s_triangle.c

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

         break;
      }
      break;
   }
   
   ASSERT(span->arrayMask & SPAN_RGBA);
   _swrast_write_rgba_span(ctx, span);

#undef SPAN_NEAREST
#undef SPAN_LINEAR

   /* restore state */
   ctx->Texture._EnabledUnits = savedTexEnable;
}


/*
 * Render an perspective corrected RGB/RGBA textured triangle.
 * The Q (aka V in Mesa) coordinate must be zero such that the divide
 * by interpolated Q/W comes out right.
 *
 */
#define NAME persp_textured_triangle
#define INTERP_Z 1
#define INTERP_RGB 1
#define INTERP_ALPHA 1
#define INTERP_ATTRIBS 1

#define SETUP_CODE							\
   struct persp_info info;						\
   const struct gl_texture_unit *unit = ctx->Texture.Unit+0;		\
   const struct gl_texture_object *obj = unit->Current2D;		\
   const GLint b = obj->BaseLevel;					\
   info.texture = (const GLchan *) obj->Image[0][b]->Data;		\
   info.twidth_log2 = obj->Image[0][b]->WidthLog2;			\
   info.smask = obj->Image[0][b]->Width - 1;				\
   info.tmask = obj->Image[0][b]->Height - 1;				\
   info.format = obj->Image[0][b]->_BaseFormat;				\
   info.filter = obj->MinFilter;					\
   info.envmode = unit->EnvMode;					\
									\
   if (info.envmode == GL_BLEND) {					\
      /* potential off-by-one error here? (1.0f -> 2048 -> 0) */	\
      info.er = FloatToFixed(unit->EnvColor[RCOMP] * CHAN_MAXF);	\
      info.eg = FloatToFixed(unit->EnvColor[GCOMP] * CHAN_MAXF);	\
      info.eb = FloatToFixed(unit->EnvColor[BCOMP] * CHAN_MAXF);	\
      info.ea = FloatToFixed(unit->EnvColor[ACOMP] * CHAN_MAXF);	\
   }									\
   if (!info.texture) {							\
      /* this shouldn't happen */					\
      return;								\
   }									\
									\
   switch (info.format) {						\
   case GL_ALPHA:							\
   case GL_LUMINANCE:							\
   case GL_INTENSITY:							\
      info.tbytesline = obj->Image[0][b]->Width;			\
      break;								\
   case GL_LUMINANCE_ALPHA:						\
      info.tbytesline = obj->Image[0][b]->Width * 2;			\
      break;								\
   case GL_RGB:								\
      info.tbytesline = obj->Image[0][b]->Width * 3;			\
      break;								\
   case GL_RGBA:							\
      info.tbytesline = obj->Image[0][b]->Width * 4;			\
      break;								\
   default:								\
      _mesa_problem(NULL, "Bad texture format in persp_textured_triangle");\
      return;								\
   }									\
   info.tsize = obj->Image[0][b]->Height * info.tbytesline;

#define RENDER_SPAN( span )			\
   span.interpMask &= ~SPAN_RGBA;		\
   span.arrayMask |= SPAN_RGBA;			\
   fast_persp_span(ctx, &span, &info);

#include "s_tritemp.h"

#endif /*CHAN_TYPE != GL_FLOAT*/



/*
 * Render an RGBA triangle with arbitrary attributes.
 */
#define NAME general_triangle
#define INTERP_Z 1
#define INTERP_RGB 1
#define INTERP_ALPHA 1
#define INTERP_ATTRIBS 1
#define RENDER_SPAN( span )   _swrast_write_rgba_span(ctx, &span);
#include "s_tritemp.h"




/*
 * Special tri function for occlusion testing
 */
#define NAME occlusion_zless_triangle
#define INTERP_Z 1
#define SETUP_CODE							\
   struct gl_renderbuffer *rb = ctx->DrawBuffer->_DepthBuffer;		\
   struct gl_query_object *q = ctx->Query.CurrentOcclusionObject;	\
   ASSERT(ctx->Depth.Test);						\
   ASSERT(!ctx->Depth.Mask);						\
   ASSERT(ctx->Depth.Func == GL_LESS);					\
   if (!q) {								\
      return;								\
   }
#define RENDER_SPAN( span )						\
   if (rb->DepthBits <= 16) {						\
      GLuint i;								\
      const GLushort *zRow = (const GLushort *)				\
         rb->GetPointer(ctx, rb, span.x, span.y);			\
      for (i = 0; i < span.end; i++) {					\
         GLuint z = FixedToDepth(span.z);				\
         if (z < zRow[i]) {						\
            q->Result++;						\
         }								\
         span.z += span.zStep;						\
      }									\
   }									\
   else {								\
      GLuint i;								\
      const GLuint *zRow = (const GLuint *)				\
         rb->GetPointer(ctx, rb, span.x, span.y);			\
      for (i = 0; i < span.end; i++) {					\
         if ((GLuint)span.z < zRow[i]) {				\
            q->Result++;						\
         }								\
         span.z += span.zStep;						\
      }									\
   }
#include "s_tritemp.h"



static void
nodraw_triangle( GLcontext *ctx,
                 const SWvertex *v0,
                 const SWvertex *v1,
                 const SWvertex *v2 )
{
   (void) (ctx && v0 && v1 && v2);
}


