Split vertex clipping code out into vertex-clipping.c
This commit is contained in:
Sam Spilsbury
committed by
Kristian Høgsberg
Kristian Høgsberg
parent
4a4704a7d0
commit
619859ce90
+3
-1
@@ -52,7 +52,9 @@ weston_SOURCES = \
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if ENABLE_EGL
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if ENABLE_EGL
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weston_SOURCES += \
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weston_SOURCES += \
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gl-renderer.c
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gl-renderer.c \
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vertex-clipping.c \
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vertex-clipping.h
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endif
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endif
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git-version.h : .FORCE
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git-version.h : .FORCE
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+4
-288
@@ -33,6 +33,7 @@
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#include <linux/input.h>
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#include <linux/input.h>
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#include "gl-renderer.h"
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#include "gl-renderer.h"
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#include "vertex-clipping.h"
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#include <EGL/eglext.h>
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#include <EGL/eglext.h>
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#include "weston-egl-ext.h"
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#include "weston-egl-ext.h"
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@@ -179,270 +180,8 @@ gl_renderer_print_egl_error_state(void)
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egl_error_string(code), (long)code);
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egl_error_string(code), (long)code);
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}
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}
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struct polygon8 {
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GLfloat x[8];
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GLfloat y[8];
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int n;
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};
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struct clip_context {
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struct {
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GLfloat x;
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GLfloat y;
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} prev;
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struct {
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GLfloat x1, y1;
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GLfloat x2, y2;
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} clip;
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struct {
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GLfloat *x;
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GLfloat *y;
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} vertices;
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};
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static GLfloat
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float_difference(GLfloat a, GLfloat b)
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{
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/* http://www.altdevblogaday.com/2012/02/22/comparing-floating-point-numbers-2012-edition/ */
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static const GLfloat max_diff = 4.0f * FLT_MIN;
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static const GLfloat max_rel_diff = 4.0e-5;
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GLfloat diff = a - b;
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GLfloat adiff = fabsf(diff);
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if (adiff <= max_diff)
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return 0.0f;
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a = fabsf(a);
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b = fabsf(b);
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if (adiff <= (a > b ? a : b) * max_rel_diff)
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return 0.0f;
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return diff;
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}
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/* A line segment (p1x, p1y)-(p2x, p2y) intersects the line x = x_arg.
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* Compute the y coordinate of the intersection.
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*/
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static GLfloat
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clip_intersect_y(GLfloat p1x, GLfloat p1y, GLfloat p2x, GLfloat p2y,
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GLfloat x_arg)
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{
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GLfloat a;
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GLfloat diff = float_difference(p1x, p2x);
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/* Practically vertical line segment, yet the end points have already
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* been determined to be on different sides of the line. Therefore
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* the line segment is part of the line and intersects everywhere.
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* Return the end point, so we use the whole line segment.
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*/
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if (diff == 0.0f)
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return p2y;
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a = (x_arg - p2x) / diff;
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return p2y + (p1y - p2y) * a;
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}
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/* A line segment (p1x, p1y)-(p2x, p2y) intersects the line y = y_arg.
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* Compute the x coordinate of the intersection.
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*/
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static GLfloat
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clip_intersect_x(GLfloat p1x, GLfloat p1y, GLfloat p2x, GLfloat p2y,
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GLfloat y_arg)
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{
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GLfloat a;
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GLfloat diff = float_difference(p1y, p2y);
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/* Practically horizontal line segment, yet the end points have already
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* been determined to be on different sides of the line. Therefore
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* the line segment is part of the line and intersects everywhere.
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* Return the end point, so we use the whole line segment.
