xref: /external/mesa3d/src/mesa/main/lines.c

/*
 * Mesa 3-D graphics library
 *
 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */


#include "glheader.h"
#include "context.h"
#include "lines.h"
#include "macros.h"
#include "mtypes.h"


/**
 * Set the line width.
 *
 * \param width line width in pixels.
 *
 * \sa glLineWidth().
 */
void GLAPIENTRY
_mesa_LineWidth( GLfloat width )
{
   GET_CURRENT_CONTEXT(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glLineWidth %f\n", width);

   /* If width is unchanged, there can't be an error */
   if (ctx->Line.Width == width)
      return;

   if (width <= 0.0F) {
      _mesa_error( ctx, GL_INVALID_VALUE, "glLineWidth" );
      return;
   }

   /* Page 407 (page 423 of the PDF) of the OpenGL 3.0 spec says (in the list
    * of deprecated functionality):
    *
    *     "Wide lines and line stipple - LineWidth is not deprecated, but
    *     values greater than 1.0 will generate an INVALID_VALUE error;"
    *
    * This is one of the very few cases where functionality was deprecated but
    * *NOT* removed in a later spec.  Therefore, we only disallow this in a
    * forward compatible context.
    */
   if (ctx->API == API_OPENGL_CORE
       && ((ctx->Const.ContextFlags & GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT)
           != 0)
       && width > 1.0F) {
      _mesa_error( ctx, GL_INVALID_VALUE, "glLineWidth" );
      return;
   }

   FLUSH_VERTICES(ctx, _NEW_LINE);
   ctx->Line.Width = width;

   if (ctx->Driver.LineWidth)
      ctx->Driver.LineWidth(ctx, width);
}


/**
 * Set the line stipple pattern.
 *
 * \param factor pattern scale factor.
 * \param pattern bit pattern.
 *
 * \sa glLineStipple().
 *
 * Updates gl_line_attrib::StippleFactor and gl_line_attrib::StipplePattern. On
 * change flushes the vertices and notifies the driver via
 * the dd_function_table::LineStipple callback.
 */
void GLAPIENTRY
_mesa_LineStipple( GLint factor, GLushort pattern )
{
   GET_CURRENT_CONTEXT(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glLineStipple %d %u\n", factor, pattern);

   factor = CLAMP( factor, 1, 256 );

   if (ctx->Line.StippleFactor == factor &&
       ctx->Line.StipplePattern == pattern)
      return;

   FLUSH_VERTICES(ctx, _NEW_LINE);
   ctx->Line.StippleFactor = factor;
   ctx->Line.StipplePattern = pattern;

   if (ctx->Driver.LineStipple)
      ctx->Driver.LineStipple( ctx, factor, pattern );
}


/**
 * Initialize the context line state.
 *
 * \param ctx GL context.
 *
 * Initializes __struct gl_contextRec::Line and line related constants in
 * __struct gl_contextRec::Const.
 */
void GLAPIENTRY
_mesa_init_line( struct gl_context * ctx )
{
   ctx->Line.SmoothFlag = GL_FALSE;
   ctx->Line.StippleFlag = GL_FALSE;
   ctx->Line.Width = 1.0;
   ctx->Line.StipplePattern = 0xffff;
   ctx->Line.StippleFactor = 1;
}