osmesa.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

      /* override with our functions */
      functions.GetString = get_string;
      functions.UpdateState = osmesa_update_state;
      functions.GetBufferSize = NULL;

      if (!_mesa_initialize_context(&osmesa->mesa,
                                    osmesa->gl_visual,
                                    sharelist ? &sharelist->mesa
                                              : (GLcontext *) NULL,
                                    &functions, (void *) osmesa)) {
         _mesa_destroy_visual( osmesa->gl_visual );
         _mesa_free(osmesa);
         return NULL;
      }

      _mesa_enable_sw_extensions(&(osmesa->mesa));
      _mesa_enable_1_3_extensions(&(osmesa->mesa));
      _mesa_enable_1_4_extensions(&(osmesa->mesa));
      _mesa_enable_1_5_extensions(&(osmesa->mesa));
      _mesa_enable_2_0_extensions(&(osmesa->mesa));
      _mesa_enable_2_1_extensions(&(osmesa->mesa));

      osmesa->gl_buffer = _mesa_create_framebuffer(osmesa->gl_visual);
      if (!osmesa->gl_buffer) {
         _mesa_destroy_visual( osmesa->gl_visual );
         _mesa_free_context_data( &osmesa->mesa );
         _mesa_free(osmesa);
         return NULL;
      }

      /* create front color buffer in user-provided memory (no back buffer) */
      osmesa->rb = new_osmesa_renderbuffer(&osmesa->mesa, format, type);
      _mesa_add_renderbuffer(osmesa->gl_buffer, BUFFER_FRONT_LEFT, osmesa->rb);
      assert(osmesa->rb->RefCount == 2);
                        
      _mesa_add_soft_renderbuffers(osmesa->gl_buffer,
                                   GL_FALSE, /* color */
                                   osmesa->gl_visual->haveDepthBuffer,
                                   osmesa->gl_visual->haveStencilBuffer,
                                   osmesa->gl_visual->haveAccumBuffer,
                                   GL_FALSE, /* alpha */
                                   GL_FALSE /* aux */ );

      osmesa->format = format;
      osmesa->userRowLength = 0;
      osmesa->yup = GL_TRUE;
      osmesa->rInd = rind;
      osmesa->gInd = gind;
      osmesa->bInd = bind;
      osmesa->aInd = aind;

      /* Initialize the software rasterizer and helper modules. */
      {
	 GLcontext *ctx = &osmesa->mesa;
         SWcontext *swrast;
         TNLcontext *tnl;

	 if (!_swrast_CreateContext( ctx ) ||
             !_vbo_CreateContext( ctx ) ||
             !_tnl_CreateContext( ctx ) ||
             !_swsetup_CreateContext( ctx )) {
            _mesa_destroy_visual(osmesa->gl_visual);
            _mesa_free_context_data(ctx);
            _mesa_free(osmesa);
            return NULL;
         }
	
	 _swsetup_Wakeup( ctx );

         /* use default TCL pipeline */
         tnl = TNL_CONTEXT(ctx);
         tnl->Driver.RunPipeline = _tnl_run_pipeline;

         /* Extend the software rasterizer with our optimized line and triangle
          * drawing functions.
          */
         swrast = SWRAST_CONTEXT( ctx );
         swrast->choose_line = osmesa_choose_line;
         swrast->choose_triangle = osmesa_choose_triangle;
      }
   }
   return osmesa;
}


/**
 * Destroy an Off-Screen Mesa rendering context.
 *
 * \param osmesa  the context to destroy
 */
GLAPI void GLAPIENTRY
OSMesaDestroyContext( OSMesaContext osmesa )
{
   if (osmesa) {
      if (osmesa->rb)
         _mesa_reference_renderbuffer(&osmesa->rb, NULL);

      _swsetup_DestroyContext( &osmesa->mesa );
      _tnl_DestroyContext( &osmesa->mesa );
      _vbo_DestroyContext( &osmesa->mesa );
      _swrast_DestroyContext( &osmesa->mesa );

      _mesa_destroy_visual( osmesa->gl_visual );
      _mesa_unreference_framebuffer( &osmesa->gl_buffer );

