--- /dev/null
+/**************************************************************************
+ *
+ * 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
projects / mesa.git / blobdiff