/* $Id: fog.c,v 1.8 2000/03/07 17:40:34 brianp Exp $ */ /* * Mesa 3-D graphics library * Version: 3.3 * * Copyright (C) 1999-2000 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. */ #ifdef PC_HEADER #include "all.h" #else #include "glheader.h" #include "context.h" #include "fog.h" #include "macros.h" #include "mmath.h" #include "types.h" #include "xform.h" #endif void _mesa_Fogf(GLenum pname, GLfloat param) { _mesa_Fogfv(pname, ¶m); } void _mesa_Fogi(GLenum pname, GLint param ) { GLfloat fparam = (GLfloat) param; _mesa_Fogfv(pname, &fparam); } void _mesa_Fogiv(GLenum pname, const GLint *params ) { GLfloat p[4]; switch (pname) { case GL_FOG_MODE: case GL_FOG_DENSITY: case GL_FOG_START: case GL_FOG_END: case GL_FOG_INDEX: p[0] = (GLfloat) *params; break; case GL_FOG_COLOR: p[0] = INT_TO_FLOAT( params[0] ); p[1] = INT_TO_FLOAT( params[1] ); p[2] = INT_TO_FLOAT( params[2] ); p[3] = INT_TO_FLOAT( params[3] ); break; default: /* Error will be caught later in _mesa_Fogfv */ ; } _mesa_Fogfv(pname, p); } void _mesa_Fogfv( GLenum pname, const GLfloat *params ) { GET_CURRENT_CONTEXT(ctx); GLenum m; switch (pname) { case GL_FOG_MODE: m = (GLenum) (GLint) *params; if (m==GL_LINEAR || m==GL_EXP || m==GL_EXP2) { ctx->Fog.Mode = m; } else { gl_error( ctx, GL_INVALID_ENUM, "glFog" ); return; } break; case GL_FOG_DENSITY: if (*params<0.0) { gl_error( ctx, GL_INVALID_VALUE, "glFog" ); return; } else { ctx->Fog.Density = *params; } break; case GL_FOG_START: ctx->Fog.Start = *params; break; case GL_FOG_END: ctx->Fog.End = *params; break; case GL_FOG_INDEX: ctx->Fog.Index = *params; break; case GL_FOG_COLOR: ctx->Fog.Color[0] = params[0]; ctx->Fog.Color[1] = params[1]; ctx->Fog.Color[2] = params[2]; ctx->Fog.Color[3] = params[3]; break; default: gl_error( ctx, GL_INVALID_ENUM, "glFog" ); return; } if (ctx->Driver.Fogfv) { (*ctx->Driver.Fogfv)( ctx, pname, params ); } ctx->NewState |= NEW_FOG; } typedef void (*fog_func)( struct vertex_buffer *VB, GLuint side, GLubyte flag ); typedef void (*fog_coord_func)( struct vertex_buffer *VB, const GLvector4f *from, GLubyte flag ); static fog_func fog_ci_tab[2]; static fog_func fog_rgba_tab[2]; static fog_coord_func make_fog_coord_tab[2]; /* * Compute the fogged color for an array of vertices. * Input: n - number of vertices * v - array of vertices * color - the original vertex colors * Output: color - the fogged colors * */ #define TAG(x) x##_raw #define CULLCHECK #define IDX 0 #include "fog_tmp.h" #define TAG(x) x##_masked #define CULLCHECK if (cullmask[i]&flag) #define IDX 1 #include "fog_tmp.h" void _mesa_init_fog( void ) { init_fog_tab_masked(); init_fog_tab_raw(); } /* * Compute fog for the vertices in the vertex buffer. */ void _mesa_fog_vertices( struct vertex_buffer *VB ) { GLcontext *ctx = VB->ctx; GLuint i = VB->CullMode & 1; if (ctx->Visual->RGBAflag) { /* Fog RGB colors */ if (ctx->TriangleCaps & DD_TRI_LIGHT_TWOSIDE) { fog_rgba_tab[i]( VB, 0, VERT_FACE_FRONT ); fog_rgba_tab[i]( VB, 1, VERT_FACE_REAR ); } else { fog_rgba_tab[i]( VB, 0, VERT_FACE_FRONT|VERT_FACE_REAR ); } } else { /* Fog color indexes */ if (ctx->TriangleCaps & DD_TRI_LIGHT_TWOSIDE) { fog_ci_tab[i]( VB, 0, VERT_FACE_FRONT ); fog_ci_tab[i]( VB, 1, VERT_FACE_REAR ); } else { fog_ci_tab[i]( VB, 0, VERT_FACE_FRONT|VERT_FACE_REAR ); } } } static void check_fog_coords( GLcontext *ctx, struct gl_pipeline_stage *d ) { d->type = 0; if (ctx->FogMode==FOG_FRAGMENT) { d->type = PIPE_IMMEDIATE|PIPE_PRECALC; d->inputs = VERT_OBJ_ANY; d->outputs = VERT_FOG_COORD; } } static void gl_make_fog_coords( struct vertex_buffer *VB ) { GLcontext *ctx = VB->ctx; /* If full eye coords weren't required, just calculate the eye Z * values. */ if (!ctx->NeedEyeCoords) { GLfloat *m = ctx->ModelView.m; GLfloat plane[4]; plane[0] = m[2]; plane[1] = m[6]; plane[2] = m[10]; plane[3] = m[14]; gl_dotprod_tab[0][VB->ObjPtr->size](&VB->Eye, 2, /* fill z coordinates */ VB->ObjPtr, plane, 