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*/
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if (diff == 0.0f)
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return p2x;
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a = (y_arg - p2y) / diff;
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return p2x + (p1x - p2x) * a;
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}
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enum path_transition {
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PATH_TRANSITION_OUT_TO_OUT = 0,
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PATH_TRANSITION_OUT_TO_IN = 1,
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PATH_TRANSITION_IN_TO_OUT = 2,
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PATH_TRANSITION_IN_TO_IN = 3,
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};
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static void
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clip_append_vertex(struct clip_context *ctx, GLfloat x, GLfloat y)
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{
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*ctx->vertices.x++ = x;
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*ctx->vertices.y++ = y;
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}
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static enum path_transition
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path_transition_left_edge(struct clip_context *ctx, GLfloat x, GLfloat y)
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{
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return ((ctx->prev.x >= ctx->clip.x1) << 1) | (x >= ctx->clip.x1);
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}
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static enum path_transition
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path_transition_right_edge(struct clip_context *ctx, GLfloat x, GLfloat y)
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{
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return ((ctx->prev.x < ctx->clip.x2) << 1) | (x < ctx->clip.x2);
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}
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static enum path_transition
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path_transition_top_edge(struct clip_context *ctx, GLfloat x, GLfloat y)
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{
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return ((ctx->prev.y >= ctx->clip.y1) << 1) | (y >= ctx->clip.y1);
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}
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static enum path_transition
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path_transition_bottom_edge(struct clip_context *ctx, GLfloat x, GLfloat y)
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{
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return ((ctx->prev.y < ctx->clip.y2) << 1) | (y < ctx->clip.y2);
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}
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static void
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clip_polygon_leftright(struct clip_context *ctx,
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enum path_transition transition,
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GLfloat x, GLfloat y, GLfloat clip_x)
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{
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GLfloat yi;
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switch (transition) {
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case PATH_TRANSITION_IN_TO_IN:
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clip_append_vertex(ctx, x, y);
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break;
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case PATH_TRANSITION_IN_TO_OUT:
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yi = clip_intersect_y(ctx->prev.x, ctx->prev.y, x, y, clip_x);
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clip_append_vertex(ctx, clip_x, yi);
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break;
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case PATH_TRANSITION_OUT_TO_IN:
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yi = clip_intersect_y(ctx->prev.x, ctx->prev.y, x, y, clip_x);
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clip_append_vertex(ctx, clip_x, yi);
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clip_append_vertex(ctx, x, y);
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break;
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case PATH_TRANSITION_OUT_TO_OUT:
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/* nothing */
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break;
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default:
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assert(0 && "bad enum path_transition");
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}
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ctx->prev.x = x;
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ctx->prev.y = y;
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}
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static void
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clip_polygon_topbottom(struct clip_context *ctx,
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enum path_transition transition,
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GLfloat x, GLfloat y, GLfloat clip_y)
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{
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GLfloat xi;
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switch (transition) {
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case PATH_TRANSITION_IN_TO_IN:
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clip_append_vertex(ctx, x, y);
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break;
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case PATH_TRANSITION_IN_TO_OUT:
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xi = clip_intersect_x(ctx->prev.x, ctx->prev.y, x, y, clip_y);
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clip_append_vertex(ctx, xi, clip_y);
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break;
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case PATH_TRANSITION_OUT_TO_IN:
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xi = clip_intersect_x(ctx->prev.x, ctx->prev.y, x, y, clip_y);
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clip_append_vertex(ctx, xi, clip_y);
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clip_append_vertex(ctx, x, y);
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break;
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case PATH_TRANSITION_OUT_TO_OUT:
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/* nothing */
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break;
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default:
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assert(0 && "bad enum path_transition");
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}
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ctx->prev.x = x;
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ctx->prev.y = y;
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}
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static void
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clip_context_prepare(struct clip_context *ctx, const struct polygon8 *src,
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GLfloat *dst_x, GLfloat *dst_y)
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{
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ctx->prev.x = src->x[src->n - 1];
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ctx->prev.y = src->y[src->n - 1];
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ctx->vertices.x = dst_x;
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ctx->vertices.y = dst_y;
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}
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static int
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clip_polygon_left(struct clip_context *ctx, const struct polygon8 *src,
