/* * Mesa 3-D graphics library * Version: 7.5 * * 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 "main/glheader.h" #include "main/colormac.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 "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 /** * 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 = obj->Image[0][obj->BaseLevel]; 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 > 1.0 && 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 & (1 << 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, 0.0, 255.0); ASSERT(coverage[i] >= 0.0); ASSERT(coverage[i] <= 1.0); } } 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, 0.0, 65535.0); } } 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 newType, GLuint output) { GLvoid *src, *dst; if (output > 0 || span->array->ChanType == GL_FLOAT) { src = span->array->attribs[VARYING_SLOT_COL0 + output]; span->array->ChanType = GL_FLOAT; } else if (span->array->ChanType == GL_UNSIGNED_BYTE) { src = span->array->rgba8; } else { ASSERT(span->array->ChanType == 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, 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", __FUNCTION__, 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_fragment_program *fp = ctx->FragmentProgram._Current; const GLboolean multiFragOutputs = _swrast_use_fragment_program(ctx) && fp->Base.OutputsWritten >= (1 << FRAG_RESULT_DATA0); 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); GLenum colorType = srb->ColorType; assert(colorType == GL_UNSIGNED_BYTE || colorType == GL_FLOAT); /* set span->array->rgba to colors for renderbuffer's datatype */ if (span->array->ChanType != colorType) { convert_color_type(span, colorType, 0); } else { if (span->array->ChanType == 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); 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; }