framebuffer.c

winNT技术操作系统,国外开放的原代码和LIUX一样

         rb->RefCount--;
         if (rb->RefCount == 0) {
            rb->Delete(rb);
         }
      }
      att->Type = GL_NONE;
      att->Renderbuffer = NULL;
   }
}


/**
 * Resize the given framebuffer's renderbuffers to the new width and height.
 * This should only be used for window-system framebuffers, not
 * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 * This will typically be called via ctx->Driver.ResizeBuffers()
 */
void
_mesa_resize_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb,
                         GLuint width, GLuint height)
{
   GLuint i;

   /* For window system framebuffers, Name is zero */
   assert(fb->Name == 0);

   for (i = 0; i < BUFFER_COUNT; i++) {
      struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
      if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
         struct gl_renderbuffer *rb = att->Renderbuffer;
         /* only resize if size is changing */
         if (rb->Width != width || rb->Height != height) {
            if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
               rb->Width = width;
               rb->Height = height;
            }
            else {
               _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
            }
         }
      }
   }

   fb->Width = width;
   fb->Height = height;

   /* to update scissor / window bounds */
   ctx->NewState |= _NEW_BUFFERS;
}


/**
 * Examine all the framebuffer's renderbuffers to update the Width/Height
 * fields of the framebuffer.  If we have renderbuffers with different
 * sizes, set the framebuffer's width and height to zero.
 * Note: this is only intended for user-created framebuffers, not
 * window-system framebuffes.
 */
static void
update_framebuffer_size(struct gl_framebuffer *fb)
{
   GLboolean haveSize = GL_FALSE;
   GLuint i;

   /* user-created framebuffers only */
   assert(fb->Name);

   for (i = 0; i < BUFFER_COUNT; i++) {
      struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
      const struct gl_renderbuffer *rb = att->Renderbuffer;
      if (rb) {
         if (haveSize) {
            if (rb->Width != fb->Width && rb->Height != fb->Height) {
               /* size mismatch! */
               fb->Width = 0;
               fb->Height = 0;
               return;
            }
         }
         else {
            fb->Width = rb->Width;
            fb->Height = rb->Height;
            haveSize = GL_TRUE;
         }
      }
   }
}


/**
 * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 * These values are computed from the buffer's width and height and
 * the scissor box, if it's enabled.
 * \param ctx  the GL context.
 */
void
_mesa_update_draw_buffer_bounds(GLcontext *ctx)
{
   struct gl_framebuffer *buffer = ctx->DrawBuffer;

   if (buffer->Name) {
      /* user-created framebuffer size depends on the renderbuffers */
      update_framebuffer_size(buffer);
   }

   buffer->_Xmin = 0;
   buffer->_Ymin = 0;
   buffer->_Xmax = buffer->Width;
   buffer->_Ymax = buffer->Height;

   if (ctx->Scissor.Enabled) {
      if (ctx->Scissor.X > buffer->_Xmin) {
	 buffer->_Xmin = ctx->Scissor.X;
      }
      if (ctx->Scissor.Y > buffer->_Ymin) {
	 buffer->_Ymin = ctx->Scissor.Y;
      }
      if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
	 buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
      }
      if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
	 buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
      }
      /* finally, check for empty region */
      if (buffer->_Xmin > buffer->_Xmax) {
         buffer->_Xmin = buffer->_Xmax;
      }
      if (buffer->_Ymin > buffer->_Ymax) {
         buffer->_Ymin = buffer->_Ymax;
      }
   }

   ASSERT(buffer->_Xmin <= buffer->_Xmax);
   ASSERT(buffer->_Ymin <= buffer->_Ymax);
}


/**
 * The glGet queries of the framebuffer red/green/blue size, stencil size,
 * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 * change depending on the renderbuffer bindings.  This function update's
 * the given framebuffer's Visual from the current renderbuffer bindings.
 * This is only intended for user-created framebuffers.
 */
void
_mesa_update_framebuffer_visual(struct gl_framebuffer *fb)
{
   GLuint i;

   assert(fb->Name != 0);