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GLfloat *dst_x, GLfloat *dst_y)
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{
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enum path_transition trans;
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int i;
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clip_context_prepare(ctx, src, dst_x, dst_y);
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for (i = 0; i < src->n; i++) {
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trans = path_transition_left_edge(ctx, src->x[i], src->y[i]);
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clip_polygon_leftright(ctx, trans, src->x[i], src->y[i],
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ctx->clip.x1);
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}
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return ctx->vertices.x - dst_x;
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}
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static int
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clip_polygon_right(struct clip_context *ctx, const struct polygon8 *src,
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GLfloat *dst_x, GLfloat *dst_y)
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{
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enum path_transition trans;
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int i;
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clip_context_prepare(ctx, src, dst_x, dst_y);
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for (i = 0; i < src->n; i++) {
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trans = path_transition_right_edge(ctx, src->x[i], src->y[i]);
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clip_polygon_leftright(ctx, trans, src->x[i], src->y[i],
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ctx->clip.x2);
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}
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return ctx->vertices.x - dst_x;
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}
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static int
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clip_polygon_top(struct clip_context *ctx, const struct polygon8 *src,
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GLfloat *dst_x, GLfloat *dst_y)
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{
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enum path_transition trans;
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int i;
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clip_context_prepare(ctx, src, dst_x, dst_y);
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for (i = 0; i < src->n; i++) {
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trans = path_transition_top_edge(ctx, src->x[i], src->y[i]);
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clip_polygon_topbottom(ctx, trans, src->x[i], src->y[i],
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ctx->clip.y1);
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}
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return ctx->vertices.x - dst_x;
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}
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static int
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clip_polygon_bottom(struct clip_context *ctx, const struct polygon8 *src,
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GLfloat *dst_x, GLfloat *dst_y)
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{
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enum path_transition trans;
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int i;
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clip_context_prepare(ctx, src, dst_x, dst_y);
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for (i = 0; i < src->n; i++) {
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trans = path_transition_bottom_edge(ctx, src->x[i], src->y[i]);
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clip_polygon_topbottom(ctx, trans, src->x[i], src->y[i],
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ctx->clip.y2);
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}
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return ctx->vertices.x - dst_x;
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}
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#define max(a, b) (((a) > (b)) ? (a) : (b))
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#define max(a, b) (((a) > (b)) ? (a) : (b))
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#define min(a, b) (((a) > (b)) ? (b) : (a))
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#define min(a, b) (((a) > (b)) ? (b) : (a))
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#define clip(x, a, b) min(max(x, a), b)
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/*
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/*
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* Compute the boundary vertices of the intersection of the global coordinate
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* Compute the boundary vertices of the intersection of the global coordinate
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@@ -457,7 +196,7 @@ static int
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calculate_edges(struct weston_surface *es, pixman_box32_t *rect,
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calculate_edges(struct weston_surface *es, pixman_box32_t *rect,
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pixman_box32_t *surf_rect, GLfloat *ex, GLfloat *ey)
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pixman_box32_t *surf_rect, GLfloat *ex, GLfloat *ey)
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{
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{
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struct polygon8 polygon;
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struct clip_context ctx;
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struct clip_context ctx;
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int i, n;
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int i, n;
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GLfloat min_x, max_x, min_y, max_y;
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GLfloat min_x, max_x, min_y, max_y;
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@@ -500,11 +239,7 @@ calculate_edges(struct weston_surface *es, pixman_box32_t *rect,
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* vertices to the clip rect bounds:
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* vertices to the clip rect bounds:
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*/
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*/
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if (!es->transform.enabled) {
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if (!es->transform.enabled) {
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for (i = 0; i < surf.n; i++) {
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return clip_simple(&ctx, &surf, ex, ey);
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ex[i] = clip(surf.x[i], ctx.clip.x1, ctx.clip.x2);
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ey[i] = clip(surf.y[i], ctx.clip.y1, ctx.clip.y2);
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}
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return surf.n;
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}
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}
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/* Transformed case: use a general polygon clipping algorithm to
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/* Transformed case: use a general polygon clipping algorithm to
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@@ -513,26 +248,7 @@ calculate_edges(struct weston_surface *es, pixman_box32_t *rect,
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* http://www.codeguru.com/cpp/misc/misc/graphics/article.php/c8965/Polygon-Clipping.htm
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* http://www.codeguru.com/cpp/misc/misc/graphics/article.php/c8965/Polygon-Clipping.htm
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* but without looking at any of that code.
