[libgis] Add texture coords to tiles

[Andy Spencer <andys src gnome org>]

commit 07cebdd8475eeaf5f9cd155ff0424e937aa5c6d8
Author: Andy Spencer <andy753421 gmail com>
Date:   Mon May 3 04:38:28 2010 +0000

    Add texture coords to tiles

 src/gis-opengl.c       |   25 +++++++++++++++++--------
 src/objects/gis-tile.c |    1 +
 src/objects/gis-tile.h |    5 ++++-
 3 files changed, 22 insertions(+), 9 deletions(-)
---
diff --git a/src/gis-opengl.c b/src/gis-opengl.c
index fc0c55e..d01a23c 100644
--- a/src/gis-opengl.c
+++ b/src/gis-opengl.c
@@ -133,6 +133,17 @@ static void _draw_tile(GisOpenGL *opengl, GisTile *tile, GList *triangles)
 			tile->edge.n, tile->edge.s, tile->edge.e, tile->edge.w);
 	//g_message("drawing %4d triangles for tile edges=%7.2f,%7.2f,%7.2f,%7.2f",
 	//		g_list_length(triangles), tile->edge.n, tile->edge.s, tile->edge.e, tile->edge.w);
+	gdouble n = tile->edge.n;
+	gdouble s = tile->edge.s;
+	gdouble e = tile->edge.e;
+	gdouble w = tile->edge.w;
+
+	gdouble londist = e - w;
+	gdouble latdist = n - s;
+
+	gdouble xscale = tile->coords.e - tile->coords.w;
+	gdouble yscale = tile->coords.s - tile->coords.n;
+
 	for (GList *cur = triangles; cur; cur = cur->next) {
 		RoamTriangle *tri = cur->data;
 
@@ -145,14 +156,6 @@ static void _draw_tile(GisOpenGL *opengl, GisTile *tile, GList *triangles)
 			if (lon[2] > 90) lon[2] -= 360;
 		}
 
-		gdouble n = tile->edge.n;
-		gdouble s = tile->edge.s;
-		gdouble e = tile->edge.e;
-		gdouble w = tile->edge.w;
-
-		gdouble londist = e - w;
-		gdouble latdist = n - s;
-
 		gdouble xy[3][2] = {
 			{(lon[0]-w)/londist, 1-(lat[0]-s)/latdist},
 			{(lon[1]-w)/londist, 1-(lat[1]-s)/latdist},
@@ -177,6 +180,12 @@ static void _draw_tile(GisOpenGL *opengl, GisTile *tile, GList *triangles)
 		if (lat[1] == 90 || lat[1] == -90) xy[1][0] = 0.5;
 		if (lat[2] == 90 || lat[2] == -90) xy[2][0] = 0.5;
 
+		/* Scale to tile coords */
+		for (int i = 0; i < 3; i++) {
+			xy[i][0] = tile->coords.w + xy[i][0]*xscale;
+			xy[i][1] = tile->coords.n + xy[i][1]*yscale;
+		}
+
 		glEnable(GL_TEXTURE_2D);
 		glEnable(GL_POLYGON_OFFSET_FILL);
 		glBindTexture(GL_TEXTURE_2D, *(guint*)tile->data);
diff --git a/src/objects/gis-tile.c b/src/objects/gis-tile.c
index 24214ad..fbffd6f 100644
--- a/src/objects/gis-tile.c
+++ b/src/objects/gis-tile.c
@@ -58,6 +58,7 @@ GisTile *gis_tile_new(GisTile *parent,
 	GisTile *tile = g_object_new(GIS_TYPE_TILE, NULL);
 	tile->parent = parent;
 	tile->atime  = time(NULL);
+	gis_bbox_set_bounds(&tile->coords, 0, 1, 1, 0);
 	gis_bbox_set_bounds(&tile->edge, n, s, e, w);
 	return tile;
 }
diff --git a/src/objects/gis-tile.h b/src/objects/gis-tile.h
index e2b7252..c912b5a 100644
--- a/src/objects/gis-tile.h
+++ b/src/objects/gis-tile.h
@@ -38,12 +38,15 @@ struct _GisTile {
 	/* Pointer to the tile data */
 	gpointer data;
 
-	/* Pointer to the tile data */
+	/* Drawing order */
 	gint zindex;
 
 	/* North,South,East,West limits */
 	GisBBox edge;
 
+	/* Texture mapping coordinates */
+	GisBBox coords;
+
 	/* Pointers to parent/child nodes */
 	GisTile *parent;
 	GisTile *children[2][2];