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authorBrian Paul <brian.paul@tungstengraphics.com>2004-02-17 21:03:03 +0000
committerBrian Paul <brian.paul@tungstengraphics.com>2004-02-17 21:03:03 +0000
commit09da0b8e6621a831e3eeb9381430f2bed18a22ad (patch)
treee7e307c3a5ddd773b469cf17d0331822388b466e /src
parent9a389d4bdb8026063034767e1599be975cb4e2f2 (diff)
A bit of an overhaul of the fog code.
glFogCoord didn't always work reliably. ARB fragment program fog options work now. Per-fragment fog computations are now perspective corrected.
Diffstat (limited to 'src')
-rw-r--r--src/mesa/swrast/s_context.c47
-rw-r--r--src/mesa/swrast/s_context.h8
-rw-r--r--src/mesa/swrast/s_fog.c391
-rw-r--r--src/mesa/swrast/s_span.c4
-rw-r--r--src/mesa/swrast/s_triangle.c1
-rw-r--r--src/mesa/swrast/s_tritemp.h10
-rw-r--r--src/mesa/tnl/t_context.c13
-rw-r--r--src/mesa/tnl/t_context.h37
-rw-r--r--src/mesa/tnl/t_vb_fog.c58
-rw-r--r--src/mesa/tnl/tnl.h6
10 files changed, 336 insertions, 239 deletions
diff --git a/src/mesa/swrast/s_context.c b/src/mesa/swrast/s_context.c
index c69d4cfd5d..800f79080f 100644
--- a/src/mesa/swrast/s_context.c
+++ b/src/mesa/swrast/s_context.c
@@ -1,8 +1,8 @@
/*
* Mesa 3-D graphics library
- * Version: 5.1
+ * Version: 6.1
*
- * Copyright (C) 1999-2003 Brian Paul All Rights Reserved.
+ * Copyright (C) 1999-2004 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"),
@@ -28,6 +28,7 @@
#include "imports.h"
#include "context.h"
+#include "colormac.h"
#include "mtypes.h"
#include "texobj.h"
#include "nvfragprog.h"
@@ -141,15 +142,17 @@ _swrast_update_polygon( GLcontext *ctx )
static void
-_swrast_update_hint( GLcontext *ctx )
+_swrast_update_fog_hint( GLcontext *ctx )
{
SWcontext *swrast = SWRAST_CONTEXT(ctx);
swrast->_PreferPixelFog = (!swrast->AllowVertexFog ||
+ ctx->FragmentProgram.Enabled ||
(ctx->Hint.Fog == GL_NICEST &&
swrast->AllowPixelFog));
}
+
/*
* Update the swrast->_AnyTextureCombine flag.
*/
@@ -169,6 +172,36 @@ _swrast_update_texture_env( GLcontext *ctx )
}
+/*
+ * Update swrast->_FogColor and swrast->_FogEnable values.
+ */
+static void
+_swrast_update_fog_state( GLcontext *ctx )
+{
+ SWcontext *swrast = SWRAST_CONTEXT(ctx);
+
+ /* convert fog color to GLchan values */
+ CLAMPED_FLOAT_TO_CHAN(swrast->_FogColor[RCOMP], ctx->Fog.Color[RCOMP]);
+ CLAMPED_FLOAT_TO_CHAN(swrast->_FogColor[GCOMP], ctx->Fog.Color[GCOMP]);
+ CLAMPED_FLOAT_TO_CHAN(swrast->_FogColor[BCOMP], ctx->Fog.Color[BCOMP]);
+
+ /* determine if fog is needed */
+ swrast->_FogEnabled = GL_FALSE;
+ if (ctx->Fog.Enabled) {
+ swrast->_FogEnabled = GL_TRUE;
+ }
+ else if (ctx->FragmentProgram.Enabled &&
+ ctx->FragmentProgram.Current->Base.Target == GL_FRAGMENT_PROGRAM_ARB) {
+ const struct fragment_program *p;
+ p = (struct fragment_program *) ctx->FragmentProgram.Current;
+ if (p->FogOption != GL_NONE) {
+ swrast->_FogEnabled = GL_TRUE;
+ }
+ }
+}
+
+
+
#define _SWRAST_NEW_DERIVED (_SWRAST_NEW_RASTERMASK | \
_NEW_TEXTURE | \
_NEW_HINT | \
@@ -393,12 +426,16 @@ _swrast_validate_derived( GLcontext *ctx )
if (swrast->NewState & _NEW_POLYGON)
_swrast_update_polygon( ctx );
- if (swrast->NewState & _NEW_HINT)
- _swrast_update_hint( ctx );
+ if (swrast->NewState & (_NEW_HINT | _NEW_PROGRAM))
+ _swrast_update_fog_hint( ctx );
if (swrast->NewState & _SWRAST_NEW_TEXTURE_ENV_MODE)
_swrast_update_texture_env( ctx );
+ if (swrast->NewState & _NEW_FOG) {
+ _swrast_update_fog_state( ctx );
+ }
+
swrast->NewState = 0;
swrast->StateChanges = 0;
swrast->InvalidateState = _swrast_invalidate_state;
diff --git a/src/mesa/swrast/s_context.h b/src/mesa/swrast/s_context.h
index a9144af700..081d2557ad 100644
--- a/src/mesa/swrast/s_context.h
+++ b/src/mesa/swrast/s_context.h
@@ -1,8 +1,8 @@
/*
* Mesa 3-D graphics library
- * Version: 5.1
+ * Version: 6.1
*
- * Copyright (C) 1999-2003 Brian Paul All Rights Reserved.
