;
- case GL_EXP2:
- {
- GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = -d / (c+ndcz);
- GLfloat tmp, f;
- if (eyez < 0.0)
- eyez = -eyez;
- tmp = negDensitySquared * eyez * eyez;
-#ifdef __alpha__
- /* XXX this underflow check may be needed for other systems */
- if (tmp < FLT_MIN_10_EXP)
- f = exp( FLT_MIN_10_EXP );
- else
-#endif
- f = exp( tmp );
- f = CLAMP( f, 0.0F, 1.0F );
- index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index);
- }
- }
- break;
- default:
- gl_problem(ctx, "Bad fog mode in _mesa_fog_ci_pixels");
- return;
- }