-/* $Id: s_fog.c,v 1.1 2000/10/31 18:00:04 keithw Exp $ */
+/* $Id: s_fog.c,v 1.22 2002/02/17 17:30:58 brianp Exp $ */
/*
* Mesa 3-D graphics library
- * Version: 3.5
- *
- * Copyright (C) 1999-2000 Brian Paul All Rights Reserved.
- *
+ * Version: 4.1
+ *
+ * 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"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
- *
+ *
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
- *
+ *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
#include "macros.h"
#include "mmath.h"
+#include "s_context.h"
#include "s_fog.h"
-
-
-/*
- * Apply fog to an array of RGBA pixels.
- * Input: n - number of pixels
- * fog - array of interpolated screen-space fog coordinates in [0..1]
- * 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 GLfixed fog[],
- GLchan rgba[][4] )
-{
- GLfixed rFog = ctx->Fog.Color[0] * CHAN_MAXF;
- GLfixed gFog = ctx->Fog.Color[1] * CHAN_MAXF;
- GLfixed bFog = ctx->Fog.Color[2] * CHAN_MAXF;
- GLuint i;
-
- for (i=0;i<n;i++) {
- GLfixed f = CLAMP(fog[i], 0, FIXED_ONE);
- GLfixed g = FIXED_ONE - f;
- rgba[i][0] = (f*rgba[i][0] + g*rFog) >> FIXED_SHIFT;
- rgba[i][1] = (f*rgba[i][1] + g*gFog) >> FIXED_SHIFT;
- rgba[i][2] = (f*rgba[i][2] + g*bFog) >> FIXED_SHIFT;
- }
-}
+#include "s_span.h"
-/*
- * 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
+/**
+ * Used to convert current raster distance to a fog factor in [0,1].
*/
-void
-_mesa_fog_ci_pixels( const GLcontext *ctx,
- GLuint n, const GLfixed fog[], GLuint index[] )
+GLfloat
+_mesa_z_to_fogfactor(GLcontext *ctx, GLfloat z)
{
- GLuint idx = ctx->Fog.Index;
- GLuint i;
+ GLfloat d, f;
- for (i=0;i<n;i++) {
- GLfixed f = FixedToFloat(CLAMP(fog[i], 0, FIXED_ONE));
- index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * idx);
+ switch (ctx->Fog.Mode) {
+ case GL_LINEAR:
+ if (ctx->Fog.Start == ctx->Fog.End)
+ d = 1.0F;
+ else
+ d = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
+ f = (ctx->Fog.End - z) * d;
+ return CLAMP(f, 0.0F, 1.0F);
+ case GL_EXP:
+ d = ctx->Fog.Density;
+ f = (GLfloat) exp(-d * z);
+ return f;
+ case GL_EXP2:
+ d = ctx->Fog.Density;
+ f = (GLfloat) exp(-(d * d * z * z));
+ return f;
+ default:
+ _mesa_problem(ctx, "Bad fog mode in _mesa_z_to_fogfactor");
+ return 0.0;
}
}
-/*
- * Calculate fog coords from window z values
+/**
+ * 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?
+ * Use lookup table & interpolation?
*/
-void
-_mesa_win_fog_coords_from_z( const GLcontext *ctx,
- GLuint n,
- const GLdepth z[],
- GLfixed fogcoord[] )
+static void
+compute_fog_factors_from_z( const GLcontext *ctx,
+ GLuint n,
+ const GLdepth z[],
+ GLfloat fogFact[] )
{
- GLfloat c = ctx->ProjectionMatrix.m[10];
- GLfloat d = ctx->ProjectionMatrix.m[14];
+ 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;
- GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ];
- GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ];
+ 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) {
case GL_LINEAR:
{
GLfloat fogEnd = ctx->Fog.End;
- GLfloat fogScale = (GLfloat) FIXED_ONE / (ctx->Fog.End -
- ctx->Fog.Start);
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = -d / (c+ndcz);
- if (eyez < 0.0) eyez = -eyez;
- fogcoord[i] = (GLint)(fogEnd - eyez) * fogScale;
+ 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;
+ }
}
}
break;
case GL_EXP:
- for (i=0;i<n;i++) {
- GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv;
- GLfloat eyez = d / (c+ndcz);
- if (eyez < 0.0) eyez = -eyez;
- fogcoord[i] = FloatToFixed(exp( -ctx->Fog.Density * eyez ));
- }
+ 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 );
+ }
+ }
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 = negDensitySquared * eyez * eyez;
+ 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;
+ /* XXX this underflow check may be needed for other systems*/
+ if (tmp < FLT_MIN_10_EXP)
+ tmp = FLT_MIN_10_EXP;
#endif
- fogcoord[i] = FloatToFixed(exp( tmp ));
+ fogFact[i] = (GLfloat) exp( tmp );
+ }
}
}
break;
default:
- gl_problem(ctx, "Bad fog mode in _mesa_win_fog_coords_from_z");
+ _mesa_problem(ctx, "Bad fog mode in compute_fog_factors_from_z");
return;
}
}
-/*
- * 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
+
+/**
+ * Apply fog to a span of RGBA pixels.
+ * 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,
- GLuint n, const GLdepth z[], GLchan rgba[][4] )
+_mesa_fog_rgba_span( const GLcontext *ctx, struct sw_span *span )
{
- GLfixed fog[MAX_WIDTH];
- _mesa_win_fog_coords_from_z( ctx, n, z, fog );
- _mesa_fog_rgba_pixels( ctx, n, fog, rgba );
+ 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->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->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 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
+/**
+ * As above, but color index mode.
*/
void
-_mesa_depth_fog_ci_pixels( const GLcontext *ctx,
- GLuint n, const GLdepth z[], GLuint index[] )
+_mesa_fog_ci_span( const GLcontext *ctx, struct sw_span *span )
{
- GLfixed fog[MAX_WIDTH];
- _mesa_win_fog_coords_from_z( ctx, n, z, fog );
- _mesa_fog_ci_pixels( ctx, n, fog, index );
-}
+ const SWcontext *swrast = SWRAST_CONTEXT(ctx);
+ const GLuint n = span->end;
+ GLuint *index = span->color.index;
+
+ ASSERT(ctx->Fog.Enabled);
+ 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;
+ }
+ 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;
+ }
+ }
+}
projects / mesa.git / blobdiff