/*
* Mesa 3-D graphics library
*
* Copyright (C) 1999-2008 Brian Paul All Rights Reserved.
* Copyright (C) 2009 VMware, Inc. 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.
*/
/**
* \file swrast/s_span.c
* \brief Span processing functions used by all rasterization functions.
* This is where all the per-fragment tests are performed
* \author Brian Paul
*/
#include "c99_math.h"
#include "main/glheader.h"
#include "main/format_pack.h"
#include "main/format_unpack.h"
#include "main/macros.h"
#include "main/imports.h"
#include "main/image.h"
#include "main/samplerobj.h"
#include "main/teximage.h"
#include "s_atifragshader.h"
#include "s_alpha.h"
#include "s_blend.h"
#include "s_context.h"
#include "s_depth.h"
#include "s_fog.h"
#include "s_logic.h"
#include "s_masking.h"
#include "s_fragprog.h"
#include "s_span.h"
#include "s_stencil.h"
#include "s_texcombine.h"
#include <stdbool.h>
/**
* Set default fragment attributes for the span using the
* current raster values. Used prior to glDraw/CopyPixels
* and glBitmap.
*/
void
_swrast_span_default_attribs(struct gl_context *ctx, SWspan *span)
{
GLchan r, g, b, a;
/* Z*/
{
const GLfloat depthMax = ctx->DrawBuffer->_DepthMaxF;
if (ctx->DrawBuffer->Visual.depthBits <= 16)
span->z = FloatToFixed(ctx->Current.RasterPos[2] * depthMax + 0.5F);
else {
GLfloat tmpf = ctx->Current.RasterPos[2] * depthMax;
tmpf = MIN2(tmpf, depthMax);
span->z = (GLint)tmpf;
}
span->zStep = 0;
span->interpMask |= SPAN_Z;
}
/* W (for perspective correction) */
span->attrStart[VARYING_SLOT_POS][3] = 1.0;
span->attrStepX[VARYING_SLOT_POS][3] = 0.0;
span->attrStepY[VARYING_SLOT_POS][3] = 0.0;
/* primary color, or color index */
UNCLAMPED_FLOAT_TO_CHAN(r, ctx->Current.RasterColor[0]);
UNCLAMPED_FLOAT_TO_CHAN(g, ctx->Current.RasterColor[1]);
UNCLAMPED_FLOAT_TO_CHAN(b, ctx->Current.RasterColor[2]);
UNCLAMPED_FLOAT_TO_CHAN(a, ctx->Current.RasterColor[3]);
#if CHAN_TYPE == GL_FLOAT
span->red = r;
span->green = g;
span->blue = b;
span->alpha = a;
#else
span->red = IntToFixed(r);
span->green = IntToFixed(g);
span->blue = IntToFixed(b);
span->alpha = IntToFixed(a);
#endif
span->redStep = 0;
span->greenStep = 0;
span->blueStep = 0;
span->alphaStep = 0;
span->interpMask |= SPAN_RGBA;
COPY_4V(span->attrStart[VARYING_SLOT_COL0], ctx->Current.RasterColor);
ASSIGN_4V(span->attrStepX[VARYING_SLOT_COL0], 0.0, 0.0, 0.0, 0.0);
ASSIGN_4V(span->attrStepY[VARYING_SLOT_COL0], 0.0, 0.0, 0.0, 0.0);
/* Secondary color */
if (ctx->Light.Enabled || ctx->Fog.ColorSumEnabled)
{
COPY_4V(span->attrStart[VARYING_SLOT_COL1], ctx->Current.RasterSecondaryColor);
ASSIGN_4V(span->attrStepX[VARYING_SLOT_COL1], 0.0, 0.0, 0.0, 0.0);
ASSIGN_4V(span->attrStepY[VARYING_SLOT_COL1], 0.0, 0.0, 0.0, 0.0);
}
/* fog */
{
const SWcontext *swrast = SWRAST_CONTEXT(ctx);
GLfloat fogVal; /* a coord or a blend factor */
if (swrast->_PreferPixelFog) {
/* fog blend factors will be computed from fog coordinates per pixel */
fogVal = ctx->Current.RasterDistance;
}
else {
/* fog blend factor should be computed from fogcoord now */
fogVal = _swrast_z_to_fogfactor(ctx, ctx->Current.RasterDistance);
}
span->attrStart[VARYING_SLOT_FOGC][0] = fogVal;
span->attrStepX[VARYING_SLOT_FOGC][0] = 0.0;
span->attrStepY[VARYING_SLOT_FOGC][0] = 0.0;
}
/* texcoords */
{
GLuint i;
for (i = 0; i < ctx->Const.MaxTextureCoordUnits; i++) {
const GLuint attr = VARYING_SLOT_TEX0 + i;
const GLfloat *tc = ctx->Current.RasterTexCoords[i];
if (_swrast_use_fragment_program(ctx) ||
ctx->ATIFragmentShader._Enabled) {
COPY_4V(span->attrStart[attr], tc);
}
else if (tc[3] > 0.0F) {
/* use (s/q, t/q, r/q, 1) */
span->attrStart[attr][0] = tc[0] / tc[3];
span->attrStart[attr][1] = tc[1] / tc[3];
span->attrStart[attr][2] = tc[2] / tc[3];
span->attrStart[attr][3] = 1.0;
}
else {
ASSIGN_4V(span->attrStart[attr], 0.0F, 0.0F, 0.0F, 1.0F);
}
ASSIGN_4V(span->attrStepX[attr], 0.0F, 0.0F, 0.0F, 0.0F);
ASSIGN_4V(span->attrStepY[attr], 0.0F, 0.0F, 0.0F, 0.0F);
}
}
}
/**
* Interpolate the active attributes (and'd with attrMask) to
* fill in span->array->attribs[].
* Perspective correction will be done. The point/line/triangle function
* should have computed attrStart/Step values for VARYING_SLOT_POS[3]!
*/
static inline void
interpolate_active_attribs(struct gl_context *ctx, SWspan *span,
GLbitfield64 attrMask)
{
const SWcontext *swrast = SWRAST_CONTEXT(ctx);
/*
* Don't overwrite existing array values, such as colors that may have
* been produced by glDraw/CopyPixels.
