src/mesa/main/shader_query.cpp

   1 /*
   2  * Copyright © 2011 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * \file shader_query.cpp
  26  * C-to-C++ bridge functions to query GLSL shader data
  27  *
  28  * \author Ian Romanick <ian.d.romanick@intel.com>
  29  */
  30
  31 #include "main/core.h"
  32 #include "glsl_symbol_table.h"
  33 #include "ir.h"
  34 #include "shaderobj.h"
  35
  36 extern "C" {
  37 #include "shaderapi.h"
  38 }
  39
  40 GLint GLAPIENTRY
  41 _mesa_GetAttribLocationARB(GLhandleARB program, const GLcharARB * name)
  42 {
  43    GET_CURRENT_CONTEXT(ctx);
  44    struct gl_shader_program *const shProg =
  45       _mesa_lookup_shader_program_err(ctx, program, "glGetAttribLocation");
  46
  47    if (!shProg) {
  48       return -1;
  49    }
  50
  51    if (!shProg->LinkStatus) {
  52       _mesa_error(ctx, GL_INVALID_OPERATION,
  53                   "glGetAttribLocation(program not linked)");
  54       return -1;
  55    }
  56
  57    if (!name)
  58       return -1;
  59
  60    /* Not having a vertex shader is not an error.
  61     */
  62    if (shProg->_LinkedShaders[MESA_SHADER_VERTEX] == NULL)
  63       return -1;
  64
  65    exec_list *ir = shProg->_LinkedShaders[MESA_SHADER_VERTEX]->ir;
  66    foreach_list(node, ir) {
  67       const ir_variable *const var = ((ir_instruction *) node)->as_variable();
  68
  69       /* The extra check against VERT_ATTRIB_GENERIC0 is because
  70        * glGetAttribLocation cannot be used on "conventional" attributes.
  71        *
  72        * From page 95 of the OpenGL 3.0 spec:
  73        *
  74        *     "If name is not an active attribute, if name is a conventional
  75        *     attribute, or if an error occurs, -1 will be returned."
  76        */
  77       if (var == NULL
  78           || var->mode != ir_var_in
  79           || var->location == -1
  80           || var->location < VERT_ATTRIB_GENERIC0)
  81          continue;
  82
  83       if (strcmp(var->name, name) == 0)
  84          return var->location - VERT_ATTRIB_GENERIC0;
  85    }
  86
  87    return -1;
  88 }