src/mesa/main/scissor.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * 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  * Set scissor rectangle data directly in ScissorArray
  34  *
  35  * This is an internal function that performs no error checking on the
  36  * supplied data.  It also does \b not call \c dd_function_table::Scissor.
  37  *
  38  * \sa _mesa_set_scissor
  39  */
  40 static void
  41 set_scissor_no_notify(struct gl_context *ctx, unsigned idx,
  42                       GLint x, GLint y, GLsizei width, GLsizei height)
  43 {
  44    if (x == ctx->Scissor.ScissorArray[idx].X &&
  45        y == ctx->Scissor.ScissorArray[idx].Y &&
  46        width == ctx->Scissor.ScissorArray[idx].Width &&
  47        height == ctx->Scissor.ScissorArray[idx].Height)
  48       return;
  49
  50    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
  51    ctx->Scissor.ScissorArray[idx].X = x;
  52    ctx->Scissor.ScissorArray[idx].Y = y;
  53    ctx->Scissor.ScissorArray[idx].Width = width;
  54    ctx->Scissor.ScissorArray[idx].Height = height;
  55 }
  56
  57 /**
  58  * Called via glScissor
  59  */
  60 void GLAPIENTRY
  61 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
  62 {
  63    GET_CURRENT_CONTEXT(ctx);
  64
  65    if (MESA_VERBOSE & VERBOSE_API)
  66       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
  67
  68    if (width < 0 || height < 0) {
  69       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
  70       return;
  71    }
  72
  73    _mesa_set_scissor(ctx, x, y, width, height);
  74 }
  75
  76
  77 /**
  78  * Define the scissor box.
  79  *
  80  * \param x, y coordinates of the scissor box lower-left corner.
  81  * \param width width of the scissor box.
  82  * \param height height of the scissor box.
  83  *
  84  * \sa glScissor().
  85  *
  86  * Verifies the parameters and updates __struct gl_contextRec::Scissor. On a
  87  * change flushes the vertices and notifies the driver via
  88  * the dd_function_table::Scissor callback.
  89  */
  90 void
  91 _mesa_set_scissor(struct gl_context *ctx,
  92                   GLint x, GLint y, GLsizei width, GLsizei height)
  93 {
  94    set_scissor_no_notify(ctx, 0, x, y, width, height);
  95
  96    if (ctx->Driver.Scissor)
  97       ctx->Driver.Scissor(ctx);
  98 }
  99
 100
 101 /**
 102  * Initialize the context's scissor state.
 103  * \param ctx  the GL context.
 104  */
 105 void
 106 _mesa_init_scissor(struct gl_context *ctx)
 107 {
 108    /* Scissor group */
 109    ctx->Scissor.EnableFlags = GL_FALSE;
 110    set_scissor_no_notify(ctx, 0, 0, 0, 0, 0);
 111 }