diff options
Diffstat (limited to 'src/gallium/drivers/llvmpipe/lp_setup_coef.c')
-rw-r--r-- | src/gallium/drivers/llvmpipe/lp_setup_coef.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/src/gallium/drivers/llvmpipe/lp_setup_coef.c b/src/gallium/drivers/llvmpipe/lp_setup_coef.c new file mode 100644 index 0000000000..95e3e8fffe --- /dev/null +++ b/src/gallium/drivers/llvmpipe/lp_setup_coef.c @@ -0,0 +1,258 @@ +/************************************************************************** + * + * 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 struct lp_tri_info *info) +{ + unsigned fragcoord_usage_mask = TGSI_WRITEMASK_XYZ; + unsigned slot; + unsigned i; + + /* 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 |