src/mesa/main/viewport.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.5
   4  *
   5  * Copyright (C) 2009  VMware, Inc.  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 /**
  27  * \file viewport.c
  28  * glViewport and glDepthRange functions.
  29  */
  30
  31
  32 #include "context.h"
  33 #include "macros.h"
  34 #include "viewport.h"
  35
  36
  37 /**
  38  * Set the viewport.
  39  * \sa Called via glViewport() or display list execution.
  40  *
  41  * Flushes the vertices and calls _mesa_set_viewport() with the given
  42  * parameters.
  43  */
  44 void GLAPIENTRY
  45 _mesa_Viewport(GLint x, GLint y, GLsizei width, GLsizei height)
  46 {
  47    GET_CURRENT_CONTEXT(ctx);
  48    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
  49    _mesa_set_viewport(ctx, x, y, width, height);
  50 }
  51
  52
  53 /**
  54  * Set new viewport parameters and update derived state (the _WindowMap
  55  * matrix).  Usually called from _mesa_Viewport().
  56  *
  57  * \param ctx GL context.
  58  * \param x, y coordinates of the lower left corner of the viewport rectangle.
  59  * \param width width of the viewport rectangle.
  60  * \param height height of the viewport rectangle.
  61  */
  62 void
  63 _mesa_set_viewport(GLcontext *ctx, GLint x, GLint y,
  64                     GLsizei width, GLsizei height)
  65 {
  66    if (MESA_VERBOSE & VERBOSE_API)
  67       _mesa_debug(ctx, "glViewport %d %d %d %d\n", x, y, width, height);
  68
  69    if (width < 0 || height < 0) {
  70       _mesa_error(ctx,  GL_INVALID_VALUE,
  71                    "glViewport(%d, %d, %d, %d)", x, y, width, height);
  72       return;
  73    }
  74
  75    /* clamp width and height to the implementation dependent range */
  76    width  = MIN2(width, (GLsizei) ctx->Const.MaxViewportWidth);
  77    height = MIN2(height, (GLsizei) ctx->Const.MaxViewportHeight);
  78
  79    ctx->Viewport.X = x;
  80    ctx->Viewport.Width = width;
  81    ctx->Viewport.Y = y;
  82    ctx->Viewport.Height = height;
  83    ctx->NewState |= _NEW_VIEWPORT;
  84
  85 #if 1
  86    /* XXX remove this someday.  Currently the DRI drivers rely on
  87     * the WindowMap matrix being up to date in the driver's Viewport
  88     * and DepthRange functions.
  89     */
  90    _math_matrix_viewport(&ctx->Viewport._WindowMap,
  91                          ctx->Viewport.X, ctx->Viewport.Y,
  92                          ctx->Viewport.Width, ctx->Viewport.Height,
  93                          ctx->Viewport.Near, ctx->Viewport.Far,
  94                          ctx->DrawBuffer->_DepthMaxF);
  95 #endif
  96
  97    if (ctx->Driver.Viewport) {
  98       /* Many drivers will use this call to check for window size changes
  99        * and reallocate the z/stencil/accum/etc buffers if needed.
 100        */
 101       ctx->Driver.Viewport(ctx, x, y, width, height);
 102    }
 103 }
 104
 105
 106 /**
 107  * Called by glDepthRange
 108  *
 109  * \param nearval  specifies the Z buffer value which should correspond to
 110  *                 the near clip plane
 111  * \param farval  specifies the Z buffer value which should correspond to
 112  *                the far clip plane
 113  */
 114 void GLAPIENTRY
 115 _mesa_DepthRange(GLclampd nearval, GLclampd farval)
 116 {
 117    GET_CURRENT_CONTEXT(ctx);
 118    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 119
 120    if (MESA_VERBOSE&VERBOSE_API)
 121       _mesa_debug(ctx, "glDepthRange %f %f\n", nearval, farval);
 122
 123    if (ctx->Viewport.Near == nearval &&
 124        ctx->Viewport.Far == farval)
 125       return;
 126
 127    ctx->Viewport.Near = (GLfloat) CLAMP(nearval, 0.0, 1.0);
 128    ctx->Viewport.Far = (GLfloat) CLAMP(farval, 0.0, 1.0);
 129    ctx->NewState |= _NEW_VIEWPORT;
 130
 131 #if 1
 132    /* XXX remove this someday.  Currently the DRI drivers rely on
 133     * the WindowMap matrix being up to date in the driver's Viewport
 134     * and DepthRange functions.
 135     */
 136    _math_matrix_viewport(&ctx->Viewport._WindowMap,
 137                          ctx->Viewport.X, ctx->Viewport.Y,
 138                          ctx->Viewport.Width, ctx->Viewport.Height,
 139                          ctx->Viewport.Near, ctx->Viewport.Far,
 140                          ctx->DrawBuffer->_DepthMaxF);
 141 #endif
 142
 143    if (ctx->Driver.DepthRange) {
 144       ctx->Driver.DepthRange(ctx, nearval, farval);
 145    }
 146 }
 147
 148
 149
 150 /**
 151  * Initialize the context viewport attribute group.
 152  * \param ctx  the GL context.
 153  */
 154 void _mesa_init_viewport(GLcontext *ctx)
 155 {
 156    GLfloat depthMax = 65535.0F; /* sorf of arbitrary */
 157
 158    /* Viewport group */
 159    ctx->Viewport.X = 0;
 160    ctx->Viewport.Y = 0;
 161    ctx->Viewport.Width = 0;
 162    ctx->Viewport.Height = 0;
 163    ctx->Viewport.Near = 0.0;
 164    ctx->Viewport.Far = 1.0;
 165    _math_matrix_ctr(&ctx->Viewport._WindowMap);
 166
 167    _math_matrix_viewport(&ctx->Viewport._WindowMap, 0, 0, 0, 0,
 168                          0.0F, 1.0F, depthMax);
 169 }
 170
 171
 172 /**
 173  * Free the context viewport attribute group data.
 174  * \param ctx  the GL context.
 175  */
 176 void _mesa_free_viewport_data(GLcontext *ctx)
 177 {
 178    _math_matrix_dtr(&ctx->Viewport._WindowMap);
 179 }
 180