+ * Copyright (C) 1999-2004 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"),
@@ -271,8 +271,10 @@ typedef struct
GLuint _RasterMask;
GLfloat _MinMagThresh[MAX_TEXTURE_IMAGE_UNITS];
GLfloat _BackfaceSign;
- GLboolean _PreferPixelFog;
+ GLboolean _PreferPixelFog; /* Compute fog blend factor per fragment? */
GLboolean _AnyTextureCombine;
+ GLchan _FogColor[3];
+ GLboolean _FogEnabled;
/* Accum buffer temporaries.
*/
diff --git a/src/mesa/swrast/s_fog.c b/src/mesa/swrast/s_fog.c
index da06e3f354..c46032b53c 100644
--- a/src/mesa/swrast/s_fog.c
+++ b/src/mesa/swrast/s_fog.c
@@ -67,204 +67,144 @@ _swrast_z_to_fogfactor(GLcontext *ctx, GLfloat z)
}
-
/**
- * Calculate fog factors (in [0,1]) from window z values
- * 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
- *
- * Use lookup table & interpolation?
+ * Apply fog to a span of RGBA pixels.
+ * The fog value are either in the span->array->fog array or interpolated from
+ * the fog/fogStep values.
+ * They fog values are either fog coordinates (Z) or fog blend factors.
+ * _PreferPixelFog should be in sync with that state!
*/
-static void
-compute_fog_factors_from_z( const GLcontext *ctx,
- GLuint n,
- const GLdepth z[],
- GLfloat fogFact[] )
+void
+_swrast_fog_rgba_span( const GLcontext *ctx, struct sw_span *span )
{
- const GLfloat *proj = ctx->ProjectionMatrixStack.Top->m;
- const GLboolean ortho = (proj[15] != 0.0F);
- const GLfloat p10 = proj[10];
- const GLfloat p14 = proj[14];
- const GLfloat tz = ctx->Viewport._WindowMap.m[MAT_TZ];
- GLfloat szInv;
- GLuint i;
+ const SWcontext *swrast = SWRAST_CONTEXT(ctx);
+ const GLchan rFog = swrast->_FogColor[RCOMP];
+ const GLchan gFog = swrast->_FogColor[GCOMP];
+ const GLchan bFog = swrast->_FogColor[BCOMP];
+ const GLuint haveW = (span->interpMask & SPAN_W);
+ GLchan (*rgba)[4] = (GLchan (*)[4]) span->array->rgba;
- if (ctx->Viewport._WindowMap.m[MAT_SZ] == 0.0)
- szInv = 1.0F;
- else
- szInv = 1.0F / ctx->Viewport._WindowMap.m[MAT_SZ];
+ ASSERT(swrast->_FogEnabled);
+ ASSERT((span->interpMask | span->arrayMask) & SPAN_FOG);
+ ASSERT(span->arrayMask & SPAN_RGBA);
- /*
- * Note: to compute eyeZ from the ndcZ we have to solve the following:
- *
- * p[10] * eyeZ + p[14] * eyeW
- * ndcZ = ---------------------------
- * p[11] * eyeZ + p[15] * eyeW
- *
- * Thus:
- *
- * p[14] * eyeW - p[15] * eyeW * ndcZ
- * eyeZ = ----------------------------------
- * p[11] * ndcZ - p[10]
- *
- * If we note:
- * a) if using an orthographic projection, p[11] = 0 and p[15] = 1.
- * b) if using a perspective projection, p[11] = -1 and p[15] = 0.
- * c) we assume eyeW = 1 (not always true- glVertex4)
- *
- * Then we can simplify the calculation of eyeZ quite a bit. We do
- * separate calculations for the orthographic and perspective cases below.
- * Note that we drop a negative sign or two since they don't matter.
+ /* NOTE: if haveW is true, that means the fog start/step values are
+ * perspective-corrected and we have to divide each fog coord by W.
