scissor.c revision f6d7cd4a11e70b816733cff681dde7d03588d1c8 
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 */
40static void
41set_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 */
60void 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, 0, 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 */
90void
91_mesa_set_scissor(struct gl_context *ctx, unsigned idx,
92                  GLint x, GLint y, GLsizei width, GLsizei height)
93{
94   set_scissor_no_notify(ctx, idx, 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 */
105void
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}
112