src/mesa/drivers/dri/i965/brw_meta_util.c

   1 /*
   2  * Copyright © 2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 #include "brw_meta_util.h"
  25 #include "main/fbobject.h"
  26
  27 /**
  28  * Helper function for handling mirror image blits.
  29  *
  30  * If coord0 > coord1, swap them and invert the "mirror" boolean.
  31  */
  32 static inline void
  33 fixup_mirroring(bool *mirror, float *coord0, float *coord1)
  34 {
  35    if (*coord0 > *coord1) {
  36       *mirror = !*mirror;
  37       float tmp = *coord0;
  38       *coord0 = *coord1;
  39       *coord1 = tmp;
  40    }
  41 }
  42
  43 /**
  44  * Adjust {src,dst}_x{0,1} to account for clipping and scissoring of
  45  * destination coordinates.
  46  *
  47  * Return true if there is still blitting to do, false if all pixels got
  48  * rejected by the clip and/or scissor.
  49  *
  50  * For clarity, the nomenclature of this function assumes we are clipping and
  51  * scissoring the X coordinate; the exact same logic applies for Y
  52  * coordinates.
  53  *
  54  * Note: this function may also be used to account for clipping of source
  55  * coordinates, by swapping the roles of src and dst.
  56  */
  57 static inline bool
  58 clip_or_scissor(bool mirror,
  59                 GLfloat *src_x0, GLfloat *src_x1,
  60                 GLfloat *dst_x0, GLfloat *dst_x1,
  61                 GLfloat fb_xmin, GLfloat fb_xmax)
  62 {
  63    float scale = (float) (*src_x1 - *src_x0) / (*dst_x1 - *dst_x0);
  64    /* If we are going to scissor everything away, stop. */
  65    if (!(fb_xmin < fb_xmax &&
  66          *dst_x0 < fb_xmax &&
  67          fb_xmin < *dst_x1 &&
  68          *dst_x0 < *dst_x1)) {
  69       return false;
  70    }
  71
  72    /* Clip the destination rectangle, and keep track of how many pixels we
  73     * clipped off of the left and right sides of it.
  74     */
  75    int pixels_clipped_left = 0;
  76    int pixels_clipped_right = 0;
  77    if (*dst_x0 < fb_xmin) {
  78       pixels_clipped_left = fb_xmin - *dst_x0;
  79       *dst_x0 = fb_xmin;
  80    }
  81    if (fb_xmax < *dst_x1) {
  82       pixels_clipped_right = *dst_x1 - fb_xmax;
  83       *dst_x1 = fb_xmax;
  84    }
  85
  86    /* If we are mirrored, then before applying pixels_clipped_{left,right} to
  87     * the source coordinates, we need to flip them to account for the
  88     * mirroring.
  89     */
  90    if (mirror) {
  91       int tmp = pixels_clipped_left;
  92       pixels_clipped_left = pixels_clipped_right;
  93       pixels_clipped_right = tmp;
  94    }
  95
  96    /* Adjust the source rectangle to remove the pixels corresponding to those
  97     * that were clipped/scissored out of the destination rectangle.
  98     */
  99    *src_x0 += pixels_clipped_left * scale;
 100    *src_x1 -= pixels_clipped_right * scale;
 101
 102    return true;
 103 }
 104
 105 bool
 106 brw_meta_mirror_clip_and_scissor(const struct gl_context *ctx,
 107                                  const struct gl_framebuffer *read_fb,
 108                                  const struct gl_framebuffer *draw_fb,
 109                                  GLfloat *srcX0, GLfloat *srcY0,
 110                                  GLfloat *srcX1, GLfloat *srcY1,
 111                                  GLfloat *dstX0, GLfloat *dstY0,
 112                                  GLfloat *dstX1, GLfloat *dstY1,
 113                                  bool *mirror_x, bool *mirror_y)
 114 {
 115    *mirror_x = false;
 116    *mirror_y = false;
 117
 118    /* Detect if the blit needs to be mirrored */
 119    fixup_mirroring(mirror_x, srcX0, srcX1);
 120    fixup_mirroring(mirror_x, dstX0, dstX1);
 121    fixup_mirroring(mirror_y, srcY0, srcY1);
 122    fixup_mirroring(mirror_y, dstY0, dstY1);
 123
 124    /* If the destination rectangle needs to be clipped or scissored, do so. */
 125    if (!(clip_or_scissor(*mirror_x, srcX0, srcX1, dstX0, dstX1,
 126                          draw_fb->_Xmin, draw_fb->_Xmax) &&
 127          clip_or_scissor(*mirror_y, srcY0, srcY1, dstY0, dstY1,
 128                          draw_fb->_Ymin, draw_fb->_Ymax))) {
 129       /* Everything got clipped/scissored away, so the blit was successful. */
 130       return true;
 131    }
 132
 133    /* If the source rectangle needs to be clipped or scissored, do so. */
 134    if (!(clip_or_scissor(*mirror_x, dstX0, dstX1, srcX0, srcX1,
 135                          0, read_fb->Width) &&
 136          clip_or_scissor(*mirror_y, dstY0, dstY1, srcY0, srcY1,
 137                          0, read_fb->Height))) {
 138       /* Everything got clipped/scissored away, so the blit was successful. */
 139       return true;
 140    }
 141
 142    /* Account for the fact that in the system framebuffer, the origin is at
 143     * the lower left.
 144     */
 145    if (_mesa_is_winsys_fbo(read_fb)) {
 146       GLint tmp = read_fb->Height - *srcY0;
 147       *srcY0 = read_fb->Height - *srcY1;
 148       *srcY1 = tmp;
 149       *mirror_y = !*mirror_y;
 150    }
 151    if (_mesa_is_winsys_fbo(draw_fb)) {
 152       GLint tmp = draw_fb->Height - *dstY0;
 153       *dstY0 = draw_fb->Height - *dstY1;
 154       *dstY1 = tmp;
 155       *mirror_y = !*mirror_y;
 156    }
 157
 158    return false;
 159 }