Git conversion: Make reactos the root directory, move rosapps, rostests, wallpapers into modules, and delete rossubsys.

dll/opengl/mesa/tnl/t_vb_fog.c

@@ -0,0 +1,265 @@
+/*
+ * Mesa 3-D graphics library
+ * Version:  6.5
+ *
+ * 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.
+ *
+ * Authors:
+ *    Keith Whitwell <keith@tungstengraphics.com>
+ */
+
+#include <precomp.h>
+
+struct fog_stage_data {
+   GLvector4f fogcoord;		/* has actual storage allocated */
+};
+
+#define FOG_STAGE_DATA(stage) ((struct fog_stage_data *)stage->privatePtr)
+
+#define FOG_EXP_TABLE_SIZE 256
+#define FOG_MAX (10.0)
+#define EXP_FOG_MAX .0006595
+#define FOG_INCR (FOG_MAX/FOG_EXP_TABLE_SIZE)
+static GLfloat exp_table[FOG_EXP_TABLE_SIZE];
+static GLfloat inited = 0;
+
+#if 1
+#define NEG_EXP( result, narg )						\
+do {									\
+   GLfloat f = (GLfloat) (narg * (1.0/FOG_INCR));			\
+   GLint k = (GLint) f;							\
+   if (k > FOG_EXP_TABLE_SIZE-2) 					\
+      result = (GLfloat) EXP_FOG_MAX;					\
+   else									\
+      result = exp_table[k] + (f-k)*(exp_table[k+1]-exp_table[k]);	\
+} while (0)
+#else
+#define NEG_EXP( result, narg )					\
+do {								\
+   result = exp(-narg);						\
+} while (0)
+#endif
+
+
+/**
+ * Initialize the exp_table[] lookup table for approximating exp().
+ */
+static void
+init_static_data( void )
+{
+   GLfloat f = 0.0F;
+   GLint i = 0;
+   for ( ; i < FOG_EXP_TABLE_SIZE ; i++, f += FOG_INCR) {
+      exp_table[i] = EXPF(-f);
+   }
+   inited = 1;
+}
+
+
+/**
+ * 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 that fogcoords may be negative, if eye z is source absolute
+ * value must be taken earlier.
+ * Fog blend factors are in the range [0,1].
+ */
+static void
+compute_fog_blend_factors(struct gl_context *ctx, GLvector4f *out, const GLvector4f *in)
+{
+   GLfloat end  = ctx->Fog.End;
+   GLfloat *v = in->start;
+   GLuint stride = in->stride;
+   GLuint n = in->count;
+   GLfloat (*data)[4] = out->data;
+   GLfloat d;
+   GLuint i;
+
+   out->count = in->count;
+
+   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);
+      for ( i = 0 ; i < n ; i++, STRIDE_F(v, stride)) {
+         const GLfloat z = *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)) {
+         const GLfloat z = *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)) {
+         const GLfloat z = *v;
+         NEG_EXP( data[i][0], d * z * z );
+      }
+      break;
+   default:
+      _mesa_problem(ctx, "Bad fog mode in make_fog_coord");
+      return;
+   }
+}
+
+
+static GLboolean
+run_fog_stage(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
+{
+   TNLcontext *tnl = TNL_CONTEXT(ctx);
+   struct vertex_buffer *VB = &tnl->vb;
+   struct fog_stage_data *store = FOG_STAGE_DATA(stage);
+   GLvector4f *input;
+
+
+   if (!ctx->Fog.Enabled)
+      return GL_TRUE;
+
+   if (ctx->Fog.FogCoordinateSource == GL_FRAGMENT_DEPTH_EXT) {
+      GLuint i;
+      GLfloat *coord;
+      /* Fog is computed from vertex or fragment Z values */
+      /* source = VB->AttribPtr[_TNL_ATTRIB_POS] or VB->EyePtr coords */
+      /* dest = VB->AttribPtr[_TNL_ATTRIB_FOG] = fog stage private storage */
+      VB->AttribPtr[_TNL_ATTRIB_FOG] = &store->fogcoord;
+
+      if (!ctx->_NeedEyeCoords) {
+         /* compute fog coords from object coords */
+	 const GLfloat *m = ctx->ModelviewMatrixStack.Top->m;
+	 GLfloat plane[4];
+
+	 /* Use this to store calculated eye z values:
+	  */
+	 input = &store->fogcoord;
+
+	 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.
