src/mesa/main/scissor.c

   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/scissor.h"
  29
  30
  31 /**
  32  * Called via glScissor
  33  */
  34 void GLAPIENTRY
  35 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
  36 {
  37    GET_CURRENT_CONTEXT(ctx);
  38    ASSERT_OUTSIDE_BEGIN_END(ctx);
  39
  40    if (MESA_VERBOSE & VERBOSE_API)
  41       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
  42
  43    if (width < 0 || height < 0) {
  44       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
  45       return;
  46    }
  47
  48    _mesa_set_scissor(ctx, x, y, width, height);
  49 }
  50
  51
  52 /**
  53  * Define the scissor box.
  54  *
  55  * \param x, y coordinates of the scissor box lower-left corner.
  56  * \param width width of the scissor box.
  57  * \param height height of the scissor box.
  58  *
  59  * \sa glScissor().
  60  *
  61  * Verifies the parameters and updates __struct gl_contextRec::Scissor. On a
  62  * change flushes the vertices and notifies the driver via
  63  * the dd_function_table::Scissor callback.
  64  */
  65 void
  66 _mesa_set_scissor(struct gl_context *ctx,
  67                   GLint x, GLint y, GLsizei width, GLsizei height)
  68 {
  69    if (x == ctx->Scissor.X &&
  70        y == ctx->Scissor.Y &&
  71        width == ctx->Scissor.Width &&
  72        height == ctx->Scissor.Height)
  73       return;
  74
  75    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
  76    ctx->Scissor.X = x;
  77    ctx->Scissor.Y = y;
  78    ctx->Scissor.Width = width;
  79    ctx->Scissor.Height = height;
  80
  81    if (ctx->Driver.Scissor)
  82       ctx->Driver.Scissor( ctx, x, y, width, height );
  83 }
  84
  85
  86 /**
  87  * Initialize the context's scissor state.
  88  * \param ctx  the GL context.
  89  */
  90 void
  91 _mesa_init_scissor(struct gl_context *ctx)
  92 {
  93    /* Scissor group */
  94    ctx->Scissor.Enabled = GL_FALSE;
  95    ctx->Scissor.X = 0;
  96    ctx->Scissor.Y = 0;
  97    ctx->Scissor.Width = 0;
  98    ctx->Scissor.Height = 0;
  99 }