0 ); make_fog_coord_tab[0]( VB, &VB->Eye, 0 ); } else { make_fog_coord_tab[0]( VB, VB->EyePtr, 0 ); } } /* Drivers that want fog coordinates in VB->Spec[0] alpha, can substitute this * stage for the default PIPE_OP_FOG pipeline stage. */ struct gl_pipeline_stage gl_fog_coord_stage = { "build fog coordinates", PIPE_OP_FOG, PIPE_PRECALC|PIPE_IMMEDIATE, 0, NEW_FOG, NEW_LIGHTING|NEW_RASTER_OPS|NEW_FOG|NEW_MODELVIEW, 0, 0, 0, 0, 0, check_fog_coords, gl_make_fog_coords }; /* * 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_fog_rgba_pixels( const GLcontext *ctx, GLuint n, const GLdepth z[], GLubyte rgba[][4] ) { GLfloat c = ctx->ProjectionMatrix.m[10]; GLfloat d = ctx->ProjectionMatrix.m[14]; GLuint i; GLfloat rFog = ctx->Fog.Color[0] * 255.0F; GLfloat gFog = ctx->Fog.Color[1] * 255.0F; GLfloat bFog = ctx->Fog.Color[2] * 255.0F; GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ]; GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ]; switch (ctx->Fog.Mode) { case GL_LINEAR: { GLfloat fogEnd = ctx->Fog.End; GLfloat fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start); for (i=0;i<n;i++) { GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv; GLfloat eyez = -d / (c+ndcz); GLfloat f, g; if (eyez < 0.0) eyez = -eyez; f = (fogEnd - eyez) * fogScale; f = CLAMP( f, 0.0F, 1.0F ); g = 1.0F - f; rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog); rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog); rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog); } } break; case GL_EXP: for (i=0;i<n;i++) { GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv; GLfloat eyez = d / (c+ndcz); GLfloat f, g; if (eyez < 0.0) eyez = -eyez; f = exp( -ctx->Fog.Density * eyez ); g = 1.0F - f; rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog); rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog); rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog); } 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 f, g; GLfloat tmp = negDensitySquared * eyez * eyez; #ifdef __alpha__ /* XXX this underflow check may be needed for other systems */ if (tmp < FLT_MIN_10_EXP) f = exp( FLT_MIN_10_EXP ); else #endif f = exp( tmp ); g = 1.0F - f; rgba[i][RCOMP] = (GLint) (f * rgba[i][RCOMP] + g * rFog); rgba[i][GCOMP] = (GLint) (f * rgba[i][GCOMP] + g * gFog); rgba[i][BCOMP] = (GLint) (f * rgba[i][BCOMP] + g * bFog); } } break; default: gl_problem(ctx, "Bad fog mode in _mesa_fog_rgba_pixels"); return; } } /* * 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 GLdepth z[], GLuint index[] ) { GLfloat c = ctx->ProjectionMatrix.m[10]; GLfloat d = ctx->ProjectionMatrix.m[14]; GLuint i; GLfloat tz = ctx->Viewport.WindowMap.m[MAT_TZ]; GLfloat szInv = 1.0F / ctx->Viewport.WindowMap.m[MAT_SZ]; switch (ctx->Fog.Mode) { case GL_LINEAR: { GLfloat fogEnd = ctx->Fog.End; GLfloat fogScale = 1.0F / (ctx->Fog.End - ctx->Fog.Start); for (i=0;i<n;i++) { GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv; GLfloat eyez = -d / (c+ndcz); GLfloat f; if (eyez < 0.0) eyez = -eyez; f = (fogEnd - eyez) * fogScale; f = CLAMP( f, 0.0F, 1.0F ); index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index); } } break; case GL_EXP: for (i=0;i<n;i++) { GLfloat ndcz = ((GLfloat) z[i] - tz) * szInv; GLfloat eyez = -d / (c+ndcz); GLfloat f; if (eyez < 0.0) eyez = -eyez; f = exp( -ctx->Fog.Density * eyez ); f = CLAMP( f, 0.0F, 1.0F ); index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index); } 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, f; if (eyez < 0.0) eyez = -eyez; tmp = negDensitySquared * eyez * eyez; #ifdef __alpha__ /* XXX this underflow check may be needed for other systems */ if (tmp < FLT_MIN_10_EXP) f = exp( FLT_MIN_10_EXP ); else #endif f = exp( tmp ); f = CLAMP( f, 0.0F, 1.0F ); index[i] = (GLuint) ((GLfloat) index[i] + (1.0F-f) * ctx->Fog.Index); } } break; default: gl_problem(ctx, "Bad fog mode in _mesa_fog_ci_pixels"); return; } }