*/
- switch (ctx->Fog.Mode) {
+ /* we need to compute fog blend factors */
+ if (swrast->_PreferPixelFog) {
+ /* The span's fog values are fog coordinates, now compute blend factors
+ * and blend the fragment colors with the fog color.
+ */
+ switch (ctx->Fog.Mode) {
case GL_LINEAR:
{
- GLfloat fogEnd = ctx->Fog.End;
- GLfloat fogScale;
- if (ctx->Fog.Start == ctx->Fog.End)
- fogScale = 1.0;
- else
- fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
- if (ortho) {
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = (ndcz - p14) / p10;
- GLfloat f;
- if (eyez < 0.0)
- eyez = -eyez;
- f = (fogEnd - eyez) * fogScale;
- fogFact[i] = CLAMP(f, 0.0F, 1.0F);
- }
- }
- else {
- /* perspective */
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = p14 / (ndcz + p10);
- GLfloat f;
- if (eyez < 0.0)
- eyez = -eyez;
- f = (fogEnd - eyez) * fogScale;
- fogFact[i] = CLAMP(f, 0.0F, 1.0F);
- }
+ const GLfloat fogEnd = ctx->Fog.End;
+ const GLfloat fogScale = (ctx->Fog.Start == ctx->Fog.End)
+ ? 1.0F : 1.0F / (ctx->Fog.End - ctx->Fog.Start);
+ const GLfloat fogStep = span->fogStep;
+ GLfloat fogCoord = span->fog;
+ const GLfloat wStep = haveW ? span->dwdx : 0.0F;
+ GLfloat w = haveW ? span->w : 1.0F;
+ GLuint i;
+ for (i = 0; i < span->end; i++) {
+ GLfloat f, oneMinusF;
+ f = (fogEnd - FABSF(fogCoord/w)) * fogScale;
+ f = CLAMP(f, 0.0F, 1.0F);
+ oneMinusF = 1.0F - f;
+ rgba[i][RCOMP] = (GLchan) (f * rgba[i][RCOMP] + oneMinusF * rFog);
+ rgba[i][GCOMP] = (GLchan) (f * rgba[i][GCOMP] + oneMinusF * gFog);
+ rgba[i][BCOMP] = (GLchan) (f * rgba[i][BCOMP] + oneMinusF * bFog);
+ fogCoord += fogStep;
+ w += wStep;
}
}
- break;
+ break;
case GL_EXP:
- if (ortho) {
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = (ndcz - p14) / p10;
- if (eyez < 0.0)
- eyez = -eyez;
- fogFact[i] = (GLfloat) exp( -ctx->Fog.Density * eyez );
- }
- }
- else {
- /* perspective */
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = p14 / (ndcz + p10);
- if (eyez < 0.0)
- eyez = -eyez;
- fogFact[i] = (GLfloat) exp( -ctx->Fog.Density * eyez );
+ {
+ const GLfloat density = -ctx->Fog.Density;
+ const GLfloat fogStep = span->fogStep;
+ GLfloat fogCoord = span->fog;
+ const GLfloat wStep = haveW ? span->dwdx : 0.0F;
+ GLfloat w = haveW ? span->w : 1.0F;
+ GLuint i;
+ for (i = 0; i < span->end; i++) {
+ GLfloat f, oneMinusF;
+ f = (GLfloat) exp(density * FABSF(fogCoord/w));
+ oneMinusF = 1.0F - f;
+ rgba[i][RCOMP] = (GLchan) (f * rgba[i][RCOMP] + oneMinusF * rFog);
+ rgba[i][GCOMP] = (GLchan) (f * rgba[i][GCOMP] + oneMinusF * gFog);
+ rgba[i][BCOMP] = (GLchan) (f * rgba[i][BCOMP] + oneMinusF * bFog);
+ fogCoord += fogStep;
+ w += wStep;
}
}
- break;
+ break;
case GL_EXP2:
{
- GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
- if (ortho) {
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = (ndcz - p14) / p10;
- GLfloat tmp = negDensitySquared * eyez * eyez;
+ const GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
+ const GLfloat fogStep = span->fogStep;
+ GLfloat fogCoord = span->fog;
+ const GLfloat wStep = haveW ? span->dwdx : 0.0F;
+ GLfloat w = haveW ? span->w : 1.0F;
+ GLuint i;
+ for (i = 0; i < span->end; i++) {
+ const GLfloat coord = fogCoord / w;
+ GLfloat tmp = negDensitySquared * coord * coord;
+ GLfloat f, oneMinusF;
#if defined(__alpha__) || defined(__alpha)
- /* XXX this underflow check may be needed for other systems*/
- if (tmp < FLT_MIN_10_EXP)
- tmp = FLT_MIN_10_EXP;
+ /* XXX this underflow check may be needed for other systems*/
+ if (tmp < FLT_MIN_10_EXP)
+ tmp = FLT_MIN_10_EXP;
#endif
- fogFact[i] = (GLfloat) exp( tmp );
- }
- }
- else {
- /* perspective */
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = p14 / (ndcz + p10);
- GLfloat tmp = negDensitySquared * eyez * eyez;
