source/texunit.cpp

   1 #include <stdexcept>
   2 #include <msp/gl/extensions/arb_multitexture.h>
   3 #include <msp/gl/extensions/arb_vertex_shader.h>
   4 #include <msp/gl/extensions/msp_legacy_features.h>
   5 #include "gl.h"
   6 #include "misc.h"
   7 #include "texunit.h"
   8
   9 using namespace std;
  10
  11 namespace Msp {
  12 namespace GL {
  13
  14 vector<TexUnit> TexUnit::units;
  15 TexUnit *TexUnit::cur_unit = 0;
  16
  17 TexUnit::TexUnit():
  18         legacy(false),
  19         texture(0)
  20 { }
  21
  22 bool TexUnit::set_texture(const Texture *tex)
  23 {
  24         bool result = (tex!=texture);
  25         texture = tex;
  26         return result;
  27 }
  28
  29 void TexUnit::bind()
  30 {
  31         if(cur_unit!=this && (cur_unit || index))
  32                 glActiveTexture(GL_TEXTURE0+index);
  33         cur_unit = this;
  34 }
  35
  36 unsigned TexUnit::get_n_units()
  37 {
  38         static int count = -1;
  39         if(count<0)
  40         {
  41                 if(ARB_vertex_shader)
  42                         count = get_i(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS);
  43                 else if(ARB_multitexture)
  44                         count = get_i(GL_MAX_TEXTURE_UNITS);
  45                 else
  46                         count = 1;
  47         }
  48         return count;
  49 }
  50
  51 unsigned TexUnit::get_n_legacy_units()
  52 {
  53         static int count = -1;
  54         if(count<0)
  55         {
  56                 if(MSP_legacy_features)
  57                         count = get_i(GL_MAX_TEXTURE_UNITS);
  58                 else
  59                         count = 0;
  60         }
  61         return count;
  62 }
  63
  64 TexUnit &TexUnit::get_unit(unsigned n)
  65 {
  66         if(n>0)
  67                 static Require _req(ARB_multitexture);
  68         if(n>=get_n_units())
  69                 throw out_of_range("TexUnit::get_unit");
  70
  71         if(units.size()<=n)
  72         {
  73                 unsigned i = units.size();
  74                 unsigned n_legacy = get_n_legacy_units();
  75                 units.resize(n+1, TexUnit());
  76                 for(; i<units.size(); ++i)
  77                 {
  78                         units[i].index = i;
  79                         units[i].legacy = (i<n_legacy);
  80                 }
  81         }
  82
  83         return units[n];
  84 }
  85
  86 TexUnit &TexUnit::current()
  87 {
  88         if(!cur_unit)
  89                 get_unit(0).bind();
  90         return *cur_unit;
  91 }
  92
  93 TexUnit *TexUnit::find_unit(const Texture *tex)
  94 {
  95         for(vector<TexUnit>::iterator i=units.begin(); i!=units.end(); ++i)
  96                 if(i->texture==tex)
  97                         return &*i;
  98         return 0;
  99 }
 100
 101 } // namespace GL
 102 } // namespace Msp