source/backends/opengl/texture_backend.cpp

   1 #include <msp/gl/extensions/arb_direct_state_access.h>
   2 #include <msp/gl/extensions/arb_texture_swizzle.h>
   3 #include <msp/gl/extensions/ext_framebuffer_object.h>
   4 #include <msp/gl/extensions/khr_debug.h>
   5 #include "gl.h"
   6 #include "error.h"
   7 #include "texture.h"
   8 #include "texture_backend.h"
   9
  10 using namespace std;
  11
  12 namespace Msp {
  13 namespace GL {
  14
  15 int OpenGLTexture::swizzle_orders[] =
  16 {
  17         GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA,
  18         GL_RED, GL_RED, GL_RED, GL_ONE,
  19         GL_RED, GL_RED, GL_RED, GL_GREEN,
  20         GL_BLUE, GL_GREEN, GL_RED, GL_ALPHA
  21 };
  22
  23 OpenGLTexture *OpenGLTexture::scratch_binding = 0;
  24
  25 OpenGLTexture::OpenGLTexture(unsigned t, bool create):
  26         id(0),
  27         target(t)
  28 {
  29         if(create)
  30                 generate_id();
  31
  32         static bool alignment_init = false;
  33         if(!alignment_init)
  34         {
  35                 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  36                 alignment_init = true;
  37         }
  38 }
  39
  40 OpenGLTexture::~OpenGLTexture()
  41 {
  42         if(this==scratch_binding)
  43                 unbind_scratch();
  44         if(id)
  45                 glDeleteTextures(1, &id);
  46 }
  47
  48 void OpenGLTexture::generate_id()
  49 {
  50         if(id)
  51                 throw invalid_operation("OpenGLTexture::generate_id");
  52         if(ARB_direct_state_access)
  53                 glCreateTextures(target, 1, &id);
  54         else
  55                 glGenTextures(1, &id);
  56
  57 #ifdef DEBUG
  58         if(!debug_name.empty() && KHR_debug)
  59                 glObjectLabel(GL_TEXTURE, id, debug_name.size(), debug_name.c_str());
  60 #endif
  61 }
  62
  63 void OpenGLTexture::require_swizzle()
  64 {
  65         static Require _req(ARB_texture_swizzle);
  66 }
  67
  68 void OpenGLTexture::apply_swizzle()
  69 {
  70         Texture::FormatSwizzle swizzle = static_cast<const Texture *>(this)->swizzle;
  71         if(swizzle==Texture::NO_SWIZZLE)
  72                 return;
  73
  74         if(get_backend_api()==OPENGL_ES)
  75         {
  76                 set_parameter_i(GL_TEXTURE_SWIZZLE_R, swizzle_orders[swizzle*4]);
  77                 set_parameter_i(GL_TEXTURE_SWIZZLE_G, swizzle_orders[swizzle*4+1]);
  78                 set_parameter_i(GL_TEXTURE_SWIZZLE_B, swizzle_orders[swizzle*4+2]);
  79                 set_parameter_i(GL_TEXTURE_SWIZZLE_A, swizzle_orders[swizzle*4+3]);
  80         }
  81         else
  82         {
  83                 if(ARB_direct_state_access)
  84                         glTextureParameteriv(id, GL_TEXTURE_SWIZZLE_RGBA, swizzle_orders+swizzle*4);
  85                 else
  86                         glTexParameteriv(target, GL_TEXTURE_SWIZZLE_RGBA, swizzle_orders+swizzle*4);
  87         }
  88 }
  89
  90 void OpenGLTexture::set_parameter_i(unsigned param, int value) const
  91 {
  92         if(ARB_direct_state_access)
  93                 glTextureParameteri(id, param, value);
  94         else
  95                 glTexParameteri(target, param, value);
  96 }
  97
  98 void OpenGLTexture::generate_mipmap()
  99 {
 100         // glGenerateMipmap is defined here
 101         static Require _req(EXT_framebuffer_object);
 102
 103         if(ARB_direct_state_access)
 104                 glGenerateTextureMipmap(id);
 105         else
 106         {
 107                 bind_scratch();
 108                 glGenerateMipmap(target);
 109         }
 110 }
 111
 112 void OpenGLTexture::set_debug_name(const string &name)
 113 {
 114 #ifdef DEBUG
 115         debug_name = name;
 116         if(id && KHR_debug)
 117                 glObjectLabel(GL_TEXTURE, id, name.size(), name.c_str());
 118 #else
 119         (void)name;
 120 #endif
 121 }
 122
 123 void OpenGLTexture::bind_scratch()
 124 {
 125         if(!scratch_binding)
 126                 glActiveTexture(GL_TEXTURE0);
 127         if(scratch_binding!=this)
 128         {
 129                 if(scratch_binding && scratch_binding->target!=target)
 130                         glBindTexture(scratch_binding->target, 0);
 131                 glBindTexture(target, id);
 132                 scratch_binding = this;
 133         }
 134 }
 135
 136 void OpenGLTexture::unbind_scratch()
 137 {
 138         if(scratch_binding)
 139         {
 140                 glBindTexture(scratch_binding->target, 0);
 141                 scratch_binding = 0;
 142         }
 143 }
 144
 145 } // namespace GL
 146 } // namespace Msp