*/
attrMask &= ~span->arrayAttribs;
ATTRIB_LOOP_BEGIN
if (attrMask & BITFIELD64_BIT(attr)) {
const GLfloat dwdx = span->attrStepX[VARYING_SLOT_POS][3];
GLfloat w = span->attrStart[VARYING_SLOT_POS][3];
const GLfloat dv0dx = span->attrStepX[attr][0];
const GLfloat dv1dx = span->attrStepX[attr][1];
const GLfloat dv2dx = span->attrStepX[attr][2];
const GLfloat dv3dx = span->attrStepX[attr][3];
GLfloat v0 = span->attrStart[attr][0] + span->leftClip * dv0dx;
GLfloat v1 = span->attrStart[attr][1] + span->leftClip * dv1dx;
GLfloat v2 = span->attrStart[attr][2] + span->leftClip * dv2dx;
GLfloat v3 = span->attrStart[attr][3] + span->leftClip * dv3dx;
GLuint k;
for (k = 0; k < span->end; k++) {
const GLfloat invW = 1.0f / w;
span->array->attribs[attr][k][0] = v0 * invW;
span->array->attribs[attr][k][1] = v1 * invW;
span->array->attribs[attr][k][2] = v2 * invW;
span->array->attribs[attr][k][3] = v3 * invW;
v0 += dv0dx;
v1 += dv1dx;
v2 += dv2dx;
v3 += dv3dx;
w += dwdx;
}
assert((span->arrayAttribs & BITFIELD64_BIT(attr)) == 0);
span->arrayAttribs |= BITFIELD64_BIT(attr);
}
ATTRIB_LOOP_END
}
/**
* Interpolate primary colors to fill in the span->array->rgba8 (or rgb16)
* color array.
*/
static inline void
interpolate_int_colors(struct gl_context *ctx, SWspan *span)
{
#if CHAN_BITS != 32
const GLuint n = span->end;
GLuint i;
assert(!(span->arrayMask & SPAN_RGBA));
#endif
switch (span->array->ChanType) {
#if CHAN_BITS != 32
case GL_UNSIGNED_BYTE:
{
GLubyte (*rgba)[4] = span->array->rgba8;
if (span->interpMask & SPAN_FLAT) {
GLubyte color[4];
color[RCOMP] = FixedToInt(span->red);
color[GCOMP] = FixedToInt(span->green);
color[BCOMP] = FixedToInt(span->blue);
color[ACOMP] = FixedToInt(span->alpha);
for (i = 0; i < n; i++) {
COPY_4UBV(rgba[i], color);
}
}
else {
GLfixed r = span->red;
GLfixed g = span->green;
GLfixed b = span->blue;
GLfixed a = span->alpha;
GLint dr = span->redStep;
GLint dg = span->greenStep;
GLint db = span->blueStep;
GLint da = span->alphaStep;
for (i = 0; i < n; i++) {
rgba[i][RCOMP] = FixedToChan(r);
rgba[i][GCOMP] = FixedToChan(g);
rgba[i][BCOMP] = FixedToChan(b);
rgba[i][ACOMP] = FixedToChan(a);
r += dr;
g += dg;
b += db;
a += da;
}
}
}
break;
case GL_UNSIGNED_SHORT:
{
GLushort (*rgba)[4] = span->array->rgba16;
if (span->interpMask & SPAN_FLAT) {
GLushort color[4];
color[RCOMP] = FixedToInt(span->red);
color[GCOMP] = FixedToInt(span->green);
color[BCOMP] = FixedToInt(span->blue);
color[ACOMP] = FixedToInt(span->alpha);
for (i = 0; i < n; i++) {
COPY_4V(rgba[i], color);
}
}
else {
GLushort (*rgba)[4] = span->array->rgba16;
GLfixed r, g, b, a;
GLint dr, dg, db, da;
r = span->red;
g = span->green;
b = span->blue;
a = span->alpha;
dr = span->redStep;
dg = span->greenStep;
db = span->blueStep;
da = span->alphaStep;
for (i = 0; i < n; i++) {
rgba[i][RCOMP] = FixedToChan(r);
rgba[i][GCOMP] = FixedToChan(g);
rgba[i][BCOMP] = FixedToChan(b);
rgba[i][ACOMP] = FixedToChan(a);
r += dr;
g += dg;
b += db;
a += da;
}
}
}
break;
#endif
case GL_FLOAT:
interpolate_active_attribs(ctx, span, VARYING_BIT_COL0);
break;
default:
_mesa_problem(ctx, "bad datatype 0x%x in interpolate_int_colors",
span->array->ChanType);
}
span->arrayMask |= SPAN_RGBA;
}
/**
* Populate the VARYING_SLOT_COL0 array.
*/
static inline void
interpolate_float_colors(SWspan *span)
{
GLfloat (*col0)[4] = span->array->attribs[VARYING_SLOT_COL0];
const GLuint n = span->end;
GLuint i;
assert(!(span->arrayAttribs & VARYING_BIT_COL0));
if (span->arrayMask & SPAN_RGBA) {
/* convert array of int colors */
for (i = 0; i < n; i++) {
col0[i][0] = UBYTE_TO_FLOAT(span->array->rgba8[i][0]);
col0[i][1] = UBYTE_TO_FLOAT(span->array->rgba8[i][1]);
col0[i][2] = UBYTE_TO_FLOAT(span->array->rgba8[i][2]);
col0[i][3] = UBYTE_TO_FLOAT(span->array->rgba8[i][3]);
}
}
else {
/* interpolate red/green/blue/alpha to get float colors */
assert(span->interpMask & SPAN_RGBA);
if (span->interpMask & SPAN_FLAT) {
GLfloat r = FixedToFloat(span->red);
GLfloat g = FixedToFloat(span->green);
GLfloat b = FixedToFloat(span->blue);
GLfloat a = FixedToFloat(span->alpha);
for (i = 0; i < n; i++) {
ASSIGN_4V(col0[i], r, g, b, a);
}
}
else {
GLfloat r = FixedToFloat(span->red);
GLfloat g = FixedToFloat(span->green);
GLfloat b = FixedToFloat(span->blue);
GLfloat a = FixedToFloat(span->alpha);
GLfloat dr = FixedToFloat(span->redStep);
GLfloat dg = FixedToFloat(span->greenStep);
GLfloat db = FixedToFloat(span->blueStep);
GLfloat da = FixedToFloat(span->alphaStep);
for (i = 0; i < n; i++) {
col0[i][0] = r;
col0[i][1] = g;
col0[i][2] = b;
col0[i][3] = a;
r += dr;
g += dg;
b += db;
a += da;
}
}
}
span->arrayAttribs |= VARYING_BIT_COL0;
span->array->ChanType = GL_FLOAT;
}
/**
* Fill in the span.zArray array from the span->z, zStep values.