+	  */
+	 _mesa_dotprod_tab[VB->AttribPtr[_TNL_ATTRIB_POS]->size]
+	    ( (GLfloat *) input->data,
+	      4 * sizeof(GLfloat),
+	      VB->AttribPtr[_TNL_ATTRIB_POS], plane );
+
+	 input->count = VB->AttribPtr[_TNL_ATTRIB_POS]->count;
+
+	 /* make sure coords are really positive
+	    NOTE should avoid going through array twice */
+	 coord = input->start;
+	 for (i = 0; i < input->count; i++) {
+	    *coord = FABSF(*coord);
+	    STRIDE_F(coord, input->stride);
+	 }
+      }
+      else {
+         /* fog coordinates = eye Z coordinates - need to copy for ABS */
+	 input = &store->fogcoord;
+
+	 if (VB->EyePtr->size < 2)
+	    _mesa_vector4f_clean_elem( VB->EyePtr, VB->Count, 2 );
+
+	 input->stride = 4 * sizeof(GLfloat);
+	 input->count = VB->EyePtr->count;
+	 coord = VB->EyePtr->start;
+	 for (i = 0 ; i < VB->EyePtr->count; i++) {
+	    input->data[i][0] = FABSF(coord[2]);
+	    STRIDE_F(coord, VB->EyePtr->stride);
+	 }
+      }
+   }
+   else {
+      /* use glFogCoord() coordinates */
+      input = VB->AttribPtr[_TNL_ATTRIB_FOG];  /* source data */
+
+      /* input->count may be one if glFogCoord was only called once
+       * before glBegin.  But we need to compute fog for all vertices.
+       */
+      input->count = VB->AttribPtr[_TNL_ATTRIB_POS]->count;
+
+      VB->AttribPtr[_TNL_ATTRIB_FOG] = &store->fogcoord;  /* dest data */
+   }
+
+   if (tnl->_DoVertexFog) {
+      /* compute blend factors from fog coordinates */
+      compute_fog_blend_factors( ctx, VB->AttribPtr[_TNL_ATTRIB_FOG], input );
+   }
+   else {
+      /* results = incoming fog coords (compute fog per-fragment later) */
+      VB->AttribPtr[_TNL_ATTRIB_FOG] = input;
+   }
+
+   return GL_TRUE;
+}
+
+
+
+/* Called the first time stage->run() is invoked.
+ */
+static GLboolean
+alloc_fog_data(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
+{
+   TNLcontext *tnl = TNL_CONTEXT(ctx);
+   struct fog_stage_data *store;
+   stage->privatePtr = MALLOC(sizeof(*store));
+   store = FOG_STAGE_DATA(stage);
+   if (!store)
+      return GL_FALSE;
+
+   _mesa_vector4f_alloc( &store->fogcoord, 0, tnl->vb.Size, 32 );
+
+   if (!inited)
+      init_static_data();
+
+   return GL_TRUE;
+}
+
+
+static void
+free_fog_data(struct tnl_pipeline_stage *stage)
+{
+   struct fog_stage_data *store = FOG_STAGE_DATA(stage);
+   if (store) {
+      _mesa_vector4f_free( &store->fogcoord );
+      FREE( store );
+      stage->privatePtr = NULL;
+   }
+}
+
+
+const struct tnl_pipeline_stage _tnl_fog_coordinate_stage =
+{
+   "build fog coordinates",	/* name */
+   NULL,			/* private_data */
+   alloc_fog_data,		/* dtr */
+   free_fog_data,		/* dtr */
+   NULL,		/* check */
+   run_fog_stage		/* run -- initially set to init. */
+};