      _mesa_free_context_data( &osmesa->mesa );
      _mesa_free( osmesa );
   }
}


/**
 * Bind an OSMesaContext to an image buffer.  The image buffer is just a
 * block of memory which the client provides.  Its size must be at least
 * as large as width*height*sizeof(type).  Its address should be a multiple
 * of 4 if using RGBA mode.
 *
 * Image data is stored in the order of glDrawPixels:  row-major order
 * with the lower-left image pixel stored in the first array position
 * (ie. bottom-to-top).
 *
 * If the context's viewport hasn't been initialized yet, it will now be
 * initialized to (0,0,width,height).
 *
 * Input:  osmesa - the rendering context
 *         buffer - the image buffer memory
 *         type - data type for pixel components
 *            Normally, only GL_UNSIGNED_BYTE and GL_UNSIGNED_SHORT_5_6_5
 *            are supported.  But if Mesa's been compiled with CHAN_BITS==16
 *            then type may be GL_UNSIGNED_SHORT or GL_UNSIGNED_BYTE.  And if
 *            Mesa's been build with CHAN_BITS==32 then type may be GL_FLOAT,
 *            GL_UNSIGNED_SHORT or GL_UNSIGNED_BYTE.
 *         width, height - size of image buffer in pixels, at least 1
 * Return:  GL_TRUE if success, GL_FALSE if error because of invalid osmesa,
 *          invalid buffer address, invalid type, width<1, height<1,
 *          width>internal limit or height>internal limit.
 */
GLAPI GLboolean GLAPIENTRY
OSMesaMakeCurrent( OSMesaContext osmesa, void *buffer, GLenum type,
                   GLsizei width, GLsizei height )
{
   if (!osmesa || !buffer ||
       width < 1 || height < 1 ||
       width > MAX_WIDTH || height > MAX_HEIGHT) {
      return GL_FALSE;
   }

   if (osmesa->format == OSMESA_RGB_565 && type != GL_UNSIGNED_SHORT_5_6_5) {
      return GL_FALSE;
   }

#if 0
   if (!(type == GL_UNSIGNED_BYTE ||
         (type == GL_UNSIGNED_SHORT && CHAN_BITS >= 16) ||
         (type == GL_FLOAT && CHAN_BITS == 32))) {
      /* i.e. is sizeof(type) * 8 > CHAN_BITS? */
      return GL_FALSE;
   }
#endif

   osmesa_update_state( &osmesa->mesa, 0 );

   /* Call this periodically to detect when the user has begun using
    * GL rendering from multiple threads.
    */
   _glapi_check_multithread();

   /* Set renderbuffer fields.  Set width/height = 0 to force 
    * osmesa_renderbuffer_storage() being called by _mesa_resize_framebuffer()
    */
   osmesa->rb->Data = buffer;
   osmesa->rb->DataType = type;
   osmesa->rb->Width = osmesa->rb->Height = 0;

   /* Set the framebuffer's size.  This causes the
    * osmesa_renderbuffer_storage() function to get called.
    */
   _mesa_resize_framebuffer(&osmesa->mesa, osmesa->gl_buffer, width, height);
   osmesa->gl_buffer->Initialized = GL_TRUE; /* XXX TEMPORARY? */

   _mesa_make_current( &osmesa->mesa, osmesa->gl_buffer, osmesa->gl_buffer );

   /* Remove renderbuffer attachment, then re-add.  This installs the
    * renderbuffer adaptor/wrapper if needed (for bpp conversion).
    */
   _mesa_remove_renderbuffer(osmesa->gl_buffer, BUFFER_FRONT_LEFT);
   _mesa_add_renderbuffer(osmesa->gl_buffer, BUFFER_FRONT_LEFT, osmesa->rb);


   /* this updates the visual's red/green/blue/alphaBits fields */
   _mesa_update_framebuffer_visual(osmesa->gl_buffer);

   /* update the framebuffer size */
   _mesa_resize_framebuffer(&osmesa->mesa, osmesa->gl_buffer, width, height);

   return GL_TRUE;
}



GLAPI OSMesaContext GLAPIENTRY
OSMesaGetCurrentContext( void )
{
   GLcontext *ctx = _mesa_get_current_context();
   if (ctx)
      return (OSMesaContext) ctx;
   else
      return NULL;
}



GLAPI void GLAPIENTRY
OSMesaPixelStore( GLint pname, GLint value )
{
   OSMesaContext osmesa = OSMesaGetCurrentContext();

   switch (pname) {
      case OSMESA_ROW_LENGTH:
         if (value<0) {
            _mesa_error( &osmesa->mesa, GL_INVALID_VALUE,
                      "OSMesaPixelStore(value)" );
            return;
         }
         osmesa->userRowLength = value;
         break;
      case OSMESA_Y_UP:
         osmesa->yup = value ? GL_TRUE : GL_FALSE;
         break;
      default:
         _mesa_error( &osmesa->mesa, GL_INVALID_ENUM, "OSMesaPixelStore(pname)" );
         return;
   }

   compute_row_addresses( osmesa );
}


GLAPI void GLAPIENTRY
OSMesaGetIntegerv( GLint pname, GLint *value )
{
   OSMesaContext osmesa = OSMesaGetCurrentContext();