*/
void
_swrast_span_interpolate_z( const struct gl_context *ctx, SWspan *span )
{
const GLuint n = span->end;
GLuint i;
assert(!(span->arrayMask & SPAN_Z));
if (ctx->DrawBuffer->Visual.depthBits <= 16) {
GLfixed zval = span->z;
GLuint *z = span->array->z;
for (i = 0; i < n; i++) {
z[i] = FixedToInt(zval);
zval += span->zStep;
}
}
else {
/* Deep Z buffer, no fixed->int shift */
GLuint zval = span->z;
GLuint *z = span->array->z;
for (i = 0; i < n; i++) {
z[i] = zval;
zval += span->zStep;
}
}
span->interpMask &= ~SPAN_Z;
span->arrayMask |= SPAN_Z;
}
/**
* Compute mipmap LOD from partial derivatives.
* This the ideal solution, as given in the OpenGL spec.
*/
GLfloat
_swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
GLfloat s, GLfloat t, GLfloat q, GLfloat invQ)
{
GLfloat dudx = texW * ((s + dsdx) / (q + dqdx) - s * invQ);
GLfloat dvdx = texH * ((t + dtdx) / (q + dqdx) - t * invQ);
GLfloat dudy = texW * ((s + dsdy) / (q + dqdy) - s * invQ);
GLfloat dvdy = texH * ((t + dtdy) / (q + dqdy) - t * invQ);
GLfloat x = sqrtf(dudx * dudx + dvdx * dvdx);
GLfloat y = sqrtf(dudy * dudy + dvdy * dvdy);
GLfloat rho = MAX2(x, y);
GLfloat lambda = LOG2(rho);
return lambda;
}
/**
* Compute mipmap LOD from partial derivatives.
* This is a faster approximation than above function.
*/
#if 0
GLfloat
_swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy,
GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH,
GLfloat s, GLfloat t, GLfloat q, GLfloat invQ)
{
GLfloat dsdx2 = (s + dsdx) / (q + dqdx) - s * invQ;
GLfloat dtdx2 = (t + dtdx) / (q + dqdx) - t * invQ;
GLfloat dsdy2 = (s + dsdy) / (q + dqdy) - s * invQ;
GLfloat dtdy2 = (t + dtdy) / (q + dqdy) - t * invQ;
GLfloat maxU, maxV, rho, lambda;
dsdx2 = fabsf(dsdx2);
dsdy2 = fabsf(dsdy2);
dtdx2 = fabsf(dtdx2);
dtdy2 = fabsf(dtdy2);
maxU = MAX2(dsdx2, dsdy2) * texW;
maxV = MAX2(dtdx2, dtdy2) * texH;
rho = MAX2(maxU, maxV);
lambda = LOG2(rho);
return lambda;
}
#endif
/**
* Fill in the span.array->attrib[VARYING_SLOT_TEXn] arrays from the
* using the attrStart/Step values.
*
* This function only used during fixed-function fragment processing.
*
* Note: in the places where we divide by Q (or mult by invQ) we're
* really doing two things: perspective correction and texcoord
* projection. Remember, for texcoord (s,t,r,q) we need to index
* texels with (s/q, t/q, r/q).
*/
static void
interpolate_texcoords(struct gl_context *ctx, SWspan *span)
{
const GLuint maxUnit
= (ctx->Texture._EnabledCoordUnits > 1) ? ctx->Const.MaxTextureUnits : 1;
GLuint u;
/* XXX CoordUnits vs. ImageUnits */
for (u = 0; u < maxUnit; u++) {
if (ctx->Texture._EnabledCoordUnits & (1 << u)) {
const GLuint attr = VARYING_SLOT_TEX0 + u;
const struct gl_texture_object *obj = ctx->Texture.Unit[u]._Current;
GLfloat texW, texH;
GLboolean needLambda;
GLfloat (*texcoord)[4] = span->array->attribs[attr];
GLfloat *lambda = span->array->lambda[u];
const GLfloat dsdx = span->attrStepX[attr][0];
const GLfloat dsdy = span->attrStepY[attr][0];
const GLfloat dtdx = span->attrStepX[attr][1];
const GLfloat dtdy = span->attrStepY[attr][1];
const GLfloat drdx = span->attrStepX[attr][2];
const GLfloat dqdx = span->attrStepX[attr][3];
const GLfloat dqdy = span->attrStepY[attr][3];
GLfloat s = span->attrStart[attr][0] + span->leftClip * dsdx;
GLfloat t = span->attrStart[attr][1] + span->leftClip * dtdx;
GLfloat r = span->attrStart[attr][2] + span->leftClip * drdx;
GLfloat q = span->attrStart[attr][3] + span->leftClip * dqdx;
if (obj) {
const struct gl_texture_image *img = _mesa_base_tex_image(obj);
const struct swrast_texture_image *swImg =
swrast_texture_image_const(img);
const struct gl_sampler_object *samp = _mesa_get_samplerobj(ctx, u);
needLambda = (samp->MinFilter != samp->MagFilter)
|| _swrast_use_fragment_program(ctx);
/* LOD is calculated directly in the ansiotropic filter, we can
* skip the normal lambda function as the result is ignored.
