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linetemp.h
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2000-01-07
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/* $Id: linetemp.h,v 1.1.1.1.2.1 1999/11/18 23:47:14 brianp Exp $ */
/*
* Mesa 3-D graphics library
* Version: 3.1
*
* Copyright (C) 1999 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.
*/
/*
* Line Rasterizer Template
*
* This file is #include'd to generate custom line rasterizers.
*
* The following macros may be defined to indicate what auxillary information
* must be interplated along the line:
* INTERP_Z - if defined, interpolate Z values
* INTERP_RGB - if defined, interpolate RGB values
* INTERP_SPEC - if defined, interpolate specular RGB values
* INTERP_ALPHA - if defined, interpolate Alpha values
* INTERP_INDEX - if defined, interpolate color index values
* INTERP_ST - if defined, interpolate integer ST texcoords
* (fast, simple 2-D texture mapping)
* INTERP_STUV0 - if defined, interpolate unit 0 STU texcoords with
* perspective correction
* NOTE: OpenGL STRQ = Mesa STUV (R was taken for red)
* INTERP_STUV1 - if defined, interpolate unit 1 STU texcoords
*
* When one can directly address pixels in the color buffer the following
* macros can be defined and used to directly compute pixel addresses during
* rasterization (see pixelPtr):
* PIXEL_TYPE - the datatype of a pixel (GLubyte, GLushort, GLuint)
* BYTES_PER_ROW - number of bytes per row in the color buffer
* PIXEL_ADDRESS(X,Y) - returns the address of pixel at (X,Y) where
* Y==0 at bottom of screen and increases upward.
*
* Optionally, one may provide one-time setup code
* SETUP_CODE - code which is to be executed once per line
*
* To enable line stippling define STIPPLE = 1
* To enable wide lines define WIDE = 1
*
* To actually "plot" each pixel either the PLOT macro or
* (XMAJOR_PLOT and YMAJOR_PLOT macros) must be defined...
* PLOT(X,Y) - code to plot a pixel. Example:
* if (Z < *zPtr) {
* *zPtr = Z;
* color = pack_rgb( FixedToInt(r0), FixedToInt(g0),
* FixedToInt(b0) );
* put_pixel( X, Y, color );
* }
*
* This code was designed for the origin to be in the lower-left corner.
*
*/
/*void line( GLcontext *ctx, GLuint vert0, GLuint vert1, GLuint pvert )*/
{
const struct vertex_buffer *VB = ctx->VB;
GLint x0 = (GLint) VB->Win.data[vert0][0];
GLint x1 = (GLint) VB->Win.data[vert1][0];
GLint y0 = (GLint) VB->Win.data[vert0][1];
GLint y1 = (GLint) VB->Win.data[vert1][1];
GLint dx, dy;
#if INTERP_XY
GLint xstep, ystep;
#endif
#if INTERP_Z
GLint z0, z1, dz, zPtrXstep, zPtrYstep;
GLdepth *zPtr;
#endif
#if INTERP_RGB
GLfixed r0 = IntToFixed(VB->ColorPtr->data[vert0][0]);
GLfixed dr = IntToFixed(VB->ColorPtr->data[vert1][0]) - r0;
GLfixed g0 = IntToFixed(VB->ColorPtr->data[vert0][1]);
GLfixed dg = IntToFixed(VB->ColorPtr->data[vert1][1]) - g0;
GLfixed b0 = IntToFixed(VB->ColorPtr->data[vert0][2]);
GLfixed db = IntToFixed(VB->ColorPtr->data[vert1][2]) - b0;
#endif
#if INTERP_SPEC
GLfixed sr0 = VB->Specular ? IntToFixed(VB->Specular[vert0][0]) : 0;