-#if defined(__alpha__) || defined(__alpha)
- /* XXX this underflow check may be needed for other systems*/
- if (tmp < FLT_MIN_10_EXP)
- tmp = FLT_MIN_10_EXP;
-#endif
- fogFact[i] = (GLfloat) exp( tmp );
- }
+ f = (GLfloat) exp(tmp);
+ f = CLAMP(f, 0.0F, 1.0F);
+ oneMinusF = 1.0F - f;
+ rgba[i][RCOMP] = (GLchan) (f * rgba[i][RCOMP] + oneMinusF * rFog);
+ rgba[i][GCOMP] = (GLchan) (f * rgba[i][GCOMP] + oneMinusF * gFog);
+ rgba[i][BCOMP] = (GLchan) (f * rgba[i][BCOMP] + oneMinusF * bFog);
+ fogCoord += fogStep;
+ w += wStep;
}
}
- break;
+ break;
default:
- _mesa_problem(ctx, "Bad fog mode in compute_fog_factors_from_z");
+ _mesa_problem(ctx, "Bad fog mode in _swrast_fog_rgba_span");
return;
+ }
}
-}
-
-
-
-/**
- * Apply fog to a span of RGBA pixels.
- * The fog factors are either in the span->array->fog or stored as base/step.
- * These are fog _factors_, not fog coords. Fog coords were converted to
- * fog factors per vertex.
- */
-void
-_swrast_fog_rgba_span( const GLcontext *ctx, struct sw_span *span )
-{
- const SWcontext *swrast = SWRAST_CONTEXT(ctx);
- const GLuint n = span->end;
- GLchan (*rgba)[4] = (GLchan (*)[4]) span->array->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)
- _swrast_span_interpolate_z(ctx, span);
- compute_fog_factors_from_z(ctx, n, span->array->z, span->array->fog);
- span->arrayMask |= SPAN_FOG;
- }
-
- if (span->arrayMask & SPAN_FOG) {
- /* use fog array in span */
+ else if (span->arrayMask & SPAN_FOG) {
+ /* The span's fog array values are blend factors.
+ * They were previously computed per-vertex.
+ */
GLuint i;
- for (i = 0; i < n; i++) {
- const GLfloat fog = span->array->fog[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);
+ for (i = 0; i < span->end; i++) {
+ const GLfloat f = span->array->fog[i];
+ const GLfloat oneMinusF = 1.0F - f;
+ rgba[i][RCOMP] = (GLchan) (f * rgba[i][RCOMP] + oneMinusF * rFog);
+ rgba[i][GCOMP] = (GLchan) (f * rgba[i][GCOMP] + oneMinusF * gFog);
+ rgba[i][BCOMP] = (GLchan) (f * rgba[i][BCOMP] + oneMinusF * bFog);
}
}
else {
- /* interpolate fog factors */
- GLfloat fog = span->fog, dFog = span->fogStep;
+ /* The span's fog start/step values are blend factors.
+ * They were previously computed per-vertex.
+ */
+ const GLfloat fogStep = span->fogStep;
+ GLfloat fog = span->fog;
+ const GLfloat wStep = haveW ? span->dwdx : 0.0F;
+ GLfloat w = haveW ? span->w : 1.0F;
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;
+ ASSERT(span->interpMask & SPAN_FOG);
+ for (i = 0; i < span->end; i++) {
+ const GLfloat fact = fog / w;
+ const GLfloat oneMinusF = 1.0F - fact;
+ rgba[i][RCOMP] = (GLchan) (fact * rgba[i][RCOMP] + oneMinusF * rFog);
+ rgba[i][GCOMP] = (GLchan) (fact * rgba[i][GCOMP] + oneMinusF * gFog);
+ rgba[i][BCOMP] = (GLchan) (fact * rgba[i][BCOMP] + oneMinusF * bFog);
+ fog += fogStep;
+ w += wStep;
}
}
}
@@ -277,37 +217,110 @@ void
_swrast_fog_ci_span( const GLcontext *ctx, struct sw_span *span )
{
const SWcontext *swrast = SWRAST_CONTEXT(ctx);
- const GLuint n = span->end;
+ const GLuint haveW = (span->interpMask & SPAN_W);
+ const GLuint fogIndex = (GLuint) ctx->Fog.Index;
GLuint *index = span->array->index;
- ASSERT(ctx->Fog.Enabled);
+ ASSERT(swrast->_FogEnabled);
ASSERT(span->arrayMask & SPAN_INDEX);
ASSERT((span->interpMask | span->arrayMask) & SPAN_FOG);
+ /* we need to compute fog blend factors */
if (swrast->_PreferPixelFog) {
- /* compute fog factor from each fragment's Z value */
- if ((span->interpMask & SPAN_Z) && (span->arrayMask & SPAN_Z) == 0)
- _swrast_span_interpolate_z(ctx, span);
- compute_fog_factors_from_z(ctx, n, span->array->z, span->array->fog);
- span->arrayMask |= SPAN_FOG;
+ /* The span's fog values are fog coordinates, now compute blend factors
+ * and blend the fragment colors with the fog color.
