s_span.c

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

#endif

   /* we have to wait until after occlusion to do this test */
   if (ctx->Color.IndexMask == 0) {
      /* write no pixels */
      span->arrayMask = origArrayMask;
      return;
   }

   /* Interpolate the color indexes if needed */
   if (swrast->_FogEnabled ||
       ctx->Color.IndexLogicOpEnabled ||
       ctx->Color.IndexMask != 0xffffffff ||
       (span->arrayMask & SPAN_COVERAGE)) {
      if (!(span->arrayMask & SPAN_INDEX) /*span->interpMask & SPAN_INDEX*/) {
         interpolate_indexes(ctx, span);
      }
   }

   /* Fog */
   if (swrast->_FogEnabled) {
      _swrast_fog_ci_span(ctx, span);
   }

   /* Antialias coverage application */
   if (span->arrayMask & SPAN_COVERAGE) {
      const GLfloat *coverage = span->array->coverage;
      GLuint *index = span->array->index;
      GLuint i;
      for (i = 0; i < span->end; i++) {
         ASSERT(coverage[i] < 16);
         index[i] = (index[i] & ~0xf) | ((GLuint) coverage[i]);
      }
   }

   /*
    * Write to renderbuffers
    */
   {
      const GLuint numBuffers = fb->_NumColorDrawBuffers;
      GLuint buf;

      for (buf = 0; buf < numBuffers; buf++) {
         struct gl_renderbuffer *rb = fb->_ColorDrawBuffers[buf];
         GLuint indexSave[MAX_WIDTH];

         ASSERT(rb->_BaseFormat == GL_COLOR_INDEX);

         if (numBuffers > 1) {
            /* save indexes for second, third renderbuffer writes */
            _mesa_memcpy(indexSave, span->array->index,
                         span->end * sizeof(indexSave[0]));
         }

         if (ctx->Color.IndexLogicOpEnabled) {
            _swrast_logicop_ci_span(ctx, rb, span);
         }

         if (ctx->Color.IndexMask != 0xffffffff) {
            _swrast_mask_ci_span(ctx, rb, span);
         }

         if (!(span->arrayMask & SPAN_INDEX) && span->indexStep == 0) {
            /* all fragments have same color index */
            GLubyte index8;
            GLushort index16;
            GLuint index32;
            void *value;

            if (rb->DataType == GL_UNSIGNED_BYTE) {
               index8 = FixedToInt(span->index);
               value = &index8;
            }
            else if (rb->DataType == GL_UNSIGNED_SHORT) {
               index16 = FixedToInt(span->index);
               value = &index16;
            }
            else {
               ASSERT(rb->DataType == GL_UNSIGNED_INT);
               index32 = FixedToInt(span->index);
               value = &index32;
            }

            if (span->arrayMask & SPAN_XY) {
               rb->PutMonoValues(ctx, rb, span->end, span->array->x, 
                                 span->array->y, value, span->array->mask);
            }
            else {
               rb->PutMonoRow(ctx, rb, span->end, span->x, span->y,
                              value, span->array->mask);
            }
         }
         else {
            /* each fragment is a different color */
            GLubyte index8[MAX_WIDTH];
            GLushort index16[MAX_WIDTH];
            void *values;

            if (rb->DataType == GL_UNSIGNED_BYTE) {
               GLuint k;
               for (k = 0; k < span->end; k++) {
                  index8[k] = (GLubyte) span->array->index[k];
               }
               values = index8;
            }
            else if (rb->DataType == GL_UNSIGNED_SHORT) {
               GLuint k;
               for (k = 0; k < span->end; k++) {
                  index16[k] = (GLushort) span->array->index[k];
               }
               values = index16;
            }
            else {
               ASSERT(rb->DataType == GL_UNSIGNED_INT);
               values = span->array->index;
            }

            if (span->arrayMask & SPAN_XY) {
               rb->PutValues(ctx, rb, span->end,
                             span->array->x, span->array->y,
                             values, span->array->mask);
            }
            else {
               rb->PutRow(ctx, rb, span->end, span->x, span->y,
                          values, span->array->mask);
            }
         }

         if (buf + 1 < numBuffers) {
            /* restore original span values */
            _mesa_memcpy(span->array->index, indexSave,
                         span->end * sizeof(indexSave[0]));
         }
      } /* for buf */
   }

   span->interpMask = origInterpMask;
   span->arrayMask = origArrayMask;
}


/**
 * Add specular colors to primary colors.
 * Only called during fixed-function operation.
 * Result is float color array (FRAG_ATTRIB_COL0).
 */
static INLINE void
add_specular(GLcontext *ctx, SWspan *span)
{
   const SWcontext *swrast = SWRAST_CONTEXT(ctx);
   const GLubyte *mask = span->array->mask;
   GLfloat (*col0)[4] = span->array->attribs[FRAG_ATTRIB_COL0];
   GLfloat (*col1)[4] = span->array->attribs[FRAG_ATTRIB_COL1];
   GLuint i;

