src/mesa/main/viewport.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 2009  VMware, Inc.  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 /**
  27  * \file viewport.c
  28  * glViewport and glDepthRange functions.
  29  */
  30
  31
  32 #include "context.h"
  33 #include "enums.h"
  34 #include "macros.h"
  35 #include "mtypes.h"
  36 #include "viewport.h"
  37
  38 static void
  39 set_viewport_no_notify(struct gl_context *ctx, unsigned idx,
  40                        GLfloat x, GLfloat y,
  41                        GLfloat width, GLfloat height)
  42 {
  43    /* clamp width and height to the implementation dependent range */
  44    width  = MIN2(width, (GLfloat) ctx->Const.MaxViewportWidth);
  45    height = MIN2(height, (GLfloat) ctx->Const.MaxViewportHeight);
  46
  47    /* The GL_ARB_viewport_array spec says:
  48     *
  49     *     "The location of the viewport's bottom-left corner, given by (x,y),
  50     *     are clamped to be within the implementation-dependent viewport
  51     *     bounds range.  The viewport bounds range [min, max] tuple may be
  52     *     determined by calling GetFloatv with the symbolic constant
  53     *     VIEWPORT_BOUNDS_RANGE (see section 6.1)."
  54     */
  55    if (ctx->Extensions.ARB_viewport_array) {
  56       x = CLAMP(x,
  57                 ctx->Const.ViewportBounds.Min, ctx->Const.ViewportBounds.Max);
  58       y = CLAMP(y,
  59                 ctx->Const.ViewportBounds.Min, ctx->Const.ViewportBounds.Max);
  60    }
  61
  62    if (ctx->ViewportArray[idx].X == x &&
  63        ctx->ViewportArray[idx].Width == width &&
  64        ctx->ViewportArray[idx].Y == y &&
  65        ctx->ViewportArray[idx].Height == height)
  66       return;
  67
  68    ctx->ViewportArray[idx].X = x;
  69    ctx->ViewportArray[idx].Width = width;
  70    ctx->ViewportArray[idx].Y = y;
  71    ctx->ViewportArray[idx].Height = height;
  72    ctx->NewState |= _NEW_VIEWPORT;
  73 }
  74
  75 struct gl_viewport_inputs {
  76    GLfloat X, Y;                /**< position */
  77    GLfloat Width, Height;       /**< size */
  78 };
  79
  80 struct gl_depthrange_inputs {
  81    GLdouble Near, Far;          /**< Depth buffer range */
  82 };
  83
  84 /**
  85  * Set the viewport.
  86  * \sa Called via glViewport() or display list execution.
  87  *
  88  * Flushes the vertices and calls _mesa_set_viewport() with the given
  89  * parameters.
  90  */
  91 void GLAPIENTRY
  92 _mesa_Viewport(GLint x, GLint y, GLsizei width, GLsizei height)
  93 {
  94    unsigned i;
  95    GET_CURRENT_CONTEXT(ctx);
  96    FLUSH_VERTICES(ctx, 0);
  97
  98    if (MESA_VERBOSE & VERBOSE_API)
  99       _mesa_debug(ctx, "glViewport %d %d %d %d\n", x, y, width, height);
 100
 101    if (width < 0 || height < 0) {
 102       _mesa_error(ctx,  GL_INVALID_VALUE,
 103                    "glViewport(%d, %d, %d, %d)", x, y, width, height);
 104       return;
 105    }
 106
 107    /* The GL_ARB_viewport_array spec says:
 108     *
 109     *     "Viewport sets the parameters for all viewports to the same values
 110     *     and is equivalent (assuming no errors are generated) to:
 111     *
 112     *     for (uint i = 0; i < MAX_VIEWPORTS; i++)
 113     *         ViewportIndexedf(i, 1, (float)x, (float)y, (float)w, (float)h);"
 114     *
 115     * Set all of the viewports supported by the implementation, but only
 116     * signal the driver once at the end.
