/************************************************************************** * * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas. * All Rights Reserved. * * 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, sub license, 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 NON-INFRINGEMENT. * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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. * **************************************************************************/ /* * Binning code for triangles */ #include "lp_setup_context.h" #include "lp_rast.h" #include "util/u_math.h" #include "util/u_memory.h" #define NUM_CHANNELS 4 /** * Compute a0 for a constant-valued coefficient (GL_FLAT shading). */ static void constant_coef( struct lp_rast_triangle *tri, unsigned slot, const float value, unsigned i ) { tri->inputs.a0[slot][i] = value; tri->inputs.dadx[slot][i] = 0; tri->inputs.dady[slot][i] = 0; } /** * Compute a0, dadx and dady for a linearly interpolated coefficient, * for a triangle. */ static void linear_coef( struct lp_rast_triangle *tri, float oneoverarea, unsigned slot, const float (*v1)[4], const float (*v2)[4], const float (*v3)[4], unsigned vert_attr, unsigned i) { float a1 = v1[vert_attr][i]; float a2 = v2[vert_attr][i]; float a3 = v3[vert_attr][i]; float da12 = a1 - a2; float da31 = a3 - a1; float dadx = (da12 * tri->dy31 - tri->dy12 * da31) * oneoverarea; float dady = (da31 * tri->dx12 - tri->dx31 * da12) * oneoverarea; tri->inputs.dadx[slot][i] = dadx; tri->inputs.dady[slot][i] = dady; /* calculate a0 as the value which would be sampled for the * fragment at (0,0), taking into account that we want to sample at * pixel centers, in other words (0.5, 0.5). * * this is neat but unfortunately not a good way to do things for * triangles with very large values of dadx or dady as it will * result in the subtraction and re-addition from a0 of a very * large number, which means we'll end up loosing a lot of the * fractional bits and precision from a0. the way to fix this is * to define a0 as the sample at a pixel center somewhere near vmin * instead - i'll switch to this later. */ tri->inputs.a0[slot][i] = (v1[vert_attr][i] - (dadx * (v1[0][0] - 0.5f) + dady * (v1[0][1] - 0.5f))); } /** * Compute a0, dadx and dady for a perspective-corrected interpolant, * for a triangle. * We basically multiply the vertex value by 1/w before computing * the plane coefficients (a0, dadx, dady). * Later, when we compute the value at a particular fragment position we'll * divide the interpolated value by the interpolated W at that fragment. */ static void perspective_coef( struct lp_rast_triangle *tri, float oneoverarea, unsigned slot, const float (*v1)[4], const float (*v2)[4], const float (*v3)[4], unsigned vert_attr, unsigned i) { /* premultiply by 1/w (v[0][3] is always 1/w): */ float a1 = v1[vert_attr][i] * v1[0][3]; float a2 = v2[vert_attr][i] * v2[0][3]; float a3 = v3[vert_attr][i] * v3[0][3]; float da12 = a1 - a2; float da31 = a3 - a1; float dadx = (da12 * tri->dy31 - tri->dy12 * da31) * oneoverarea; float dady = (da31 * tri->dx12 - tri->dx31 * da12) * oneoverarea; tri->inputs.dadx[slot][i] = dadx; tri->inputs.dady[slot][i] = dady; tri->inputs.a0[slot][i] = (a1 - (dadx * (v1[0][0] - 0.5f) + dady * (v1[0][1] - 0.5f))); } /** * Special coefficient setup for gl_FragCoord. * X and Y are trivial, though Y has to be inverted for OpenGL. * Z and W are copied from position_coef which should have already been computed. * We could do a bit less work if we'd examine gl_FragCoord's swizzle mask. */ static void setup_fragcoord_coef(struct lp_rast_triangle *tri, float oneoverarea, unsigned slot, const float (*v1)[4], const float (*v2)[4], const float (*v3)[4]) { /*X*/ tri->inputs.a0[slot][0] = 0.0; tri->inputs.dadx[slot][0] = 1.0; tri->inputs.dady[slot][0] = 0.0; /*Y*/ tri->inputs.a0[slot][1] = 0.0; tri->inputs.dadx[slot][1] = 0.0; tri->inputs.dady[slot][1] = 1.0; /*Z*/ linear_coef(tri, oneoverarea, slot, v1, v2, v3, 0, 2); /*W*/ linear_coef(tri, oneoverarea, slot, v1, v2, v3, 0, 3); } static void setup_facing_coef( struct lp_rast_triangle *tri, unsigned slot, boolean frontface ) { constant_coef( tri, slot, 1.0f - frontface, 0 ); constant_coef( tri, slot, 0.0f, 1 ); /* wasted */ constant_coef( tri, slot, 0.0f, 2 ); /* wasted */ constant_coef( tri, slot, 0.0f, 3 ); /* wasted */ } /** * Compute the tri->coef[] array dadx, dady, a0 values. */ static void setup_tri_coefficients( struct setup_context *setup, struct lp_rast_triangle *tri, float oneoverarea, const float (*v1)[4], const float (*v2)[4], const float (*v3)[4], boolean frontface) { struct lp_scene *scene = lp_setup_get_current_scene(setup); unsigned slot; /* Allocate space for the a0, dadx and dady arrays */ { unsigned bytes; bytes = (setup->fs.nr_inputs + 1) * 4 * sizeof(float); tri->inputs.a0 = lp_scene_alloc_aligned( scene, bytes, 16 ); tri->inputs.dadx = lp_scene_alloc_aligned( scene, bytes, 16 ); tri->inputs.dady = lp_scene_alloc_aligned( scene, bytes, 16 ); } /* The internal position input is in slot zero: */ setup_fragcoord_coef(tri, oneoverarea, 0, v1, v2, v3); /* setup interpolation for all the remaining attributes: */ for (slot = 0; slot < setup->fs.nr_inputs; slot++) { unsigned vert_attr = setup->fs.input[slot].src_index; unsigned i; switch (setup->fs.input[slot].interp) { case LP_INTERP_CONSTANT: for (i = 0; i < NUM_CHANNELS; i++) constant_coef(tri, slot+1, v3[vert_attr][i], i); break; case LP_INTERP_LINEAR: for (i = 0; i < NUM_CHANNELS; i++) linear_coef(tri, oneoverarea, slot+1, v1, v2, v3, vert_attr, i); break; case LP_INTERP_PERSPECTIVE: for (i = 0; i < NUM_CHANNELS; i++) perspective_coef(tri, oneoverarea, slot+1, v1, v2, v3, vert_attr, i); break; case LP_INTERP_POSITION: /* XXX: fix me - duplicates the values in slot zero. */ setup_fragcoord_coef(tri, oneoverarea, slot+1, v1, v2, v3); break; case LP_INTERP_FACING: setup_facing_coef(tri, slot+1, frontface); break; default: assert(0); } } } static inline int subpixel_snap( float a ) { return util_iround(FIXED_ONE * a); } /** * Do basic setup for triangle rasterization and determine which * framebuffer tiles are touched. Put the triangle in the scene's * bins for the tiles which we overlap. */ static void do_triangle_ccw(struct setup_context *setup, const float (*v1)[4], const float (*v2)[4], const float (*v3)[4], boolean frontfacing ) { /* x/y positions in fixed point */ const