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* but without looking at any of that code.
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*/
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*/
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polygon.n = clip_polygon_left(&ctx, &surf, polygon.x, polygon.y);
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n = clip_transformed(&ctx, &surf, ex, ey);
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surf.n = clip_polygon_right(&ctx, &polygon, surf.x, surf.y);
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polygon.n = clip_polygon_top(&ctx, &surf, polygon.x, polygon.y);
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surf.n = clip_polygon_bottom(&ctx, &polygon, surf.x, surf.y);
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/* Get rid of duplicate vertices */
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ex[0] = surf.x[0];
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ey[0] = surf.y[0];
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n = 1;
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for (i = 1; i < surf.n; i++) {
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if (float_difference(ex[n - 1], surf.x[i]) == 0.0f &&
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float_difference(ey[n - 1], surf.y[i]) == 0.0f)
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continue;
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ex[n] = surf.x[i];
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ey[n] = surf.y[i];
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n++;
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}
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if (float_difference(ex[n - 1], surf.x[0]) == 0.0f &&
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float_difference(ey[n - 1], surf.y[0]) == 0.0f)
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n--;
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if (n < 3)
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if (n < 3)
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return 0;
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return 0;
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@@ -0,0 +1,317 @@
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/*
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* Copyright © 2012 Intel Corporation
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*
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* Permission to use, copy, modify, distribute, and sell this software and
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* its documentation for any purpose is hereby granted without fee, provided
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* that the above copyright notice appear in all copies and that both that
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* copyright notice and this permission notice appear in supporting
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* documentation, and that the name of the copyright holders not be used in
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* advertising or publicity pertaining to distribution of the software
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* without specific, written prior permission. The copyright holders make
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* no representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
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* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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||||||
|
* FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
|
||||||
|
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
|
||||||
|
* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
|
||||||
|
* CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
|
||||||
|
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
||||||
|
*/
|
||||||
|
#include <assert.h>
|
||||||
|
#include <float.h>
|
||||||
|
#include <math.h>
|
||||||
|
|
||||||
|
#include <GLES2/gl2.h>
|
||||||
|
|
||||||
|
#include "vertex-clipping.h"
|
||||||
|
|
||||||
|
GLfloat
|
||||||
|
float_difference(GLfloat a, GLfloat b)
|
||||||
|
{
|
||||||
|
/* http://www.altdevblogaday.com/2012/02/22/comparing-floating-point-numbers-2012-edition/ */
|
||||||
|
static const GLfloat max_diff = 4.0f * FLT_MIN;
|
||||||
|
static const GLfloat max_rel_diff = 4.0e-5;
|
||||||
|
GLfloat diff = a - b;
|
||||||
|
GLfloat adiff = fabsf(diff);
|
||||||
|
|
||||||
|
if (adiff <= max_diff)
|
||||||
|
return 0.0f;
|
||||||
|
|
||||||
|
a = fabsf(a);
|
||||||
|
b = fabsf(b);
|
||||||
|
if (adiff <= (a > b ? a : b) * max_rel_diff)
|
||||||
|
return 0.0f;
|
||||||
|
|
||||||
|
return diff;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* A line segment (p1x, p1y)-(p2x, p2y) intersects the line x = x_arg.
|
||||||
|
* Compute the y coordinate of the intersection.
|
||||||
|
*/
|
||||||
|
static GLfloat
|
||||||
|
clip_intersect_y(GLfloat p1x, GLfloat p1y, GLfloat p2x, GLfloat p2y,
|
||||||
|
GLfloat x_arg)
|
||||||
|
{
|
||||||
|
GLfloat a;
|
||||||
|
GLfloat diff = float_difference(p1x, p2x);
|
||||||
|
|
||||||
|
/* Practically vertical line segment, yet the end points have already
|
||||||
|
* been determined to be on different sides of the line. Therefore
|
||||||
|
* the line segment is part of the line and intersects everywhere.
