+#define NUM_CHANNELS 4
+
+struct point_info {
+ /* x,y deltas */
+ int dy01, dy12;
+ int dx01, dx12;
+
+ const float (*v0)[4];
+
+ float (*a0)[4];
+ float (*dadx)[4];
+ float (*dady)[4];
+
+ boolean frontfacing;
+};
+
+
+/**
+ * Compute a0 for a constant-valued coefficient (GL_FLAT shading).
+ */
+static void
+constant_coef(struct lp_setup_context *setup,
+ struct point_info *info,
+ unsigned slot,
+ const float value,
+ unsigned i)
+{
+ info->a0[slot][i] = value;
+ info->dadx[slot][i] = 0.0f;
+ info->dady[slot][i] = 0.0f;
+}
+
+
+static void
+point_persp_coeff(struct lp_setup_context *setup,
+ const struct point_info *info,
+ unsigned slot,
+ unsigned i)
+{
+ /*
+ * Fragment shader expects pre-multiplied w for LP_INTERP_PERSPECTIVE. A
+ * better stratergy would be to take the primitive in consideration when
+ * generating the fragment shader key, and therefore avoid the per-fragment
+ * perspective divide.
+ */
+
+ float w0 = info->v0[0][3];
+
+ assert(i < 4);
+
+ info->a0[slot][i] = info->v0[slot][i]*w0;
+ info->dadx[slot][i] = 0.0f;
+ info->dady[slot][i] = 0.0f;
+}
+
+
+/**
+ * Setup automatic texcoord coefficients (for sprite rendering).
+ * \param slot the vertex attribute slot to setup
+ * \param i the attribute channel in [0,3]
+ * \param sprite_coord_origin one of PIPE_SPRITE_COORD_x
+ * \param perspective does the shader expects pre-multiplied w, i.e.,
+ * LP_INTERP_PERSPECTIVE is specified in the shader key
+ */
+static void
+texcoord_coef(struct lp_setup_context *setup,
+ const struct point_info *info,
+ unsigned slot,
+ unsigned i,
+ unsigned sprite_coord_origin,
+ boolean perspective)
+{
+ float w0 = info->v0[0][3];
+
+ assert(i < 4);
+
+ if (i == 0) {
+ float dadx = FIXED_ONE / (float)info->dx12;
+ float dady = 0.0f;
+ float x0 = info->v0[0][0] - setup->pixel_offset;
+ float y0 = info->v0[0][1] - setup->pixel_offset;
+
+ info->dadx[slot][0] = dadx;
+ info->dady[slot][0] = dady;
+ info->a0[slot][0] = 0.5 - (dadx * x0 + dady * y0);
+
+ if (perspective) {
+ info->dadx[slot][0] *= w0;
+ info->dady[slot][0] *= w0;
+ info->a0[slot][0] *= w0;
+ }
+ }
+ else if (i == 1) {
+ float dadx = 0.0f;
+ float dady = FIXED_ONE / (float)info->dx12;
+ float x0 = info->v0[0][0] - setup->pixel_offset;
+ float y0 = info->v0[0][1] - setup->pixel_offset;
+
+ if (sprite_coord_origin == PIPE_SPRITE_COORD_LOWER_LEFT) {
+ dady = -dady;
+ }
+
+ info->dadx[slot][1] = dadx;
+ info->dady[slot][1] = dady;
+ info->a0[slot][1] = 0.5 - (dadx * x0 + dady * y0);
+
+ if (perspective) {
+ info->dadx[slot][1] *= w0;
+ info->dady[slot][1] *= w0;
+ info->a0[slot][1] *= w0;
+ }
+ }
+ else if (i == 2) {
+ info->a0[slot][2] = 0.0f;
+ info->dadx[slot][2] = 0.0f;
+ info->dady[slot][2] = 0.0f;
+ }
+ else {
+ info->a0[slot][3] = perspective ? w0 : 1.0f;
+ info->dadx[slot][3] = 0.0f;
+ info->dady[slot][3] = 0.0f;
+ }
+}
+
+
+/**
+ * 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_point_fragcoord_coef(struct lp_setup_context *setup,
+ struct point_info *info,
+ unsigned slot,
+ unsigned usage_mask)
+{
+ /*X*/
+ if (usage_mask & TGSI_WRITEMASK_X) {
+ info->a0[slot][0] = 0.0;
+ info->dadx[slot][0] = 1.0;
+ info->dady[slot][0] = 0.0;
+ }
+
+ /*Y*/
+ if (usage_mask & TGSI_WRITEMASK_Y) {
+ info->a0[slot][1] = 0.0;
+ info->dadx[slot][1] = 0.0;
+ info->dady[slot][1] = 1.0;
+ }
+
+ /*Z*/
+ if (usage_mask & TGSI_WRITEMASK_Z) {
+ constant_coef(setup, info, slot, info->v0[0][2], 2);
+ }
+
+ /*W*/
+ if (usage_mask & TGSI_WRITEMASK_W) {
+ constant_coef(setup, info, slot, info->v0[0][3], 3);
+ }
+}
+
+
+/**
+ * Compute the point->coef[] array dadx, dady, a0 values.