int x1 = subpixel_snap(v1[0][0]); const int x2 = subpixel_snap(v2[0][0]); const int x3 = subpixel_snap(v3[0][0]); const int y1 = subpixel_snap(v1[0][1]); const int y2 = subpixel_snap(v2[0][1]); const int y3 = subpixel_snap(v3[0][1]); struct lp_scene *scene = lp_setup_get_current_scene(setup); struct lp_rast_triangle *tri = lp_scene_alloc_aligned( scene, sizeof *tri, 16 ); float area, oneoverarea; int minx, maxx, miny, maxy; tri->dx12 = x1 - x2; tri->dx23 = x2 - x3; tri->dx31 = x3 - x1; tri->dy12 = y1 - y2; tri->dy23 = y2 - y3; tri->dy31 = y3 - y1; area = (tri->dx12 * tri->dy31 - tri->dx31 * tri->dy12); /* Cull non-ccw and zero-sized triangles. * * XXX: subject to overflow?? */ if (area <= 0) { lp_scene_putback_data( scene, sizeof *tri ); return; } /* Bounding rectangle (in pixels) */ tri->minx = (MIN3(x1, x2, x3) + 0xf) >> FIXED_ORDER; tri->maxx = (MAX3(x1, x2, x3) + 0xf) >> FIXED_ORDER; tri->miny = (MIN3(y1, y2, y3) + 0xf) >> FIXED_ORDER; tri->maxy = (MAX3(y1, y2, y3) + 0xf) >> FIXED_ORDER; if (tri->miny == tri->maxy || tri->minx == tri->maxx) { lp_scene_putback_data( scene, sizeof *tri ); return; } /* */ oneoverarea = ((float)FIXED_ONE) / (float)area; /* Setup parameter interpolants: */ setup_tri_coefficients( setup, tri, oneoverarea, v1, v2, v3, frontfacing ); /* half-edge constants, will be interated over the whole * rendertarget. */ tri->c1 = tri->dy12 * x1 - tri->dx12 * y1; tri->c2 = tri->dy23 * x2 - tri->dx23 * y2; tri->c3 = tri->dy31 * x3 - tri->dx31 * y3; /* correct for top-left fill convention: */ if (tri->dy12 < 0 || (tri->dy12 == 0 && tri->dx12 > 0)) tri->c1++; if (tri->dy23 < 0 || (tri->dy23 == 0 && tri->dx23 > 0)) tri->c2++; if (tri->dy31 < 0 || (tri->dy31 == 0 && tri->dx31 > 0)) tri->c3++; tri->dy12 *= FIXED_ONE; tri->dy23 *= FIXED_ONE; tri->dy31 *= FIXED_ONE; tri->dx12 *= FIXED_ONE; tri->dx23 *= FIXED_ONE; tri->dx31 *= FIXED_ONE; /* find trivial reject offsets for each edge for a single-pixel * sized block. These will be scaled up at each recursive level to * match the active blocksize. Scaling in this way works best if * the blocks are square. */ tri->eo1 = 0; if (tri->dy12 < 0) tri->eo1 -= tri->dy12; if (tri->dx12 > 0) tri->eo1 += tri->dx12; tri->eo2 = 0; if (tri->dy23 < 0) tri->eo2 -= tri->dy23; if (tri->dx23 > 0) tri->eo2 += tri->dx23; tri->eo3 = 0; if (tri->dy31 < 0) tri->eo3 -= tri->dy31; if (tri->dx31 > 0) tri->eo3 += tri->dx31; /* Calculate trivial accept offsets from the above. */ tri->ei1 = tri->dx12 - tri->dy12 - tri->eo1; tri->ei2 = tri->dx23 - tri->dy23 - tri->eo2; tri->ei3 = tri->dx31 - tri->dy31 - tri->eo3; { const int xstep1 = -tri->dy12; const int xstep2 = -tri->dy23; const int xstep3 = -tri->dy31; const int ystep1 = tri->dx12; const int ystep2 = tri->dx23; const int ystep3 = tri->dx31; int qx, qy, ix, iy; int i = 0; for (qy = 0; qy < 2; qy++) { for (qx = 0; qx < 2; qx++) { for (iy = 0; iy < 2; iy++) { for (ix = 0; ix < 2; ix++, i++) { int x = qx * 2 + ix; int y = qy * 2 + iy; tri->inputs.step[0][i] = x * xstep1 + y * ystep1; tri->inputs.step[1][i] = x * xstep2 + y * ystep2; tri->inputs.step[2][i] = x * xstep3 + y * ystep3; } } } } } /* * All fields of 'tri' are now set. The remaining code here is * concerned with