GLfixed dsr = VB->Specular ? IntToFixed(VB->Specular[vert1][0]) - sr0 : 0;
GLfixed sg0 = VB->Specular ? IntToFixed(VB->Specular[vert0][1]) : 0;
GLfixed dsg = VB->Specular ? IntToFixed(VB->Specular[vert1][1]) - sg0 : 0;
GLfixed sb0 = VB->Specular ? IntToFixed(VB->Specular[vert0][2]) : 0;
GLfixed dsb = VB->Specular ? IntToFixed(VB->Specular[vert1][2]) - sb0 : 0;
#endif
#if INTERP_ALPHA
GLfixed a0 = IntToFixed(VB->ColorPtr->data[vert0][3]);
GLfixed da = IntToFixed(VB->ColorPtr->data[vert1][3]) - a0;
#endif
#if INTERP_INDEX
GLint i0 = VB->IndexPtr->data[vert0] << 8;
GLint di = (GLint) (VB->IndexPtr->data[vert1] << 8)-i0;
#endif
#if INTERP_ST
GLfixed s0 = FloatToFixed(VB->TexCoord[vert0][0] * S_SCALE);
GLfixed ds = FloatToFixed(VB->TexCoord[vert1][0] * S_SCALE) - s0;
GLfixed t0 = FloatToFixed(VB->TexCoord[vert0][1] * T_SCALE);
GLfixed dt = FloatToFixed(VB->TexCoord[vert1][1] * T_SCALE) - t0;
#endif
#if INTERP_STUV0 || INTERP_STUV1
GLfloat invw0 = VB->Win.data[vert0][3];
GLfloat invw1 = VB->Win.data[vert1][3];
#endif
#if INTERP_STUV0
/* h denotes hyperbolic */
GLfloat hs0 = invw0 * VB->TexCoordPtr[0]->data[vert0][0];
GLfloat dhs = invw1 * VB->TexCoordPtr[0]->data[vert1][0] - hs0;
GLfloat ht0 = invw0 * VB->TexCoordPtr[0]->data[vert0][1];
GLfloat dht = invw1 * VB->TexCoordPtr[0]->data[vert1][1] - ht0;
GLfloat hu0 = 0, dhu = 0;
GLfloat hv0 = invw0, dhv = invw1 - invw0;
#endif
#if INTERP_STUV1
GLfloat hs01 = invw0 * VB->TexCoordPtr[1]->data[vert0][0];
GLfloat dhs1 = invw1 * VB->TexCoordPtr[1]->data[vert1][0] - hs01;
GLfloat ht01 = invw0 * VB->TexCoordPtr[1]->data[vert0][1];
GLfloat dht1 = invw1 * VB->TexCoordPtr[1]->data[vert1][1] - ht01;
GLfloat hu01 = 0, dhu1 = 0;
GLfloat hv01 = invw0, dhv1 = invw1 - invw0;
#endif
#ifdef PIXEL_ADDRESS
PIXEL_TYPE *pixelPtr;
GLint pixelXstep, pixelYstep;
#endif
#if WIDE
/* for wide lines, draw all X in [x+min, x+max] or Y in [y+min, y+max] */
GLint width, min, max;
width = (GLint) CLAMP( ctx->Line.Width, MIN_LINE_WIDTH, MAX_LINE_WIDTH );
min = (width-1) / -2;
max = min + width - 1;
#endif
#if INTERP_STUV0
if (VB->TexCoordPtr[0]->size > 2) {
hu0 = invw0 * VB->TexCoordPtr[0]->data[vert0][2];
dhu = invw1 * VB->TexCoordPtr[0]->data[vert1][2] - hu0;
if (VB->TexCoordPtr[0]->size > 3) {
hv0 = invw0 * VB->TexCoordPtr[0]->data[vert0][3];
dhv = invw1 * VB->TexCoordPtr[0]->data[vert1][3] - hv0;
}
}
#endif
#if INTERP_STUV1
if (VB->TexCoordPtr[1]->size > 2) {
hu01 = invw0 * VB->TexCoordPtr[1]->data[vert0][2];
dhu1 = invw1 * VB->TexCoordPtr[1]->data[vert1][2] - hu01;
if (VB->TexCoordPtr[1]->size > 3) {
hv01 = invw0 * VB->TexCoordPtr[1]->data[vert0][3];
dhv1 = invw1 * VB->TexCoordPtr[1]->data[vert1][3] - hv01;
}
}
#endif
/*
* Despite being clipped to the view volume, the line's window coordinates
* may just lie outside the window bounds. That is, if the legal window
* coordinates are [0,W-1][0,H-1], it's possible for x==W and/or y==H.
* This quick and dirty code nudges the endpoints inside the window if
* necessary.
