-/* $Id: s_fog.c,v 1.7 2001/01/03 15:59:30 brianp Exp $ */
-
/*
* Mesa 3-D graphics library
- * Version: 3.5
- *
- * Copyright (C) 1999-2000 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"),
* 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
- * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
- * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
*/
-#include "glheader.h"
-#include "colormac.h"
-#include "context.h"
-#include "macros.h"
-#include "mmath.h"
+#include "c99_math.h"
+#include "main/errors.h"
+#include "main/glheader.h"
+#include "main/macros.h"
#include "s_context.h"
#include "s_fog.h"
-#include "s_pb.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
+/**
+ * Used to convert current raster distance to a fog factor in [0,1].
*/
-void
-_mesa_fog_rgba_pixels( const GLcontext *ctx,
- GLuint n,
- const GLfixed fog[],
- GLchan rgba[][4] )
+GLfloat
+_swrast_z_to_fogfactor(struct gl_context *ctx, GLfloat z)
{
- GLuint i;
- GLchan rFog, gFog, bFog;
+ GLfloat d, f;
- 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 CHAN_TYPE == GL_FLOAT
- for (i = 0; i < n; i++) {
- const GLfixed cf = CLAMP(fog[i], 0, FIXED_ONE);
- const GLfloat f = FixedToFloat(cf);
- const GLfloat g = 1.0F - f;
- rgba[i][RCOMP] = f * rgba[i][RCOMP] + g * rFog;
- rgba[i][GCOMP] = f * rgba[i][GCOMP] + g * gFog;
- rgba[i][BCOMP] = f * rgba[i][BCOMP] + g * bFog;
- }
-#else
- for (i = 0; i < n; i++) {
- const GLfixed f = CLAMP(fog[i], 0, FIXED_ONE);
- const 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;
+ 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 = expf(-d * z);
+ f = CLAMP(f, 0.0F, 1.0F);
+ return f;
+ case GL_EXP2:
+ d = ctx->Fog.Density;
+ f = expf(-(d * d * z * z));
+ f = CLAMP(f, 0.0F, 1.0F);
+ return f;
+ default:
+ _mesa_problem(ctx, "Bad fog mode in _swrast_z_to_fogfactor");
+ return 0.0;
}
-#endif
}
+#define LINEAR_FOG(f, coord) f = (fogEnd - coord) * fogScale
-/*
- * 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
- */
-void
-_mesa_fog_ci_pixels( const GLcontext *ctx,
- GLuint n, const GLfixed fog[], GLuint index[] )
-{
- GLuint idx = ctx->Fog.Index;
- GLuint i;
+#define EXP_FOG(f, coord) f = expf(density * coord)
- for (i=0;i<n;i++) {
- GLfloat f = FixedToFloat(CLAMP(fog[i], 0, FIXED_ONE));
- index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * idx);
- }
-}
+#define EXP2_FOG(f, coord) \
+do { \
+ GLfloat tmp = negDensitySquared * coord * coord; \
+ if (tmp < FLT_MIN_10_EXP) \
+ tmp = FLT_MIN_10_EXP; \
+ f = expf(tmp); \
+ } while(0)
+#define BLEND_FOG(f, coord) f = coord
-/*
- * Calculate fog coords 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?
+
+
+/**
+ * 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, FOG_FUNC) \
+if (span->arrayAttribs & VARYING_BIT_FOGC) { \
+ GLuint i; \
+ for (i = 0; i < span->end; i++) { \
+ const GLfloat fogCoord = span->array->attribs[VARYING_SLOT_FOGC][i][0]; \
+ const GLfloat c = fabsf(fogCoord); \
+ GLfloat f, oneMinusF; \
+ FOG_FUNC(f, c); \
+ 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); \
+ } \
+} \
+else { \
+ const GLfloat fogStep = span->attrStepX[VARYING_SLOT_FOGC][0]; \
+ GLfloat fogCoord = span->attrStart[VARYING_SLOT_FOGC][0]; \
+ const GLfloat wStep = span->attrStepX[VARYING_SLOT_POS][3]; \
+ GLfloat w = span->attrStart[VARYING_SLOT_POS][3]; \
+ GLuint i; \
+ for (i = 0; i < span->end; i++) { \
+ const GLfloat c = fabsf(fogCoord) / w; \
+ GLfloat f, oneMinusF; \
+ FOG_FUNC(f, c); \
+ 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; \
+ } \
+}
+
+/**
+ * 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!
*/
void
-_mesa_win_fog_coords_from_z( const GLcontext *ctx,
- GLuint n,
- const GLdepth z[],
- GLfixed fogcoord[] )
+_swrast_fog_rgba_span( const struct gl_context *ctx, SWspan *span )
{
- const GLboolean ortho = (ctx->ProjectionMatrix.m[15] != 0.0F);
- const GLfloat p10 = ctx->ProjectionMatrix.m[10];
- const GLfloat p14 = ctx->ProjectionMatrix.m[14];
- const GLfloat tz = ctx->Viewport._WindowMap.m[MAT_TZ];
- const GLfloat szInv = 1.0F / ctx->Viewport._WindowMap.m[MAT_SZ];
- GLuint i;
+ const SWcontext *swrast = CONST_SWRAST_CONTEXT(ctx);
+ GLfloat rFog, gFog, bFog;
- /*
- * 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.