+ */
+static void
+setup_point_coefficients( struct lp_setup_context *setup,
+ struct point_info *info)
+{
+ const struct lp_setup_variant_key *key = &setup->setup.variant->key;
+ const struct lp_fragment_shader *shader = setup->fs.current.variant->shader;
+ unsigned fragcoord_usage_mask = TGSI_WRITEMASK_XYZ;
+ unsigned slot;
+
+ /* setup interpolation for all the remaining attributes:
+ */
+ for (slot = 0; slot < key->num_inputs; slot++) {
+ unsigned vert_attr = key->inputs[slot].src_index;
+ unsigned usage_mask = key->inputs[slot].usage_mask;
+ enum lp_interp interp = key->inputs[slot].interp;
+ boolean perspective = !!(interp == LP_INTERP_PERSPECTIVE);
+ unsigned i;
+
+ if (perspective & usage_mask) {
+ fragcoord_usage_mask |= TGSI_WRITEMASK_W;
+ }
+
+ switch (interp) {
+ 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_LINEAR:
+ /* Sprite tex coords may use linear interpolation someday */
+ /* fall-through */
+ case LP_INTERP_PERSPECTIVE:
+ /* check if the sprite coord flag is set for this attribute.
+ * If so, set it up so it up so x and y vary from 0 to 1.
+ */
+ if (shader->info.base.input_semantic_name[slot] == TGSI_SEMANTIC_GENERIC) {
+ unsigned semantic_index = shader->info.base.input_semantic_index[slot];
+ /* Note that sprite_coord enable is a bitfield of
+ * PIPE_MAX_SHADER_OUTPUTS bits.
+ */
+ if (semantic_index < PIPE_MAX_SHADER_OUTPUTS &&
+ (setup->sprite_coord_enable & (1 << semantic_index))) {
+ for (i = 0; i < NUM_CHANNELS; i++) {
+ if (usage_mask & (1 << i)) {
+ texcoord_coef(setup, info, slot + 1, i,
+ setup->sprite_coord_origin,
+ perspective);
+ }
+ }
+ break;
+ }
+ }
+ /* fall-through */
+ case LP_INTERP_CONSTANT:
+ for (i = 0; i < NUM_CHANNELS; i++) {
+ if (usage_mask & (1 << i)) {
+ if (perspective) {
+ point_persp_coeff(setup, info, slot+1, i);
+ }
+ else {
+ constant_coef(setup, info, slot+1, info->v0[vert_attr][i], i);
+ }
+ }
+ }
+ break;
+
+ case LP_INTERP_FACING:
+ for (i = 0; i < NUM_CHANNELS; i++)
+ if (usage_mask & (1 << i))
+ constant_coef(setup, info, slot+1,
+ info->frontfacing ? 1.0f : -1.0f, i);
+ break;
+
+ default:
+ assert(0);
+ break;
+ }
+ }
+
+ /* The internal position input is in slot zero:
+ */
+ setup_point_fragcoord_coef(setup, info, 0,
+ fragcoord_usage_mask);
+}
+
+
+static inline int
+subpixel_snap(float a)
+{
+ return util_iround(FIXED_ONE * a);
+}
+
+/**
+ * Print point vertex attribs (for debug).
