fuchsia / third_party / mesa / 2cbf6ace6fb6b7c4b8ce2b886e8f58cd0107ce45 / . / src / intel / common / intel_guardband.h

/* | |

* Copyright © 2019 Intel Corporation | |

* | |

* Permission is hereby granted, free of charge, to any person obtaining a | |

* copy of this software and associated documentation files (the "Software"), | |

* to deal in the Software without restriction, including without limitation | |

* the rights to use, copy, modify, merge, publish, distribute, sublicense, | |

* and/or sell copies of the Software, and to permit persons to whom the | |

* Software is furnished to do so, subject to the following conditions: | |

* | |

* The above copyright notice and this permission notice (including the next | |

* paragraph) shall be included in all copies or substantial portions of the | |

* Software. | |

* | |

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |

* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |

* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |

* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |

* IN THE SOFTWARE. | |

*/ | |

#ifndef INTEL_GUARDBAND_H | |

#define INTEL_GUARDBAND_H | |

static inline void | |

intel_calculate_guardband_size(uint32_t x_min, uint32_t x_max, | |

uint32_t y_min, uint32_t y_max, | |

float m00, float m11, float m30, float m31, | |

float *xmin, float *xmax, | |

float *ymin, float *ymax) | |

{ | |

/* According to the "Vertex X,Y Clamping and Quantization" section of the | |

* Strips and Fans documentation: | |

* | |

* "The vertex X and Y screen-space coordinates are also /clamped/ to the | |

* fixed-point "guardband" range supported by the rasterization hardware" | |

* | |

* and | |

* | |

* "In almost all circumstances, if an object’s vertices are actually | |

* modified by this clamping (i.e., had X or Y coordinates outside of | |

* the guardband extent the rendered object will not match the intended | |

* result. Therefore software should take steps to ensure that this does | |

* not happen - e.g., by clipping objects such that they do not exceed | |

* these limits after the Drawing Rectangle is applied." | |

* | |

* I believe the fundamental restriction is that the rasterizer (in | |

* the SF/WM stages) have a limit on the number of pixels that can be | |

* rasterized. We need to ensure any coordinates beyond the rasterizer | |

* limit are handled by the clipper. So effectively that limit becomes | |

* the clipper's guardband size. | |

* | |

* It goes on to say: | |

* | |

* "In addition, in order to be correctly rendered, objects must have a | |

* screenspace bounding box not exceeding 8K in the X or Y direction. | |

* This additional restriction must also be comprehended by software, | |

* i.e., enforced by use of clipping." | |

* | |

* This makes no sense. Gfx7+ hardware supports 16K render targets, | |

* and you definitely need to be able to draw polygons that fill the | |

* surface. Our assumption is that the rasterizer was limited to 8K | |

* on Sandybridge, which only supports 8K surfaces, and it was actually | |

* increased to 16K on Ivybridge and later. | |

* | |

* So, limit the guardband to 16K on Gfx7+ and 8K on Sandybridge. | |

*/ | |

const float gb_size = GFX_VER >= 7 ? 16384.0f : 8192.0f; | |

/* Workaround: prevent gpu hangs on SandyBridge | |

* by disabling guardband clipping for odd dimensions. | |

*/ | |

if (GFX_VER == 6 && (x_min & 1 || x_max & 1 || y_min & 1 || y_max & 1)) { | |

*xmin = -1.0f; | |

*xmax = 1.0f; | |

*ymin = -1.0f; | |

*ymax = 1.0f; | |

return; | |

} | |

if (m00 != 0 && m11 != 0) { | |

/* First, we compute the screen-space render area */ | |

const float ss_ra_xmin = MIN3(x_min, m30 + m00, m30 - m00); | |

const float ss_ra_xmax = MAX3(x_max, m30 + m00, m30 - m00); | |

const float ss_ra_ymin = MIN3(y_min, m31 + m11, m31 - m11); | |

const float ss_ra_ymax = MAX3(y_max, m31 + m11, m31 - m11); | |

/* We want the guardband to be centered on that */ | |

const float ss_gb_xmin = (ss_ra_xmin + ss_ra_xmax) / 2 - gb_size; | |

const float ss_gb_xmax = (ss_ra_xmin + ss_ra_xmax) / 2 + gb_size; | |

const float ss_gb_ymin = (ss_ra_ymin + ss_ra_ymax) / 2 - gb_size; | |

const float ss_gb_ymax = (ss_ra_ymin + ss_ra_ymax) / 2 + gb_size; | |

/* Now we need it in native device coordinates */ | |

const float ndc_gb_xmin = (ss_gb_xmin - m30) / m00; | |

const float ndc_gb_xmax = (ss_gb_xmax - m30) / m00; | |

const float ndc_gb_ymin = (ss_gb_ymin - m31) / m11; | |

const float ndc_gb_ymax = (ss_gb_ymax - m31) / m11; | |

/* Thanks to Y-flipping and ORIGIN_UPPER_LEFT, the Y coordinates may be | |

* flipped upside-down. X should be fine though. | |

*/ | |

assert(ndc_gb_xmin <= ndc_gb_xmax); | |

*xmin = ndc_gb_xmin; | |

*xmax = ndc_gb_xmax; | |

*ymin = MIN2(ndc_gb_ymin, ndc_gb_ymax); | |

*ymax = MAX2(ndc_gb_ymin, ndc_gb_ymax); | |

} else { | |

/* The viewport scales to 0, so nothing will be rendered. */ | |

*xmin = 0.0f; | |

*xmax = 0.0f; | |

*ymin = 0.0f; | |

*ymax = 0.0f; | |

} | |

} | |

#endif /* INTEL_GUARDBAND_H */ |