From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Sun, 17 Feb 2002 17:30:57 +0000 (+0000)
Subject: Simplified fog code.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=711e27fda27e4235b20a4cf73c2767c984ab2b81;p=mesa.git

Simplified fog code.
---

diff --git a/src/mesa/swrast/s_fog.c b/src/mesa/swrast/s_fog.c
index caaefcb688f..0988ebb1a7d 100644
--- a/src/mesa/swrast/s_fog.c
+++ b/src/mesa/swrast/s_fog.c
@@ -1,4 +1,4 @@
-/* $Id: s_fog.c,v 1.21 2002/02/02 21:40:33 brianp Exp $ */
+/* $Id: s_fog.c,v 1.22 2002/02/17 17:30:58 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -33,6 +33,7 @@
 
 #include "s_context.h"
 #include "s_fog.h"
+#include "s_span.h"
 
 
 
@@ -62,134 +63,13 @@ _mesa_z_to_fogfactor(GLcontext *ctx, GLfloat z)
       f = (GLfloat) exp(-(d * d * z * z));
       return f;
    default:
-      _mesa_problem(ctx, "Bad fog mode in make_fog_coord");
+      _mesa_problem(ctx, "Bad fog mode in _mesa_z_to_fogfactor");
       return 0.0; 
    }
 }
 
 
 
-/**
- * Apply fog to a span of RGBA pixels.
- * Input:  ctx  -
- *         span - where span->fog and span->fogStep have to be set.
- *         red, green, blue, alpha - pixel colors
- * Output:  red, green, blue, alpha - fogged pixel colors
- */
-void
-_mesa_fog_rgba_pixels( const GLcontext *ctx, struct sw_span *span,
-		       GLchan rgba[][4] )
-{
-   GLuint i;
-   GLfloat fog = span->fog, Dfog = span->fogStep;
-   GLchan rFog, gFog, bFog;
-
-   ASSERT(ctx->Fog.Enabled);
-   ASSERT(span->interpMask & 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]);
-
-   for (i = 0; i < span->end; i++) {
-      const GLfloat one_min_fog = 1.0F - fog;
-      rgba[i][RCOMP] = (GLchan) (fog * rgba[i][RCOMP] + one_min_fog * rFog);
-      rgba[i][GCOMP] = (GLchan) (fog * rgba[i][GCOMP] + one_min_fog * gFog);
-      rgba[i][BCOMP] = (GLchan) (fog * rgba[i][BCOMP] + one_min_fog * bFog);
-      fog += Dfog;
-   }
-}
-
-
-/**
- * Apply fog given in an array to RGBA pixels.
- * Input:  ctx  -
- *         span - 
- *         fog  - array of fog factors in [0,1]
- *         red, green, blue, alpha - pixel colors
- * Output:  red, green, blue, alpha - fogged pixel colors
- */
-void
-_mesa_fog_rgba_pixels_with_array( const GLcontext *ctx, struct sw_span *span,
-				  const GLfloat fog[], GLchan rgba[][4] )
-{
-   GLuint i;
-   GLchan rFog, gFog, bFog;
-
-   ASSERT(fog != NULL);
-   ASSERT(ctx->Fog.Enabled);
-   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]);
-
-   for (i = span->start; i < span->end; i++) {
-      const GLfloat f = fog[i];
-      const GLfloat g = 1.0F - f;
-      rgba[i][RCOMP] = (GLchan) (f * rgba[i][RCOMP] + g * rFog);
-      rgba[i][GCOMP] = (GLchan) (f * rgba[i][GCOMP] + g * gFog);
-      rgba[i][BCOMP] = (GLchan) (f * rgba[i][BCOMP] + g * bFog);
-   }
-}
-
-
-
-/**
- * Apply fog to a span of color index pixels.
- * Input:  ctx  -
- *         span - where span->fog and span->fogStep have to be set.
- *         index - pixel color indexes
- * Output:  index - fogged pixel color indexes
- */
-void
-_mesa_fog_ci_pixels( const GLcontext *ctx, struct sw_span *span,
-		     GLuint index[] )
-{
-   GLuint idx = (GLuint) ctx->Fog.Index;
-   GLuint i;
-   GLfloat fog = span->fog, Dfog = span->fogStep;
-
-   ASSERT(ctx->Fog.Enabled);
-   ASSERT(span->interpMask & SPAN_FOG);
-   ASSERT(span->arrayMask & SPAN_INDEX);
-
-   for (i = 0; i < span->end; i++) {
-      const GLfloat f = CLAMP(fog, 0.0F, 1.0F);
-      index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * idx);
-      fog += Dfog;
-   }
-}
-
-
-/**
- * Apply fog given in an array to a span of color index pixels.
- * Input:  ctx  -
- *         span - 
- *         fog  - array of fog factors in [0,1]
- *         index - pixel color indexes
- * Output:  index - fogged pixel color indexes
- */
-void
-_mesa_fog_ci_pixels_with_array( const GLcontext *ctx, struct sw_span *span,
-				const GLfloat fog[], GLuint index[] )
-{
-   GLuint idx = (GLuint) ctx->Fog.Index;
-   GLuint i;
-
-   ASSERT(fog != NULL);
-   ASSERT(ctx->Fog.Enabled);
-   ASSERT(span->arrayMask & SPAN_INDEX);
-
-   for (i = span->start; i < span->end; i++) {
-      const GLfloat f = CLAMP(fog[i], 0.0F, 1.0F);
-      index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * idx);
-   }
-}
-
-
-
 /**
  * Calculate fog factors (in [0,1]) from window z values
  * Input:  n - number of pixels
@@ -331,45 +211,99 @@ compute_fog_factors_from_z( const GLcontext *ctx,
 }
 
