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      1 /*
      2  * Mesa 3-D graphics library
      3  * Version:  7.1
      4  *
      5  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
      6  *
      7  * Permission is hereby granted, free of charge, to any person obtaining a
      8  * copy of this software and associated documentation files (the "Software"),
      9  * to deal in the Software without restriction, including without limitation
     10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     11  * and/or sell copies of the Software, and to permit persons to whom the
     12  * Software is furnished to do so, subject to the following conditions:
     13  *
     14  * The above copyright notice and this permission notice shall be included
     15  * in all copies or substantial portions of the Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
     21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     23  */
     24 
     25 
     26 #include "main/glheader.h"
     27 #include "main/context.h"
     28 #include "main/mtypes.h"
     29 #include "main/scissor.h"
     30 
     31 
     32 /**
     33  * Called via glScissor
     34  */
     35 void GLAPIENTRY
     36 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
     37 {
     38    GET_CURRENT_CONTEXT(ctx);
     39    ASSERT_OUTSIDE_BEGIN_END(ctx);
     40 
     41    if (MESA_VERBOSE & VERBOSE_API)
     42       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
     43 
     44    if (width < 0 || height < 0) {
     45       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
     46       return;
     47    }
     48 
     49    _mesa_set_scissor(ctx, x, y, width, height);
     50 }
     51 
     52 
     53 /**
     54  * Define the scissor box.
     55  *
     56  * \param x, y coordinates of the scissor box lower-left corner.
     57  * \param width width of the scissor box.
     58  * \param height height of the scissor box.
     59  *
     60  * \sa glScissor().
     61  *
     62  * Verifies the parameters and updates __struct gl_contextRec::Scissor. On a
     63  * change flushes the vertices and notifies the driver via
     64  * the dd_function_table::Scissor callback.
     65  */
     66 void
     67 _mesa_set_scissor(struct gl_context *ctx,
     68                   GLint x, GLint y, GLsizei width, GLsizei height)
     69 {
     70    if (x == ctx->Scissor.X &&
     71        y == ctx->Scissor.Y &&
     72        width == ctx->Scissor.Width &&
     73        height == ctx->Scissor.Height)
     74       return;
     75 
     76    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
     77    ctx->Scissor.X = x;
     78    ctx->Scissor.Y = y;
     79    ctx->Scissor.Width = width;
     80    ctx->Scissor.Height = height;
     81 
     82    if (ctx->Driver.Scissor)
     83       ctx->Driver.Scissor( ctx, x, y, width, height );
     84 }
     85 
     86 
     87 /**
     88  * Initialize the context's scissor state.
     89  * \param ctx  the GL context.
     90  */
     91 void
     92 _mesa_init_scissor(struct gl_context *ctx)
     93 {
     94    /* Scissor group */
     95    ctx->Scissor.Enabled = GL_FALSE;
     96    ctx->Scissor.X = 0;
     97    ctx->Scissor.Y = 0;
     98    ctx->Scissor.Width = 0;
     99    ctx->Scissor.Height = 0;
    100 }
    101