-/* $Id: s_fog.c,v 1.23 2002/08/07 00:45:07 brianp Exp $ */
-
/*
* Mesa 3-D graphics library
- * Version: 4.1
+ * Version: 6.5.2
*
- * Copyright (C) 1999-2002 Brian Paul All Rights Reserved.
+ * Copyright (C) 1999-2006 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 _mesa_z_to_fogfactor");
+ _mesa_problem(ctx, "Bad fog mode in _swrast_z_to_fogfactor");
return 0.0;
}
}
+/**
+ * Template code for computing fog blend factor and applying it to colors.
+ * \param TYPE either GLubyte, GLushort or GLfloat.
+ * \param COMPUTE_F code to compute the fog blend factor, f.
+ */
+#define FOG_LOOP(TYPE, COMPUTE_F) \
+do { \
+ const GLfloat fogStep = span->attrStepX[FRAG_ATTRIB_FOGC][0]; \
+ GLfloat fogCoord = span->attrStart[FRAG_ATTRIB_FOGC][0]; \
+ const GLfloat wStep = haveW ? span->attrStepX[FRAG_ATTRIB_WPOS][3] : 0.0F;\
+ GLfloat w = haveW ? span->attrStart[FRAG_ATTRIB_WPOS][3] : 1.0F; \
+ GLuint i; \
+ for (i = 0; i < span->end; i++) { \
+ GLfloat f, oneMinusF; \
+ COMPUTE_F; \
+ f = CLAMP(f, 0.0F, 1.0F); \
+ oneMinusF = 1.0F - f; \
+ rgba[i][RCOMP] = (TYPE) (f * rgba[i][RCOMP] + oneMinusF * rFog); \
+ rgba[i][GCOMP] = (TYPE) (f * rgba[i][GCOMP] + oneMinusF * gFog); \
+ rgba[i][BCOMP] = (TYPE) (f * rgba[i][BCOMP] + oneMinusF * bFog); \
+ fogCoord += fogStep; \
+ w += wStep; \
+ } \
+} while (0)
+
+
/**
- * 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, SWspan *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);
+ GLfloat rFog, gFog, bFog;
+ const GLuint haveW = (span->interpMask & SPAN_W);
- 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);
+
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ rFog = ctx->Fog.Color[RCOMP] * 255.0;
+ gFog = ctx->Fog.Color[GCOMP] * 255.0;
+ bFog = ctx->Fog.Color[BCOMP] * 255.0;
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ rFog = ctx->Fog.Color[RCOMP] * 65535.0;
+ gFog = ctx->Fog.Color[GCOMP] * 65535.0;
+ bFog = ctx->Fog.Color[BCOMP] * 65535.0;
+ }
+ else {
+ rFog = ctx->Fog.Color[RCOMP];
+ gFog = ctx->Fog.Color[GCOMP];
+ bFog = ctx->Fog.Color[BCOMP];
+ }
- /*
- * 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.
+ */
+ 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 density = -ctx->Fog.Density;
+ const GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
+
+ switch (swrast->_FogMode) {
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);
- }
- }
+#define COMPUTE_F f = (fogEnd - FABSF(fogCoord) / w) * fogScale;
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->color.sz1.rgba;
+ FOG_LOOP(GLubyte, COMPUTE_F);
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->color.sz2.rgba;
+ FOG_LOOP(GLushort, COMPUTE_F);
}
- break;
+ else {
+ GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
+ ASSERT(span->array->ChanType == GL_FLOAT);
+ FOG_LOOP(GLfloat, COMPUTE_F);
+ }
+#undef COMPUTE_F
+ 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 );
- }
+#define COMPUTE_F f = EXPF(density * FABSF(fogCoord) / w);
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->color.sz1.rgba;
+ FOG_LOOP(GLubyte, COMPUTE_F);
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->color.sz2.rgba;
+ FOG_LOOP(GLushort, COMPUTE_F);
}
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 );
- }
+ GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
+ ASSERT(span->array->ChanType == GL_FLOAT);
+ FOG_LOOP(GLfloat, COMPUTE_F);
}
- break;
+#undef COMPUTE_F
+ 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;
-#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 );
- }
- }
+#define COMPUTE_F const GLfloat coord = fogCoord / w; \
+ GLfloat tmp = negDensitySquared * coord * coord; \
+ if (tmp < FLT_MIN_10_EXP) \
+ tmp = FLT_MIN_10_EXP; \
+ f = EXPF(tmp);
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->color.sz1.rgba;
+ FOG_LOOP(GLubyte, COMPUTE_F);
}
- break;
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->color.sz2.rgba;
+ FOG_LOOP(GLushort, COMPUTE_F);
+ }
+ else {
+ GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
+ ASSERT(span->array->ChanType == GL_FLOAT);
