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/*
* Mesa 3-D graphics library
*
* Copyright (C) 1999-2007 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
* THE AUTHORS OR COPYRIGHT HOLDERS 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_ATTRIBS - if defined, interpolate attribs (texcoords, varying, etc)
*
* 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.
*
* Similarly, for direct depth buffer access, this type is used for depth
* buffer addressing:
* DEPTH_TYPE - either GLushort or GLuint
*
* Optionally, one may provide one-time setup code
* SETUP_CODE - code which is to be executed once per line
*
* To actually "plot" each pixel the PLOT macro 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.
*
*/
static void
NAME( struct gl_context *ctx, const SWvertex *vert0, const SWvertex *vert1 )
{
const SWcontext *swrast = SWRAST_CONTEXT(ctx);
SWspan span;
GLuint interpFlags = 0;
GLint x0 = (GLint) vert0->attrib[VARYING_SLOT_POS][0];
GLint x1 = (GLint) vert1->attrib[VARYING_SLOT_POS][0];
GLint y0 = (GLint) vert0->attrib[VARYING_SLOT_POS][1];
GLint y1 = (GLint) vert1->attrib[VARYING_SLOT_POS][1];
GLint dx, dy;
GLint numPixels;
GLint xstep, ystep;
#if defined(DEPTH_TYPE)
const GLint depthBits = ctx->DrawBuffer->Visual.depthBits;
const GLint fixedToDepthShift = depthBits <= 16 ? FIXED_SHIFT : 0;
struct gl_renderbuffer *zrb = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
#define FixedToDepth(F) ((F) >> fixedToDepthShift)
GLint zPtrXstep, zPtrYstep;
DEPTH_TYPE *zPtr;
#elif defined(INTERP_Z)
const GLint depthBits = ctx->DrawBuffer->Visual.depthBits;
#endif
#ifdef PIXEL_ADDRESS
PIXEL_TYPE *pixelPtr;
GLint pixelXstep, pixelYstep;
#endif
#ifdef SETUP_CODE
SETUP_CODE
#endif
(void) swrast;
/* Cull primitives with malformed coordinates.
*/
{
GLfloat tmp = vert0->attrib[VARYING_SLOT_POS][0] + vert0->attrib[VARYING_SLOT_POS][1]
+ vert1->attrib[VARYING_SLOT_POS][0] + vert1->attrib[VARYING_SLOT_POS][1];
if (IS_INF_OR_NAN(tmp))
return;
}
/*
printf("%s():\n", __func__);
printf(" (%f, %f, %f) -> (%f, %f, %f)\n",
vert0->attrib[VARYING_SLOT_POS][0],
vert0->attrib[VARYING_SLOT_POS][1],
vert0->attrib[VARYING_SLOT_POS][2],
vert1->attrib[VARYING_SLOT_POS][0],
vert1->attrib[VARYING_SLOT_POS][1],
vert1->attrib[VARYING_SLOT_POS][2]);
printf(" (%d, %d, %d) -> (%d, %d, %d)\n",
vert0->color[0], vert0->color[1], vert0->color[2],
vert1->color[0], vert1->color[1], vert1->color[2]);
printf(" (%d, %d, %d) -> (%d, %d, %d)\n",
vert0->specular[0], vert0->specular[1], vert0->specular[2],
vert1->specular[0], vert1->specular[1], vert1->specular[2]);
*/
/*
* 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.
*/
#ifdef CLIP_HACK
{
GLint w = ctx->DrawBuffer->Width;
GLint h = ctx->DrawBuffer->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;
/*
printf("%s %d,%d %g %g %g %g %g %g %g %g\n", __func__, dx, dy,
vert0->attrib[VARYING_SLOT_COL1][0],
vert0->attrib[VARYING_SLOT_COL1][1],
vert0->attrib[VARYING_SLOT_COL1][2],
vert0->attrib[VARYING_SLOT_COL1][3],
vert1->attrib[VARYING_SLOT_COL1][0],
vert1->attrib[VARYING_SLOT_COL1][1],
vert1->attrib[VARYING_SLOT_COL1][2],
vert1->attrib[VARYING_SLOT_COL1][3]);
*/
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) _swrast_pixel_address(zrb, x0, y0);
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE *) PIXEL_ADDRESS(x0,y0);
#endif
if (dx<0) {
dx = -dx; /* make positive */
xstep = -1;
#ifdef DEPTH_TYPE
zPtrXstep = -((GLint)sizeof(DEPTH_TYPE));
#endif
#ifdef PIXEL_ADDRESS
pixelXstep = -((GLint)sizeof(PIXEL_TYPE));
#endif
}
else {
xstep = 1;
#ifdef DEPTH_TYPE
zPtrXstep = ((GLint)sizeof(DEPTH_TYPE));
#endif
#ifdef PIXEL_ADDRESS
pixelXstep = ((GLint)sizeof(PIXEL_TYPE));
#endif
}
if (dy<0) {
dy = -dy; /* make positive */
ystep = -1;
#ifdef DEPTH_TYPE
zPtrYstep = -((GLint) (ctx->DrawBuffer->Width * sizeof(DEPTH_TYPE)));
#endif
#ifdef PIXEL_ADDRESS
pixelYstep = BYTES_PER_ROW;
#endif
}
else {
ystep = 1;
#ifdef DEPTH_TYPE
zPtrYstep = (GLint) (ctx->DrawBuffer->Width * sizeof(DEPTH_TYPE));
#endif
#ifdef PIXEL_ADDRESS
pixelYstep = -(BYTES_PER_ROW);
#endif
}
assert(dx >= 0);
assert(dy >= 0);
numPixels = MAX2(dx, dy);
/*
* Span setup: compute start and step values for all interpolated values.
