The Render X extension can draw triangles as well as trapezoids, but the implementation has always converted them to trapezoids. This patch moves the X server's triangle conversion code into pixman, where we can reuse the pixman_composite_trapezoid() code. --- pixman/pixman-trap.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++ pixman/pixman.h | 15 ++++++ 2 files changed, 151 insertions(+), 0 deletions(-)
diff --git a/pixman/pixman-trap.c b/pixman/pixman-trap.c index a924326..31144c4 100644 --- a/pixman/pixman-trap.c +++ b/pixman/pixman-trap.c @@ -1,4 +1,5 @@ /* + * Copyright © 2002 Keith Packard, member of The XFree86 Project, Inc. * Copyright © 2004 Keith Packard * * Permission to use, copy, modify, distribute, and sell this software and its @@ -25,6 +26,7 @@ #endif #include <stdio.h> +#include <stdlib.h> #include "pixman-private.h" /* @@ -477,3 +479,137 @@ pixman_composite_trapezoids (pixman_op_t op, pixman_image_unref (tmp); } + +static int +greater_y (pixman_point_fixed_t *a, pixman_point_fixed_t *b) +{ + if (a->y == b->y) + return a->x > b->x; + return a->y > b->y; +} + +/* + * Note that the definition of this function is a bit odd because + * of the X coordinate space (y increasing downwards). + */ +static int +clockwise (pixman_point_fixed_t *ref, + pixman_point_fixed_t *a, + pixman_point_fixed_t *b) +{ + pixman_point_fixed_t ad, bd; + + ad.x = a->x - ref->x; + ad.y = a->y - ref->y; + bd.x = b->x - ref->x; + bd.y = b->y - ref->y; + + return ((pixman_fixed_32_32_t) bd.y * ad.x - + (pixman_fixed_32_32_t) ad.y * bd.x) < 0; +} + +static void +triangle_to_trapezoids (pixman_triangle_t *tri, pixman_trapezoid_t *traps) +{ + pixman_point_fixed_t *top, *left, *right, *tmp; + + top = &tri->p1; + left = &tri->p2; + right = &tri->p3; + + if (greater_y (top, left)) + { + tmp = left; + left = top; + top = tmp; + } + + if (greater_y (top, right)) + { + tmp = right; + right = top; + top = tmp; + } + + if (clockwise (top, right, left)) + { + tmp = right; + right = left; + left = tmp; + } + + /* + * Two cases: + * + * + + + * / \ / \ + * / \ / \ + * / + + \ + * / -- -- \ + * / -- -- \ + * / --- --- \ + * +-- --+ + */ + + traps->top = top->y; + traps->left.p1 = *top; + traps->left.p2 = *left; + traps->right.p1 = *top; + traps->right.p2 = *right; + + if (right->y < left->y) + traps->bottom = right->y; + else + traps->bottom = left->y; + + traps++; + + *traps = *(traps - 1); + + if (right->y < left->y) + { + traps->top = right->y; + traps->bottom = left->y; + traps->right.p1 = *right; + traps->right.p2 = *left; + } + else + { + traps->top = left->y; + traps->bottom = right->y; + traps->left.p1 = *left; + traps->left.p2 = *right; + } +} + +PIXMAN_EXPORT void +pixman_composite_triangles (pixman_op_t op, + pixman_image_t * src, + pixman_image_t * dst, + pixman_format_code_t mask_format, + int x_src, + int y_src, + int x_dst, + int y_dst, + int n_tris, + pixman_triangle_t * tris) +{ + pixman_trapezoid_t *trapezoids; + int i; + + if (n_tris <= 0) + return; + + trapezoids = malloc (2 * n_tris * sizeof (pixman_trapezoid_t)); + if (!trapezoids) + return; + + for (i = 0; i < n_tris; ++i) + triangle_to_trapezoids (&(tris[i]), trapezoids + 2 * i); + + pixman_composite_trapezoids (op, src, dst, mask_format, + x_src, y_src, x_dst, y_dst, + n_tris * 2, trapezoids); + + free (trapezoids); +} diff --git a/pixman/pixman.h b/pixman/pixman.h index c2f7da3..582d9cf 100644 --- a/pixman/pixman.h +++ b/pixman/pixman.h @@ -868,6 +868,7 @@ typedef struct pixman_edge pixman_edge_t; typedef struct pixman_trapezoid pixman_trapezoid_t; typedef struct pixman_trap pixman_trap_t; typedef struct pixman_span_fix pixman_span_fix_t; +typedef struct pixman_triangle pixman_triangle_t; /* * An edge structure. This represents a single polygon edge @@ -895,6 +896,10 @@ struct pixman_trapezoid pixman_line_fixed_t left, right; }; +struct pixman_triangle +{ + pixman_point_fixed_t p1, p2, p3; +}; /* whether 't' is a well defined not obviously empty trapezoid */ #define pixman_trapezoid_valid(t) \ @@ -960,6 +965,16 @@ void pixman_composite_trapezoids (pixman_op_t op, int y_dst, int n_traps, pixman_trapezoid_t * traps); +void pixman_composite_triangles (pixman_op_t op, + pixman_image_t * src, + pixman_image_t * dst, + pixman_format_code_t mask_format, + int x_src, + int y_src, + int x_dst, + int y_dst, + int n_tris, + pixman_triangle_t * tris); PIXMAN_END_DECLS -- 1.7.3.1 _______________________________________________ xorg-devel@lists.x.org: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel