src/mesa/drivers/dri/i965/gen7_viewport_state.c

   1 /*
   2  * Copyright © 2011 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_context.h"
  25 #include "brw_state.h"
  26 #include "brw_defines.h"
  27 #include "intel_batchbuffer.h"
  28 #include "main/fbobject.h"
  29 #include "main/framebuffer.h"
  30 #include "main/viewport.h"
  31
  32 static void
  33 gen7_upload_sf_clip_viewport(struct brw_context *brw)
  34 {
  35    struct gl_context *ctx = &brw->ctx;
  36    GLfloat y_scale, y_bias;
  37    const bool render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer);
  38    struct gen7_sf_clip_viewport *vp;
  39
  40    /* BRW_NEW_VIEWPORT_COUNT */
  41    const unsigned viewport_count = brw->clip.viewport_count;
  42
  43    vp = brw_state_batch(brw, AUB_TRACE_SF_VP_STATE,
  44                         sizeof(*vp) * viewport_count, 64,
  45                         &brw->sf.vp_offset);
  46    /* Also assign to clip.vp_offset in case something uses it. */
  47    brw->clip.vp_offset = brw->sf.vp_offset;
  48
  49    /* _NEW_BUFFERS */
  50    if (render_to_fbo) {
  51       y_scale = 1.0;
  52       y_bias = 0.0;
  53    } else {
  54       y_scale = -1.0;
  55       y_bias = (float)_mesa_geometric_height(ctx->DrawBuffer);
  56    }
  57
  58    for (unsigned i = 0; i < viewport_count; i++) {
  59       float scale[3], translate[3];
  60       _mesa_get_viewport_xform(ctx, i, scale, translate);
  61
  62       /* According to the "Vertex X,Y Clamping and Quantization" section of
  63        * the Strips and Fans documentation, objects must not have a
  64        * screen-space extents of over 8192 pixels, or they may be
  65        * mis-rasterized.  The maximum screen space coordinates of a small
  66        * object may larger, but we have no way to enforce the object size
  67        * other than through clipping.
  68        *
  69        * If you're surprised that we set clip to -gbx to +gbx and it seems
  70        * like we'll end up with 16384 wide, note that for a 8192-wide render
  71        * target, we'll end up with a normal (-1, 1) clip volume that just
  72        * covers the drawable.
  73        */
  74       const float maximum_guardband_extent = 8192;
  75       const float gbx = maximum_guardband_extent / ctx->ViewportArray[i].Width;
  76       const float gby = maximum_guardband_extent / ctx->ViewportArray[i].Height;
  77
  78       vp[i].guardband.xmin = -gbx;
  79       vp[i].guardband.xmax = gbx;
  80       vp[i].guardband.ymin = -gby;
  81       vp[i].guardband.ymax = gby;
  82
  83       /* _NEW_VIEWPORT */
  84       vp[i].viewport.m00 = scale[0];
  85       vp[i].viewport.m11 = scale[1] * y_scale;
  86       vp[i].viewport.m22 = scale[2];
  87       vp[i].viewport.m30 = translate[0];
  88       vp[i].viewport.m31 = translate[1] * y_scale + y_bias;
  89       vp[i].viewport.m32 = translate[2];
  90    }
  91
  92    BEGIN_BATCH(2);
  93    OUT_BATCH(_3DSTATE_VIEWPORT_STATE_POINTERS_SF_CL << 16 | (2 - 2));
  94    OUT_BATCH(brw->sf.vp_offset);
  95    ADVANCE_BATCH();
  96 }
  97
  98 const struct brw_tracked_state gen7_sf_clip_viewport = {
  99    .dirty = {
 100       .mesa = _NEW_BUFFERS |
 101               _NEW_VIEWPORT,
 102       .brw = BRW_NEW_BATCH |
 103              BRW_NEW_BLORP |
 104              BRW_NEW_VIEWPORT_COUNT,
 105    },
 106    .emit = gen7_upload_sf_clip_viewport,
 107 };