+ */
+ switch (ctx->Fog.Mode) {
+ case GL_LINEAR:
+ {
+ const GLfloat fogEnd = ctx->Fog.End;
+ const GLfloat fogScale = (ctx->Fog.Start == ctx->Fog.End)
+ ? 1.0F : 1.0F / (ctx->Fog.End - ctx->Fog.Start);
+ const GLfloat fogStep = span->fogStep;
+ GLfloat fogCoord = span->fog;
+ const GLfloat wStep = haveW ? span->dwdx : 0.0F;
+ GLfloat w = haveW ? span->w : 1.0F;
+ GLuint i;
+ for (i = 0; i < span->end; i++) {
+ GLfloat f = (fogEnd - FABSF(fogCoord/w)) * fogScale;
+ f = CLAMP(f, 0.0F, 1.0F);
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex);
+ fogCoord += fogStep;
+ w += wStep;
+ }
+ }
+ break;
+ case GL_EXP:
+ {
+ const GLfloat density = -ctx->Fog.Density;
+ const GLfloat fogStep = span->fogStep;
+ GLfloat fogCoord = span->fog;
+ const GLfloat wStep = haveW ? span->dwdx : 0.0F;
+ GLfloat w = haveW ? span->w : 1.0F;
+ GLuint i;
+ for (i = 0; i < span->end; i++) {
+ GLfloat f = (GLfloat) exp(density * FABSF(fogCoord/w));
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex);
+ fogCoord += fogStep;
+ w += wStep;
+ }
+ }
+ break;
+ case GL_EXP2:
+ {
+ const GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
+ const GLfloat fogStep = span->fogStep;
+ GLfloat fogCoord = span->fog;
+ const GLfloat wStep = haveW ? span->dwdx : 0.0F;
+ GLfloat w = haveW ? span->w : 1.0F;
+ GLuint i;
+ for (i = 0; i < span->end; i++) {
+ const GLfloat coord = fogCoord / w;
+ GLfloat tmp = negDensitySquared * coord * coord;
+ GLfloat f;
+#if defined(__alpha__) || defined(__alpha)
+ /* XXX this underflow check may be needed for other systems*/
+ if (tmp < FLT_MIN_10_EXP)
+ tmp = FLT_MIN_10_EXP;
+#endif
+ f = (GLfloat) exp(tmp);
+ f = CLAMP(f, 0.0F, 1.0F);
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex);
+ fogCoord += fogStep;
+ w += wStep;
+ }
+ }
+ break;
+ default:
+ _mesa_problem(ctx, "Bad fog mode in _swrast_fog_ci_span");
+ return;
+ }
}
-
- if (span->arrayMask & SPAN_FOG) {
- const GLuint idx = (GLuint) ctx->Fog.Index;
+ else if (span->arrayMask & SPAN_FOG) {
+ /* The span's fog array values are blend factors.
+ * They were previously computed per-vertex.
+ */
GLuint i;
- for (i = 0; i < n; i++) {
- const GLfloat f = CLAMP(span->array->fog[i], 0.0F, 1.0F);
- index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * idx);
+ for (i = 0; i < span->end; i++) {
+ const GLfloat f = span->array->fog[i];
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex);
}
}
else {
- GLfloat fog = span->fog, dFog = span->fogStep;
- const GLuint idx = (GLuint) ctx->Fog.Index;
+ /* The span's fog start/step values are blend factors.
+ * They were previously computed per-vertex.