|
||||||
|
* Return the end point, so we use the whole line segment.
|
||||||
|
*/
|
||||||
|
if (diff == 0.0f)
|
||||||
|
return p2y;
|
||||||
|
|
||||||
|
a = (x_arg - p2x) / diff;
|
||||||
|
return p2y + (p1y - p2y) * a;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* A line segment (p1x, p1y)-(p2x, p2y) intersects the line y = y_arg.
|
||||||
|
* Compute the x coordinate of the intersection.
|
||||||
|
*/
|
||||||
|
static GLfloat
|
||||||
|
clip_intersect_x(GLfloat p1x, GLfloat p1y, GLfloat p2x, GLfloat p2y,
|
||||||
|
GLfloat y_arg)
|
||||||
|
{
|
||||||
|
GLfloat a;
|
||||||
|
GLfloat diff = float_difference(p1y, p2y);
|
||||||
|
|
||||||
|
/* Practically horizontal line segment, yet the end points have already
|
||||||
|
* been determined to be on different sides of the line. Therefore
|
||||||
|
* the line segment is part of the line and intersects everywhere.
|
||||||
|
* Return the end point, so we use the whole line segment.
|
||||||
|
*/
|
||||||
|
if (diff == 0.0f)
|
||||||
|
return p2x;
|
||||||
|
|
||||||
|
a = (y_arg - p2y) / diff;
|
||||||
|
return p2x + (p1x - p2x) * a;
|
||||||
|
}
|
||||||
|
|
||||||
|
enum path_transition {
|
||||||
|
PATH_TRANSITION_OUT_TO_OUT = 0,
|
||||||
|
PATH_TRANSITION_OUT_TO_IN = 1,
|
||||||
|
PATH_TRANSITION_IN_TO_OUT = 2,
|
||||||
|
PATH_TRANSITION_IN_TO_IN = 3,
|
||||||
|
};
|
||||||
|
|
||||||
|
static void
|
||||||
|
clip_append_vertex(struct clip_context *ctx, GLfloat x, GLfloat y)
|
||||||
|
{
|
||||||
|
*ctx->vertices.x++ = x;
|
||||||
|
*ctx->vertices.y++ = y;
|
||||||
|
}
|
||||||
|
|
||||||
|
static enum path_transition
|
||||||
|
path_transition_left_edge(struct clip_context *ctx, GLfloat x, GLfloat y)
|
||||||
|
{
|
||||||
|
return ((ctx->prev.x >= ctx->clip.x1) << 1) | (x >= ctx->clip.x1);
|
||||||
|
}
|
||||||
|
|
||||||
|
static enum path_transition
|
||||||
|
path_transition_right_edge(struct clip_context *ctx, GLfloat x, GLfloat y)
|
||||||
|
{
|
||||||
|
return ((ctx->prev.x < ctx->clip.x2) << 1) | (x < ctx->clip.x2);
|
||||||
|
}
|
||||||
|
|
||||||
|
static enum path_transition
|
||||||
|
path_transition_top_edge(struct clip_context *ctx, GLfloat x, GLfloat y)
|
||||||
|
{
|
||||||
|
return ((ctx->prev.y >= ctx->clip.y1) << 1) | (y >= ctx->clip.y1);
|
||||||
|
}
|
||||||
|
|
||||||
|
static enum path_transition
|
||||||
|
path_transition_bottom_edge(struct clip_context *ctx, GLfloat x, GLfloat y)
|
||||||
|
{
|
||||||
|
return ((ctx->prev.y < ctx->clip.y2) << 1) | (y < ctx->clip.y2);
|
||||||
|
}
|
||||||
|
|
||||||
|
static void
|
||||||
|
clip_polygon_leftright(struct clip_context *ctx,
|
||||||
|
enum path_transition transition,
|
||||||
|
GLfloat x, GLfloat y, GLfloat clip_x)
|
||||||
|
{
|
||||||
|
GLfloat yi;
|
||||||
|
|
||||||
|
switch (transition) {
|
||||||
|
case PATH_TRANSITION_IN_TO_IN:
|
||||||
|
clip_append_vertex(ctx, x, y);