+ FOG_LOOP(GLfloat, COMPUTE_F);
+ }
+#undef COMPUTE_F
+ 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
-_mesa_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)
- _mesa_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);
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->color.sz1.rgba;
+ for (i = 0; i < span->end; i++) {
+ const GLfloat f = span->array->attribs[FRAG_ATTRIB_FOGC][i][0];
+ const GLfloat oneMinusF = 1.0F - f;
+ rgba[i][RCOMP] = (GLubyte) (f * rgba[i][RCOMP] + oneMinusF * rFog);
+ rgba[i][GCOMP] = (GLubyte) (f * rgba[i][GCOMP] + oneMinusF * gFog);
+ rgba[i][BCOMP] = (GLubyte) (f * rgba[i][BCOMP] + oneMinusF * bFog);
+ }
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->color.sz2.rgba;
+ for (i = 0; i < span->end; i++) {
+ const GLfloat f = span->array->attribs[FRAG_ATTRIB_FOGC][i][0];
+ const GLfloat oneMinusF = 1.0F - f;
+ rgba[i][RCOMP] = (GLushort) (f * rgba[i][RCOMP] + oneMinusF * rFog);
+ rgba[i][GCOMP] = (GLushort) (f * rgba[i][GCOMP] + oneMinusF * gFog);
+ rgba[i][BCOMP] = (GLushort) (f * rgba[i][BCOMP] + oneMinusF * bFog);
+ }
+ }
+ else {
+ GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
+ ASSERT(span->array->ChanType == GL_FLOAT);
+ for (i = 0; i < span->end; i++) {
+ const GLfloat f = span->array->attribs[FRAG_ATTRIB_FOGC][i][0];
+ const GLfloat oneMinusF = 1.0F - f;
+ rgba[i][RCOMP] = f * rgba[i][RCOMP] + oneMinusF * rFog;
+ rgba[i][GCOMP] = f * rgba[i][GCOMP] + oneMinusF * gFog;
+ rgba[i][BCOMP] = f * rgba[i][BCOMP] + oneMinusF * bFog;
+ }
}
+
}
else {
- /* interpolate fog factors */
- 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;
+ /* The span's fog start/step values are blend factors.
+ * They were previously computed per-vertex.
+ */
+#define COMPUTE_F f = fogCoord / w;
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->color.sz1.rgba;
+ FOG_LOOP(GLubyte, COMPUTE_F);
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->color.sz2.rgba;
+ FOG_LOOP(GLushort, COMPUTE_F);
}
+ else {
+ GLfloat (*rgba)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
+ ASSERT(span->array->ChanType == GL_FLOAT);
+ FOG_LOOP(GLfloat, COMPUTE_F);
+ }
+#undef COMPUTE_F
}
}
* As above, but color index mode.
*/
void
-_mesa_fog_ci_span( const GLcontext *ctx, struct sw_span *span )
+_swrast_fog_ci_span( const GLcontext *ctx, SWspan *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)
- _mesa_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->attrStepX[FRAG_ATTRIB_FOGC][0];
+ GLfloat fogCoord = span->attrStart[FRAG_ATTRIB_FOGC][0];
+ const GLfloat wStep = haveW ? span->attrStepX[FRAG_ATTRIB_WPOS][3] : 0.0F;
+ GLfloat w = haveW ? span->attrStart[FRAG_ATTRIB_WPOS][3] : 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;
+ case GL_EXP:
+ {
+ const GLfloat density = -ctx->Fog.Density;
+ const GLfloat fogStep = span->attrStepX[FRAG_ATTRIB_FOGC][0];
+ GLfloat fogCoord = span->attrStart[FRAG_ATTRIB_FOGC][0];
+ const GLfloat wStep = haveW ? span->attrStepX[FRAG_ATTRIB_WPOS][3] : 0.0F;
+ GLfloat w = haveW ? span->attrStart[FRAG_ATTRIB_WPOS][3] : 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;
+ case GL_EXP2:
+ {
+ const GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
+ const GLfloat fogStep = span->attrStepX[FRAG_ATTRIB_FOGC][0];
+ GLfloat fogCoord = span->attrStart[FRAG_ATTRIB_FOGC][0];
+ const GLfloat wStep = haveW ? span->attrStepX[FRAG_ATTRIB_WPOS][3] : 0.0F;
+ GLfloat w = haveW ? span->attrStart[FRAG_ATTRIB_WPOS][3] : 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 = EXPF(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->attribs[FRAG_ATTRIB_FOGC][i][0];
+ 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->attrStepX[FRAG_ATTRIB_FOGC][0];
+ GLfloat fog = span->attrStart[FRAG_ATTRIB_FOGC][0];
+ const GLfloat wStep = haveW ? span->attrStepX[FRAG_ATTRIB_WPOS][3] : 0.0F;
+ GLfloat w = haveW ? span->attrStart[FRAG_ATTRIB_WPOS][3] : 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;
}
}
}
projects / mesa.git / blobdiff