 117     */
 118    for (i = 0; i < ctx->Const.MaxViewports; i++)
 119       set_viewport_no_notify(ctx, i, x, y, width, height);
 120
 121    if (ctx->Driver.Viewport) {
 122       /* Many drivers will use this call to check for window size changes
 123        * and reallocate the z/stencil/accum/etc buffers if needed.
 124        */
 125       ctx->Driver.Viewport(ctx);
 126    }
 127 }
 128
 129
 130 /**
 131  * Set new viewport parameters and update derived state.
 132  * Usually called from _mesa_Viewport().
 133  *
 134  * \param ctx GL context.
 135  * \param idx    Index of the viewport to be updated.
 136  * \param x, y coordinates of the lower left corner of the viewport rectangle.
 137  * \param width width of the viewport rectangle.
 138  * \param height height of the viewport rectangle.
 139  */
 140 void
 141 _mesa_set_viewport(struct gl_context *ctx, unsigned idx, GLfloat x, GLfloat y,
 142                     GLfloat width, GLfloat height)
 143 {
 144    set_viewport_no_notify(ctx, idx, x, y, width, height);
 145
 146    if (ctx->Driver.Viewport) {
 147       /* Many drivers will use this call to check for window size changes
 148        * and reallocate the z/stencil/accum/etc buffers if needed.
 149        */
 150       ctx->Driver.Viewport(ctx);
 151    }
 152 }
 153
 154 void GLAPIENTRY
 155 _mesa_ViewportArrayv(GLuint first, GLsizei count, const GLfloat *v)
 156 {
 157    int i;
 158    const struct gl_viewport_inputs *const p = (struct gl_viewport_inputs *) v;
 159    GET_CURRENT_CONTEXT(ctx);
 160
 161    if (MESA_VERBOSE & VERBOSE_API)
 162       _mesa_debug(ctx, "glViewportArrayv %d %d\n", first, count);
 163
 164    if ((first + count) > ctx->Const.MaxViewports) {
 165       _mesa_error(ctx, GL_INVALID_VALUE,
 166                   "glViewportArrayv: first (%d) + count (%d) > MaxViewports "
 167                   "(%d)",
 168                   first, count, ctx->Const.MaxViewports);
 169       return;
 170    }
 171
 172    /* Verify width & height */
 173    for (i = 0; i < count; i++) {
 174       if (p[i].Width < 0 || p[i].Height < 0) {
 175          _mesa_error(ctx, GL_INVALID_VALUE,
 176                      "glViewportArrayv: index (%d) width or height < 0 "
 177                      "(%f, %f)",
 178                      i + first, p[i].Width, p[i].Height);
 179          return;
 180       }
 181    }
 182
 183    for (i = 0; i < count; i++)
 184       set_viewport_no_notify(ctx, i + first,
 185                              p[i].X, p[i].Y,
 186                              p[i].Width, p[i].Height);
 187
 188    if (ctx->Driver.Viewport)
 189       ctx->Driver.Viewport(ctx);
 190 }
 191
 192 static void
 193 ViewportIndexedf(GLuint index, GLfloat x, GLfloat y,
 194                  GLfloat w, GLfloat h, const char *function)
 195 {
 196    GET_CURRENT_CONTEXT(ctx);
 197
 198    if (MESA_VERBOSE & VERBOSE_API)
 199       _mesa_debug(ctx, "%s(%d, %f, %f, %f, %f)\n",