 
+
 /**
  * Apply fog to a span of RGBA pixels.
- * Input:  ctx  -
- *         span - where span->zArray has to be filled.
- *         red, green, blue, alpha - pixel colors
- * Output:  red, green, blue, alpha - fogged pixel colors
+ * The fog factors are either in the span->fogArray or stored as base/step.
+ * These are fog _factors_, not fog coords.  Fog coords were converted to
+ * fog factors per vertex.
  */
 void
-_mesa_depth_fog_rgba_pixels(const GLcontext *ctx, struct sw_span *span,
-			    GLchan rgba[][4])
+_mesa_fog_rgba_span( const GLcontext *ctx, struct sw_span *span )
 {
-   GLfloat fogFact[MAX_WIDTH];
+   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->arrayMask & SPAN_Z);
-   ASSERT(span->end <= MAX_WIDTH);
+   ASSERT((span->interpMask | span->arrayMask) & SPAN_FOG);
+   ASSERT(span->arrayMask & SPAN_RGBA);
 
-   compute_fog_factors_from_z(ctx, span->end, span->zArray, fogFact );
-   _mesa_fog_rgba_pixels_with_array( ctx, span, fogFact, 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;
+      }
+   }
 }
 
 
 /**
- * Apply fog to a span of color index pixels.
- * Input:  ctx  -
- *         span - where span->zArray has to be filled.
- *         index - pixel color indexes
- * Output:  index - fogged pixel color indexes
+ * As above, but color index mode.
  */
 void
-_mesa_depth_fog_ci_pixels( const GLcontext *ctx, struct sw_span *span,
-			   GLuint index[] )
+_mesa_fog_ci_span( const GLcontext *ctx, struct sw_span *span )
 {
-   GLfloat fogFact[MAX_WIDTH];
+   const SWcontext *swrast = SWRAST_CONTEXT(ctx);
+   const GLuint n = span->end;
+   GLuint *index = span->color.index;
 
    ASSERT(ctx->Fog.Enabled);
-   ASSERT(span->arrayMask & SPAN_Z);
-   ASSERT(span->end <= MAX_WIDTH);
+   ASSERT(span->arrayMask & SPAN_INDEX);
+   ASSERT((span->interpMask | span->arrayMask) & SPAN_FOG);
+
+   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;
+   }
 