*/
interpFlags |= SPAN_RGBA;
if (ctx->Light.ShadeModel == GL_SMOOTH) {
span.red = ChanToFixed(vert0->color[0]);
span.green = ChanToFixed(vert0->color[1]);
span.blue = ChanToFixed(vert0->color[2]);
span.alpha = ChanToFixed(vert0->color[3]);
span.redStep = (ChanToFixed(vert1->color[0]) - span.red ) / numPixels;
span.greenStep = (ChanToFixed(vert1->color[1]) - span.green) / numPixels;
span.blueStep = (ChanToFixed(vert1->color[2]) - span.blue ) / numPixels;
span.alphaStep = (ChanToFixed(vert1->color[3]) - span.alpha) / numPixels;
}
else {
span.red = ChanToFixed(vert1->color[0]);
span.green = ChanToFixed(vert1->color[1]);
span.blue = ChanToFixed(vert1->color[2]);
span.alpha = ChanToFixed(vert1->color[3]);
span.redStep = 0;
span.greenStep = 0;
span.blueStep = 0;
span.alphaStep = 0;
}
#if defined(INTERP_Z) || defined(DEPTH_TYPE)
interpFlags |= SPAN_Z;
{
if (depthBits <= 16) {
span.z = FloatToFixed(vert0->attrib[VARYING_SLOT_POS][2]) + FIXED_HALF;
span.zStep = FloatToFixed( vert1->attrib[VARYING_SLOT_POS][2]
- vert0->attrib[VARYING_SLOT_POS][2]) / numPixels;
}
else {
/* don't use fixed point */
span.z = (GLuint) vert0->attrib[VARYING_SLOT_POS][2];
span.zStep = (GLint) (( vert1->attrib[VARYING_SLOT_POS][2]
- vert0->attrib[VARYING_SLOT_POS][2]) / numPixels);
}
}
#endif
#if defined(INTERP_ATTRIBS)
{
const GLfloat invLen = 1.0F / numPixels;
const GLfloat invw0 = vert0->attrib[VARYING_SLOT_POS][3];
const GLfloat invw1 = vert1->attrib[VARYING_SLOT_POS][3];
span.attrStart[VARYING_SLOT_POS][3] = invw0;
span.attrStepX[VARYING_SLOT_POS][3] = (invw1 - invw0) * invLen;
span.attrStepY[VARYING_SLOT_POS][3] = 0.0;
ATTRIB_LOOP_BEGIN
if (swrast->_InterpMode[attr] == GL_FLAT) {
COPY_4V(span.attrStart[attr], vert1->attrib[attr]);
ASSIGN_4V(span.attrStepX[attr], 0.0, 0.0, 0.0, 0.0);
}
else {
GLuint c;
for (c = 0; c < 4; c++) {
float da;
span.attrStart[attr][c] = invw0 * vert0->attrib[attr][c];
da = (invw1 * vert1->attrib[attr][c]) - span.attrStart[attr][c];
span.attrStepX[attr][c] = da * invLen;
}
}
ASSIGN_4V(span.attrStepY[attr], 0.0, 0.0, 0.0, 0.0);
ATTRIB_LOOP_END
}
#endif
INIT_SPAN(span, GL_LINE);
span.end = numPixels;
span.interpMask = interpFlags;
span.arrayMask = SPAN_XY;
span.facing = swrast->PointLineFacing;
/*
* Draw
*/
if (dx > dy) {
/*** X-major line ***/
GLint i;
GLint errorInc = dy+dy;
GLint error = errorInc-dx;
GLint errorDec = error-dx;
for (i = 0; i < dx; i++) {
#ifdef DEPTH_TYPE
GLuint Z = FixedToDepth(span.z);
#endif
#ifdef PLOT
PLOT( x0, y0 );
#else
span.array->x[i] = x0;
span.array->y[i] = y0;
#endif
x0 += xstep;
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrXstep);
span.z += span.zStep;
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep);
#endif
if (error < 0) {
error += errorInc;
}
else {
error += errorDec;
y0 += ystep;
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) ((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;
for (i=0;i<dy;i++) {
#ifdef DEPTH_TYPE
GLuint Z = FixedToDepth(span.z);
#endif
#ifdef PLOT
PLOT( x0, y0 );
#else
span.array->x[i] = x0;
span.array->y[i] = y0;
#endif
y0 += ystep;
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrYstep);
span.z += span.zStep;
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelYstep);
#endif
if (error<0) {
error += errorInc;
}
else {
error += errorDec;
x0 += xstep;
#ifdef DEPTH_TYPE
zPtr = (DEPTH_TYPE *) ((GLubyte*) zPtr + zPtrXstep);
#endif
#ifdef PIXEL_ADDRESS
pixelPtr = (PIXEL_TYPE*) ((GLubyte*) pixelPtr + pixelXstep);
#endif
}
}
}
#ifdef RENDER_SPAN
RENDER_SPAN( span );
#endif
(void)span;
}
#undef NAME
#undef INTERP_Z
#undef INTERP_ATTRIBS
#undef PIXEL_ADDRESS
#undef PIXEL_TYPE
#undef DEPTH_TYPE
#undef BYTES_PER_ROW
#undef SETUP_CODE
#undef PLOT
#undef CLIP_HACK
#undef FixedToDepth
#undef RENDER_SPAN
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