 200                   function, index, x, y, w, h);
 201
 202    if (index >= ctx->Const.MaxViewports) {
 203       _mesa_error(ctx, GL_INVALID_VALUE,
 204                   "%s: index (%d) >= MaxViewports (%d)",
 205                   function, index, ctx->Const.MaxViewports);
 206       return;
 207    }
 208
 209    /* Verify width & height */
 210    if (w < 0 || h < 0) {
 211       _mesa_error(ctx, GL_INVALID_VALUE,
 212                   "%s: index (%d) width or height < 0 (%f, %f)",
 213                   function, index, w, h);
 214       return;
 215    }
 216
 217    _mesa_set_viewport(ctx, index, x, y, w, h);
 218 }
 219
 220 void GLAPIENTRY
 221 _mesa_ViewportIndexedf(GLuint index, GLfloat x, GLfloat y,
 222                        GLfloat w, GLfloat h)
 223 {
 224    ViewportIndexedf(index, x, y, w, h, "glViewportIndexedf");
 225 }
 226
 227 void GLAPIENTRY
 228 _mesa_ViewportIndexedfv(GLuint index, const GLfloat *v)
 229 {
 230    ViewportIndexedf(index, v[0], v[1], v[2], v[3], "glViewportIndexedfv");
 231 }
 232
 233 static void
 234 set_depth_range_no_notify(struct gl_context *ctx, unsigned idx,
 235                           GLclampd nearval, GLclampd farval)
 236 {
 237    if (ctx->ViewportArray[idx].Near == nearval &&
 238        ctx->ViewportArray[idx].Far == farval)
 239       return;
 240
 241    ctx->ViewportArray[idx].Near = CLAMP(nearval, 0.0, 1.0);
 242    ctx->ViewportArray[idx].Far = CLAMP(farval, 0.0, 1.0);
 243    ctx->NewState |= _NEW_VIEWPORT;
 244 }
 245
 246 void
 247 _mesa_set_depth_range(struct gl_context *ctx, unsigned idx,
 248                       GLclampd nearval, GLclampd farval)
 249 {
 250    set_depth_range_no_notify(ctx, idx, nearval, farval);
 251
 252    if (ctx->Driver.DepthRange)
 253       ctx->Driver.DepthRange(ctx);
 254 }
 255
 256 /**
 257  * Called by glDepthRange
 258  *
 259  * \param nearval  specifies the Z buffer value which should correspond to
 260  *                 the near clip plane
 261  * \param farval  specifies the Z buffer value which should correspond to
 262  *                the far clip plane
 263  */
 264 void GLAPIENTRY
 265 _mesa_DepthRange(GLclampd nearval, GLclampd farval)
 266 {
 267    unsigned i;
 268    GET_CURRENT_CONTEXT(ctx);
 269
 270    FLUSH_VERTICES(ctx, 0);
 271
 272    if (MESA_VERBOSE&VERBOSE_API)
 273       _mesa_debug(ctx, "glDepthRange %f %f\n", nearval, farval);
 274
 275    /* The GL_ARB_viewport_array spec says:
 276     *
 277     *     "DepthRange sets the depth range for all viewports to the same
 278     *     values and is equivalent (assuming no errors are generated) to:
 279     *
 280     *     for (uint i = 0; i < MAX_VIEWPORTS; i++)
 281     *         DepthRangeIndexed(i, n, f);"
 282     *
 283     * Set the depth range for all of the viewports supported by the
 284     * implementation, but only signal the driver once at the end.