*/
#if CLIP_HACK
{
GLint w = ctx->Buffer->Width;
GLint h = ctx->Buffer->Height;
if ((x0==w) | (x1==w)) {
if ((x0==w) & (x1==w))
return;
x0 -= x0==w;
x1 -= x1==w;
}
if ((y0==h) | (y1==h)) {
if ((y0==h) & (y1==h))
return;
y0 -= y0==h;
y1 -= y1==h;
}
}
#endif
dx = x1 - x0;
dy = y1 - y0;
if (dx==0 && dy==0) {
return;
}
/*
* Setup
*/
#ifdef SETUP_CODE
SETUP_CODE
#endif
#if INTERP_Z
zPtr = Z_ADDRESS(ctx,x0,y0);
# if DEPTH_BITS==16
z0 = FloatToFixed(VB->Win.data[vert0][2]);
z1 = FloatToFixed(VB->Win.data[vert1][2]);
# else
z0 = (int) VB->Win.data[vert0][2];
z1 = (int) VB->Win.data[vert1][2];
# endif
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE *) PIXEL_ADDRESS(x0,y0);
#endif
if (dx<0) {
dx = -dx; /* make positive */
#if INTERP_XY
xstep = -1;
#endif
#ifdef INTERP_Z
zPtrXstep = -((GLint)sizeof(GLdepth));
#endif
#ifdef PIXEL_ADDRESS
pixelXstep = -((GLint)sizeof(PIXEL_TYPE));
#endif
}
else {
#if INTERP_XY
xstep = 1;
#endif
#if INTERP_Z
zPtrXstep = ((GLint)sizeof(GLdepth));
#endif
#ifdef PIXEL_ADDRESS
pixelXstep = ((GLint)sizeof(PIXEL_TYPE));
#endif
}
if (dy<0) {
dy = -dy; /* make positive */
#if INTERP_XY
ystep = -1;
#endif
#if INTERP_Z
zPtrYstep = -ctx->Buffer->Width * ((GLint)sizeof(GLdepth));
#endif
#ifdef PIXEL_ADDRESS
pixelYstep = BYTES_PER_ROW;
#endif
}
else {
#if INTERP_XY
ystep = 1;
#endif
#if INTERP_Z
zPtrYstep = ctx->Buffer->Width * ((GLint)sizeof(GLdepth));
#endif
#ifdef PIXEL_ADDRESS
pixelYstep = -(BYTES_PER_ROW);
#endif
}
/*
* Draw
*/
if (dx>dy) {
/*** X-major line ***/
GLint i;
GLint errorInc = dy+dy;
GLint error = errorInc-dx;
GLint errorDec = error-dx;
#if INTERP_Z
dz = (z1-z0) / dx;
#endif
#if INTERP_RGB
dr /= dx; /* convert from whole line delta to per-pixel delta */
dg /= dx;
db /= dx;
#endif
#if INTERP_SPEC
dsr /= dx; /* convert from whole line delta to per-pixel delta */
dsg /= dx;
dsb /= dx;
#endif
#if INTERP_ALPHA
da /= dx;
#endif
#if INTERP_INDEX
di /= dx;
#endif
#if INTERP_ST
ds /= dx;
dt /= dx;
#endif
#if INTERP_STUV0
{
GLfloat invDx = 1.0F / (GLfloat) dx;
dhs *= invDx;
dht *= invDx;
dhu *= invDx;
dhv *= invDx;
}
#endif
#if INTERP_STUV1
{
GLfloat invDx = 1.0F / (GLfloat) dx;
dhs1 *= invDx;
dht1 *= invDx;
dhu1 *= invDx;
dhv1 *= invDx;
}
#endif
for (i=0;i<dx;i++) {
#if STIPPLE
GLushort m;
m = 1 << ((ctx->StippleCounter/ctx->Line.StippleFactor) & 0xf);
if (ctx->Line.StipplePattern & m) {
#endif
#if INTERP_Z
# if DEPTH_BITS==16
GLdepth Z = FixedToInt(z0);
# else
GLdepth Z = z0;
# endif
#endif
#if INTERP_INDEX
GLint I = i0 >> 8;
#endif
#if INTERP_STUV0
GLfloat invQ = 1.0F / hv0;
GLfloat s = hs0 * invQ;
GLfloat t = ht0 * invQ;
GLfloat u = hu0 * invQ;
#endif
#if INTERP_STUV1
GLfloat invQ1 = 1.0F / hv01;
GLfloat s1 = hs01 * invQ1;
GLfloat t1 = ht01 * invQ1;
GLfloat u1 = hu01 * invQ1;
#endif
#if WIDE
GLint yy;
GLint ymin = y0 + min;
GLint ymax = y0 + max;
for (yy=ymin;yy<=ymax;yy++) {
PLOT( x0, yy );
}
#else
# ifdef XMAJOR_PLOT
XMAJOR_PLOT( x0, y0 );
# else
PLOT( x0, y0 );
# endif
#endif /*WIDE*/
#if STIPPLE
}
ctx->StippleCounter++;
#endif
#if INTERP_XY
x0 += xstep;
#endif
#if INTERP_Z
zPtr = (GLdepth *) ((GLubyte*) zPtr + zPtrXstep);
z0 += dz;
#endif
#if INTERP_RGB
r0 += dr;
g0 += dg;
b0 += db;
#endif
#if INTERP_SPEC
sr0 += dsr;
sg0 += dsg;
