/************************************************************************** * * Copyright 2010, VMware. * 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 VMWARE 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 "util/u_math.h" #include "util/u_memory.h" #include "lp_perf.h" #include "lp_setup_context.h" #include "lp_setup_coef.h" #include "lp_rast.h" #include "lp_state_fs.h" #if !defined(PIPE_ARCH_SSE) /** * Compute a0 for a constant-valued coefficient (GL_FLAT shading). */ static void constant_coef( struct lp_rast_shader_inputs *inputs, unsigned slot, const float value, unsigned i ) { inputs->a0[slot][i] = value; inputs->dadx[slot][i] = 0.0f; inputs->dady[slot][i] = 0.0f; } static void linear_coef( struct lp_rast_shader_inputs *inputs, const struct lp_tri_info *info, unsigned slot, unsigned vert_attr, unsigned i) { float a0 = info->v0[vert_attr][i]; float a1 = info->v1[vert_attr][i]; float a2 = info->v2[vert_attr][i]; float da01 = a0 - a1; float da20 = a2 - a0; float dadx = (da01 * info->dy20_ooa - info->dy01_ooa * da20); float dady = (da20 * info->dx01_ooa - info->dx20_ooa * da01); inputs->dadx[slot][i] = dadx; 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. */ inputs->a0[slot][i] = a0 - (dadx * info->x0_center + dady * info->y0_center); } /** * 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_shader_inputs *inputs, const struct lp_tri_info *info, unsigned slot, unsigned vert_attr, unsigned i) { /* premultiply by 1/w (v[0][3] is always 1/w): */ float a0 = info->v0[vert_attr][i] * info->v0[0][3]; float a1 = info->v1[vert_attr][i] * info->v1[0][3]; float a2 = info->v2[vert_attr][i] * info->v2[0][3]; float da01 = a0 - a1; float da20 = a2 - a0; float dadx = da01 * info->dy20_ooa - info->dy01_ooa * da20; float dady = da20 * info->dx01_ooa - info->dx20_ooa * da01; inputs->dadx[slot][i] = dadx; inputs->dady[slot][i] = dady; inputs->a0[slot][i] = a0 - (dadx * info->x0_center + dady * info->y0_center); } /** * Special coefficient setup for gl_FragCoord. * X and Y are trivial * 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_shader_inputs *inputs, const struct lp_tri_info *info, unsigned slot, unsigned usage_mask) { /*X*/ if (usage_mask & TGSI_WRITEMASK_X) { inputs->a0[slot][0] = 0.0; inputs->dadx[slot][0] = 1.0; inputs->dady[slot][0] = 0.0; } /*Y*/ if (usage_mask & TGSI_WRITEMASK_Y) { inputs->a0[slot][1] = 0.0; inputs->dadx[slot][1] = 0.0; inputs->dady[slot][1] = 1.0; } /*Z*/ if (usage_mask & TGSI_WRITEMASK_Z) { linear_coef(inputs, info, slot, 0, 2); } /*W*/ if (usage_mask & TGSI_WRITEMASK_W) { linear_coef(inputs, info, slot, 0, 3); } } /** * Setup the fragment input attribute with the front-facing value. * \param frontface is the triangle front facing? */ static void setup_facing_coef( struct lp_rast_shader_inputs *inputs, unsigned slot, boolean frontface, unsigned usage_mask) { /* convert TRUE to 1.0 and FALSE to -1.0 */ if (usage_mask & TGSI_WRITEMASK_X) constant_coef( inputs, slot, 2.0f * frontface - 1.0f, 0 ); if (usage_mask & TGSI_WRITEMASK_Y) constant_coef( inputs, slot, 0.0f, 1 ); /* wasted */ if (usage_mask & TGSI_WRITEMASK_Z) constant_coef( inputs, slot, 0.0f, 2 ); /* wasted */ if (usage_mask & TGSI_WRITEMASK_W) constant_coef( inputs, slot, 0.0f, 3 ); /* wasted */ } /** * Compute the tri->coef[] array dadx, dady, a0 values. */ void lp_setup_tri_coef( struct lp_setup_context *setup, struct lp_rast_shader_inputs *inputs, const float (*v0)[4], const float (*v1)[4], const float (*v2)[4], boolean frontfacing) { unsigned fragcoord_usage_mask = TGSI_WRITEMASK_XYZ; unsigned slot; unsigned i; struct lp_tri_info info; float dx01 = v0[0][0] - v1[0][0]; float dy01 = v0[0][1] - v1[0][1]; float dx20 = v2[0][0] - v0[0][0]; float dy20 = v2[0][1] - v0[0][1]; float oneoverarea = 1.0f / (dx01 * dy20 - dx20 * dy01); info.v0 = v0; info.v1 = v1; info.v2 = v2; info.frontfacing = frontfacing; info.x0_center = v0[0][0] - setup->pixel_offset; info.y0_center = v0[0][1] - setup->pixel_offset; info.dx01_ooa = dx01 * oneoverarea; info.dx20_ooa = dx20 * oneoverarea; info.dy01_ooa = dy01 * oneoverarea; info.dy20_ooa = dy20 * oneoverarea; /* 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 usage_mask = setup->fs.input[slot].usage_mask; switch (setup->fs.input[slot].interp) { case LP_INTERP_CONSTANT: if (setup->flatshade_first) { for (i = 0; i < NUM_CHANNELS; i++) if (usage_mask & (1 << i)) constant_coef(inputs, slot+1, info.v0[vert_attr][i], i); } else { for (i = 0; i < NUM_CHANNELS; i++) if (usage_mask & (1 << i)) constant_coef(inputs, slot+1, info.v2[vert_attr][i], i); } break; case LP_INTERP_LINEAR: for (i = 0; i < NUM_CHANNELS; i++) if (usage_mask & (1 << i)) linear_coef(inputs, &info, slot+1, vert_attr, i); break; case LP_INTERP_PERSPECTIVE: for (i = 0; i < NUM_CHANNELS; i++) if (usage_mask & (1 << i)) perspective_coef(inputs, &info, slot+1, vert_attr, i); fragcoord_usage_mask |= TGSI_WRITEMASK_W; break; case LP_INTERP_POSITION: /* * The generated pixel interpolators will pick up the coeffs from * slot 0, so all need to ensure that the usage mask is covers all * usages. */ fragcoord_usage_mask |= usage_mask; break; case LP_INTERP_FACING: setup_facing_coef(inputs, slot+1, info.frontfacing, usage_mask); break; default: assert(0); } } /* The internal position input is in slot zero: */ setup_fragcoord_coef(inputs, &info, 0, fragcoord_usage_mask); } #else extern void lp_setup_coef_dummy(void); void lp_setup_coef_dummy(void) { } #endif