+ */
+ const GLfloat fogStep = span->fogStep;
+ GLfloat fog = span->fog;
+ const GLfloat wStep = haveW ? span->dwdx : 0.0F;
+ GLfloat w = haveW ? span->w : 1.0F;
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;
+ ASSERT(span->interpMask & SPAN_FOG);
+ for (i = 0; i < span->end; i++) {
+ const GLfloat f = fog / w;
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex);
+ fog += fogStep;
+ w += wStep;
}
}
}
diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c
index ee46f32307..cdd97f613a 100644
--- a/src/mesa/swrast/s_span.c
+++ b/src/mesa/swrast/s_span.c
@@ -1079,7 +1079,7 @@ _swrast_write_rgba_span( GLcontext *ctx, struct sw_span *span)
}
/* Fog */
- if (ctx->Fog.Enabled) {
+ if (swrast->_FogEnabled) {
_swrast_fog_rgba_span(ctx, span);
monoColor = GL_FALSE;
}
@@ -1354,7 +1354,7 @@ _swrast_write_texture_span( GLcontext *ctx, struct sw_span *span)
}
/* Fog */
- if (ctx->Fog.Enabled) {
+ if (swrast->_FogEnabled) {
_swrast_fog_rgba_span(ctx, span);
}
diff --git a/src/mesa/swrast/s_triangle.c b/src/mesa/swrast/s_triangle.c
index 257f06c24d..01cd754e4a 100644
--- a/src/mesa/swrast/s_triangle.c
+++ b/src/mesa/swrast/s_triangle.c
@@ -798,6 +798,7 @@ fast_persp_span(GLcontext *ctx, struct sw_span *span,
*/
#define NAME persp_textured_triangle
#define INTERP_Z 1
+#define INTERP_W 1
#define INTERP_FOG 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define INTERP_RGB 1
diff --git a/src/mesa/swrast/s_tritemp.h b/src/mesa/swrast/s_tritemp.h
index 28a80dee66..2e25e531cc 100644
--- a/src/mesa/swrast/s_tritemp.h
+++ b/src/mesa/swrast/s_tritemp.h
@@ -411,8 +411,14 @@ static void NAME(GLcontext *ctx, const SWvertex *v0,
#ifdef INTERP_FOG
span.interpMask |= SPAN_FOG;
{
+# ifdef INTERP_W
+ const GLfloat wMax = vMax->win[3], wMin = vMin->win[3], wMid = vMid->win[3];
+ const GLfloat eMaj_dfog = vMax->fog * wMax - vMin->fog * wMin;
+ const GLfloat eBot_dfog = vMid->fog * wMid - vMin->fog * wMin;
+# else
const GLfloat eMaj_dfog = vMax->fog - vMin->fog;
const GLfloat eBot_dfog = vMid->fog - vMin->fog;
+# endif
span.dfogdx = oneOverArea * (eMaj_dfog * eBot.dy - eMaj.dy * eBot_dfog);
span.dfogdy = oneOverArea * (eMaj.dx * eBot_dfog - eMaj_dfog * eBot.dx);
span.fogStep = span.dfogdx;
@@ -802,7 +808,11 @@ static void NAME(GLcontext *ctx, const SWvertex *v0,
dwOuter = span.dwdy + dxOuter * span.dwdx;
#endif
#ifdef INTERP_FOG
+# ifdef INTERP_W
+ fogLeft = vLower->fog * vLower->win[3] + (span.dfogdx * adjx + span.dfogdy * adjy) * (1.0F/FIXED_SCALE);
+# else
fogLeft = vLower->fog + (span.dfogdx * adjx + span.dfogdy * adjy) * (1.0F/FIXED_SCALE);
+# endif
dfogOuter = span.dfogdy + dxOuter * span.dfogdx;
#endif
#ifdef INTERP_RGB
diff --git a/src/mesa/tnl/t_context.c b/src/mesa/tnl/t_context.c
index ec5f88cd96..626aa5290e 100644
--- a/src/mesa/tnl/t_context.c
+++ b/src/mesa/tnl/t_context.c
@@ -102,6 +102,7 @@ _tnl_CreateContext( GLcontext *ctx )
tnl->NeedNdcCoords = GL_TRUE;
tnl->LoopbackDListCassettes = GL_FALSE;
tnl->CalcDListNormalLengths = GL_TRUE;
+ tnl->AllowVertexFog = GL_TRUE;
/* Hook our functions into exec and compile dispatch tables.
*/
@@ -144,6 +145,10 @@ _tnl_InvalidateState( GLcontext *ctx, GLuint new_state )
{
TNLcontext *tnl = TNL_CONTEXT(ctx);
+ if (new_state & (_NEW_HINT)) {
+ tnl->_DoVertexFog = tnl->AllowVertexFog && (ctx->Hint.Fog != GL_NICEST);
+ }
+
if (new_state & _NEW_ARRAY) {
tnl->pipeline.run_input_changes |= ctx->Array.NewState; /* overkill */
}
@@ -259,3 +264,11 @@ _tnl_isolate_materials( GLcontext *ctx, GLboolean mode )
TNLcontext *tnl = TNL_CONTEXT(ctx);
tnl->IsolateMaterials = mode;
}
+
+void
+_tnl_allow_vertex_fog( GLcontext *ctx, GLboolean value )
+{
+ TNLcontext *tnl = TNL_CONTEXT(ctx);
+ tnl->AllowVertexFog = value;
+}
+
diff --git a/src/mesa/tnl/t_context.h b/src/mesa/tnl/t_context.h
index a9d36d2488..b7aff6c626 100644
--- a/src/mesa/tnl/t_context.h
+++ b/src/mesa/tnl/t_context.h
@@ -364,11 +364,6 @@ struct tnl_save {
};
-
-
-
-
-
struct tnl_vertex_arrays
{
/* Conventional vertex attribute arrays */
@@ -433,14 +428,13 @@ struct vertex_buffer
/* Private data from _tnl_render_stage that has no business being
* in this struct.