-   compute_fog_factors_from_z(ctx, span->end, span->zArray, fogFact );
-   _mesa_fog_ci_pixels_with_array( ctx, span, fogFact, index );
+   if (span->arrayMask & SPAN_FOG) {
+      const GLuint idx = (GLuint) ctx->Fog.Index;
+      GLuint i;
+      for (i = 0; i < n; i++) {
+         const GLfloat f = CLAMP(span->fogArray[i], 0.0F, 1.0F);
+         index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * idx);
+      }
+   }
+   else {
+      GLfloat fog = span->fog, dFog = span->fogStep;
+      const GLuint idx = (GLuint) ctx->Fog.Index;
+      GLuint i;
+      for (i = 0; i < n; i++) {
+         const GLfloat f = CLAMP(fog, 0.0F, 1.0F);
+         index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * idx);
+         fog += dFog;
+      }
+   }
 }
diff --git a/src/mesa/swrast/s_fog.h b/src/mesa/swrast/s_fog.h
index e254f8dd51d..c7b234aee6e 100644
--- a/src/mesa/swrast/s_fog.h
+++ b/src/mesa/swrast/s_fog.h
@@ -1,10 +1,10 @@
-/* $Id: s_fog.h,v 1.8 2002/02/02 21:40:33 brianp Exp $ */
+/* $Id: s_fog.h,v 1.9 2002/02/17 17:30:58 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
- * Version:  3.5
+ * Version:  4.1
  *
- * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
+ * Copyright (C) 1999-2002  Brian Paul   All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -36,34 +36,11 @@
 extern GLfloat
 _mesa_z_to_fogfactor(GLcontext *ctx, GLfloat z);
 
-
-extern void
-_mesa_fog_rgba_pixels( const GLcontext *ctx, struct sw_span *span,
-		       GLchan rgba[][4]);
 extern void
-_mesa_fog_rgba_pixels_with_array( const GLcontext *ctx, struct sw_span *span,
-				  const GLfloat fog[], GLchan rgba[][4] );
-
+_mesa_fog_rgba_span( const GLcontext *ctx, struct sw_span *span );
 
 extern void
-_mesa_fog_ci_pixels( const GLcontext *ctx, struct sw_span *span,
-		     GLuint indx[]);
-extern void
-_mesa_fog_ci_pixels_with_array( const GLcontext *ctx, struct sw_span *span,
-				const GLfloat fog[], GLuint index[] );
+_mesa_fog_ci_span( const GLcontext *ctx, struct sw_span *span );
 
-extern void
-_mesa_win_fog_coords_from_z( const GLcontext *ctx,
-			     GLuint n,
-			     const GLdepth z[],
-			     GLfloat fogcoord[] );
-
-extern void
-_mesa_depth_fog_rgba_pixels( const GLcontext *ctx, struct sw_span *span,
-			     GLchan rgba[][4] );
-
-extern void
-_mesa_depth_fog_ci_pixels( const GLcontext *ctx, struct sw_span *span,
-			   GLuint index[] );
 
 #endif
diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c
index 4ed37c66040..90de11b86a3 100644
--- a/src/mesa/swrast/s_span.c
+++ b/src/mesa/swrast/s_span.c
@@ -1,4 +1,4 @@
-/* $Id: s_span.c,v 1.35 2002/02/17 01:49:31 brianp Exp $ */
+/* $Id: s_span.c,v 1.36 2002/02/17 17:30:57 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -235,8 +235,8 @@ interpolate_specular(GLcontext *ctx, struct sw_span *span)
 
 
 /* Fill in the span.zArray array from the interpolation values */
-static void
-interpolate_z(GLcontext *ctx, struct sw_span *span)
+void
+_mesa_span_interpolate_z( const GLcontext *ctx, struct sw_span *span )
 {
    const GLuint n = span->end;
    GLuint i;
@@ -784,7 +784,7 @@ _mesa_write_index_span( GLcontext *ctx, struct sw_span *span,
    /* Depth test and stencil */
    if (ctx->Depth.Test || ctx->Stencil.Enabled) {
       if (span->interpMask & SPAN_Z)
-         interpolate_z(ctx, span);
+         _mesa_span_interpolate_z(ctx, span);
 
       if (ctx->Stencil.Enabled) {
          if (!_mesa_stencil_and_ztest_span(ctx, span)) {
@@ -819,15 +819,8 @@ _mesa_write_index_span( GLcontext *ctx, struct sw_span *span,
    }
 
    /* Fog */
-   /* XXX try to simplify the fog code! */
    if (ctx->Fog.Enabled) {
-      if ((span->arrayMask & SPAN_FOG) && !swrast->_PreferPixelFog)
-         _mesa_fog_ci_pixels_with_array( ctx, span, span->fogArray,
-                                         span->color.index);
-      else if ((span->interpMask & SPAN_FOG) && !swrast->_PreferPixelFog)
-         _mesa_fog_ci_pixels( ctx, span, span->color.index);
-      else
-         _mesa_depth_fog_ci_pixels( ctx, span, span->color.index);
+      _mesa_fog_ci_span(ctx, span);
    }
 