/*
 * This is used when separate specular color is enabled, but not
 * texturing.  We add the specular color to the primary color,
 * draw the triangle, then restore the original primary color.
 * Inefficient, but seldom needed.
 */
void
_swrast_add_spec_terms_triangle(GLcontext *ctx, const SWvertex *v0,
                                const SWvertex *v1, const SWvertex *v2)
{
   SWvertex *ncv0 = (SWvertex *)v0; /* drop const qualifier */
   SWvertex *ncv1 = (SWvertex *)v1;
   SWvertex *ncv2 = (SWvertex *)v2;
   GLfloat rSum, gSum, bSum;
   GLchan cSave[3][4];

   /* save original colors */
   COPY_CHAN4( cSave[0], ncv0->color );
   COPY_CHAN4( cSave[1], ncv1->color );
   COPY_CHAN4( cSave[2], ncv2->color );
   /* sum v0 */
   rSum = CHAN_TO_FLOAT(ncv0->color[0]) + ncv0->attrib[FRAG_ATTRIB_COL1][0];
   gSum = CHAN_TO_FLOAT(ncv0->color[1]) + ncv0->attrib[FRAG_ATTRIB_COL1][1];
   bSum = CHAN_TO_FLOAT(ncv0->color[2]) + ncv0->attrib[FRAG_ATTRIB_COL1][2];
   UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[0], rSum);
   UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[1], gSum);
   UNCLAMPED_FLOAT_TO_CHAN(ncv0->color[2], bSum);
   /* sum v1 */
   rSum = CHAN_TO_FLOAT(ncv1->color[0]) + ncv1->attrib[FRAG_ATTRIB_COL1][0];
   gSum = CHAN_TO_FLOAT(ncv1->color[1]) + ncv1->attrib[FRAG_ATTRIB_COL1][1];
   bSum = CHAN_TO_FLOAT(ncv1->color[2]) + ncv1->attrib[FRAG_ATTRIB_COL1][2];
   UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[0], rSum);
   UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[1], gSum);
   UNCLAMPED_FLOAT_TO_CHAN(ncv1->color[2], bSum);
   /* sum v2 */
   rSum = CHAN_TO_FLOAT(ncv2->color[0]) + ncv2->attrib[FRAG_ATTRIB_COL1][0];
   gSum = CHAN_TO_FLOAT(ncv2->color[1]) + ncv2->attrib[FRAG_ATTRIB_COL1][1];
   bSum = CHAN_TO_FLOAT(ncv2->color[2]) + ncv2->attrib[FRAG_ATTRIB_COL1][2];
   UNCLAMPED_FLOAT_TO_CHAN(ncv2->color[0], rSum);
   UNCLAMPED_FLOAT_TO_CHAN(ncv2->color[1], gSum);
   UNCLAMPED_FLOAT_TO_CHAN(ncv2->color[2], bSum);
   /* draw */
   SWRAST_CONTEXT(ctx)->SpecTriangle( ctx, ncv0, ncv1, ncv2 );
   /* restore original colors */
   COPY_CHAN4( ncv0->color, cSave[0] );
   COPY_CHAN4( ncv1->color, cSave[1] );
   COPY_CHAN4( ncv2->color, cSave[2] );
}



#ifdef DEBUG

/* record the current triangle function name */
const char *_mesa_triFuncName = NULL;

#define USE(triFunc)				\
do {						\
    _mesa_triFuncName = #triFunc;		\
    /*printf("%s\n", _mesa_triFuncName);*/	\
    swrast->Triangle = triFunc;			\
} while (0)

#else

#define USE(triFunc)  swrast->Triangle = triFunc;

#endif




/*
 * Determine which triangle rendering function to use given the current
 * rendering context.
 *
 * Please update the summary flag _SWRAST_NEW_TRIANGLE if you add or
 * remove tests to this code.
 */
void
_swrast_choose_triangle( GLcontext *ctx )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);
   const GLboolean rgbmode = ctx->Visual.rgbMode;

   if (ctx->Polygon.CullFlag &&
       ctx->Polygon.CullFaceMode == GL_FRONT_AND_BACK) {
      USE(nodraw_triangle);
      return;
   }

   if (ctx->RenderMode==GL_RENDER) {

      if (ctx->Polygon.SmoothFlag) {
         _swrast_set_aa_triangle_function(ctx);
         ASSERT(swrast->Triangle);
         return;
      }