   _mesa_bzero(&fb->Visual, sizeof(fb->Visual));
   fb->Visual.rgbMode = GL_TRUE;

   /* find first RGB or CI renderbuffer */
   for (i = 0; i < BUFFER_COUNT; i++) {
      if (fb->Attachment[i].Renderbuffer) {
         const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
         if (rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB) {
            fb->Visual.redBits = rb->ComponentSizes[0];
            fb->Visual.greenBits = rb->ComponentSizes[1];
            fb->Visual.blueBits = rb->ComponentSizes[2];
            fb->Visual.alphaBits = rb->ComponentSizes[3];
            fb->Visual.floatMode = GL_FALSE;
            break;
         }
         else if (rb->_BaseFormat == GL_COLOR_INDEX) {
            fb->Visual.indexBits = rb->ComponentSizes[0];
            fb->Visual.rgbMode = GL_FALSE;
            break;
         }
      }
   }

   if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
      fb->Visual.haveDepthBuffer = GL_TRUE;
      fb->Visual.depthBits
         = fb->Attachment[BUFFER_DEPTH].Renderbuffer->ComponentSizes[0];
   }

   if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
      fb->Visual.haveStencilBuffer = GL_TRUE;
      fb->Visual.stencilBits
         = fb->Attachment[BUFFER_STENCIL].Renderbuffer->ComponentSizes[0];
   }

   compute_depth_max(fb);
}


/**
 * Given a framebuffer and a buffer bit (like BUFFER_BIT_FRONT_LEFT), return
 * the corresponding renderbuffer.
 */
static struct gl_renderbuffer *
get_renderbuffer(struct gl_framebuffer *fb, GLuint bufferBit)
{
   GLuint index;
   for (index = 0; index < BUFFER_COUNT; index++) {
      if ((1 << index) == bufferBit) {
         return fb->Attachment[index].Renderbuffer;
      }
   }
   _mesa_problem(NULL, "Bad bufferBit in get_renderbuffer");
   return NULL;
}


/**
 * Update state related to the current draw/read framebuffers.
 * If the current framebuffer is user-created, make sure it's complete.
 */
void
_mesa_update_framebuffer(GLcontext *ctx)
{
   struct gl_framebuffer *fb = ctx->DrawBuffer;
   GLuint output;

   /* Completeness only matters for user-created framebuffers */
   if (fb->Name != 0) {
      _mesa_test_framebuffer_completeness(ctx, fb);
      _mesa_update_framebuffer_visual(fb);
   }

   /*
    * Update the list of drawing renderbuffer pointers.
    * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
    * writing colors.  We have a loop because glDrawBuffer(GL_FRONT_AND_BACK)
    * can specify writing to two or four color buffers.
    */
   for (output = 0; output < ctx->Const.MaxDrawBuffers; output++) {
      GLuint bufferMask = fb->_ColorDrawBufferMask[output];
      GLuint count = 0;
      GLuint bufferBit;
      /* for each bit that's set in the bufferMask... */
      for (bufferBit = 1; bufferMask; bufferBit <<= 1) {
         if (bufferBit & bufferMask) {
            struct gl_renderbuffer *rb = get_renderbuffer(fb, bufferBit);
            if (rb) {
               fb->_ColorDrawBuffers[output][count] = rb;
               fb->_ColorDrawBit[output][count] = bufferBit;
               count++;
            }
            else {
               /*_mesa_warning(ctx, "DrawBuffer names a missing buffer!");*/
            }
            bufferMask &= ~bufferBit;
         }
      }
      fb->_NumColorDrawBuffers[output] = count;
   }

   /*
    * Update the read renderbuffer pointer.
    * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
    */
   if (fb->_ColorReadBufferMask == 0x0)
      fb->_ColorReadBuffer = NULL; /* legal! */
   else
      fb->_ColorReadBuffer = get_renderbuffer(fb, fb->_ColorReadBufferMask);

   compute_depth_max(fb);
}