| /************************************************************************** |
| |
| Copyright 2000 Silicon Integrated Systems Corp, Inc., HsinChu, Taiwan. |
| Copyright 2003 Eric Anholt |
| 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 |
| on the rights to use, copy, modify, merge, publish, distribute, sub |
| license, 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 (including the next |
| paragraph) 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 NON-INFRINGEMENT. IN NO EVENT SHALL |
| ERIC ANHOLT OR SILICON INTEGRATED SYSTEMS CORP 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. |
| |
| **************************************************************************/ |
| /* $XFree86: xc/lib/GL/mesa/src/drv/sis/sis_fog.c,v 1.3 2000/09/26 15:56:48 tsi Exp $ */ |
| |
| /* |
| * Authors: |
| * Sung-Ching Lin <sclin@sis.com.tw> |
| * Eric Anholt <anholt@FreeBSD.org> |
| */ |
| |
| #include "sis_context.h" |
| #include "sis_state.h" |
| #include "swrast/swrast.h" |
| |
| #include "macros.h" |
| |
| static GLint convertFtToFogFt( GLfloat dwInValue ); |
| static GLint doFPtoFixedNoRound( GLfloat dwInValue, int nFraction ); |
| |
| void |
| sisDDFogfv( GLcontext *ctx, GLenum pname, const GLfloat *params ) |
| { |
| sisContextPtr smesa = SIS_CONTEXT(ctx); |
| __GLSiSHardware *prev = &smesa->prev; |
| __GLSiSHardware *current = &smesa->current; |
| |
| float fArg; |
| GLint fogColor; |
| |
| switch (pname) |
| { |
| case GL_FOG_COORDINATE_SOURCE_EXT: |
| current->hwFog &= ~MASK_FogMode; |
| switch (ctx->Fog.FogCoordinateSource) |
| { |
| case GL_FOG_COORDINATE_EXT: |
| current->hwFog &= ~MASK_FogZLookup; |
| break; |
| case GL_FRAGMENT_DEPTH_EXT: |
| current->hwFog |= MASK_FogZLookup; |
| break; |
| } |
| if (current->hwFog != prev->hwFog) { |
| prev->hwFog = current->hwFog; |
| smesa->GlobalFlag |= GFLAG_FOGSETTING; |
| } |
| break; |
| case GL_FOG_MODE: |
| current->hwFog &= ~MASK_FogMode; |
| switch (ctx->Fog.Mode) |
| { |
| case GL_LINEAR: |
| current->hwFog |= FOGMODE_LINEAR; |
| break; |
| case GL_EXP: |
| current->hwFog |= FOGMODE_EXP; |
| break; |
| case GL_EXP2: |
| current->hwFog |= FOGMODE_EXP2; |
| break; |
| } |
| if (current->hwFog != prev->hwFog) { |
| prev->hwFog = current->hwFog; |
| smesa->GlobalFlag |= GFLAG_FOGSETTING; |
| } |
| break; |
| case GL_FOG_DENSITY: |
| current->hwFogDensity = convertFtToFogFt( ctx->Fog.Density ); |
| if (current->hwFogDensity != prev->hwFogDensity) { |
| prev->hwFogDensity = current->hwFogDensity; |
| smesa->GlobalFlag |= GFLAG_FOGSETTING; |
| } |
| break; |
| case GL_FOG_START: |
| case GL_FOG_END: |
| fArg = 1.0 / (ctx->Fog.End - ctx->Fog.Start); |
| current->hwFogInverse = doFPtoFixedNoRound( fArg, 10 ); |
| if (pname == GL_FOG_END) |
| { |
| if (smesa->Chipset == PCI_CHIP_SIS300) |
| current->hwFogFar = doFPtoFixedNoRound( ctx->Fog.End, 10 ); |
| else |
| current->hwFogFar = doFPtoFixedNoRound( ctx->Fog.End, 6 ); |
| } |
| if (current->hwFogFar != prev->hwFogFar || |
| current->hwFogInverse != prev->hwFogInverse) |
| { |
| prev->hwFogFar = current->hwFogFar; |
| prev->hwFogInverse = current->hwFogInverse; |
| smesa->GlobalFlag |= GFLAG_FOGSETTING; |
| } |
| break; |
| case GL_FOG_INDEX: |
| /* TODO */ |
| break; |
| case GL_FOG_COLOR: |
| fogColor = FLOAT_TO_UBYTE( ctx->Fog.Color[0] ) << 16; |
| fogColor |= FLOAT_TO_UBYTE( ctx->Fog.Color[1] ) << 8; |
| fogColor |= FLOAT_TO_UBYTE( ctx->Fog.Color[2] ); |
| current->hwFog &= 0xff000000; |
| current->hwFog |= fogColor; |
| if (current->hwFog != prev->hwFog) { |
| prev->hwFog = current->hwFog; |
| smesa->GlobalFlag |= GFLAG_FOGSETTING; |
| } |
| break; |
| } |
| } |
| |
| static GLint |
| doFPtoFixedNoRound( GLfloat dwInValue, int nFraction ) |
| { |
| GLint dwMantissa; |
| int nTemp; |
| union { int i; float f; } u; |
| GLint val; |
| |
| u.f = dwInValue; |
| val = u.i; |
| |
| if (val == 0) |
| return 0; |
| nTemp = (int) (val & 0x7F800000) >> 23; |
| nTemp = nTemp - 127 + nFraction - 23; |
| dwMantissa = (val & 0x007FFFFF) | 0x00800000; |
| |
| if (nTemp < -25) |
| return 0; |
| if (nTemp > 0) |
| dwMantissa <<= nTemp; |
| else { |
| nTemp = -nTemp; |
| dwMantissa >>= nTemp; |
| } |
| if (val & 0x80000000) |
| dwMantissa = ~dwMantissa + 1; |
| return dwMantissa; |
| } |
| |
| /* s[8].23->s[7].10 */ |
| static GLint |
| convertFtToFogFt( GLfloat dwInValue ) |
| { |
| GLint dwMantissa, dwExp; |
| GLint dwRet; |
| union { int i; float f; } u; |
| GLint val; |
| |
| u.f = dwInValue; |
| val = u.i; |
| |
| if (val == 0) |
| return 0; |
| |
| /* ----- Standard float Format: s[8].23 ----- |
| * ----- = (-1)^S * 2^(E - 127) * (1 + M / 2^23) ----- |
| * ----- = (-1)^S * 2^((E-63) - 64) * (1 + (M/2^13) / 2^10) ----- |
| * ----- Density float Format: s[7].10 ----- |
| * ----- New Exponential = E - 63 ----- |
| * ----- New Mantissa = M / 2^13 ----- |
| * ----- ----- |
| */ |
| |
| dwExp = (val & 0x7F800000) >> 23; |
| dwExp -= 63; |
| |
| if (dwExp < 0) |
| return 0; |
| |
| if (dwExp <= 0x7F) |
| dwMantissa = (val & 0x007FFFFF) >> (23 - 10); |
| else { |
| /* ----- To Return +Max(or -Max) ----- */ |
| dwExp = 0x7F; |
| dwMantissa = 0x3FF; |
| } |
| |
| dwRet = (val & 0x80000000) >> (31 - 17); /* Shift Sign Bit */ |
| |
| dwRet |= (dwExp << 10) | dwMantissa; |
| |
| return dwRet; |
| } |
