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