*/
if (samp->MaxAnisotropy > 1.0F &&
samp->MinFilter == GL_LINEAR_MIPMAP_LINEAR) {
needLambda = GL_FALSE;
}
texW = swImg->WidthScale;
texH = swImg->HeightScale;
}
else {
/* using a fragment program */
texW = 1.0;
texH = 1.0;
needLambda = GL_FALSE;
}
if (needLambda) {
GLuint i;
if (_swrast_use_fragment_program(ctx)
|| ctx->ATIFragmentShader._Enabled) {
/* do perspective correction but don't divide s, t, r by q */
const GLfloat dwdx = span->attrStepX[VARYING_SLOT_POS][3];
GLfloat w = span->attrStart[VARYING_SLOT_POS][3] + span->leftClip * dwdx;
for (i = 0; i < span->end; i++) {
const GLfloat invW = 1.0F / w;
texcoord[i][0] = s * invW;
texcoord[i][1] = t * invW;
texcoord[i][2] = r * invW;
texcoord[i][3] = q * invW;
lambda[i] = _swrast_compute_lambda(dsdx, dsdy, dtdx, dtdy,
dqdx, dqdy, texW, texH,
s, t, q, invW);
s += dsdx;
t += dtdx;
r += drdx;
q += dqdx;
w += dwdx;
}
}
else {
for (i = 0; i < span->end; i++) {
const GLfloat invQ = (q == 0.0F) ? 1.0F : (1.0F / q);
texcoord[i][0] = s * invQ;
texcoord[i][1] = t * invQ;
texcoord[i][2] = r * invQ;
texcoord[i][3] = q;
lambda[i] = _swrast_compute_lambda(dsdx, dsdy, dtdx, dtdy,
dqdx, dqdy, texW, texH,
s, t, q, invQ);
s += dsdx;
t += dtdx;
r += drdx;
q += dqdx;
}
}
span->arrayMask |= SPAN_LAMBDA;
}
else {
GLuint i;
if (_swrast_use_fragment_program(ctx) ||
ctx->ATIFragmentShader._Enabled) {
/* do perspective correction but don't divide s, t, r by q */
const GLfloat dwdx = span->attrStepX[VARYING_SLOT_POS][3];
GLfloat w = span->attrStart[VARYING_SLOT_POS][3] + span->leftClip * dwdx;
for (i = 0; i < span->end; i++) {
const GLfloat invW = 1.0F / w;
texcoord[i][0] = s * invW;
texcoord[i][1] = t * invW;
texcoord[i][2] = r * invW;
texcoord[i][3] = q * invW;
lambda[i] = 0.0;
s += dsdx;
t += dtdx;
r += drdx;
q += dqdx;
w += dwdx;
}
}
else if (dqdx == 0.0F) {
/* Ortho projection or polygon's parallel to window X axis */
const GLfloat invQ = (q == 0.0F) ? 1.0F : (1.0F / q);
for (i = 0; i < span->end; i++) {
texcoord[i][0] = s * invQ;
texcoord[i][1] = t * invQ;
texcoord[i][2] = r * invQ;
texcoord[i][3] = q;
lambda[i] = 0.0;
s += dsdx;
t += dtdx;
r += drdx;
}
}
else {
for (i = 0; i < span->end; i++) {
const GLfloat invQ = (q == 0.0F) ? 1.0F : (1.0F / q);
texcoord[i][0] = s * invQ;
texcoord[i][1] = t * invQ;
texcoord[i][2] = r * invQ;
texcoord[i][3] = q;
lambda[i] = 0.0;
s += dsdx;
t += dtdx;
r += drdx;
q += dqdx;
}
}
} /* lambda */
} /* if */
} /* for */
}
/**
* Fill in the arrays->attribs[VARYING_SLOT_POS] array.
*/
static inline void
interpolate_wpos(struct gl_context *ctx, SWspan *span)
{
GLfloat (*wpos)[4] = span->array->attribs[VARYING_SLOT_POS];
GLuint i;
const GLfloat zScale = 1.0F / ctx->DrawBuffer->_DepthMaxF;
GLfloat w, dw;
if (span->arrayMask & SPAN_XY) {
for (i = 0; i < span->end; i++) {
wpos[i][0] = (GLfloat) span->array->x[i];
wpos[i][1] = (GLfloat) span->array->y[i];
}
}
else {
for (i = 0; i < span->end; i++) {
wpos[i][0] = (GLfloat) span->x + i;
wpos[i][1] = (GLfloat) span->y;
}
}
dw = span->attrStepX[VARYING_SLOT_POS][3];
w = span->attrStart[VARYING_SLOT_POS][3] + span->leftClip * dw;
for (i = 0; i < span->end; i++) {
wpos[i][2] = (GLfloat) span->array->z[i] * zScale;
wpos[i][3] = w;
w += dw;
}
}
/**
* Apply the current polygon stipple pattern to a span of pixels.
*/
static inline void
stipple_polygon_span(struct gl_context *ctx, SWspan *span)
{
GLubyte *mask = span->array->mask;
assert(ctx->Polygon.StippleFlag);
if (span->arrayMask & SPAN_XY) {
/* arrays of x/y pixel coords */
GLuint i;
for (i = 0; i < span->end; i++) {
const GLint col = span->array->x[i] % 32;
const GLint row = span->array->y[i] % 32;
const GLuint stipple = ctx->PolygonStipple[row];
if (((1 << col) & stipple) == 0) {
mask[i] = 0;
}
}
}
else {
/* horizontal span of pixels */
const GLuint highBit = 1 << 31;
const GLuint stipple = ctx->PolygonStipple[span->y % 32];
GLuint i, m = highBit >> (GLuint) (span->x % 32);
for (i = 0; i < span->end; i++) {
if ((m & stipple) == 0) {
mask[i] = 0;
}
m = m >> 1;
if (m == 0) {
m = highBit;
}
}
}
span->writeAll = GL_FALSE;
}
/**
* Clip a pixel span to the current buffer/window boundaries:
* DrawBuffer->_Xmin, _Xmax, _Ymin, _Ymax. This will accomplish
* window clipping and scissoring.
* Return: GL_TRUE some pixels still visible
* GL_FALSE nothing visible
*/
static inline GLuint
clip_span( struct gl_context *ctx, SWspan *span )
{
const GLint xmin = ctx->DrawBuffer->_Xmin;
const GLint xmax = ctx->DrawBuffer->_Xmax;
const GLint ymin = ctx->DrawBuffer->_Ymin;
const GLint ymax = ctx->DrawBuffer->_Ymax;
span->leftClip = 0;
if (span->arrayMask & SPAN_XY) {
/* arrays of x/y pixel coords */
const GLint *x = span->array->x;
const GLint *y = span->array->y;
const GLint n = span->end;
GLubyte *mask = span->array->mask;
GLint i;
GLuint passed = 0;
if (span->arrayMask & SPAN_MASK) {
/* note: using & intead of && to reduce branches */
for (i = 0; i < n; i++) {
mask[i] &= (x[i] >= xmin) & (x[i] < xmax)
& (y[i] >= ymin) & (y[i] < ymax);
passed += mask[i];
}
}
else {
/* note: using & intead of && to reduce branches */
for (i = 0; i < n; i++) {
mask[i] = (x[i] >= xmin) & (x[i] < xmax)
& (y[i] >= ymin) & (y[i] < ymax);
passed += mask[i];
}
}
return passed > 0;
}
else {
/* horizontal span of pixels */
const GLint x = span->x;
const GLint y = span->y;
GLint n = span->end;
/* Trivial rejection tests */
if (y < ymin || y >= ymax || x + n <= xmin || x >= xmax) {
span->end = 0;
return GL_FALSE; /* all pixels clipped */
}
/* Clip to right */
if (x + n > xmax) {
assert(x < xmax);
n = span->end = xmax - x;
}
/* Clip to the left */
if (x < xmin) {
const GLint leftClip = xmin - x;
GLuint i;
assert(leftClip > 0);
assert(x + n > xmin);
/* Clip 'leftClip' pixels from the left side.
* The span->leftClip field will be applied when we interpolate
* fragment attributes.
* For arrays of values, shift them left.
