altos/draw: Use float for polygon coords

This makes polygons look way better.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/draw/Makefile b/src/draw/Makefile
index e56acf2958f1b110ef4782d0bb2af6738139de95..ca5628b6f0216af071c1e7b5b9589c71d18f4aba 100644 (file)
--- a/src/draw/Makefile
+++ b/src/draw/Makefile
@@ -35,7 +35,7 @@ SRCS=\
 
 OBJS=$(SRCS:.c=.o)
 
-LIBS=-lXrender -lX11
+LIBS=-lXrender -lX11 -lm
 
 CFLAGS=-O0 -g
 

diff --git a/src/draw/ao_draw.h b/src/draw/ao_draw.h
index 43301cafbcb1632c3d1a5fc7065414e03d668e7b..8d487a9975e57658ae0a602e0958a401c55a5035 100644 (file)
--- a/src/draw/ao_draw.h
+++ b/src/draw/ao_draw.h
@@ -27,7 +27,7 @@ struct ao_bitmap {
 };
 
 struct ao_coord {
-       int16_t         x, y;
+       float   x, y;
 };
 
 struct ao_pattern {

diff --git a/src/draw/ao_poly.c b/src/draw/ao_poly.c
index d60d73344588121d688c4e6bf79bcd15c89698fe..7fa351be7d70bbf26f436eb96f3f4565ea5bca67 100644 (file)
--- a/src/draw/ao_poly.c
+++ b/src/draw/ao_poly.c
@@ -19,6 +19,8 @@
 #include "ao_draw.h"
 #include "ao_draw_int.h"
 #include <stdio.h>
+#include <math.h>
+#include <float.h>
 
 /*
  * Return if the given edge is 'live' at the specified y coordinate.
@@ -29,11 +31,11 @@ static bool
 ao_edge_live(const struct ao_coord     *coords,
             uint16_t                   ncoords,
             uint16_t                   edge,
-            int16_t                    y)
+            float                      y)
 {
        int next_edge = (edge == ncoords - 1) ? 0 : edge + 1;
-       int16_t y1 = coords[edge].y;
-       int16_t y2 = coords[next_edge].y;
+       float y1 = coords[edge].y;
+       float y2 = coords[next_edge].y;
 
        if (y1 > y2)
                return y2 <= y && y < y1;
@@ -48,22 +50,22 @@ static int16_t
 ao_edge_x(const struct ao_coord        *coords,
          uint16_t              ncoords,
          uint16_t              edge,
-         int16_t               y)
+         float                 y)
 {
        int     next_edge = (edge == ncoords - 1) ? 0 : edge + 1;
-       int16_t x1 = coords[edge].x;
-       int16_t x2 = coords[next_edge].x;
-       int16_t y1 = coords[edge].y;
-       int16_t y2 = coords[next_edge].y;
-       int16_t dx = x2 - x1;
-       int16_t dy = y2 - y1;
-       int16_t off_y = y - y1;
+       float x1 = coords[edge].x;
+       float x2 = coords[next_edge].x;
+       float y1 = coords[edge].y;
+       float y2 = coords[next_edge].y;
+       float dx = x2 - x1;
+       float dy = y2 - y1;
+       float off_y = y - y1;
 
        return x1 + (off_y * dx) / dy;
 }
 
 struct next_x {
-       int16_t         x;
+       float           x;
        uint16_t        edge;
 };
 
@@ -76,16 +78,16 @@ static bool
 ao_next_x(const struct ao_coord        *coords,
          uint16_t              ncoords,
          struct next_x         *this_x,
-         int16_t               y)
+         float         y)
 {
        uint16_t        edge;
-       int16_t         next_x = INT16_MAX;
+       float           next_x = FLT_MAX;
        uint16_t        next_edge = UINT16_MAX;
        bool            ret = false;
 
        for (edge = 0; edge < ncoords; edge++) {
                if (ao_edge_live(coords, ncoords, edge, y)) {
-                       int16_t nx = ao_edge_x(coords, ncoords, edge, y);
+                       float   nx = ao_edge_x(coords, ncoords, edge, y);
                        if (this_x->x < nx || (this_x->x == nx && this_x->edge < edge)) {
                                if (nx < next_x) {
                                        next_x = nx;
@@ -105,13 +107,16 @@ ao_next_x(const struct ao_coord   *coords,
  */
 static void
 ao_span(const struct ao_bitmap *dst,
-       int16_t                 x1,
-       int16_t                 x2,
-       int16_t                 y,
+       float                   x1,
+       float                   x2,
+       float                   y,
        uint32_t                fill,
        uint8_t                 rop)
 {
-       ao_rect(dst, x1, y, x2 - x1, 1, fill, rop);
+       int16_t ix1 = floorf(x1 + 0.5f);
+       int16_t ix2 = floorf(x2 + 0.5f);
+       int16_t iy = (int16_t) y;
+       ao_rect(dst, ix1, iy, ix2 - ix1, 1, fill, rop);
 }
 
 /*
@@ -137,10 +142,10 @@ ao_poly(const struct ao_bitmap    *dst,
        uint32_t                fill,
        uint8_t                 rop)
 {
-       int16_t         y_min, y_max;
+       float           y_min, y_max;
        uint16_t        edge;
-       int16_t         y;
-       int16_t         x;
+       float           y;
+       float           x;
        struct next_x   next_x;
        int             wind;
 
@@ -156,6 +161,9 @@ ao_poly(const struct ao_bitmap      *dst,
                        y_max = y;
        }
 
+       y_min = floorf(y_min);
+       y_max = ceilf(y_max);
+
        /*
         * Walk each scanline in the range and fill included spans
         */