sb0 += dsb;
#endif
#if INTERP_ALPHA
a0 += da;
#endif
#if INTERP_INDEX
i0 += di;
#endif
#if INTERP_ST
s0 += ds;
t0 += dt;
#endif
#if INTERP_STUV0
hs0 += dhs;
ht0 += dht;
hu0 += dhu;
hv0 += dhv;
#endif
#if INTERP_STUV1
hs01 += dhs1;
ht01 += dht1;
hu01 += dhu1;
hv01 += dhv1;
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep);
#endif
if (error<0) {
error += errorInc;
}
else {
error += errorDec;
#if INTERP_XY
y0 += ystep;
#endif
#if INTERP_Z
zPtr = (GLdepth *) ((GLubyte*) zPtr + zPtrYstep);
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelYstep);
#endif
}
}
}
else {
/*** Y-major line ***/
GLint i;
GLint errorInc = dx+dx;
GLint error = errorInc-dy;
GLint errorDec = error-dy;
#if INTERP_Z
dz = (z1-z0) / dy;
#endif
#if INTERP_RGB
dr /= dy; /* convert from whole line delta to per-pixel delta */
dg /= dy;
db /= dy;
#endif
#if INTERP_SPEC
dsr /= dy; /* convert from whole line delta to per-pixel delta */
dsg /= dy;
dsb /= dy;
#endif
#if INTERP_ALPHA
da /= dy;
#endif
#if INTERP_INDEX
di /= dy;
#endif
#if INTERP_ST
ds /= dy;
dt /= dy;
#endif
#if INTERP_STUV0
{
GLfloat invDy = 1.0F / (GLfloat) dy;
dhs *= invDy;
dht *= invDy;
dhu *= invDy;
dhv *= invDy;
}
#endif
#if INTERP_STUV1
{
GLfloat invDy = 1.0F / (GLfloat) dy;
dhs1 *= invDy;
dht1 *= invDy;
dhu1 *= invDy;
dhv1 *= invDy;
}
#endif
for (i=0;i<dy;i++) {
#if STIPPLE
GLushort m;
m = 1 << ((ctx->StippleCounter/ctx->Line.StippleFactor) & 0xf);
if (ctx->Line.StipplePattern & m) {
#endif
#if INTERP_Z
# if DEPTH_BITS==16
GLdepth Z = FixedToInt(z0);
# else
GLdepth Z = z0;
# endif
#endif
#if INTERP_INDEX
GLint I = i0 >> 8;
#endif
#if INTERP_STUV0
GLfloat invQ = 1.0F / hv0;
GLfloat s = hs0 * invQ;
GLfloat t = ht0 * invQ;
GLfloat u = hu0 * invQ;
#endif
#if INTERP_STUV1
GLfloat invQ1 = 1.0F / hv01;
GLfloat s1 = hs01 * invQ1;
GLfloat t1 = ht01 * invQ1;
GLfloat u1 = hu01 * invQ1;
#endif
#if WIDE
GLint xx;
GLint xmin = x0 + min;
GLint xmax = x0 + max;
for (xx=xmin;xx<=xmax;xx++) {
PLOT( xx, y0 );
}
#else
# ifdef YMAJOR_PLOT
YMAJOR_PLOT( x0, y0 );
# else
PLOT( x0, y0 );
# endif
#endif /*WIDE*/
#if STIPPLE
}
ctx->StippleCounter++;
#endif
#if INTERP_XY
y0 += ystep;
#endif
#if INTERP_Z
zPtr = (GLdepth *) ((GLubyte*) zPtr + zPtrYstep);
z0 += dz;
#endif
#if INTERP_RGB
r0 += dr;
g0 += dg;
b0 += db;
#endif
#if INTERP_SPEC
sr0 += dsr;
sg0 += dsg;
sb0 += dsb;
#endif
#if INTERP_ALPHA
a0 += da;
#endif
#if INTERP_INDEX
i0 += di;
#endif
#if INTERP_ST
s0 += ds;
t0 += dt;
#endif
#if INTERP_STUV0
hs0 += dhs;
ht0 += dht;
hu0 += dhu;
hv0 += dhv;
#endif
#if INTERP_STUV1
hs01 += dhs1;
ht01 += dht1;
hu01 += dhu1;
hv01 += dhv1;
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelYstep);
#endif
if (error<0) {
error += errorInc;
}
else {
error += errorDec;
#if INTERP_XY
x0 += xstep;
#endif
#if INTERP_Z
zPtr = (GLdepth *) ((GLubyte*) zPtr + zPtrXstep);
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep);
#endif
}
}
}
}
#undef INTERP_XY
#undef INTERP_Z
#undef INTERP_RGB
#undef INTERP_SPEC
#undef INTERP_ALPHA
#undef INTERP_STUV0
#undef INTERP_STUV1
#undef INTERP_INDEX
#undef PIXEL_ADDRESS
#undef PIXEL_TYPE
#undef BYTES_PER_ROW
#undef SETUP_CODE
#undef PLOT
#undef XMAJOR_PLOT
#undef YMAJOR_PLOT
#undef CLIP_HACK
#undef STIPPLE
#undef WIDE