slang_link.c

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

               else {
                  /* No user-defined binding, choose our own attribute number.
                   * Start at 1 since generic attribute 0 always aliases
                   * glVertex/position.
                   */
                  for (attr = 1; attr < MAX_VERTEX_ATTRIBS; attr++) {
                     if (((1 << attr) & usedAttributes) == 0)
                        break;
                  }
                  if (attr == MAX_VERTEX_ATTRIBS) {
                     link_error(shProg, "Too many vertex attributes");
                     return GL_FALSE;
                  }

                  /* mark this attribute as used */
                  usedAttributes |= (1 << attr);
               }

               attribMap[k] = attr;

               /* Save the final name->attrib binding so it can be queried
                * with glGetAttributeLocation().
                */
               _mesa_add_attribute(linkedProg->Attributes, name,
                                   size, type, attr);
            }

            assert(attr >= 0);

            /* update the instruction's src reg */
            inst->SrcReg[j].Index = VERT_ATTRIB_GENERIC0 + attr;
         }
      }
   }

   return GL_TRUE;
}


/**
 * Scan program instructions to update the program's NumTemporaries field.
 * Note: this implemenation relies on the code generator allocating
 * temps in increasing order (0, 1, 2, ... ).
 */
static void
_slang_count_temporaries(struct gl_program *prog)
{
   GLuint i, j;
   GLint maxIndex = -1;

   for (i = 0; i < prog->NumInstructions; i++) {
      const struct prog_instruction *inst = prog->Instructions + i;
      const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
      for (j = 0; j < numSrc; j++) {
         if (inst->SrcReg[j].File == PROGRAM_TEMPORARY) {
            if (maxIndex < inst->SrcReg[j].Index)
               maxIndex = inst->SrcReg[j].Index;
         }
         if (inst->DstReg.File == PROGRAM_TEMPORARY) {
            if (maxIndex < (GLint) inst->DstReg.Index)
               maxIndex = inst->DstReg.Index;
         }
      }
   }

   prog->NumTemporaries = (GLuint) (maxIndex + 1);
}


/**
 * Scan program instructions to update the program's InputsRead and
 * OutputsWritten fields.
 */
static void
_slang_update_inputs_outputs(struct gl_program *prog)
{
   GLuint i, j;

   prog->InputsRead = 0x0;
   prog->OutputsWritten = 0x0;

   for (i = 0; i < prog->NumInstructions; i++) {
      const struct prog_instruction *inst = prog->Instructions + i;
      const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
      for (j = 0; j < numSrc; j++) {
         if (inst->SrcReg[j].File == PROGRAM_INPUT) {
            prog->InputsRead |= 1 << inst->SrcReg[j].Index;
         }
      }
      if (inst->DstReg.File == PROGRAM_OUTPUT) {
         prog->OutputsWritten |= 1 << inst->DstReg.Index;
      }
   }
}


/** cast wrapper */
static struct gl_vertex_program *
vertex_program(struct gl_program *prog)
{
   assert(prog->Target == GL_VERTEX_PROGRAM_ARB);
   return (struct gl_vertex_program *) prog;
}


/** cast wrapper */
static struct gl_fragment_program *
fragment_program(struct gl_program *prog)
{
   assert(prog->Target == GL_FRAGMENT_PROGRAM_ARB);
   return (struct gl_fragment_program *) prog;
}


/**
 * Shader linker.  Currently:
 *
 * 1. The last attached vertex shader and fragment shader are linked.
 * 2. Varying vars in the two shaders are combined so their locations
 *    agree between the vertex and fragment stages.  They're treated as
 *    vertex program output attribs and as fragment program input attribs.
 * 3. The vertex and fragment programs are cloned and modified to update
 *    src/dst register references so they use the new, linked varying
 *    storage locations.
 */
void
_slang_link(GLcontext *ctx,
            GLhandleARB programObj,
            struct gl_shader_program *shProg)
{
   const struct gl_vertex_program *vertProg;
   const struct gl_fragment_program *fragProg;
   GLuint numSamplers = 0;
   GLuint i;

   _mesa_clear_shader_program_data(ctx, shProg);

   /* check that all programs compiled successfully */
   for (i = 0; i < shProg->NumShaders; i++) {
      if (!shProg->Shaders[i]->CompileStatus) {
         link_error(shProg, "linking with uncompiled shader\n");
         return;
      }
   }

   shProg->Uniforms = _mesa_new_uniform_list();
   shProg->Varying = _mesa_new_parameter_list();

   /**
    * Find attached vertex, fragment shaders defining main()
    */
   vertProg = NULL;
   fragProg = NULL;
   for (i = 0; i < shProg->NumShaders; i++) {
      struct gl_shader *shader = shProg->Shaders[i];
      if (shader->Type == GL_VERTEX_SHADER && shader->Main)
         vertProg = vertex_program(shader->Program);
      else if (shader->Type == GL_FRAGMENT_SHADER && shader->Main)
         fragProg = fragment_program(shader->Program);
      else
         _mesa_problem(ctx, "unexpected shader target in slang_link()");
   }

