[grits] Add ortho flag to GritsMarker

[Andy Spencer <andys src gnome org>]

commit c69956150a63153bc1ed765a265ca46c1da21374
Author: Andy Spencer <andy753421 gmail com>
Date:   Thu Feb 9 09:20:58 2012 +0000

    Add ortho flag to GritsMarker
    
    Setting ortho to true causes the marker to be drawn orthographic and
    flat against the screen. This is the default and behavior and is markers
    have been drawn in the past.
    
    Clearing the flag causes he marker to be drawn using the viewers
    perspective projection but scaled to a fixed size.

 src/objects/grits-marker.c |   94 +++++++++++++++++++------------------------
 src/objects/grits-marker.h |    1 +
 2 files changed, 43 insertions(+), 52 deletions(-)
---
diff --git a/src/objects/grits-marker.c b/src/objects/grits-marker.c
index 148289c..162e4bb 100644
--- a/src/objects/grits-marker.c
+++ b/src/objects/grits-marker.c
@@ -78,37 +78,9 @@ static void render_icon(GritsMarker *marker)
 {
 	g_assert(marker->icon_img != NULL);
 
-	/* This code assumes the icon is an image pointing toward 0 degrees
-	* (ie. north/up).  If marker->flip is set, then it will rotate the
-	* icon appropriately then reflect it across the vertical axis so
-	* it's never upside down. */
-	gdouble flip = 1.0;
-	gdouble angle = marker->angle % 360;
-	if (marker->flip && (angle < 360 && angle > 180)) {
-		/* if icon rotates to the left half it will be upside down */
-		flip = -1.0; /* flip horizontally */
-	}
-
-	cairo_save(marker->cairo);
-
 	/* move to marker location */
 	cairo_translate(marker->cairo, marker->xoff, marker->yoff);
 
-	/* perform rotation and flip in one transformation */
-	gdouble C = cos(angle*(M_PI/180.0));
-	gdouble S = sin(angle*(M_PI/180.0));
-	gdouble fx = flip; 
-	gdouble fy = 1.0;
-	gdouble tx = 0.0;
-	gdouble ty = 0.0;
-	cairo_matrix_t matrix;
-	cairo_matrix_init(&matrix,
-	        fx*C, fx*S,
-	        -S*fy, C*fy,
-	        C*tx*(1-fx)-S*ty*(fy-1)+tx-C*tx+S*ty,
-	        S*tx*(1-fx)+C*ty*(fy-1)+ty-S*tx-C*ty);
-	cairo_transform(marker->cairo, &matrix);
-
 	/* center image */
 	cairo_translate(marker->cairo, -marker->icon_width/2,
 	                               -marker->icon_height/2);
@@ -116,7 +88,6 @@ static void render_icon(GritsMarker *marker)
 	cairo_set_source_surface(marker->cairo, marker->icon_img, 0, 0);
 
 	cairo_paint(marker->cairo);
-	cairo_restore(marker->cairo);
 }
 
 static void render_all(GritsMarker *marker)
@@ -140,8 +111,8 @@ static void render_all(GritsMarker *marker)
 	glTexImage2D(GL_TEXTURE_2D, 0, 4, marker->width, marker->height,
 	        0, GL_BGRA, GL_UNSIGNED_BYTE,
 	        cairo_image_surface_get_data(cairo_get_target(marker->cairo)));
-	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 }
 
 
@@ -265,28 +236,46 @@ static void grits_marker_draw(GritsObject *_marker, GritsOpenGL *opengl)
 {
 	GritsMarker *marker = GRITS_MARKER(_marker);
 	GritsPoint  *point  = grits_object_center(marker);
-	gdouble px, py, pz;
-	grits_viewer_project(GRITS_VIEWER(opengl),
-			point->lat, point->lon, point->elev,
-			&px, &py, &pz);
-
-	gint win_width  = GTK_WIDGET(opengl)->allocation.width;
-	gint win_height = GTK_WIDGET(opengl)->allocation.height;
-	py = win_height - py;
-	if (pz > 1)
-		return;
-
-	//g_debug("GritsOpenGL: draw_marker - %s pz=%f ", marker->label, pz);
 
 	cairo_surface_t *surface = cairo_get_target(marker->cairo);
 	gdouble width  = cairo_image_surface_get_width(surface);
 	gdouble height = cairo_image_surface_get_height(surface);
 