|
||||||
|
break;
|
||||||
|
case PATH_TRANSITION_IN_TO_OUT:
|
||||||
|
yi = clip_intersect_y(ctx->prev.x, ctx->prev.y, x, y, clip_x);
|
||||||
|
clip_append_vertex(ctx, clip_x, yi);
|
||||||
|
break;
|
||||||
|
case PATH_TRANSITION_OUT_TO_IN:
|
||||||
|
yi = clip_intersect_y(ctx->prev.x, ctx->prev.y, x, y, clip_x);
|
||||||
|
clip_append_vertex(ctx, clip_x, yi);
|
||||||
|
clip_append_vertex(ctx, x, y);
|
||||||
|
break;
|
||||||
|
case PATH_TRANSITION_OUT_TO_OUT:
|
||||||
|
/* nothing */
|
||||||
|
break;
|
||||||
|
default:
|
||||||
|
assert(0 && "bad enum path_transition");
|
||||||
|
}
|
||||||
|
|
||||||
|
ctx->prev.x = x;
|
||||||
|
ctx->prev.y = y;
|
||||||
|
}
|
||||||
|
|
||||||
|
static void
|
||||||
|
clip_polygon_topbottom(struct clip_context *ctx,
|
||||||
|
enum path_transition transition,
|
||||||
|
GLfloat x, GLfloat y, GLfloat clip_y)
|
||||||
|
{
|
||||||
|
GLfloat xi;
|
||||||
|
|
||||||
|
switch (transition) {
|
||||||
|
case PATH_TRANSITION_IN_TO_IN:
|
||||||
|
clip_append_vertex(ctx, x, y);
|
||||||
|
break;
|
||||||
|
case PATH_TRANSITION_IN_TO_OUT:
|
||||||
|
xi = clip_intersect_x(ctx->prev.x, ctx->prev.y, x, y, clip_y);
|
||||||
|
clip_append_vertex(ctx, xi, clip_y);
|
||||||
|
break;
|
||||||
|
case PATH_TRANSITION_OUT_TO_IN:
|
||||||
|
xi = clip_intersect_x(ctx->prev.x, ctx->prev.y, x, y, clip_y);
|
||||||
|
clip_append_vertex(ctx, xi, clip_y);
|
||||||
|
clip_append_vertex(ctx, x, y);
|
||||||
|
break;
|
||||||
|
case PATH_TRANSITION_OUT_TO_OUT:
|
||||||
|
/* nothing */
|
||||||
|
break;
|
||||||
|
default:
|
||||||
|
assert(0 && "bad enum path_transition");
|
||||||
|
}
|
||||||
|
|
||||||
|
ctx->prev.x = x;
|
||||||
|
ctx->prev.y = y;
|
||||||
|
}
|
||||||
|
|
||||||
|
static void
|
||||||
|
clip_context_prepare(struct clip_context *ctx, const struct polygon8 *src,
|
||||||
|
GLfloat *dst_x, GLfloat *dst_y)
|
||||||
|
{
|
||||||
|
ctx->prev.x = src->x[src->n - 1];
|
||||||
|
ctx->prev.y = src->y[src->n - 1];
|
||||||
|
ctx->vertices.x = dst_x;
|
||||||
|
ctx->vertices.y = dst_y;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int
|
||||||
|
clip_polygon_left(struct clip_context *ctx, const struct polygon8 *src,
|
||||||
|
GLfloat *dst_x, GLfloat *dst_y)
|
||||||
|
{
|
||||||
|
enum path_transition trans;
|
||||||
|
int i;
|
||||||
|
|
||||||
|
clip_context_prepare(ctx, src, dst_x, dst_y);
|
||||||
|
for (i = 0; i < src->n; i++) {
|
||||||
|
trans = path_transition_left_edge(ctx, src->x[i], src->y[i]);
|
||||||
|
clip_polygon_leftright(ctx, trans, src->x[i], src->y[i],
|
||||||
|
ctx->clip.x1);
|
||||||
|
}
|
||||||
|
return ctx->vertices.x - dst_x;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int
|
||||||
|
clip_polygon_right(struct clip_context *ctx, const struct polygon8 *src,
|
||||||
|
GLfloat *dst_x, GLfloat *dst_y)
|
||||||
|
{
|
||||||
|