      /* special case for occlusion testing */
      if (ctx->Query.CurrentOcclusionObject &&
          ctx->Depth.Test &&
          ctx->Depth.Mask == GL_FALSE &&
          ctx->Depth.Func == GL_LESS &&
          !ctx->Stencil.Enabled) {
         if ((rgbmode &&
              ctx->Color.ColorMask[0] == 0 &&
              ctx->Color.ColorMask[1] == 0 &&
              ctx->Color.ColorMask[2] == 0 &&
              ctx->Color.ColorMask[3] == 0)
             ||
             (!rgbmode && ctx->Color.IndexMask == 0)) {
            USE(occlusion_zless_triangle);
            return;
         }
      }

      if (!rgbmode) {
         USE(ci_triangle);
         return;
      }

      /*
       * XXX should examine swrast->_ActiveAttribMask to determine what
       * needs to be interpolated.
       */
      if (ctx->Texture._EnabledCoordUnits ||
          ctx->FragmentProgram._Current ||
          ctx->ATIFragmentShader._Enabled ||
          NEED_SECONDARY_COLOR(ctx) ||
          swrast->_FogEnabled) {
         /* Ugh, we do a _lot_ of tests to pick the best textured tri func */
         const struct gl_texture_object *texObj2D;
         const struct gl_texture_image *texImg;
         GLenum minFilter, magFilter, envMode;
         GLint format;
         texObj2D = ctx->Texture.Unit[0].Current2D;
         texImg = texObj2D ? texObj2D->Image[0][texObj2D->BaseLevel] : NULL;
         format = texImg ? texImg->TexFormat->MesaFormat : -1;
         minFilter = texObj2D ? texObj2D->MinFilter : (GLenum) 0;
         magFilter = texObj2D ? texObj2D->MagFilter : (GLenum) 0;
         envMode = ctx->Texture.Unit[0].EnvMode;

         /* First see if we can use an optimized 2-D texture function */
         if (ctx->Texture._EnabledCoordUnits == 0x1
             && !ctx->FragmentProgram._Current
             && !ctx->ATIFragmentShader._Enabled
             && ctx->Texture.Unit[0]._ReallyEnabled == TEXTURE_2D_BIT
             && texObj2D->WrapS == GL_REPEAT
             && texObj2D->WrapT == GL_REPEAT
             && texImg->_IsPowerOfTwo
             && texImg->Border == 0
             && texImg->Width == texImg->RowStride
             && (format == MESA_FORMAT_RGB || format == MESA_FORMAT_RGBA)
             && minFilter == magFilter
             && ctx->Light.Model.ColorControl == GL_SINGLE_COLOR
             && !swrast->_FogEnabled
             && ctx->Texture.Unit[0].EnvMode != GL_COMBINE_EXT) {
	    if (ctx->Hint.PerspectiveCorrection==GL_FASTEST) {
	       if (minFilter == GL_NEAREST
		   && format == MESA_FORMAT_RGB
		   && (envMode == GL_REPLACE || envMode == GL_DECAL)
		   && ((swrast->_RasterMask == (DEPTH_BIT | TEXTURE_BIT)
			&& ctx->Depth.Func == GL_LESS
			&& ctx->Depth.Mask == GL_TRUE)
		       || swrast->_RasterMask == TEXTURE_BIT)
		   && ctx->Polygon.StippleFlag == GL_FALSE
                   && ctx->DrawBuffer->Visual.depthBits <= 16) {
		  if (swrast->_RasterMask == (DEPTH_BIT | TEXTURE_BIT)) {
		     USE(simple_z_textured_triangle);
		  }
		  else {
		     USE(simple_textured_triangle);
		  }
	       }
	       else {
#if CHAN_BITS != 8
                  USE(general_triangle);
#else
                  USE(affine_textured_triangle);
#endif
	       }
	    }
	    else {
#if CHAN_BITS != 8
               USE(general_triangle);
#else
               USE(persp_textured_triangle);
#endif
	    }
	 }
         else {
            /* general case textured triangles */
            USE(general_triangle);
         }
      }
      else {
         ASSERT(!swrast->_FogEnabled);
         ASSERT(!NEED_SECONDARY_COLOR(ctx));
	 if (ctx->Light.ShadeModel==GL_SMOOTH) {
	    /* smooth shaded, no texturing, stippled or some raster ops */
#if CHAN_BITS != 8
               USE(general_triangle);
#else
               USE(smooth_rgba_triangle);
#endif
	 }
	 else {
	    /* flat shaded, no texturing, stippled or some raster ops */
#if CHAN_BITS != 8
            USE(general_triangle);
#else
            USE(flat_rgba_triangle);
#endif
	 }
      }
   }
   else if (ctx->RenderMode==GL_FEEDBACK) {
      USE(_swrast_feedback_triangle);
   }
   else {
      /* GL_SELECT mode */
      USE(_swrast_select_triangle);
   }
}