    /* Antialias coverage application */
@@ -972,7 +965,7 @@ _mesa_write_rgba_span( GLcontext *ctx, struct sw_span *span,
    /* Stencil and Z testing */
    if (ctx->Stencil.Enabled || ctx->Depth.Test) {
       if (span->interpMask & SPAN_Z)
-         interpolate_z(ctx, span);
+         _mesa_span_interpolate_z(ctx, span);
 
       if (ctx->Stencil.Enabled) {
          if (!_mesa_stencil_and_ztest_span(ctx, span)) {
@@ -1011,20 +1004,8 @@ _mesa_write_rgba_span( GLcontext *ctx, struct sw_span *span,
    }
 
    /* Fog */
-   /* XXX try to simplify the fog code! */
    if (ctx->Fog.Enabled) {
-      if ((span->arrayMask & SPAN_FOG) && !swrast->_PreferPixelFog) {
-	 _mesa_fog_rgba_pixels_with_array(ctx, span, span->fogArray,
-                                          span->color.rgba);
-      }
-      else if ((span->interpMask & SPAN_FOG) && !swrast->_PreferPixelFog) {
-         _mesa_fog_rgba_pixels(ctx, span, span->color.rgba);
-      }
-      else {
-         if ((span->interpMask & SPAN_Z) && (span->arrayMask & SPAN_Z) == 0)
-            interpolate_z(ctx, span);
-         _mesa_depth_fog_rgba_pixels(ctx, span, span->color.rgba);
-      }
+      _mesa_fog_rgba_span(ctx, span);
       monoColor = GL_FALSE;
    }
 
@@ -1213,7 +1194,7 @@ _mesa_write_texture_span( GLcontext *ctx, struct sw_span *span,
    /* Stencil and Z testing */
    if (ctx->Stencil.Enabled || ctx->Depth.Test) {
       if (span->interpMask & SPAN_Z)
-         interpolate_z(ctx, span);
+         _mesa_span_interpolate_z(ctx, span);
 
       if (ctx->Stencil.Enabled) {
          if (!_mesa_stencil_and_ztest_span(ctx, span)) {
@@ -1267,20 +1248,8 @@ _mesa_write_texture_span( GLcontext *ctx, struct sw_span *span,
    }
 
    /* Fog */
-   /* XXX try to simplify the fog code! */
    if (ctx->Fog.Enabled) {
-      if ((span->arrayMask & SPAN_FOG) && !swrast->_PreferPixelFog) {
-	 _mesa_fog_rgba_pixels_with_array( ctx, span, span->fogArray,
-                                           span->color.rgba);
-      }
-      else if ((span->interpMask & SPAN_FOG)  &&  !swrast->_PreferPixelFog) {
-	 _mesa_fog_rgba_pixels( ctx, span, span->color.rgba );
-      }
-      else {
-         if ((span->interpMask & SPAN_Z) && (span->arrayMask & SPAN_Z) == 0)
-            interpolate_z(ctx, span);
-	 _mesa_depth_fog_rgba_pixels(ctx, span, span->color.rgba);
-      }
+      _mesa_fog_rgba_span(ctx, span);
    }
 
    /* Antialias coverage application */
diff --git a/src/mesa/swrast/s_span.h b/src/mesa/swrast/s_span.h
index 0f09c031483..d9a05987267 100644
--- a/src/mesa/swrast/s_span.h
+++ b/src/mesa/swrast/s_span.h
@@ -1,4 +1,4 @@
-/* $Id: s_span.h,v 1.14 2002/01/28 03:42:28 brianp Exp $ */
+/* $Id: s_span.h,v 1.15 2002/02/17 17:30:58 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -36,6 +36,9 @@
 extern void
 _mesa_span_default_z( GLcontext *ctx, struct sw_span *span );
 
+extern void
+_mesa_span_interpolate_z( const GLcontext *ctx, struct sw_span *span );
+
 extern void
 _mesa_span_default_fog( GLcontext *ctx, struct sw_span *span );