enum path_transition trans;
|
||||||
|
int i;
|
||||||
|
|
||||||
|
clip_context_prepare(ctx, src, dst_x, dst_y);
|
||||||
|
for (i = 0; i < src->n; i++) {
|
||||||
|
trans = path_transition_right_edge(ctx, src->x[i], src->y[i]);
|
||||||
|
clip_polygon_leftright(ctx, trans, src->x[i], src->y[i],
|
||||||
|
ctx->clip.x2);
|
||||||
|
}
|
||||||
|
return ctx->vertices.x - dst_x;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int
|
||||||
|
clip_polygon_top(struct clip_context *ctx, const struct polygon8 *src,
|
||||||
|
GLfloat *dst_x, GLfloat *dst_y)
|
||||||
|
{
|
||||||
|
enum path_transition trans;
|
||||||
|
int i;
|
||||||
|
|
||||||
|
clip_context_prepare(ctx, src, dst_x, dst_y);
|
||||||
|
for (i = 0; i < src->n; i++) {
|
||||||
|
trans = path_transition_top_edge(ctx, src->x[i], src->y[i]);
|
||||||
|
clip_polygon_topbottom(ctx, trans, src->x[i], src->y[i],
|
||||||
|
ctx->clip.y1);
|
||||||
|
}
|
||||||
|
return ctx->vertices.x - dst_x;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int
|
||||||
|
clip_polygon_bottom(struct clip_context *ctx, const struct polygon8 *src,
|
||||||
|
GLfloat *dst_x, GLfloat *dst_y)
|
||||||
|
{
|
||||||
|
enum path_transition trans;
|
||||||
|
int i;
|
||||||
|
|
||||||
|
clip_context_prepare(ctx, src, dst_x, dst_y);
|
||||||
|
for (i = 0; i < src->n; i++) {
|
||||||
|
trans = path_transition_bottom_edge(ctx, src->x[i], src->y[i]);
|
||||||
|
clip_polygon_topbottom(ctx, trans, src->x[i], src->y[i],
|
||||||
|
ctx->clip.y2);
|
||||||
|
}
|
||||||
|
return ctx->vertices.x - dst_x;
|
||||||
|
}
|
||||||
|
|
||||||
|
#define max(a, b) (((a) > (b)) ? (a) : (b))
|
||||||
|
#define min(a, b) (((a) > (b)) ? (b) : (a))
|
||||||
|
#define clip(x, a, b) min(max(x, a), b)
|
||||||
|
|
||||||
|
int
|
||||||
|
clip_simple(struct clip_context *ctx,
|
||||||
|
struct polygon8 *surf,
|
||||||
|
GLfloat *ex,
|
||||||
|
GLfloat *ey)
|
||||||
|
{
|
||||||
|
int i;
|
||||||
|
for (i = 0; i < surf->n; i++) {
|
||||||
|
ex[i] = clip(surf->x[i], ctx->clip.x1, ctx->clip.x2);
|
||||||
|
ey[i] = clip(surf->y[i], ctx->clip.y1, ctx->clip.y2);
|
||||||
|
}
|
||||||
|
return surf->n;
|
||||||
|
}
|
||||||
|
|
||||||
|
int
|
||||||
|
clip_transformed(struct clip_context *ctx,
|
||||||
|
struct polygon8 *surf,
|
||||||
|
GLfloat *ex,
|
||||||
|
GLfloat *ey)
|
||||||
|
{
|
||||||
|
struct polygon8 polygon;
|
||||||
|
int i, n;
|
||||||
|
|
||||||
|
polygon.n = clip_polygon_left(ctx, surf, polygon.x, polygon.y);
|
||||||
|
surf->n = clip_polygon_right(ctx, &polygon, surf->x, surf->y);
|
||||||
|
polygon.n = clip_polygon_top(ctx, surf, polygon.x, polygon.y);
|
||||||
|
surf->n = clip_polygon_bottom(ctx, &polygon, surf->x, surf->y);
|
||||||
|
|
||||||
|
/* Get rid of duplicate vertices */
|
||||||
|
ex[0] = surf->x[0];
|
||||||
|
ey[0] = surf->y[0];
|
||||||
|
n = 1;
|
||||||
|
for (i = 1; i < surf->n; i++) {