*/
for (i = 0; i < VARYING_SLOT_MAX; i++) {
if (span->interpMask & (1 << i)) {
GLuint j;
for (j = 0; j < 4; j++) {
span->attrStart[i][j] += leftClip * span->attrStepX[i][j];
}
}
}
span->red += leftClip * span->redStep;
span->green += leftClip * span->greenStep;
span->blue += leftClip * span->blueStep;
span->alpha += leftClip * span->alphaStep;
span->index += leftClip * span->indexStep;
span->z += leftClip * span->zStep;
span->intTex[0] += leftClip * span->intTexStep[0];
span->intTex[1] += leftClip * span->intTexStep[1];
#define SHIFT_ARRAY(ARRAY, SHIFT, LEN) \
memmove(ARRAY, ARRAY + (SHIFT), (LEN) * sizeof(ARRAY[0]))
for (i = 0; i < VARYING_SLOT_MAX; i++) {
if (span->arrayAttribs & BITFIELD64_BIT(i)) {
/* shift array elements left by 'leftClip' */
SHIFT_ARRAY(span->array->attribs[i], leftClip, n - leftClip);
}
}
SHIFT_ARRAY(span->array->mask, leftClip, n - leftClip);
SHIFT_ARRAY(span->array->rgba8, leftClip, n - leftClip);
SHIFT_ARRAY(span->array->rgba16, leftClip, n - leftClip);
SHIFT_ARRAY(span->array->x, leftClip, n - leftClip);
SHIFT_ARRAY(span->array->y, leftClip, n - leftClip);
SHIFT_ARRAY(span->array->z, leftClip, n - leftClip);
SHIFT_ARRAY(span->array->index, leftClip, n - leftClip);
for (i = 0; i < MAX_TEXTURE_COORD_UNITS; i++) {
SHIFT_ARRAY(span->array->lambda[i], leftClip, n - leftClip);
}
SHIFT_ARRAY(span->array->coverage, leftClip, n - leftClip);
#undef SHIFT_ARRAY
span->leftClip = leftClip;
span->x = xmin;
span->end -= leftClip;
span->writeAll = GL_FALSE;
}
assert(span->x >= xmin);
assert(span->x + span->end <= xmax);
assert(span->y >= ymin);
assert(span->y < ymax);
return GL_TRUE; /* some pixels visible */
}
}
/**
* Add specular colors to primary colors.
* Only called during fixed-function operation.
* Result is float color array (VARYING_SLOT_COL0).
*/
static inline void
add_specular(struct gl_context *ctx, SWspan *span)
{
const SWcontext *swrast = SWRAST_CONTEXT(ctx);
const GLubyte *mask = span->array->mask;
GLfloat (*col0)[4] = span->array->attribs[VARYING_SLOT_COL0];
GLfloat (*col1)[4] = span->array->attribs[VARYING_SLOT_COL1];
GLuint i;
assert(!_swrast_use_fragment_program(ctx));
assert(span->arrayMask & SPAN_RGBA);
assert(swrast->_ActiveAttribMask & VARYING_BIT_COL1);
(void) swrast; /* silence warning */
if (span->array->ChanType == GL_FLOAT) {
if ((span->arrayAttribs & VARYING_BIT_COL0) == 0) {
interpolate_active_attribs(ctx, span, VARYING_BIT_COL0);
}
}
else {
/* need float colors */
if ((span->arrayAttribs & VARYING_BIT_COL0) == 0) {
interpolate_float_colors(span);
}
}
if ((span->arrayAttribs & VARYING_BIT_COL1) == 0) {
/* XXX could avoid this and interpolate COL1 in the loop below */
interpolate_active_attribs(ctx, span, VARYING_BIT_COL1);
}
assert(span->arrayAttribs & VARYING_BIT_COL0);
assert(span->arrayAttribs & VARYING_BIT_COL1);
for (i = 0; i < span->end; i++) {
if (mask[i]) {
col0[i][0] += col1[i][0];
col0[i][1] += col1[i][1];
col0[i][2] += col1[i][2];
}
}
span->array->ChanType = GL_FLOAT;
}
/**
* Apply antialiasing coverage value to alpha values.
*/
static inline void
apply_aa_coverage(SWspan *span)
{
const GLfloat *coverage = span->array->coverage;
GLuint i;
if (span->array->ChanType == GL_UNSIGNED_BYTE) {
GLubyte (*rgba)[4] = span->array->rgba8;
for (i = 0; i < span->end; i++) {
const GLfloat a = rgba[i][ACOMP] * coverage[i];
rgba[i][ACOMP] = (GLubyte) CLAMP(a, 0.0F, 255.0F);
assert(coverage[i] >= 0.0F);
assert(coverage[i] <= 1.0F);
}
}
else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
GLushort (*rgba)[4] = span->array->rgba16;
for (i = 0; i < span->end; i++) {
const GLfloat a = rgba[i][ACOMP] * coverage[i];
rgba[i][ACOMP] = (GLushort) CLAMP(a, 0.0F, 65535.0F);
}
}
else {
GLfloat (*rgba)[4] = span->array->attribs[VARYING_SLOT_COL0];
for (i = 0; i < span->end; i++) {
rgba[i][ACOMP] = rgba[i][ACOMP] * coverage[i];
/* clamp later */
}
}
}
/**
* Clamp span's float colors to [0,1]
*/
static inline void
clamp_colors(SWspan *span)
{
GLfloat (*rgba)[4] = span->array->attribs[VARYING_SLOT_COL0];
GLuint i;
assert(span->array->ChanType == GL_FLOAT);
for (i = 0; i < span->end; i++) {
rgba[i][RCOMP] = CLAMP(rgba[i][RCOMP], 0.0F, 1.0F);
rgba[i][GCOMP] = CLAMP(rgba[i][GCOMP], 0.0F, 1.0F);
rgba[i][BCOMP] = CLAMP(rgba[i][BCOMP], 0.0F, 1.0F);
rgba[i][ACOMP] = CLAMP(rgba[i][ACOMP], 0.0F, 1.0F);
}
}
/**
* Convert the span's color arrays to the given type.
* The only way 'output' can be greater than zero is when we have a fragment
* program that writes to gl_FragData[1] or higher.