+ */
+static void
+print_point(struct lp_setup_context *setup,
+ const float (*v0)[4],
+ const float size)
+{
+ const struct lp_setup_variant_key *key = &setup->setup.variant->key;
+ uint i;
+
+ debug_printf("llvmpipe point, width %f\n", size);
+ for (i = 0; i < 1 + key->num_inputs; i++) {
+ debug_printf(" v0[%d]: %f %f %f %f\n", i,
+ v0[i][0], v0[i][1], v0[i][2], v0[i][3]);
+ }
+}
+
+
+static boolean
+try_setup_point( struct lp_setup_context *setup,
+ const float (*v0)[4] )
+{
+ struct llvmpipe_context *lp_context = (struct llvmpipe_context *)setup->pipe;
+ /* x/y positions in fixed point */
+ const struct lp_setup_variant_key *key = &setup->setup.variant->key;
+ const int sizeAttr = setup->psize;
+ const float size
+ = (setup->point_size_per_vertex && sizeAttr > 0) ? v0[sizeAttr][0]
+ : setup->point_size;
+
+ /* Yes this is necessary to accurately calculate bounding boxes
+ * with the two fill-conventions we support. GL (normally) ends
+ * up needing a bottom-left fill convention, which requires
+ * slightly different rounding.
+ */
+ int adj = (setup->bottom_edge_rule != 0) ? 1 : 0;
+
+ struct lp_scene *scene = setup->scene;
+ struct lp_rast_triangle *point;
+ unsigned bytes;
+ struct u_rect bbox;
+ unsigned nr_planes = 4;
+ struct point_info info;
+ unsigned viewport_index = 0;
+ unsigned layer = 0;
+ int fixed_width;
+
+ if (setup->viewport_index_slot > 0) {
+ unsigned *udata = (unsigned*)v0[setup->viewport_index_slot];
+ viewport_index = lp_clamp_viewport_idx(*udata);
+ }
+ if (setup->layer_slot > 0) {
+ layer = *(unsigned*)v0[setup->layer_slot];
+ layer = MIN2(layer, scene->fb_max_layer);
+ }
+
+ if (0)
+ print_point(setup, v0, size);
+
+ /* Bounding rectangle (in pixels) */
+ if (!lp_context->rasterizer ||
+ lp_context->rasterizer->point_quad_rasterization) {
+ /*
+ * Rasterize points as quads.
+ */
+ int x0, y0;
+ /* Point size as fixed point integer, remove rounding errors
+ * and gives minimum width for very small points.
+ */
+ fixed_width = MAX2(FIXED_ONE, subpixel_snap(size));
+
+ x0 = subpixel_snap(v0[0][0] - setup->pixel_offset) - fixed_width/2;
+ y0 = subpixel_snap(v0[0][1] - setup->pixel_offset) - fixed_width/2;
+
+ bbox.x0 = (x0 + (FIXED_ONE-1)) >> FIXED_ORDER;
+ bbox.x1 = (x0 + fixed_width + (FIXED_ONE-1)) >> FIXED_ORDER;
+ bbox.y0 = (y0 + (FIXED_ONE-1) + adj) >> FIXED_ORDER;
+ bbox.y1 = (y0 + fixed_width + (FIXED_ONE-1) + adj) >> FIXED_ORDER;
+
+ /* Inclusive coordinates:
+ */
+ bbox.x1--;
+ bbox.y1--;
+ } else {
+ /*
+ * OpenGL legacy rasterization rules for non-sprite points.
+ *
+ * Per OpenGL 2.1 spec, section 3.3.1, "Basic Point Rasterization".
+ *
+ * This type of point rasterization is only available in pre 3.0 contexts
+ * (or compatibilility contexts which we don't support) anyway.
+ */
+
+ const int x0 = subpixel_snap(v0[0][0]);
+ const int y0 = subpixel_snap(v0[0][1]) - adj;
+
+ int int_width;
+ /* Point size as fixed point integer. For GL legacy points
+ * the point size is always a whole integer.