#if FEATURE_es2_glsl
   /* must have both a vertex and fragment program for ES2 */
   if (!vertProg) {
      link_error(shProg, "missing vertex shader\n");
      return;
   }
   if (!fragProg) {
      link_error(shProg, "missing fragment shader\n");
      return;
   }
#endif

   /*
    * Make copies of the vertex/fragment programs now since we'll be
    * changing src/dst registers after merging the uniforms and varying vars.
    */
   _mesa_reference_vertprog(ctx, &shProg->VertexProgram, NULL);
   if (vertProg) {
      struct gl_vertex_program *linked_vprog =
         vertex_program(_mesa_clone_program(ctx, &vertProg->Base));
      shProg->VertexProgram = linked_vprog; /* refcount OK */
      ASSERT(shProg->VertexProgram->Base.RefCount == 1);
   }

   _mesa_reference_fragprog(ctx, &shProg->FragmentProgram, NULL);
   if (fragProg) {
      struct gl_fragment_program *linked_fprog = 
         fragment_program(_mesa_clone_program(ctx, &fragProg->Base));
      shProg->FragmentProgram = linked_fprog; /* refcount OK */
      ASSERT(shProg->FragmentProgram->Base.RefCount == 1);
   }

   /* link varying vars */
   if (shProg->VertexProgram) {
      if (!link_varying_vars(shProg, &shProg->VertexProgram->Base))
         return;
   }
   if (shProg->FragmentProgram) {
      if (!link_varying_vars(shProg, &shProg->FragmentProgram->Base))
         return;
   }

   /* link uniform vars */
   if (shProg->VertexProgram)
      link_uniform_vars(shProg, &shProg->VertexProgram->Base, &numSamplers);
   if (shProg->FragmentProgram)
      link_uniform_vars(shProg, &shProg->FragmentProgram->Base, &numSamplers);

   /*_mesa_print_uniforms(shProg->Uniforms);*/

   if (shProg->VertexProgram) {
      if (!_slang_resolve_attributes(shProg, &vertProg->Base,
                                     &shProg->VertexProgram->Base)) {
         return;
      }
   }

   if (shProg->VertexProgram) {
      _slang_update_inputs_outputs(&shProg->VertexProgram->Base);
      _slang_count_temporaries(&shProg->VertexProgram->Base);
      if (!(shProg->VertexProgram->Base.OutputsWritten & (1 << VERT_RESULT_HPOS))) {
         /* the vertex program did not compute a vertex position */
         link_error(shProg,
                    "gl_Position was not written by vertex shader\n");
         return;
      }
   }
   if (shProg->FragmentProgram) {
      _slang_count_temporaries(&shProg->FragmentProgram->Base);
      _slang_update_inputs_outputs(&shProg->FragmentProgram->Base);
   }

   /* Check that all the varying vars needed by the fragment shader are
    * actually produced by the vertex shader.
    */
   if (shProg->FragmentProgram) {
      const GLbitfield varyingRead
         = shProg->FragmentProgram->Base.InputsRead >> FRAG_ATTRIB_VAR0;
      const GLbitfield varyingWritten = shProg->VertexProgram ?
         shProg->VertexProgram->Base.OutputsWritten >> VERT_RESULT_VAR0 : 0x0;
      if ((varyingRead & varyingWritten) != varyingRead) {
         link_error(shProg,
          "Fragment program using varying vars not written by vertex shader\n");
         return;
      }         
   }


   if (fragProg && shProg->FragmentProgram) {
      /* notify driver that a new fragment program has been compiled/linked */
      ctx->Driver.ProgramStringNotify(ctx, GL_FRAGMENT_PROGRAM_ARB,
                                      &shProg->FragmentProgram->Base);
#if 0
      printf("************** original fragment program\n");
      _mesa_print_program(&fragProg->Base);
      _mesa_print_program_parameters(ctx, &fragProg->Base);
#endif
#if 0
      printf("************** linked fragment prog\n");
      _mesa_print_program(&shProg->FragmentProgram->Base);
      _mesa_print_program_parameters(ctx, &shProg->FragmentProgram->Base);
#endif
   }

   if (vertProg && shProg->VertexProgram) {
      /* notify driver that a new vertex program has been compiled/linked */
      ctx->Driver.ProgramStringNotify(ctx, GL_VERTEX_PROGRAM_ARB,
                                      &shProg->VertexProgram->Base);
#if 0
      printf("************** original vertex program\n");
      _mesa_print_program(&vertProg->Base);
      _mesa_print_program_parameters(ctx, &vertProg->Base);
#endif
#if 0
      printf("************** linked vertex prog\n");
      _mesa_print_program(&shProg->VertexProgram->Base);
      _mesa_print_program_parameters(ctx, &shProg->VertexProgram->Base);
#endif
   }

   shProg->LinkStatus = (shProg->VertexProgram || shProg->FragmentProgram);
}