* \param output which fragment program color output is being processed
*/
static inline void
convert_color_type(SWspan *span, GLenum srcType, GLenum newType, GLuint output)
{
GLvoid *src, *dst;
if (output > 0 || srcType == GL_FLOAT) {
src = span->array->attribs[VARYING_SLOT_COL0 + output];
span->array->ChanType = GL_FLOAT;
}
else if (srcType == GL_UNSIGNED_BYTE) {
src = span->array->rgba8;
}
else {
assert(srcType == GL_UNSIGNED_SHORT);
src = span->array->rgba16;
}
if (newType == GL_UNSIGNED_BYTE) {
dst = span->array->rgba8;
}
else if (newType == GL_UNSIGNED_SHORT) {
dst = span->array->rgba16;
}
else {
dst = span->array->attribs[VARYING_SLOT_COL0];
}
_mesa_convert_colors(span->array->ChanType, src,
newType, dst,
span->end, span->array->mask);
span->array->ChanType = newType;
span->array->rgba = dst;
}
/**
* Apply fragment shader, fragment program or normal texturing to span.
*/
static inline void
shade_texture_span(struct gl_context *ctx, SWspan *span)
{
if (_swrast_use_fragment_program(ctx) ||
ctx->ATIFragmentShader._Enabled) {
/* programmable shading */
if (span->primitive == GL_BITMAP && span->array->ChanType != GL_FLOAT) {
convert_color_type(span, span->array->ChanType, GL_FLOAT, 0);
}
else {
span->array->rgba = (void *) span->array->attribs[VARYING_SLOT_COL0];
}
if (span->primitive != GL_POINT ||
(span->interpMask & SPAN_RGBA) ||
ctx->Point.PointSprite) {
/* for single-pixel points, we populated the arrays already */
interpolate_active_attribs(ctx, span, ~0);
}
span->array->ChanType = GL_FLOAT;
if (!(span->arrayMask & SPAN_Z))
_swrast_span_interpolate_z (ctx, span);
#if 0
if (inputsRead & VARYING_BIT_POS)
#else
/* XXX always interpolate wpos so that DDX/DDY work */
#endif
interpolate_wpos(ctx, span);
/* Run fragment program/shader now */
if (_swrast_use_fragment_program(ctx)) {
_swrast_exec_fragment_program(ctx, span);
}
else {
assert(ctx->ATIFragmentShader._Enabled);
_swrast_exec_fragment_shader(ctx, span);
}
}
else if (ctx->Texture._EnabledCoordUnits) {
/* conventional texturing */
#if CHAN_BITS == 32
if ((span->arrayAttribs & VARYING_BIT_COL0) == 0) {
interpolate_int_colors(ctx, span);
}
#else
if (!(span->arrayMask & SPAN_RGBA))
interpolate_int_colors(ctx, span);
#endif
if ((span->arrayAttribs & VARYING_BITS_TEX_ANY) == 0x0)
interpolate_texcoords(ctx, span);
_swrast_texture_span(ctx, span);
}
}
/** Put colors at x/y locations into a renderbuffer */
static void
put_values(struct gl_context *ctx, struct gl_renderbuffer *rb,
GLenum datatype,
GLuint count, const GLint x[], const GLint y[],
const void *values, const GLubyte *mask)
{
gl_pack_ubyte_rgba_func pack_ubyte = NULL;
gl_pack_float_rgba_func pack_float = NULL;
GLuint i;
if (datatype == GL_UNSIGNED_BYTE)
pack_ubyte = _mesa_get_pack_ubyte_rgba_function(rb->Format);
else
pack_float = _mesa_get_pack_float_rgba_function(rb->Format);
for (i = 0; i < count; i++) {
if (mask[i]) {
GLubyte *dst = _swrast_pixel_address(rb, x[i], y[i]);
if (datatype == GL_UNSIGNED_BYTE) {
pack_ubyte((const GLubyte *) values + 4 * i, dst);
}
else {
assert(datatype == GL_FLOAT);
pack_float((const GLfloat *) values + 4 * i, dst);
}
}
}
}
/** Put row of colors into renderbuffer */
void
_swrast_put_row(struct gl_context *ctx, struct gl_renderbuffer *rb,
GLenum datatype,
GLuint count, GLint x, GLint y,
const void *values, const GLubyte *mask)
{
GLubyte *dst = _swrast_pixel_address(rb, x, y);
if (!mask) {
if (datatype == GL_UNSIGNED_BYTE) {
_mesa_pack_ubyte_rgba_row(rb->Format, count,
(const GLubyte (*)[4]) values, dst);
}
else {
assert(datatype == GL_FLOAT);
_mesa_pack_float_rgba_row(rb->Format, count,
(const GLfloat (*)[4]) values, dst);
}
}
else {
const GLuint bpp = _mesa_get_format_bytes(rb->Format);
GLuint i, runLen, runStart;
/* We can't pass a 'mask' array to the _mesa_pack_rgba_row() functions
* so look for runs where mask=1...
*/
runLen = runStart = 0;
for (i = 0; i < count; i++) {
if (mask[i]) {
if (runLen == 0)
runStart = i;
runLen++;
}
if (!mask[i] || i == count - 1) {
/* might be the end of a run of pixels */
if (runLen > 0) {
if (datatype == GL_UNSIGNED_BYTE) {
_mesa_pack_ubyte_rgba_row(rb->Format, runLen,
(const GLubyte (*)[4]) values + runStart,
dst + runStart * bpp);
}
else {
assert(datatype == GL_FLOAT);
_mesa_pack_float_rgba_row(rb->Format, runLen,
(const GLfloat (*)[4]) values + runStart,
dst + runStart * bpp);
}
runLen = 0;
}
}
}
}
}
/**
* Apply all the per-fragment operations to a span.
* This now includes texturing (_swrast_write_texture_span() is history).
* This function may modify any of the array values in the span.
* span->interpMask and span->arrayMask may be changed but will be restored
* to their original values before returning.
