s_span.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/*
 * Mesa 3-D graphics library
 * Version:  7.1
 *
 * 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
 * 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.
 */


/**
 * \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 "glheader.h"
#include "colormac.h"
#include "context.h"
#include "macros.h"
#include "imports.h"
#include "image.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"


/**
 * Set default fragment attributes for the span using the
 * current raster values.  Used prior to glDraw/CopyPixels
 * and glBitmap.
 */
void
_swrast_span_default_attribs(GLcontext *ctx, SWspan *span)
{
   /* 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[FRAG_ATTRIB_WPOS][3] = 1.0;
   span->attrStepX[FRAG_ATTRIB_WPOS][3] = 0.0;
   span->attrStepY[FRAG_ATTRIB_WPOS][3] = 0.0;

   /* primary color, or color index */
   if (ctx->Visual.rgbMode) {
      GLchan r, g, b, a;
      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[FRAG_ATTRIB_COL0], ctx->Current.RasterColor);
      ASSIGN_4V(span->attrStepX[FRAG_ATTRIB_COL0], 0.0, 0.0, 0.0, 0.0);
      ASSIGN_4V(span->attrStepY[FRAG_ATTRIB_COL0], 0.0, 0.0, 0.0, 0.0);
   }
   else {
      span->index = FloatToFixed(ctx->Current.RasterIndex);
      span->indexStep = 0;
      span->interpMask |= SPAN_INDEX;
   }

   /* Secondary color */
   if (ctx->Visual.rgbMode && (ctx->Light.Enabled || ctx->Fog.ColorSumEnabled))
   {
      COPY_4V(span->attrStart[FRAG_ATTRIB_COL1], ctx->Current.RasterSecondaryColor);
      ASSIGN_4V(span->attrStepX[FRAG_ATTRIB_COL1], 0.0, 0.0, 0.0, 0.0);
      ASSIGN_4V(span->attrStepY[FRAG_ATTRIB_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[FRAG_ATTRIB_FOGC][0] = fogVal;
      span->attrStepX[FRAG_ATTRIB_FOGC][0] = 0.0;
      span->attrStepY[FRAG_ATTRIB_FOGC][0] = 0.0;
   }

   /* texcoords */
   {
      GLuint i;
      for (i = 0; i < ctx->Const.MaxTextureCoordUnits; i++) {
         const GLuint attr = FRAG_ATTRIB_TEX0 + i;
         const GLfloat *tc = ctx->Current.RasterTexCoords[i];
         if (ctx->FragmentProgram._Current || 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 FRAG_ATTRIB_WPOS[3]!
 */
static INLINE void
interpolate_active_attribs(GLcontext *ctx, SWspan *span, GLbitfield 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 & (1 << attr)) {
         const GLfloat dwdx = span->attrStepX[FRAG_ATTRIB_WPOS][3];
         GLfloat w = span->attrStart[FRAG_ATTRIB_WPOS][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];
         GLfloat v1 = span->attrStart[attr][1];
         GLfloat v2 = span->attrStart[attr][2];
         GLfloat v3 = span->attrStart[attr][3];
         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 & (1 << attr)) == 0);
         span->arrayAttribs |= (1 << attr);
      }
   ATTRIB_LOOP_END
}


/**
 * Interpolate primary colors to fill in the span->array->rgba8 (or rgb16)
 * color array.
 */
static INLINE void
interpolate_int_colors(GLcontext *ctx, SWspan *span)
{
   const GLuint n = span->end;
   GLuint i;

#if CHAN_BITS != 32
   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, FRAG_BIT_COL0);
      break;
   default:
      _mesa_problem(NULL, "bad datatype in interpolate_int_colors");
   }
   span->arrayMask |= SPAN_RGBA;
}


/**
 * Populate the FRAG_ATTRIB_COL0 array.
 */
static INLINE void
interpolate_float_colors(SWspan *span)
{
   GLfloat (*col0)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
   const GLuint n = span->end;
   GLuint i;

   assert(!(span->arrayAttribs & FRAG_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 |= FRAG_BIT_COL0;
   span->array->ChanType = GL_FLOAT;
}



/* Fill in the span.color.index array from the interpolation values */
static INLINE void
interpolate_indexes(GLcontext *ctx, SWspan *span)
{
   GLfixed index = span->index;
   const GLint indexStep = span->indexStep;
   const GLuint n = span->end;
   GLuint *indexes = span->array->index;
   GLuint i;
   (void) ctx;

   ASSERT(!(span->arrayMask & SPAN_INDEX));

   if ((span->interpMask & SPAN_FLAT) || (indexStep == 0)) {
      /* constant color */
      index = FixedToInt(index);
      for (i = 0; i < n; i++) {
         indexes[i] = index;
      }
   }
   else {
      /* interpolate */
      for (i = 0; i < n; i++) {
         indexes[i] = FixedToInt(index);
         index += indexStep;
      }
   }
   span->arrayMask |= SPAN_INDEX;
   span->interpMask &= ~SPAN_INDEX;
}


/**
 * Fill in the span.zArray array from the span->z, zStep values.
 */
void
_swrast_span_interpolate_z( const GLcontext *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;
}