-	glMatrixMode(GL_PROJECTION); glLoadIdentity();
-	glMatrixMode(GL_MODELVIEW);  glLoadIdentity();
-	glOrtho(0, win_width, win_height, 0, -1, 1);
-	glTranslated(px - marker->xoff,
-	             py - marker->yoff, 0);
+	if (marker->ortho) {
+		gdouble px, py, pz;
+		grits_viewer_project(GRITS_VIEWER(opengl),
+				point->lat, point->lon, point->elev,
+				&px, &py, &pz);
+
+		gint win_width  = GTK_WIDGET(opengl)->allocation.width;
+		gint win_height = GTK_WIDGET(opengl)->allocation.height;
+		if (pz > 1)
+			return;
+
+		glMatrixMode(GL_PROJECTION); glLoadIdentity();
+		glMatrixMode(GL_MODELVIEW);  glLoadIdentity();
+		glOrtho(0, win_width, win_height, 0, 1, -1);
+		glTranslated(px, win_height-py, 0);
+		glRotatef(marker->angle, 0, 0, -1);
+		glTranslated(-marker->xoff, -marker->yoff, 0);
+	} else {
+		gdouble scale, eye[3], pos[3] =
+			{point->lat, point->lon, point->elev};
+		grits_viewer_get_location(GRITS_VIEWER(opengl),
+		       &eye[0], &eye[1], &eye[2]);
+		lle2xyz(eye[0],  eye[1],  eye[2],
+		       &eye[0], &eye[1], &eye[2]);
+		lle2xyz(pos[0],  pos[1],  pos[2],
+		       &pos[0], &pos[1], &pos[2]);
+		scale = MPPX(distd(eye, pos));
+
+		glRotatef(marker->angle, 0, 0, -1);
+		glRotatef(180, 1, 0, 0);
+		glScalef(scale, scale, 1);
+		glTranslated(-marker->xoff, -marker->yoff, 0);
+	}
+
+	//g_debug("GritsOpenGL: draw_marker - %s pz=%f ", marker->label, pz);
 
 	glDisable(GL_LIGHTING);
 	glDisable(GL_COLOR_MATERIAL);
@@ -295,10 +284,10 @@ static void grits_marker_draw(GritsObject *_marker, GritsOpenGL *opengl)
 	glBindTexture(GL_TEXTURE_2D, marker->tex);
 	glDisable(GL_CULL_FACE);
 	glBegin(GL_QUADS);
-	glTexCoord2f(1, 0); glVertex3f(width, 0     , 0);
-	glTexCoord2f(1, 1); glVertex3f(width, height, 0);
-	glTexCoord2f(0, 1); glVertex3f(0    , height, 0);
-	glTexCoord2f(0, 0); glVertex3f(0    , 0     , 0);
+	glTexCoord2f(1, 0); glVertex3f(width, 0     , 0); // 0 - 3    0 
+	glTexCoord2f(1, 1); glVertex3f(width, height, 0); // 1 - |    | 
+	glTexCoord2f(0, 1); glVertex3f(0    , height, 0); // 2 - |    | 
+	glTexCoord2f(0, 0); glVertex3f(0    , 0     , 0); // 3 - 2----1 
 	glEnd();
 }
 
@@ -307,6 +296,7 @@ static void grits_marker_draw(GritsObject *_marker, GritsOpenGL *opengl)
 G_DEFINE_TYPE(GritsMarker, grits_marker, GRITS_TYPE_OBJECT);
 static void grits_marker_init(GritsMarker *marker)
 {
+	marker->ortho = TRUE;
 }
 
 static void grits_marker_finalize(GObject *_marker)
diff --git a/src/objects/grits-marker.h b/src/objects/grits-marker.h
index 41a2f39..0e44901 100644
--- a/src/objects/grits-marker.h
+++ b/src/objects/grits-marker.h
@@ -48,6 +48,7 @@ struct _GritsMarker {
 	gchar     *label;
 	cairo_t   *cairo;
 	guint      tex;
+	gboolean   ortho;
 
 	cairo_surface_t *icon_img;