148 lines
4.3 KiB
C
148 lines
4.3 KiB
C
/******************************Module*Header*******************************\
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* Module Name: zippy.c
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*
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* Triangle drawing fast path.
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*
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* 28-Oct-1994 mikeke Created
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*
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* Copyright (c) 1994 Microsoft Corporation
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\**************************************************************************/
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/*
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** Copyright 1991, 1992, 1993, Silicon Graphics, Inc.
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** All Rights Reserved.
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**
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** This is UNPUBLISHED PROPRIETARY SOURCE CODE of Silicon Graphics, Inc.;
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** the contents of this file may not be disclosed to third parties, copied or
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** duplicated in any form, in whole or in part, without the prior written
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** permission of Silicon Graphics, Inc.
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**
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** RESTRICTED RIGHTS LEGEND:
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** Use, duplication or disclosure by the Government is subject to restrictions
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** as set forth in subdivision (c)(1)(ii) of the Rights in Technical Data
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** and Computer Software clause at DFARS 252.227-7013, and/or in similar or
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** successor clauses in the FAR, DOD or NASA FAR Supplement. Unpublished -
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** rights reserved under the Copyright Laws of the United States.
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*/
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#include "precomp.h"
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#pragma hdrstop
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/**************************************************************************\
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*
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* Subtriangle functions
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*
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\**************************************************************************/
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#define TEXTURE 1
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#define SHADE 1
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#define ZBUFFER 1
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#include "zippy.h"
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#undef ZBUFFER
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#define ZBUFFER 0
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#include "zippy.h"
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#undef SHADE
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#define SHADE 0
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#include "zippy.h"
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#undef TEXTURE
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#define TEXTURE 0
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#undef SHADE
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#define SHADE 1
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#include "zippy.h"
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#undef SHADE
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#define SHADE 0
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#include "zippy.h"
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/**************************************************************************\
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*
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* Flat subtriangle function
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*
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\**************************************************************************/
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void FASTCALL
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__ZippyFSTCI8Flat
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(__GLcontext *gc, GLint iyBottom, GLint iyTop)
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{
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__GLGENcontext *gengc = (__GLGENcontext *)gc;
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GENACCEL *pGenAccel = (GENACCEL *)(gengc->pPrivateArea);
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int scansize;
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ULONG color1;
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//
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// this function assumes all this stuff
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//
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ASSERTOPENGL((gc->drawBuffer->buf.flags & DIB_FORMAT) != 0,
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"Zippy target must have DIB format\n");
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ASSERTOPENGL((gc->drawBuffer->buf.flags & NO_CLIP) != 0,
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"Zippy doesn't support per-pixel clipping\n");
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ASSERTOPENGL(gc->state.raster.drawBuffer != GL_FRONT_AND_BACK,
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"Zippy only handles one draw buffer\n");
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ASSERTOPENGL(gc->transform.reasonableViewport,
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"Zippy requires reasonableViewport\n");
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ASSERTOPENGL(gc->transform.clipY0 <= iyBottom,
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"Zippy requires unclipped area\n");
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ASSERTOPENGL(iyTop <= gc->transform.clipY1,
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"Zippy requires unclipped area\n");
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//
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// calculate the color
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//
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color1 = gengc->pajTranslateVector[
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((pGenAccel->spanValue.r + 0x0800) >> 16) & 0xff
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];
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//
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// render the spans
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//
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scansize = gc->polygon.shader.cfb->buf.outerWidth;
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gc->polygon.shader.frag.x = gc->polygon.shader.ixLeft;
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for (gc->polygon.shader.frag.y = iyBottom;
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gc->polygon.shader.frag.y != iyTop;
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gc->polygon.shader.frag.y++
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) {
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GLint spanWidth = gc->polygon.shader.ixRight - gc->polygon.shader.frag.x;
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if (spanWidth > 0) {
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RtlFillMemory(
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pGenAccel->pPix + gengc->gc.polygon.shader.frag.x,
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spanWidth,
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color1);
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}
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pGenAccel->pPix += scansize;
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gc->polygon.shader.ixRightFrac += gc->polygon.shader.dxRightFrac;
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if (gc->polygon.shader.ixRightFrac < 0) {
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/*
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* Carry/Borrow'd. Use large step
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*/
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gc->polygon.shader.ixRight += gc->polygon.shader.dxRightBig;
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gc->polygon.shader.ixRightFrac &= ~0x80000000;
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} else {
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gc->polygon.shader.ixRight += gc->polygon.shader.dxRightLittle;
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}
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gc->polygon.shader.ixLeftFrac += gc->polygon.shader.dxLeftFrac;
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if (gc->polygon.shader.ixLeftFrac < 0) {
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/*
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* Carry/Borrow'd. Use large step
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*/
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gc->polygon.shader.frag.x += gc->polygon.shader.dxLeftBig;
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gc->polygon.shader.ixLeftFrac &= ~0x80000000;
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} else {
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/*
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* Use small step
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*/
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gc->polygon.shader.frag.x += gc->polygon.shader.dxLeftLittle;
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}
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}
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gc->polygon.shader.ixLeft = gc->polygon.shader.frag.x;
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}
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