-/* $Id: t_vb_fog.c,v 1.17 2002/01/22 14:35:17 brianp Exp $ */
-
/*
* Mesa 3-D graphics library
- * Version: 4.1
+ * Version: 6.1
*
- * Copyright (C) 1999-2002 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"),
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* Authors:
- * Keith Whitwell <keithw@valinux.com>
+ * Keith Whitwell <keith@tungstengraphics.com>
*/
#include "colormac.h"
#include "context.h"
#include "macros.h"
-#include "mem.h"
-#include "mmath.h"
+#include "imports.h"
#include "mtypes.h"
#include "math/m_xform.h"
#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;
}
-static void make_win_fog_coords( GLcontext *ctx, GLvector4f *out,
- const GLvector4f *in )
+/**
+ * Compute per-vertex fog blend factors from fog coordinates by
+ * evaluating the GL_LINEAR, GL_EXP or GL_EXP2 fog function.
+ * Fog coordinates are distances from the eye (typically between the
+ * near and far clip plane distances).
+ * Note the fog (eye Z) coords may be negative so we use ABS(z) below.
+ * Fog blend factors are in the range [0,1].
+ */
+static void
+compute_fog_blend_factors(GLcontext *ctx, GLvector4f *out, const GLvector4f *in)
{
GLfloat end = ctx->Fog.End;
GLfloat *v = in->start;
else
d = 1.0F / (ctx->Fog.End - ctx->Fog.Start);
for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) {
- GLfloat f = (end - ABSF(*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 * ABSF(*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 = FABSF(*v);
NEG_EXP( data[i][0], d * z * z );
}
break;
}
-static GLboolean run_fog_stage( GLcontext *ctx,
- struct gl_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;
- if (stage->changed_inputs == 0)
+ if (!ctx->Fog.Enabled || ctx->VertexProgram._Enabled)
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];
*/
input = &store->fogcoord;
- plane[0] = m[2];
- plane[1] = m[6];
- plane[2] = m[10];
- plane[3] = m[14];
-
+ /* NOTE: negate plane here so we get positive fog coords! */
+ plane[0] = -m[2];
+ plane[1] = -m[6];
+ plane[2] = -m[10];
+ plane[3] = -m[14];
/* Full eye coords weren't required, just calculate the
* eye Z values.
*/
input->count = VB->ObjPtr->count;
}
else {
+ /* fog coordinates = eye Z coordinates (use ABS later) */
input = &store->input;
if (VB->EyePtr->size < 2)
}
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 */
}
- make_win_fog_coords( 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 gl_pipeline_stage *stage )
-{
- stage->active = ctx->Fog.Enabled && !ctx->VertexProgram.Enabled;
-
- if (ctx->Fog.FogCoordinateSource == GL_FRAGMENT_DEPTH_EXT)
- stage->inputs = VERT_BIT_EYE;
- else
- stage->inputs = VERT_BIT_FOG;
-}
-
/* Called the first time stage->run() is invoked.
*/
-static GLboolean alloc_fog_data( GLcontext *ctx,
- struct gl_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;
return GL_FALSE;
_mesa_vector4f_alloc( &store->fogcoord, 0, tnl->vb.Size, 32 );
- _mesa_vector4f_init( &store->input, 0, 0 );
+ _mesa_vector4f_init( &store->input, 0, NULL );
if (!inited)
init_static_data();
- /* Now run the stage.
- */
- stage->run = run_fog_stage;
- return stage->run( ctx, stage );
+ return GL_TRUE;
}
-static void free_fog_data( struct gl_pipeline_stage *stage )
+static void
+free_fog_data(struct tnl_pipeline_stage *stage)
{
struct fog_stage_data *store = FOG_STAGE_DATA(stage);
if (store) {
}
-const struct gl_pipeline_stage _tnl_fog_coordinate_stage =
+const struct tnl_pipeline_stage _tnl_fog_coordinate_stage =
{
"build fog coordinates", /* name */
- _NEW_FOG, /* check_state */
- _NEW_FOG, /* run_state */
- GL_FALSE, /* active? */
- 0, /* inputs */
- VERT_BIT_FOG, /* outputs */
- 0, /* changed_inputs */
NULL, /* private_data */
+ alloc_fog_data, /* dtr */
free_fog_data, /* dtr */
- check_fog_stage, /* check */
- alloc_fog_data /* run -- initially set to init. */
+ NULL, /* check */
+ run_fog_stage /* run -- initially set to init. */
};
projects / mesa.git / blobdiff