 285     */
 286    for (i = 0; i < ctx->Const.MaxViewports; i++)
 287       set_depth_range_no_notify(ctx, i, nearval, farval);
 288
 289    if (ctx->Driver.DepthRange) {
 290       ctx->Driver.DepthRange(ctx);
 291    }
 292 }
 293
 294 void GLAPIENTRY
 295 _mesa_DepthRangef(GLclampf nearval, GLclampf farval)
 296 {
 297    _mesa_DepthRange(nearval, farval);
 298 }
 299
 300 /**
 301  * Update a range DepthRange values
 302  *
 303  * \param first   starting array index
 304  * \param count   count of DepthRange items to update
 305  * \param v       pointer to memory containing
 306  *                GLclampd near and far clip-plane values
 307  */
 308 void GLAPIENTRY
 309 _mesa_DepthRangeArrayv(GLuint first, GLsizei count, const GLclampd *v)
 310 {
 311    int i;
 312    const struct gl_depthrange_inputs *const p =
 313       (struct gl_depthrange_inputs *) v;
 314    GET_CURRENT_CONTEXT(ctx);
 315
 316    if (MESA_VERBOSE & VERBOSE_API)
 317       _mesa_debug(ctx, "glDepthRangeArrayv %d %d\n", first, count);
 318
 319    if ((first + count) > ctx->Const.MaxViewports) {
 320       _mesa_error(ctx, GL_INVALID_VALUE,
 321                   "glDepthRangev: first (%d) + count (%d) >= MaxViewports (%d)",
 322                   first, count, ctx->Const.MaxViewports);
 323       return;
 324    }
 325
 326    for (i = 0; i < count; i++)
 327       set_depth_range_no_notify(ctx, i + first, p[i].Near, p[i].Far);
 328
 329    if (ctx->Driver.DepthRange)
 330       ctx->Driver.DepthRange(ctx);
 331 }
 332
 333 void GLAPIENTRY
 334 _mesa_DepthRangeArrayfvOES(GLuint first, GLsizei count, const GLfloat *v)
 335 {
 336    int i;
 337    GET_CURRENT_CONTEXT(ctx);
 338
 339    if (MESA_VERBOSE & VERBOSE_API)
 340       _mesa_debug(ctx, "glDepthRangeArrayfv %d %d\n", first, count);
 341
 342    if ((first + count) > ctx->Const.MaxViewports) {
 343       _mesa_error(ctx, GL_INVALID_VALUE,
 344                   "glDepthRangeArrayfv: first (%d) + count (%d) >= MaxViewports (%d)",
 345                   first, count, ctx->Const.MaxViewports);
 346       return;
 347    }
 348
 349    for (i = 0; i < count; i++)
 350       set_depth_range_no_notify(ctx, i + first, v[i * 2], v[i * 2 + 1]);
 351
 352    if (ctx->Driver.DepthRange)
 353       ctx->Driver.DepthRange(ctx);
 354 }
 355
 356 /**
 357  * Update a single DepthRange
 358  *
 359  * \param index    array index to update
 360  * \param nearval  specifies the Z buffer value which should correspond to
 361  *                 the near clip plane
 362  * \param farval   specifies the Z buffer value which should correspond to
 363  *                 the far clip plane
 364  */
 365 void GLAPIENTRY
 366 _mesa_DepthRangeIndexed(GLuint index, GLclampd nearval, GLclampd farval)
 367 {
 368    GET_CURRENT_CONTEXT(ctx);
 369
 370    if (MESA_VERBOSE & VERBOSE_API)
 371       _mesa_debug(ctx, "glDepthRangeIndexed(%d, %f, %f)\n",
 372                   index, nearval, farval);
 373
 374    if (index >= ctx->Const.MaxViewports) {
 375       _mesa_error(ctx, GL_INVALID_VALUE,
 376                   "glDepthRangeIndexed: index (%d) >= MaxViewports (%d)",
 377                   index, ctx->Const.MaxViewports);
 378       return;
 379    }
 380
 381    _mesa_set_depth_range(ctx, index, nearval, farval);
 382 }
 383
 384 void GLAPIENTRY
 385 _mesa_DepthRangeIndexedfOES(GLuint index, GLfloat nearval, GLfloat farval)
 386 {
 387    _mesa_DepthRangeIndexed(index, nearval, farval);
 388 }
 389
 390 /**
 391  * Initialize the context viewport attribute group.
 392  * \param ctx  the GL context.
 393  */
 394 void _mesa_init_viewport(struct gl_context *ctx)
 395 {
 396    unsigned i;
 397
 398    ctx->Transform.ClipOrigin = GL_LOWER_LEFT;
 399    ctx->Transform.ClipDepthMode = GL_NEGATIVE_ONE_TO_ONE;
 400
 401    /* Note: ctx->Const.MaxViewports may not have been set by the driver yet,
 402     * so just initialize all of them.