*/
void
_swrast_write_rgba_span( struct gl_context *ctx, SWspan *span)
{
const SWcontext *swrast = SWRAST_CONTEXT(ctx);
const GLuint *colorMask = (GLuint *) ctx->Color.ColorMask;
const GLbitfield origInterpMask = span->interpMask;
const GLbitfield origArrayMask = span->arrayMask;
const GLbitfield64 origArrayAttribs = span->arrayAttribs;
const GLenum origChanType = span->array->ChanType;
void * const origRgba = span->array->rgba;
const GLboolean shader = (_swrast_use_fragment_program(ctx)
|| ctx->ATIFragmentShader._Enabled);
const GLboolean shaderOrTexture = shader || ctx->Texture._EnabledCoordUnits;
struct gl_framebuffer *fb = ctx->DrawBuffer;
/*
printf("%s() interp 0x%x array 0x%x\n", __func__,
span->interpMask, span->arrayMask);
*/
assert(span->primitive == GL_POINT ||
span->primitive == GL_LINE ||
span->primitive == GL_POLYGON ||
span->primitive == GL_BITMAP);
/* Fragment write masks */
if (span->arrayMask & SPAN_MASK) {
/* mask was initialized by caller, probably glBitmap */
span->writeAll = GL_FALSE;
}
else {
memset(span->array->mask, 1, span->end);
span->writeAll = GL_TRUE;
}
/* Clip to window/scissor box */
if (!clip_span(ctx, span)) {
return;
}
assert(span->end <= SWRAST_MAX_WIDTH);
/* Depth bounds test */
if (ctx->Depth.BoundsTest && fb->Visual.depthBits > 0) {
if (!_swrast_depth_bounds_test(ctx, span)) {
return;
}
}
#ifdef DEBUG
/* Make sure all fragments are within window bounds */
if (span->arrayMask & SPAN_XY) {
/* array of pixel locations */
GLuint i;
for (i = 0; i < span->end; i++) {
if (span->array->mask[i]) {
assert(span->array->x[i] >= fb->_Xmin);
assert(span->array->x[i] < fb->_Xmax);
assert(span->array->y[i] >= fb->_Ymin);
assert(span->array->y[i] < fb->_Ymax);
}
}
}
#endif
/* Polygon Stippling */
if (ctx->Polygon.StippleFlag && span->primitive == GL_POLYGON) {
stipple_polygon_span(ctx, span);
}
/* This is the normal place to compute the fragment color/Z
* from texturing or shading.
*/
if (shaderOrTexture && !swrast->_DeferredTexture) {
shade_texture_span(ctx, span);
}
/* Do the alpha test */
if (ctx->Color.AlphaEnabled) {
if (!_swrast_alpha_test(ctx, span)) {
/* all fragments failed test */
goto end;
}
}
/* Stencil and Z testing */
if (ctx->Stencil._Enabled || ctx->Depth.Test) {
if (!(span->arrayMask & SPAN_Z))
_swrast_span_interpolate_z(ctx, span);
if (ctx->Transform.DepthClamp)
_swrast_depth_clamp_span(ctx, span);
if (ctx->Stencil._Enabled) {
/* Combined Z/stencil tests */
if (!_swrast_stencil_and_ztest_span(ctx, span)) {
/* all fragments failed test */
goto end;
}
}
else if (fb->Visual.depthBits > 0) {
/* Just regular depth testing */
assert(ctx->Depth.Test);
assert(span->arrayMask & SPAN_Z);
if (!_swrast_depth_test_span(ctx, span)) {
/* all fragments failed test */
goto end;
}
}
}
if (ctx->Query.CurrentOcclusionObject) {
/* update count of 'passed' fragments */
struct gl_query_object *q = ctx->Query.CurrentOcclusionObject;
GLuint i;
for (i = 0; i < span->end; i++)
q->Result += span->array->mask[i];
}
/* We had to wait until now to check for glColorMask(0,0,0,0) because of
* the occlusion test.
*/
if (fb->_NumColorDrawBuffers == 1 && colorMask[0] == 0x0) {
/* no colors to write */
goto end;
}
/* If we were able to defer fragment color computation to now, there's
* a good chance that many fragments will have already been killed by
* Z/stencil testing.
*/
if (shaderOrTexture && swrast->_DeferredTexture) {
shade_texture_span(ctx, span);
}
#if CHAN_BITS == 32
if ((span->arrayAttribs & VARYING_BIT_COL0) == 0) {
interpolate_active_attribs(ctx, span, VARYING_BIT_COL0);
}
#else
if ((span->arrayMask & SPAN_RGBA) == 0) {
interpolate_int_colors(ctx, span);
}
#endif
assert(span->arrayMask & SPAN_RGBA);
if (span->primitive == GL_BITMAP || !swrast->SpecularVertexAdd) {
/* Add primary and specular (diffuse + specular) colors */
if (!shader) {
if (ctx->Fog.ColorSumEnabled ||
(ctx->Light.Enabled &&
ctx->Light.Model.ColorControl == GL_SEPARATE_SPECULAR_COLOR)) {
add_specular(ctx, span);
}
}
}
/* Fog */
if (swrast->_FogEnabled) {
_swrast_fog_rgba_span(ctx, span);
}
/* Antialias coverage application */
if (span->arrayMask & SPAN_COVERAGE) {
apply_aa_coverage(span);
}
/* Clamp color/alpha values over the range [0.0, 1.0] before storage */
if (ctx->Color.ClampFragmentColor == GL_TRUE &&
span->array->ChanType == GL_FLOAT) {
clamp_colors(span);
}
/*
* Write to renderbuffers.
* Depending on glDrawBuffer() state and the which color outputs are
* written by the fragment shader, we may either replicate one color to
* all renderbuffers or write a different color to each renderbuffer.
* multiFragOutputs=TRUE for the later case.
*/
{
const GLuint numBuffers = fb->_NumColorDrawBuffers;
const struct gl_program *fp = ctx->FragmentProgram._Current;
const GLboolean multiFragOutputs =
_swrast_use_fragment_program(ctx)
&& fp->info.outputs_written >= (1 << FRAG_RESULT_DATA0);
/* Save srcColorType because convert_color_type() can change it */
const GLenum srcColorType = span->array->ChanType;
GLuint buf;
for (buf = 0; buf < numBuffers; buf++) {
struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[buf];
/* color[fragOutput] will be written to buffer[buf] */
if (rb) {
/* re-use one of the attribute array buffers for rgbaSave */
GLchan (*rgbaSave)[4] = (GLchan (*)[4]) span->array->attribs[0];
struct swrast_renderbuffer *srb = swrast_renderbuffer(rb);
const GLenum dstColorType = srb->ColorType;
assert(dstColorType == GL_UNSIGNED_BYTE ||
dstColorType == GL_FLOAT);
/* set span->array->rgba to colors for renderbuffer's datatype */
if (srcColorType != dstColorType) {
convert_color_type(span, srcColorType, dstColorType,
multiFragOutputs ? buf : 0);
}
else {
if (srcColorType == GL_UNSIGNED_BYTE) {
span->array->rgba = span->array->rgba8;
}
else {
span->array->rgba = (void *)
span->array->attribs[VARYING_SLOT_COL0];
}
}
if (!multiFragOutputs && numBuffers > 1) {
/* save colors for second, third renderbuffer writes */
memcpy(rgbaSave, span->array->rgba,
4 * span->end * sizeof(GLchan));
}
assert(rb->_BaseFormat == GL_RGBA ||
rb->_BaseFormat == GL_RGB ||
rb->_BaseFormat == GL_RED ||
rb->_BaseFormat == GL_RG ||
rb->_BaseFormat == GL_ALPHA);
if (ctx->Color.ColorLogicOpEnabled) {
_swrast_logicop_rgba_span(ctx, rb, span);
}
else if ((ctx->Color.BlendEnabled >> buf) & 1) {
_swrast_blend_span(ctx, rb, span);
}
if (colorMask[buf] != 0xffffffff) {
_swrast_mask_rgba_span(ctx, rb, span, buf);
}
if (span->arrayMask & SPAN_XY) {
/* array of pixel coords */
put_values(ctx, rb,
span->array->ChanType, span->end,
span->array->x, span->array->y,
span->array->rgba, span->array->mask);
}
else {
/* horizontal run of pixels */
_swrast_put_row(ctx, rb,
span->array->ChanType,
span->end, span->x, span->y,
span->array->rgba,
span->writeAll ? NULL: span->array->mask);
}
if (!multiFragOutputs && numBuffers > 1) {
/* restore original span values */
memcpy(span->array->rgba, rgbaSave,
4 * span->end * sizeof(GLchan));
}
} /* if rb */
} /* for buf */
}
end:
/* restore these values before returning */
span->interpMask = origInterpMask;
span->arrayMask = origArrayMask;
span->arrayAttribs = origArrayAttribs;
span->array->ChanType = origChanType;
span->array->rgba = origRgba;
}
/**
* Read float RGBA pixels from a renderbuffer. Clipping will be done to
* prevent reading ouside the buffer's boundaries.