+ */
+ fixed_width = MAX2(FIXED_ONE,
+ (subpixel_snap(size) + FIXED_ONE/2 - 1) & ~(FIXED_ONE-1));
+ int_width = fixed_width >> FIXED_ORDER;
+
+ assert(setup->pixel_offset != 0);
+
+ if (int_width == 1) {
+ bbox.x0 = x0 >> FIXED_ORDER;
+ bbox.y0 = y0 >> FIXED_ORDER;
+ bbox.x1 = bbox.x0;
+ bbox.y1 = bbox.y0;
+ } else {
+ if (int_width & 1) {
+ /* Odd width */
+ bbox.x0 = (x0 >> FIXED_ORDER) - (int_width - 1)/2;
+ bbox.y0 = (y0 >> FIXED_ORDER) - (int_width - 1)/2;
+ } else {
+ /* Even width */
+ bbox.x0 = ((x0 + FIXED_ONE/2) >> FIXED_ORDER) - int_width/2;
+ bbox.y0 = ((y0 + FIXED_ONE/2) >> FIXED_ORDER) - int_width/2;
+ }
+
+ bbox.x1 = bbox.x0 + int_width - 1;
+ bbox.y1 = bbox.y0 + int_width - 1;
+ }
+ }
+
+ if (0) {
+ debug_printf(" bbox: (%i, %i) - (%i, %i)\n",
+ bbox.x0, bbox.y0,
+ bbox.x1, bbox.y1);
+ }
+
+ if (!u_rect_test_intersection(&setup->draw_regions[viewport_index], &bbox)) {
+ if (0) debug_printf("offscreen\n");
+ LP_COUNT(nr_culled_tris);
+ return TRUE;
+ }
+
+ u_rect_find_intersection(&setup->draw_regions[viewport_index], &bbox);
+
+ point = lp_setup_alloc_triangle(scene,
+ key->num_inputs,
+ nr_planes,
+ &bytes);
+ if (!point)
+ return FALSE;
+
+#ifdef DEBUG
+ point->v[0][0] = v0[0][0];
+ point->v[0][1] = v0[0][1];
+#endif
+
+ LP_COUNT(nr_tris);
+
+ if (lp_context->active_statistics_queries &&
+ !llvmpipe_rasterization_disabled(lp_context)) {
+ lp_context->pipeline_statistics.c_primitives++;
+ }
+
+ if (draw_will_inject_frontface(lp_context->draw) &&
+ setup->face_slot > 0) {
+ point->inputs.frontfacing = v0[setup->face_slot][0];
+ } else {
+ point->inputs.frontfacing = TRUE;
+ }
+
+ info.v0 = v0;
+ info.dx01 = 0;
+ info.dx12 = fixed_width;
+ info.dy01 = fixed_width;
+ info.dy12 = 0;
+ info.a0 = GET_A0(&point->inputs);
+ info.dadx = GET_DADX(&point->inputs);
+ info.dady = GET_DADY(&point->inputs);
+ info.frontfacing = point->inputs.frontfacing;
+
+ /* Setup parameter interpolants:
+ */
+ setup_point_coefficients(setup, &info);
+
+ point->inputs.disable = FALSE;
+ point->inputs.opaque = FALSE;
+ point->inputs.layer = layer;
+ point->inputs.viewport_index = viewport_index;
+
+ {
+ struct lp_rast_plane *plane = GET_PLANES(point);
+
+ plane[0].dcdx = -1;
+ plane[0].dcdy = 0;
+ plane[0].c = 1-bbox.x0;
+ plane[0].eo = 1;
+
+ plane[1].dcdx = 1;
+ plane[1].dcdy = 0;
+ plane[1].c = bbox.x1+1;
+ plane[1].eo = 0;
+
+ plane[2].dcdx = 0;
+ plane[2].dcdy = 1;
+ plane[2].c = 1-bbox.y0;
+ plane[2].eo = 1;
+
+ plane[3].dcdx = 0;
+ plane[3].dcdy = -1;
+ plane[3].c = bbox.y1+1;
+ plane[3].eo = 0;
+ }
+
+ return lp_setup_bin_triangle(setup, point, &bbox, nr_planes, viewport_index);
+}
+
+
+static void
+lp_setup_point(struct lp_setup_context *setup,
+ const float (*v0)[4])