src/mesa/drivers/dri/i965/gen8_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
  30 static void
  31 gen8_upload_sf_clip_viewport(struct brw_context *brw)
  32 {
  33    struct gl_context *ctx = &brw->ctx;
  34    const GLfloat depth_scale = 1.0F / ctx->DrawBuffer->_DepthMaxF;
  35    float y_scale, y_bias;
  36    const bool render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer);
  37
  38    float *vp = brw_state_batch(brw, AUB_TRACE_SF_VP_STATE,
  39                                16 * 4 * ctx->Const.MaxViewports,
  40                                64, &brw->sf.vp_offset);
  41    /* Also assign to clip.vp_offset in case something uses it. */
  42    brw->clip.vp_offset = brw->sf.vp_offset;
  43
  44    /* _NEW_BUFFERS */
  45    if (render_to_fbo) {
  46       y_scale = 1.0;
  47       y_bias = 0;
  48    } else {
  49       y_scale = -1.0;
  50       y_bias = ctx->DrawBuffer->Height;
  51    }
  52
  53    for (unsigned i = 0; i < ctx->Const.MaxViewports; i++) {
  54       const GLfloat *const v = ctx->ViewportArray[i]._WindowMap.m;
  55
  56       /* _NEW_VIEWPORT: Viewport Matrix Elements */
  57       vp[0] = v[MAT_SX];                    /* m00 */
  58       vp[1] = v[MAT_SY] * y_scale;          /* m11 */
  59       vp[2] = v[MAT_SZ] * depth_scale;      /* m22 */
  60       vp[3] = v[MAT_TX];                    /* m30 */
  61       vp[4] = v[MAT_TY] * y_scale + y_bias; /* m31 */
  62       vp[5] = v[MAT_TZ] * depth_scale;      /* m32 */
  63
  64       /* Reserved */
  65       vp[6] = 0;
  66       vp[7] = 0;
  67
  68       /* According to the "Vertex X,Y Clamping and Quantization" section of the
  69        * Strips and Fans documentation, objects must not have a screen-space
  70        * extents of over 8192 pixels, or they may be mis-rasterized.  The
  71        * maximum screen space coordinates of a small object may larger, but we
  72        * have no way to enforce the object size other than through clipping.
  73        *
  74        * If you're surprised that we set clip to -gbx to +gbx and it seems like
  75        * we'll end up with 16384 wide, note that for a 8192-wide render target,
  76        * we'll end up with a normal (-1, 1) clip volume that just covers the
  77        * drawable.
  78        */
  79       const float maximum_guardband_extent = 8192;
  80       float gbx = maximum_guardband_extent / ctx->ViewportArray[i].Width;
  81       float gby = maximum_guardband_extent / ctx->ViewportArray[i].Height;
  82
  83       /* _NEW_VIEWPORT: Guardband Clipping */
  84       vp[8]  = -gbx; /* x-min */
  85       vp[9]  =  gbx; /* x-max */
  86       vp[10] = -gby; /* y-min */
  87       vp[11] =  gby; /* y-max */
  88
  89       /* _NEW_SCISSOR | _NEW_VIEWPORT | _NEW_BUFFERS: Screen Space Viewport */
  90       if (render_to_fbo) {
  91          vp[12] = ctx->DrawBuffer->_Xmin;
  92          vp[13] = ctx->DrawBuffer->_Xmax - 1;
  93          vp[14] = ctx->DrawBuffer->_Ymin;
  94          vp[15] = ctx->DrawBuffer->_Ymax - 1;
  95       } else {
  96          vp[12] = ctx->DrawBuffer->_Xmin;
  97          vp[13] = ctx->DrawBuffer->_Xmax - 1;
  98          vp[14] = ctx->DrawBuffer->Height - ctx->DrawBuffer->_Ymax;
  99          vp[15] = ctx->DrawBuffer->Height - ctx->DrawBuffer->_Ymin - 1;
 100       }
 101
 102       vp += 16;
 103    }
 104
 105    BEGIN_BATCH(2);
 106    OUT_BATCH(_3DSTATE_VIEWPORT_STATE_POINTERS_SF_CL << 16 | (2 - 2));
 107    OUT_BATCH(brw->sf.vp_offset);
 108    ADVANCE_BATCH();
 109 }
 110
 111 const struct brw_tracked_state gen8_sf_clip_viewport = {
 112    .dirty = {
 113       .mesa = _NEW_BUFFERS | _NEW_SCISSOR | _NEW_VIEWPORT,
 114       .brw = BRW_NEW_BATCH,
 115       .cache = 0,
 116    },
 117    .emit = gen8_upload_sf_clip_viewport,
 118 };