binning. */ /* Convert to tile coordinates: */ minx = tri->minx / TILE_SIZE; miny = tri->miny / TILE_SIZE; maxx = tri->maxx / TILE_SIZE; maxy = tri->maxy / TILE_SIZE; /* Determine which tile(s) intersect the triangle's bounding box */ if (miny == maxy && minx == maxx) { /* Triangle is contained in a single tile: */ lp_scene_bin_command( scene, minx, miny, lp_rast_triangle, lp_rast_arg_triangle(tri) ); } else { int c1 = (tri->c1 + tri->dx12 * miny * TILE_SIZE - tri->dy12 * minx * TILE_SIZE); int c2 = (tri->c2 + tri->dx23 * miny * TILE_SIZE - tri->dy23 * minx * TILE_SIZE); int c3 = (tri->c3 + tri->dx31 * miny * TILE_SIZE - tri->dy31 * minx * TILE_SIZE); int ei1 = tri->ei1 << TILE_ORDER; int ei2 = tri->ei2 << TILE_ORDER; int ei3 = tri->ei3 << TILE_ORDER; int eo1 = tri->eo1 << TILE_ORDER; int eo2 = tri->eo2 << TILE_ORDER; int eo3 = tri->eo3 << TILE_ORDER; int xstep1 = -(tri->dy12 << TILE_ORDER); int xstep2 = -(tri->dy23 << TILE_ORDER); int xstep3 = -(tri->dy31 << TILE_ORDER); int ystep1 = tri->dx12 << TILE_ORDER; int ystep2 = tri->dx23 << TILE_ORDER; int ystep3 = tri->dx31 << TILE_ORDER; int x, y; /* Trivially accept or reject blocks, else jump to per-pixel * examination above. */ for (y = miny; y <= maxy; y++) { int cx1 = c1; int cx2 = c2; int cx3 = c3; int in = 0; for (x = minx; x <= maxx; x++) { if (cx1 + eo1 < 0 || cx2 + eo2 < 0 || cx3 + eo3 < 0) { /* do nothing */ if (in) break; } else if (cx1 + ei1 > 0 && cx2 + ei2 > 0 && cx3 + ei3 > 0) { in = 1; /* triangle covers the whole tile- shade whole tile */ lp_scene_bin_command( scene, x, y, lp_rast_shade_tile, lp_rast_arg_inputs(&tri->inputs) ); } else { in = 1; /* shade partial tile */ lp_scene_bin_command( scene, x, y, lp_rast_triangle, lp_rast_arg_triangle(tri) ); } /* Iterate cx values across the region: */ cx1 += xstep1; cx2 += xstep2; cx3 += xstep3; } /* Iterate c values down the region: */ c1 += ystep1; c2 += ystep2; c3 += ystep3; } } } static void triangle_cw( struct setup_context *setup, const float (*v0)[4], const float (*v1)[4], const float (*v2)[4] ) { do_triangle_ccw( setup, v1, v0, v2, !setup->ccw_is_frontface ); } static void triangle_ccw( struct setup_context *setup, const float (*v0)[4], const float (*v1)[4], const float (*v2)[4] ) { do_triangle_ccw( setup, v0, v1, v2, setup->ccw_is_frontface ); } static void triangle_both( struct setup_context *setup, const float (*v0)[4], const float (*v1)[4], const float (*v2)[4] ) { /* edge vectors e = v0 - v2, f = v1 - v2 */ const float ex = v0[0][0] - v2[0][0]; const float ey = v0[0][1] - v2[0][1]; const float fx = v1[0][0] - v2[0][0]; const float fy = v1[0][1] - v2[0][1]; /* det = cross(e,f).z */ if (ex * fy - ey * fx < 0) triangle_ccw( setup, v0, v1, v2 ); else triangle_cw( setup, v0, v1, v2 ); } static void triangle_nop( struct setup_context *setup, const float (*v0)[4], const float (*v1)[4], const float (*v2)[4] ) { } void lp_setup_choose_triangle( struct setup_context *setup ) { switch (setup->cullmode) { case PIPE_WINDING_NONE: setup->triangle = triangle_both; break; case PIPE_WINDING_CCW: setup->triangle = triangle_cw; break; case PIPE_WINDING_CW: setup->triangle = triangle_ccw; break; default: setup->triangle = triangle_nop; break; } }