*/
-
};
-
/** Describes an individual operation on the pipeline.
*/
-struct tnl_pipeline_stage {
+struct tnl_pipeline_stage
+{
const char *name;
GLuint check_state; /* All state referenced in check() --
* When is the pipeline_stage struct
@@ -513,7 +507,8 @@ typedef void (*insert_func)( const struct tnl_clipspace_attr *a, GLubyte *v,
const GLfloat *in );
-struct tnl_clipspace_attr {
+struct tnl_clipspace_attr
+{
int attrib;
int vertoffset;
int vertattrsize;
@@ -546,7 +541,8 @@ typedef void (*setup_func)( GLcontext *ctx,
-struct tnl_clipspace {
+struct tnl_clipspace
+{
GLboolean need_extras;
GLuint new_inputs;
@@ -564,7 +560,8 @@ struct tnl_clipspace {
};
-struct tnl_device_driver {
+struct tnl_device_driver
+{
/***
*** TNL Pipeline
***/
@@ -588,7 +585,8 @@ struct tnl_device_driver {
/***
*** Rendering -- These functions called only from t_vb_render.c
***/
- struct {
+ struct
+ {
void (*Start)(GLcontext *ctx);
void (*Finish)(GLcontext *ctx);
/* Called before and after all rendering operations, including DrawPixels,
@@ -667,8 +665,11 @@ struct tnl_device_driver {
};
-typedef struct {
-
+/**
+ * Context state for T&L context.
+ */
+typedef struct
+{
/* Driver interface.
*/
struct tnl_device_driver Driver;
@@ -693,23 +694,21 @@ typedef struct {
struct tnl_vertex_arrays current;
struct tnl_vertex_arrays array_inputs;
-
/* Clipspace/ndc/window vertex managment:
*/
struct tnl_clipspace clipspace;
-
/* Probably need a better configuration mechanism:
*/
GLboolean NeedNdcCoords;
GLboolean LoopbackDListCassettes;
GLboolean CalcDListNormalLengths;
GLboolean IsolateMaterials;
+ GLboolean AllowVertexFog;
- /*
- */
- GLuint render_inputs;
+ GLboolean _DoVertexFog; /* eval fog function at each vertex? */
+ GLuint render_inputs;
GLvertexformat exec_vtxfmt;
GLvertexformat save_vtxfmt;
diff --git a/src/mesa/tnl/t_vb_fog.c b/src/mesa/tnl/t_vb_fog.c
index 34f1e811cc..3be62e887b 100644
--- a/src/mesa/tnl/t_vb_fog.c
+++ b/src/mesa/tnl/t_vb_fog.c
@@ -71,7 +71,11 @@ do { \
#endif
-static void init_static_data( void )
+/**
+ * Initialize the exp_table[] lookup table for approximating exp().
+ */
+static void
+init_static_data( void )
{
GLfloat f = 0.0F;
GLint i = 0;
@@ -89,8 +93,8 @@ static void init_static_data( void )
* near and far clip plane distances).
* Fog blend factors are in the range [0,1].
