-/* $Id: s_fog.c,v 1.21 2002/02/02 21:40:33 brianp Exp $ */
-
/*
* Mesa 3-D graphics library
- * Version: 4.1
+ * Version: 6.3
*
- * Copyright (C) 1999-2002 Brian Paul All Rights Reserved.
+ * Copyright (C) 1999-2005 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"),
#include "colormac.h"
#include "context.h"
#include "macros.h"
-#include "mmath.h"
#include "s_context.h"
#include "s_fog.h"
-
-
+#include "s_span.h"
/**
* Used to convert current raster distance to a fog factor in [0,1].
*/
GLfloat
-_mesa_z_to_fogfactor(GLcontext *ctx, GLfloat z)
+_swrast_z_to_fogfactor(GLcontext *ctx, GLfloat z)
{
GLfloat d, f;
return CLAMP(f, 0.0F, 1.0F);
case GL_EXP:
d = ctx->Fog.Density;
- f = (GLfloat) exp(-d * z);
+ f = EXPF(-d * z);
+ f = CLAMP(f, 0.0F, 1.0F);
return f;
case GL_EXP2:
d = ctx->Fog.Density;
- f = (GLfloat) exp(-(d * d * z * z));
+ f = EXPF(-(d * d * z * z));
+ f = CLAMP(f, 0.0F, 1.0F);
return f;
default:
- _mesa_problem(ctx, "Bad fog mode in make_fog_coord");
+ _mesa_problem(ctx, "Bad fog mode in _swrast_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
+ * 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!
*/
void
-_mesa_fog_rgba_pixels( const GLcontext *ctx, struct sw_span *span,
- GLchan rgba[][4] )
+_swrast_fog_rgba_span( const GLcontext *ctx, struct sw_span *span )
{
- GLuint i;
- GLfloat fog = span->fog, Dfog = span->fogStep;
- GLchan rFog, gFog, bFog;
-
- ASSERT(ctx->Fog.Enabled);
- ASSERT(span->interpMask & SPAN_FOG);
+ 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;
+
+ ASSERT(swrast->_FogEnabled);
+ 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]);
+ /* 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.
+ */
- 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;
+ /* 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 (swrast->_FogMode) {
+ 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, 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;
+ 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, oneMinusF;
+ f = EXPF(density * FABSF(fogCoord) / w);
+ 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;
+ 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, 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;
+#endif
+ f = EXPF(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;
+ default:
+ _mesa_problem(ctx, "Bad fog mode in _swrast_fog_rgba_span");
+ return;
+ }
}
-}
-
-
-/**
- * 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);
+ 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 < 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);
+ }
}
-}
-
-
-
-/**
- * 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;
+ else {
+ /* 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;
+ 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;
+ }
}
}
/**
- * 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
+ * As above, but color index mode.
*/
void
-_mesa_fog_ci_pixels_with_array( const GLcontext *ctx, struct sw_span *span,
- const GLfloat fog[], GLuint index[] )
+_swrast_fog_ci_span( const GLcontext *ctx, struct sw_span *span )
{
- GLuint idx = (GLuint) ctx->Fog.Index;
- GLuint i;
+ const SWcontext *swrast = SWRAST_CONTEXT(ctx);
+ const GLuint haveW = (span->interpMask & SPAN_W);
+ const GLuint fogIndex = (GLuint) ctx->Fog.Index;
+ GLuint *index = span->array->index;
- ASSERT(fog != NULL);
- ASSERT(ctx->Fog.Enabled);
+ ASSERT(swrast->_FogEnabled);
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
- * z - array of integer depth values
- * red, green, blue, alpha - pixel colors
- * Output: red, green, blue, alpha - fogged pixel colors
- *
- * Use lookup table & interpolation?
- */
-static void
-compute_fog_factors_from_z( const GLcontext *ctx,
- GLuint n,
- const GLdepth z[],
- GLfloat fogFact[] )
-{
- 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;
-
- if (ctx->Viewport._WindowMap.m[MAT_SZ] == 0.0)
- szInv = 1.0F;
- else
- szInv = 1.0F / ctx->Viewport._WindowMap.m[MAT_SZ];
-
- /*
- * 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.
- */
-
- switch (ctx->Fog.Mode) {
+ ASSERT((span->interpMask | span->arrayMask) & SPAN_FOG);
+
+ /* 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;
- if (eyez < 0.0)
- eyez = -eyez;
- fogFact[i] = (fogEnd - eyez) * fogScale;
- }
- }
- 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] = (fogEnd - eyez) * fogScale;
- }
+ 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 - 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;
+ 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 = EXPF(density * fogCoord / w);
+ f = CLAMP(f, 0.0F, 1.0F);
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex);
+ 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;
-#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 );
- }
- }
- 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;
+ 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;
+ /* 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 = EXPF(tmp);
+ f = CLAMP(f, 0.0F, 1.0F);
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex);
+ 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_ci_span");
return;
+ }
+ }
+ 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 < span->end; i++) {
+ const GLfloat f = span->array->fog[i];
+ index[i] = (GLuint) ((GLfloat) index[i] + (1.0F - f) * fogIndex);
+ }
+ }
+ else {
+ /* 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;
+ 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;
+ }
}
-}
-
-
-/**
- * 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
- */
-void
-_mesa_depth_fog_rgba_pixels(const GLcontext *ctx, struct sw_span *span,
- GLchan rgba[][4])
-{
- GLfloat fogFact[MAX_WIDTH];
-
- ASSERT(ctx->Fog.Enabled);
- ASSERT(span->arrayMask & SPAN_Z);
- ASSERT(span->end <= MAX_WIDTH);
-
- compute_fog_factors_from_z(ctx, span->end, span->zArray, fogFact );
- _mesa_fog_rgba_pixels_with_array( ctx, span, fogFact, rgba );
-}
-
-
-/**
- * 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
- */
-void
-_mesa_depth_fog_ci_pixels( const GLcontext *ctx, struct sw_span *span,
- GLuint index[] )
-{
- GLfloat fogFact[MAX_WIDTH];
-
- ASSERT(ctx->Fog.Enabled);
- ASSERT(span->arrayMask & SPAN_Z);
- ASSERT(span->end <= MAX_WIDTH);
-
- compute_fog_factors_from_z(ctx, span->end, span->zArray, fogFact );
- _mesa_fog_ci_pixels_with_array( ctx, span, fogFact, index );
}
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