   switch (pname) {
      case OSMESA_WIDTH:
         if (osmesa->gl_buffer)
            *value = osmesa->gl_buffer->Width;
         else
            *value = 0;
         return;
      case OSMESA_HEIGHT:
         if (osmesa->gl_buffer)
            *value = osmesa->gl_buffer->Height;
         else
            *value = 0;
         return;
      case OSMESA_FORMAT:
         *value = osmesa->format;
         return;
      case OSMESA_TYPE:
         /* current color buffer's data type */
         if (osmesa->rb) {
            *value = osmesa->rb->DataType;
         }
         else {
            *value = 0;
         }
         return;
      case OSMESA_ROW_LENGTH:
         *value = osmesa->userRowLength;
         return;
      case OSMESA_Y_UP:
         *value = osmesa->yup;
         return;
      case OSMESA_MAX_WIDTH:
         *value = MAX_WIDTH;
         return;
      case OSMESA_MAX_HEIGHT:
         *value = MAX_HEIGHT;
         return;
      default:
         _mesa_error(&osmesa->mesa, GL_INVALID_ENUM, "OSMesaGetIntergerv(pname)");
         return;
   }
}


/**
 * Return the depth buffer associated with an OSMesa context.
 * Input:  c - the OSMesa context
 * Output:  width, height - size of buffer in pixels
 *          bytesPerValue - bytes per depth value (2 or 4)
 *          buffer - pointer to depth buffer values
 * Return:  GL_TRUE or GL_FALSE to indicate success or failure.
 */
GLAPI GLboolean GLAPIENTRY
OSMesaGetDepthBuffer( OSMesaContext c, GLint *width, GLint *height,
                      GLint *bytesPerValue, void **buffer )
{
   struct gl_renderbuffer *rb = NULL;

   if (c->gl_buffer)
      rb = c->gl_buffer->Attachment[BUFFER_DEPTH].Renderbuffer;

   if (!rb || !rb->Data) {
      *width = 0;
      *height = 0;
      *bytesPerValue = 0;
      *buffer = 0;
      return GL_FALSE;
   }
   else {
      *width = rb->Width;
      *height = rb->Height;
      if (c->gl_visual->depthBits <= 16)
         *bytesPerValue = sizeof(GLushort);
      else
         *bytesPerValue = sizeof(GLuint);
      *buffer = rb->Data;
      return GL_TRUE;
   }
}


/**
 * Return the color buffer associated with an OSMesa context.
 * Input:  c - the OSMesa context
 * Output:  width, height - size of buffer in pixels
 *          format - the pixel format (OSMESA_FORMAT)
 *          buffer - pointer to color buffer values
 * Return:  GL_TRUE or GL_FALSE to indicate success or failure.
 */
GLAPI GLboolean GLAPIENTRY
OSMesaGetColorBuffer( OSMesaContext osmesa, GLint *width,
                      GLint *height, GLint *format, void **buffer )
{
   if (osmesa->rb && osmesa->rb->Data) {
      *width = osmesa->rb->Width;
      *height = osmesa->rb->Height;
      *format = osmesa->format;
      *buffer = osmesa->rb->Data;
      return GL_TRUE;
   }
   else {
      *width = 0;
      *height = 0;
      *format = 0;
      *buffer = 0;
      return GL_FALSE;
   }
}


struct name_function
{
   const char *Name;
   OSMESAproc Function;
};

static struct name_function functions[] = {
   { "OSMesaCreateContext", (OSMESAproc) OSMesaCreateContext },
   { "OSMesaCreateContextExt", (OSMESAproc) OSMesaCreateContextExt },
   { "OSMesaDestroyContext", (OSMESAproc) OSMesaDestroyContext },
   { "OSMesaMakeCurrent", (OSMESAproc) OSMesaMakeCurrent },
   { "OSMesaGetCurrentContext", (OSMESAproc) OSMesaGetCurrentContext },
   { "OSMesaPixelsStore", (OSMESAproc) OSMesaPixelStore },
   { "OSMesaGetIntegerv", (OSMESAproc) OSMesaGetIntegerv },
   { "OSMesaGetDepthBuffer", (OSMESAproc) OSMesaGetDepthBuffer },
   { "OSMesaGetColorBuffer", (OSMESAproc) OSMesaGetColorBuffer },
   { "OSMesaGetProcAddress", (OSMESAproc) OSMesaGetProcAddress },
   { "OSMesaColorClamp", (OSMESAproc) OSMesaColorClamp },
   { NULL, NULL }
};


GLAPI OSMESAproc GLAPIENTRY
OSMesaGetProcAddress( const char *funcName )
{
   int i;
   for (i = 0; functions[i].Name; i++) {
      if (_mesa_strcmp(functions[i].Name, funcName) == 0)
         return functions[i].Function;
   }
   return _glapi_get_proc_address(funcName);
}


GLAPI void GLAPIENTRY
OSMesaColorClamp(GLboolean enable)
{
   OSMesaContext osmesa = OSMesaGetCurrentContext();

   if (enable == GL_TRUE) {
      osmesa->mesa.Color.ClampFragmentColor = GL_TRUE;
   }
   else {
      osmesa->mesa.Color.ClampFragmentColor = GL_FIXED_ONLY_ARB;
   }
}