*/
-static void compute_fog_blend_factors( GLcontext *ctx, GLvector4f *out,
- const GLvector4f *in )
+static void
+compute_fog_blend_factors(GLcontext *ctx, GLvector4f *out, const GLvector4f *in)
{
GLfloat end = ctx->Fog.End;
GLfloat *v = in->start;
@@ -109,19 +113,22 @@ static void compute_fog_blend_factors( GLcontext *ctx, GLvector4f *out,
else
d = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) {
- GLfloat f = (end - FABSF(*v)) * d;
+ const GLfloat z = FABSF(*v);
+ GLfloat f = (end - z) * d;
data[i][0] = CLAMP(f, 0.0F, 1.0F);
}
break;
case GL_EXP:
d = ctx->Fog.Density;
- for ( i = 0 ; i < n ; i++, STRIDE_F(v,stride))
- NEG_EXP( data[i][0], d * FABSF(*v) );
+ for ( i = 0 ; i < n ; i++, STRIDE_F(v,stride)) {
+ const GLfloat z = FABSF(*v);
+ NEG_EXP( data[i][0], d * z );
+ }
break;
case GL_EXP2:
d = ctx->Fog.Density*ctx->Fog.Density;
for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) {
- GLfloat z = *v;
+ const GLfloat z = *v;
NEG_EXP( data[i][0], d * z * z );
}
break;
@@ -132,10 +139,11 @@ static void compute_fog_blend_factors( GLcontext *ctx, GLvector4f *out,
}
-static GLboolean run_fog_stage( GLcontext *ctx,
- struct tnl_pipeline_stage *stage )
+static GLboolean
+run_fog_stage(GLcontext *ctx, struct tnl_pipeline_stage *stage)
{
- struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
+ TNLcontext *tnl = TNL_CONTEXT(ctx);
+ struct vertex_buffer *VB = &tnl->vb;
struct fog_stage_data *store = FOG_STAGE_DATA(stage);
GLvector4f *input;
@@ -143,12 +151,13 @@ static GLboolean run_fog_stage( GLcontext *ctx,
return GL_TRUE;
if (ctx->Fog.FogCoordinateSource == GL_FRAGMENT_DEPTH_EXT) {
- /* fog computed from Z depth */
+ /* Fog is computed from vertex or fragment Z values */
/* source = VB->ObjPtr or VB->EyePtr coords */
/* dest = VB->FogCoordPtr = fog stage private storage */
VB->FogCoordPtr = &store->fogcoord;
if (!ctx->_NeedEyeCoords) {
+ /* compute fog coords from object coords */
const GLfloat *m = ctx->ModelviewMatrixStack.Top->m;
GLfloat plane[4];
@@ -171,6 +180,7 @@ static GLboolean run_fog_stage( GLcontext *ctx,
input->count = VB->ObjPtr->count;
}
else {
+ /* fog coordinates = eye Z coordinates (use ABS later) */
input = &store->input;
if (VB->EyePtr->size < 2)
@@ -184,21 +194,26 @@ static GLboolean run_fog_stage( GLcontext *ctx,
}
else {
/* use glFogCoord() coordinates */
- /* source = VB->FogCoordPtr */
- input = VB->FogCoordPtr;
- /* dest = fog stage private storage */
- VB->FogCoordPtr = &store->fogcoord;
+ input = VB->FogCoordPtr; /* source data */
+ VB->FogCoordPtr = &store->fogcoord; /* dest data */
}
- /* compute blend factors from fog coordinates */
- compute_fog_blend_factors( ctx, VB->FogCoordPtr, input );
+ if (tnl->_DoVertexFog) {
+ /* compute blend factors from fog coordinates */
+ compute_fog_blend_factors( ctx, VB->FogCoordPtr, input );
+ }
+ else {
+ /* results = incoming fog coords (compute fog per-fragment later) */
+ VB->FogCoordPtr = input;
+ }
VB->AttribPtr[_TNL_ATTRIB_FOG] = VB->FogCoordPtr;
return GL_TRUE;
}
-static void check_fog_stage( GLcontext *ctx, struct tnl_pipeline_stage *stage )
+static void
+check_fog_stage(GLcontext *ctx, struct tnl_pipeline_stage *stage)
{
stage->active = ctx->Fog.Enabled && !ctx->VertexProgram.Enabled;
@@ -211,8 +226,8 @@ static void check_fog_stage( GLcontext *ctx, struct tnl_pipeline_stage *stage )
/* Called the first time stage->run() is invoked.
*/
-static GLboolean alloc_fog_data( GLcontext *ctx,
- struct tnl_pipeline_stage *stage )
+static GLboolean
+alloc_fog_data(GLcontext *ctx, struct tnl_pipeline_stage *stage)
{
TNLcontext *tnl = TNL_CONTEXT(ctx);
struct fog_stage_data *store;
@@ -234,7 +249,8 @@ static GLboolean alloc_fog_data( GLcontext *ctx,
}
-static void free_fog_data( struct tnl_pipeline_stage *stage )
+static void
+free_fog_data(struct tnl_pipeline_stage *stage)
{
struct fog_stage_data *store = FOG_STAGE_DATA(stage);
if (store) {
diff --git a/src/mesa/tnl/tnl.h b/src/mesa/tnl/tnl.h
index 9a2241d8fc..3be222a6e0 100644
--- a/src/mesa/tnl/tnl.h
+++ b/src/mesa/tnl/tnl.h
@@ -75,4 +75,10 @@ extern void
_tnl_isolate_materials( GLcontext *ctx, GLboolean flag );
+/* Control whether T&L does per-vertex fog
+ */
+extern void
+_tnl_allow_vertex_fog( GLcontext *ctx, GLboolean value );
+
+
#endif