 403     */
 404    for (i = 0; i < MAX_VIEWPORTS; i++) {
 405       /* Viewport group */
 406       ctx->ViewportArray[i].X = 0;
 407       ctx->ViewportArray[i].Y = 0;
 408       ctx->ViewportArray[i].Width = 0;
 409       ctx->ViewportArray[i].Height = 0;
 410       ctx->ViewportArray[i].Near = 0.0;
 411       ctx->ViewportArray[i].Far = 1.0;
 412    }
 413 }
 414
 415
 416 extern void GLAPIENTRY
 417 _mesa_ClipControl(GLenum origin, GLenum depth)
 418 {
 419    GET_CURRENT_CONTEXT(ctx);
 420
 421    if (MESA_VERBOSE&VERBOSE_API)
 422       _mesa_debug(ctx, "glClipControl(%s, %s)\n",
 423                   _mesa_enum_to_string(origin),
 424                   _mesa_enum_to_string(depth));
 425
 426    ASSERT_OUTSIDE_BEGIN_END(ctx);
 427
 428    if (!ctx->Extensions.ARB_clip_control) {
 429       _mesa_error(ctx, GL_INVALID_OPERATION, "glClipControl");
 430       return;
 431    }
 432
 433    if (origin != GL_LOWER_LEFT && origin != GL_UPPER_LEFT) {
 434       _mesa_error(ctx, GL_INVALID_ENUM, "glClipControl");
 435       return;
 436    }
 437
 438    if (depth != GL_NEGATIVE_ONE_TO_ONE && depth != GL_ZERO_TO_ONE) {
 439       _mesa_error(ctx, GL_INVALID_ENUM, "glClipControl");
 440       return;
 441    }
 442
 443    if (ctx->Transform.ClipOrigin == origin &&
 444        ctx->Transform.ClipDepthMode == depth)
 445       return;
 446
 447    /* Affects transform state and the viewport transform */
 448    FLUSH_VERTICES(ctx, _NEW_TRANSFORM | _NEW_VIEWPORT);
 449
 450    if (ctx->Transform.ClipOrigin != origin) {
 451       ctx->Transform.ClipOrigin = origin;
 452
 453       /* Affects the winding order of the front face. */
 454       ctx->NewState |= _NEW_POLYGON;
 455
 456       if (ctx->Driver.FrontFace)
 457          ctx->Driver.FrontFace(ctx, ctx->Polygon.FrontFace);
 458    }
 459
 460    if (ctx->Transform.ClipDepthMode != depth) {
 461       ctx->Transform.ClipDepthMode = depth;
 462
 463       if (ctx->Driver.DepthRange)
 464          ctx->Driver.DepthRange(ctx);
 465    }
 466 }
 467
 468 /**
 469  * Computes the scaling and the translation part of the
 470  * viewport transform matrix of the \param i-th viewport
 471  * and writes that into \param scale and \param translate.
 472  */
 473 void
 474 _mesa_get_viewport_xform(struct gl_context *ctx, unsigned i,
 475                          float scale[3], float translate[3])
 476 {
 477    float x = ctx->ViewportArray[i].X;
 478    float y = ctx->ViewportArray[i].Y;
 479    float half_width = 0.5f * ctx->ViewportArray[i].Width;
 480    float half_height = 0.5f * ctx->ViewportArray[i].Height;
 481    double n = ctx->ViewportArray[i].Near;
 482    double f = ctx->ViewportArray[i].Far;
 483
 484    scale[0] = half_width;
 485    translate[0] = half_width + x;
 486    if (ctx->Transform.ClipOrigin == GL_UPPER_LEFT) {
 487       scale[1] = -half_height;
 488    } else {
 489       scale[1] = half_height;
 490    }
 491    translate[1] = half_height + y;
 492
 493    if (ctx->Transform.ClipDepthMode == GL_NEGATIVE_ONE_TO_ONE) {
 494       scale[2] = 0.5 * (f - n);
 495       translate[2] = 0.5 * (n + f);
 496    } else {
 497       scale[2] = f - n;
 498       translate[2] = n;
 499    }
 500 }