- */
+ assert(swrast->_FogEnabled);
+ assert(span->arrayMask & SPAN_RGBA);
- switch (ctx->Fog.Mode) {
+ /* compute (scaled) fog color */
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ rFog = ctx->Fog.Color[RCOMP] * 255.0F;
+ gFog = ctx->Fog.Color[GCOMP] * 255.0F;
+ bFog = ctx->Fog.Color[BCOMP] * 255.0F;
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ rFog = ctx->Fog.Color[RCOMP] * 65535.0F;
+ gFog = ctx->Fog.Color[GCOMP] * 65535.0F;
+ bFog = ctx->Fog.Color[BCOMP] * 65535.0F;
+ }
+ else {
+ rFog = ctx->Fog.Color[RCOMP];
+ gFog = ctx->Fog.Color[GCOMP];
+ bFog = ctx->Fog.Color[BCOMP];
+ }
+
+ 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 = 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;
- fogcoord[i] = FloatToFixed((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);
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->rgba8;
+ FOG_LOOP(GLubyte, LINEAR_FOG);
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->rgba16;
+ FOG_LOOP(GLushort, LINEAR_FOG);
}
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;
- fogcoord[i] = FloatToFixed((fogEnd - eyez) * fogScale);
- }
+ GLfloat (*rgba)[4] = span->array->attribs[VARYING_SLOT_COL0];
+ assert(span->array->ChanType == GL_FLOAT);
+ FOG_LOOP(GLfloat, LINEAR_FOG);
}
}
- 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;
- fogcoord[i] = FloatToFixed(exp( -ctx->Fog.Density * eyez ));
+ {
+ const GLfloat density = -ctx->Fog.Density;
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->rgba8;
+ FOG_LOOP(GLubyte, EXP_FOG);
}
- }
- 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;
- fogcoord[i] = FloatToFixed(exp( -ctx->Fog.Density * eyez ));
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->rgba16;
+ FOG_LOOP(GLushort, EXP_FOG);
+ }
+ else {
+ GLfloat (*rgba)[4] = span->array->attribs[VARYING_SLOT_COL0];
+ assert(span->array->ChanType == GL_FLOAT);
+ FOG_LOOP(GLfloat, EXP_FOG);
}
}
- 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
- fogcoord[i] = FloatToFixed(exp( tmp ));
- }
+ const GLfloat negDensitySquared = -ctx->Fog.Density * ctx->Fog.Density;
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->rgba8;
+ FOG_LOOP(GLubyte, EXP2_FOG);
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->rgba16;
+ FOG_LOOP(GLushort, EXP2_FOG);
}
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
- fogcoord[i] = FloatToFixed(exp( tmp ));
- }
+ GLfloat (*rgba)[4] = span->array->attribs[VARYING_SLOT_COL0];
+ assert(span->array->ChanType == GL_FLOAT);
+ FOG_LOOP(GLfloat, EXP2_FOG);
}
}
- break;
+ break;
+
default:
- gl_problem(ctx, "Bad fog mode in _mesa_win_fog_coords_from_z");
+ _mesa_problem(ctx, "Bad fog mode in _swrast_fog_rgba_span");
return;
+ }
+ }
+ else {
+ /* The span's fog start/step/array values are blend factors in [0,1].
+ * They were previously computed per-vertex.
+ */
+ if (span->array->ChanType == GL_UNSIGNED_BYTE) {
+ GLubyte (*rgba)[4] = span->array->rgba8;
+ FOG_LOOP(GLubyte, BLEND_FOG);
+ }
+ else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
+ GLushort (*rgba)[4] = span->array->rgba16;
+ FOG_LOOP(GLushort, BLEND_FOG);
+ }
+ else {
+ GLfloat (*rgba)[4] = span->array->attribs[VARYING_SLOT_COL0];
+ assert(span->array->ChanType == GL_FLOAT);
+ FOG_LOOP(GLfloat, BLEND_FOG);
+ }
}
}
-
-
-/*
- * 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
- */
-void
-_mesa_depth_fog_rgba_pixels( const GLcontext *ctx,
- GLuint n, const GLdepth z[], GLchan rgba[][4] )
-{
- GLfixed fog[PB_SIZE];
- ASSERT(n <= PB_SIZE);
- _mesa_win_fog_coords_from_z( ctx, n, z, fog );
- _mesa_fog_rgba_pixels( ctx, n, fog, rgba );
-}
-
-
-/*
- * 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
- */
-void
-_mesa_depth_fog_ci_pixels( const GLcontext *ctx,
- GLuint n, const GLdepth z[], GLuint index[] )
-{
- GLfixed fog[PB_SIZE];
- ASSERT(n <= PB_SIZE);
- _mesa_win_fog_coords_from_z( ctx, n, z, fog );
- _mesa_fog_ci_pixels( ctx, n, fog, index );
-}
-
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