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