* \param rgba the returned colors
*/
void
_swrast_read_rgba_span( struct gl_context *ctx, struct gl_renderbuffer *rb,
GLuint n, GLint x, GLint y,
GLvoid *rgba)
{
struct swrast_renderbuffer *srb = swrast_renderbuffer(rb);
GLenum dstType = GL_FLOAT;
const GLint bufWidth = (GLint) rb->Width;
const GLint bufHeight = (GLint) rb->Height;
if (y < 0 || y >= bufHeight || x + (GLint) n < 0 || x >= bufWidth) {
/* completely above, below, or right */
/* XXX maybe leave rgba values undefined? */
memset(rgba, 0, 4 * n * sizeof(GLchan));
}
else {
GLint skip, length;
GLubyte *src;
if (x < 0) {
/* left edge clipping */
skip = -x;
length = (GLint) n - skip;
if (length < 0) {
/* completely left of window */
return;
}
if (length > bufWidth) {
length = bufWidth;
}
}
else if ((GLint) (x + n) > bufWidth) {
/* right edge clipping */
skip = 0;
length = bufWidth - x;
if (length < 0) {
/* completely to right of window */
return;
}
}
else {
/* no clipping */
skip = 0;
length = (GLint) n;
}
assert(rb);
assert(rb->_BaseFormat == GL_RGBA ||
rb->_BaseFormat == GL_RGB ||
rb->_BaseFormat == GL_RG ||
rb->_BaseFormat == GL_RED ||
rb->_BaseFormat == GL_LUMINANCE ||
rb->_BaseFormat == GL_INTENSITY ||
rb->_BaseFormat == GL_LUMINANCE_ALPHA ||
rb->_BaseFormat == GL_ALPHA);
assert(srb->Map);
(void) srb; /* silence unused var warning */
src = _swrast_pixel_address(rb, x + skip, y);
if (dstType == GL_UNSIGNED_BYTE) {
_mesa_unpack_ubyte_rgba_row(rb->Format, length, src,
(GLubyte (*)[4]) rgba + skip);
}
else if (dstType == GL_FLOAT) {
_mesa_unpack_rgba_row(rb->Format, length, src,
(GLfloat (*)[4]) rgba + skip);
}
else {
_mesa_problem(ctx, "unexpected type in _swrast_read_rgba_span()");
}
}
}
/**
* Get colors at x/y positions with clipping.
* \param type type of values to return
*/
static void
get_values(struct gl_context *ctx, struct gl_renderbuffer *rb,
GLuint count, const GLint x[], const GLint y[],
void *values, GLenum type)
{
GLuint i;
for (i = 0; i < count; i++) {
if (x[i] >= 0 && y[i] >= 0 &&
x[i] < (GLint) rb->Width && y[i] < (GLint) rb->Height) {
/* inside */
const GLubyte *src = _swrast_pixel_address(rb, x[i], y[i]);
if (type == GL_UNSIGNED_BYTE) {
_mesa_unpack_ubyte_rgba_row(rb->Format, 1, src,
(GLubyte (*)[4]) values + i);
}
else if (type == GL_FLOAT) {
_mesa_unpack_rgba_row(rb->Format, 1, src,
(GLfloat (*)[4]) values + i);
}
else {
_mesa_problem(ctx, "unexpected type in get_values()");
}
}
}
}
/**
* Get row of colors with clipping.
* \param type type of values to return
*/
static void
get_row(struct gl_context *ctx, struct gl_renderbuffer *rb,
GLuint count, GLint x, GLint y,
GLvoid *values, GLenum type)
{
GLint skip = 0;
GLubyte *src;
if (y < 0 || y >= (GLint) rb->Height)
return; /* above or below */
if (x + (GLint) count <= 0 || x >= (GLint) rb->Width)
return; /* entirely left or right */
if (x + count > rb->Width) {
/* right clip */
GLint clip = x + count - rb->Width;
count -= clip;
}
if (x < 0) {
/* left clip */
skip = -x;
x = 0;
count -= skip;
}
src = _swrast_pixel_address(rb, x, y);
if (type == GL_UNSIGNED_BYTE) {
_mesa_unpack_ubyte_rgba_row(rb->Format, count, src,
(GLubyte (*)[4]) values + skip);
}
else if (type == GL_FLOAT) {
_mesa_unpack_rgba_row(rb->Format, count, src,
(GLfloat (*)[4]) values + skip);
}
else {
_mesa_problem(ctx, "unexpected type in get_row()");
}
}
/**
* Get RGBA pixels from the given renderbuffer.
* Used by blending, logicop and masking functions.
* \return pointer to the colors we read.
*/
void *
_swrast_get_dest_rgba(struct gl_context *ctx, struct gl_renderbuffer *rb,
SWspan *span)
{
void *rbPixels;
/* Point rbPixels to a temporary space */
rbPixels = span->array->attribs[VARYING_SLOT_MAX - 1];
/* Get destination values from renderbuffer */
if (span->arrayMask & SPAN_XY) {
get_values(ctx, rb, span->end, span->array->x, span->array->y,
rbPixels, span->array->ChanType);
}
else {
get_row(ctx, rb, span->end, span->x, span->y,
rbPixels, span->array->ChanType);
}
return rbPixels;
}