   ASSERT(!ctx->FragmentProgram._Current);
   ASSERT(span->arrayMask & SPAN_RGBA);
   ASSERT(swrast->_ActiveAttribMask & FRAG_BIT_COL1);

   if (span->array->ChanType == GL_FLOAT) {
      if ((span->arrayAttribs & FRAG_BIT_COL0) == 0) {
         interpolate_active_attribs(ctx, span, FRAG_BIT_COL0);
      }
   }
   else {
      /* need float colors */
      if ((span->arrayAttribs & FRAG_BIT_COL0) == 0) {
         interpolate_float_colors(span);
      }
   }

   if ((span->arrayAttribs & FRAG_BIT_COL1) == 0) {
      /* XXX could avoid this and interpolate COL1 in the loop below */
      interpolate_active_attribs(ctx, span, FRAG_BIT_COL1);
   }

   ASSERT(span->arrayAttribs & FRAG_BIT_COL0);
   ASSERT(span->arrayAttribs & FRAG_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[FRAG_ATTRIB_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[FRAG_ATTRIB_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[FRAG_ATTRIB_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[FRAG_ATTRIB_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(GLcontext *ctx, SWspan *span)
{
   GLbitfield inputsRead;

   /* Determine which fragment attributes are actually needed */
   if (ctx->FragmentProgram._Current) {
      inputsRead = ctx->FragmentProgram._Current->Base.InputsRead;
   }
   else {
      /* XXX we could be a bit smarter about this */
      inputsRead = ~0;
   }

   if (ctx->FragmentProgram._Current ||
       ctx->ATIFragmentShader._Enabled) {
      /* programmable shading */
      if (span->primitive == GL_BITMAP && span->array->ChanType != GL_FLOAT) {
         convert_color_type(span, GL_FLOAT, 0);
      }
      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 & FRAG_BIT_WPOS)
#else
      /* XXX always interpolate wpos so that DDX/DDY work */
#endif
         interpolate_wpos(ctx, span);

      /* Run fragment program/shader now */
      if (ctx->FragmentProgram._Current) {
         _swrast_exec_fragment_program(ctx, span);
      }
      else {
         ASSERT(ctx->ATIFragmentShader._Enabled);
         _swrast_exec_fragment_shader(ctx, span);
      }
   }
   else if (ctx->Texture._EnabledUnits) {
      /* conventional texturing */

#if CHAN_BITS == 32
      if ((span->arrayAttribs & FRAG_BIT_COL0) == 0) {
         interpolate_int_colors(ctx, span);
      }
#else
      if (!(span->arrayMask & SPAN_RGBA))
         interpolate_int_colors(ctx, span);
#endif
      if ((span->arrayAttribs & FRAG_BITS_TEX_ANY) == 0x0)
         interpolate_texcoords(ctx, span);

      _swrast_texture_span(ctx, span);
   }
}



/**
 * 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( GLcontext *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 GLbitfield origArrayAttribs = span->arrayAttribs;
   const GLenum origChanType = span->array->ChanType;
   void * const origRgba = span->array->rgba;
   const GLboolean shader = (ctx->FragmentProgram._Current
                             || ctx->ATIFragmentShader._Enabled);
   const GLboolean shaderOrTexture = shader || ctx->Texture._EnabledUnits;
   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);
   ASSERT(span->end <= MAX_WIDTH);

   /* Fragment write masks */
   if (span->arrayMask & SPAN_MASK) {
      /* mask was initialized by caller, probably glBitmap */
      span->writeAll = GL_FALSE;
   }
   else {
      _mesa_memset(span->array->mask, 1, span->end);
      span->writeAll = GL_TRUE;
   }

   /* Clip to window/scissor box */
   if ((swrast->_RasterMask & CLIP_BIT) || (span->primitive != GL_POLYGON)) {
      if (!clip_span(ctx, span)) {
	 return;
      }
   }

#ifdef DEBUG
   /* Make sure all fragments are within window bounds */
   if (span->arrayMask & SPAN_XY) {
      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)) {
         goto end;
      }