|
||||||
|
if (float_difference(ex[n - 1], surf->x[i]) == 0.0f &&
|
||||||
|
float_difference(ey[n - 1], surf->y[i]) == 0.0f)
|
||||||
|
continue;
|
||||||
|
ex[n] = surf->x[i];
|
||||||
|
ey[n] = surf->y[i];
|
||||||
|
n++;
|
||||||
|
}
|
||||||
|
if (float_difference(ex[n - 1], surf->x[0]) == 0.0f &&
|
||||||
|
float_difference(ey[n - 1], surf->y[0]) == 0.0f)
|
||||||
|
n--;
|
||||||
|
|
||||||
|
return n;
|
||||||
|
}
|
||||||
@@ -0,0 +1,65 @@
|
|||||||
|
/*
|
||||||
|
* Copyright © 2012 Intel Corporation
|
||||||
|
*
|
||||||
|
* Permission to use, copy, modify, distribute, and sell this software and
|
||||||
|
* its documentation for any purpose is hereby granted without fee, provided
|
||||||
|
* that the above copyright notice appear in all copies and that both that
|
||||||
|
* copyright notice and this permission notice appear in supporting
|
||||||
|
* documentation, and that the name of the copyright holders not be used in
|
||||||
|
* advertising or publicity pertaining to distribution of the software
|
||||||
|
* without specific, written prior permission. The copyright holders make
|
||||||
|
* no representations about the suitability of this software for any
|
||||||
|
* purpose. It is provided "as is" without express or implied warranty.
|
||||||
|
*
|
||||||
|
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
|
||||||
|
* SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
|
||||||
|
* FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
|
||||||
|
* SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
|
||||||
|
* RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
|
||||||
|
* CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
|
||||||
|
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
||||||
|
*/
|
||||||
|
#ifndef _WESTON_VERTEX_CLIPPING_H
|
||||||
|
#define _WESTON_VERTEX_CLIPPING_H
|
||||||
|
|
||||||
|
#include <GLES2/gl2.h>
|
||||||
|
|
||||||
|
struct polygon8 {
|
||||||
|
GLfloat x[8];
|
||||||
|
GLfloat y[8];
|
||||||
|
int n;
|
||||||
|
};
|
||||||
|
|
||||||
|
struct clip_context {
|
||||||
|
struct {
|
||||||
|
GLfloat x;
|
||||||
|
GLfloat y;
|
||||||
|
} prev;
|
||||||
|
|
||||||
|
struct {
|
||||||
|
GLfloat x1, y1;
|
||||||
|
GLfloat x2, y2;
|
||||||
|
} clip;
|
||||||
|
|
||||||
|
struct {
|
||||||
|
GLfloat *x;
|
||||||
|
GLfloat *y;
|
||||||
|
} vertices;
|
||||||
|
};
|
||||||
|
|
||||||
|
GLfloat
|
||||||
|
float_difference(GLfloat a, GLfloat b);
|
||||||
|
|
||||||
|
int
|
||||||
|
clip_simple(struct clip_context *ctx,
|
||||||
|
struct polygon8 *surf,
|
||||||
|
GLfloat *ex,
|
||||||
|
GLfloat *ey);
|
||||||
|
|
||||||
|
int
|
||||||
|
clip_transformed(struct clip_context *ctx,
|
||||||
|
struct polygon8 *surf,
|
||||||
|
GLfloat *ex,
|
||||||
|
GLfloat *ey);\
|
||||||
|
|
||||||
|
#endif
|
||||||
Reference in New Issue
Block a user