GUI controls for restitution coefficient and gravity field

balls.cc

@@ -23,8 +23,6 @@ unsigned int n_balls = 50;
 // C_r == 0.0 ==> perfectly inelastic collisions
 //
 static double C_r = 1.0;
-static int c_r_display_countdown = 0;
-static int c_r_display_init = 300;
 
 void restitution_coefficient_set (double c) {
     C_r = c;
@@ -44,16 +42,10 @@ void restitution_coefficient_change (double d) {
 	C_r = 1.0;
     else if (C_r < 0.0)
 	C_r = 0.0;
-    restitution_coefficient_show ();
 }
 
-void restitution_coefficient_show () {
-    c_r_display_countdown = c_r_display_init;
-};
-
 void restitution_coefficient_draw (cairo_t * cr) {
     static const double margin = 20;
-    if (c_r_display_countdown != 0) {
     cairo_save(cr);
     cairo_new_path(cr);
     cairo_move_to(cr, margin, margin);
@@ -61,11 +53,8 @@ void restitution_coefficient_draw (cairo_t * cr) {
     cairo_set_source_rgb(cr, 1.0, 1.0, 0.0);
     cairo_set_line_width(cr, margin/2);
     cairo_stroke(cr);
-	if (c_r_display_countdown > 0)
-	    --c_r_display_countdown;
     cairo_restore(cr);
 }
-}
 
 static vec2d random_velocity() {
     double r2;

balls.h

@@ -43,7 +43,6 @@ extern void ball_ball_collision (ball * p, ball * q);
 extern void ball_reposition (ball * b);
 extern void balls_draw (cairo_t * cr);
 
-extern void restitution_coefficient_show ();
 extern void restitution_coefficient_draw (cairo_t * cr);
 extern void restitution_coefficient_set (double c);
 extern double restitution_coefficient_get ();

gravity.cc

@@ -1,19 +1,20 @@
-#include <math.h>
+#include <string>
+#include <sstream>
+#include <cmath>
 #include <gtk/gtk.h>
 
 #include "gravity.h"
 #include "game.h"
 
-static vec2d g{.x = 0, .y = 20};
+static const double constant_field_increment = 1.0;
+static const double newton_field_increment = 1000.0;
 
+static vec2d g{.x = 0, .y = 20};
 static double g_r = 50;
 static double g_g = 10000000;
 
 static int constant_field = 1;
 
-static int gravity_vector_countdown = 0;
-static int gravity_vector_init = 300;
-
 void gravity_constant_field (double x, double y) {
     constant_field = 1;
     g.x = x;
@@ -28,7 +29,6 @@ void gravity_newton_field (double r, double g) {
 
 void gravity_draw (cairo_t * cr) {
     if (constant_field) {
-	if (gravity_vector_countdown != 0) {
 	cairo_save(cr);
 	cairo_new_path(cr);
 	cairo_move_to(cr, width/2, height/2);
@@ -38,13 +38,27 @@ void gravity_draw (cairo_t * cr) {
 	cairo_stroke(cr);
 	cairo_arc(cr, width/2 + g.x, height/2 + g.y, 3, 0, 2*M_PI);
 	cairo_fill(cr);
-	    if (gravity_vector_countdown > 0)
+	cairo_restore(cr);
-		--gravity_vector_countdown;
+    } else {
+	std::ostringstream output;
+	output << (g_g/1000) << "K";
+	cairo_save (cr);
+	cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
+	cairo_select_font_face (cr, "sans-serif", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+	cairo_set_font_size (cr, 16);
+	std::string output_str = output.str();
+	cairo_text_extents_t extent;
+	cairo_text_extents (cr, output_str.c_str(), &extent);
+	cairo_move_to (cr, width/2 - extent.width/2, height/2 + extent.height/2);
+	cairo_show_text (cr, output_str.c_str());
 	cairo_restore (cr);
     }
-    } else {
+}
-	cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
+
+void gravity_draw_visible_field (cairo_t * cr) {
+    if (!constant_field) {
 	cairo_save (cr);
+	cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
 	cairo_new_path (cr);
 	cairo_arc (cr, width/2, height/2, g_r, 0, 2*M_PI);
 	cairo_set_line_width(cr, 3.0);
@@ -53,19 +67,13 @@ void gravity_draw (cairo_t * cr) {
     }
 }
 
-void gravity_show () {
-    if (constant_field)
-	gravity_vector_countdown = gravity_vector_init;
-};
-
 void gravity_change (double dx, double dy) {
     if (constant_field) {
-	g.x += dx;
+	g.x += dx*constant_field_increment;
-	g.y += dy;
+	g.y += dy*constant_field_increment;
-	gravity_show ();
     } else {
 	g_r += dx;
-	g_g += dy;
+	g_g -= dy*newton_field_increment;
     }
 }
 

gravity.h

@@ -8,9 +8,10 @@ extern void gravity_newton_field (double r, double g);
 
 extern vec2d gravity_vector (const ball * b);
 
+extern void gravity_draw_visible_field (cairo_t * cr);
+
 extern void gravity_draw (cairo_t * cr);
 extern void gravity_change (double dx, double dy);
-extern void gravity_show ();
 
 extern void gravity_collisions (ball * begin, ball * end);
 

main.cc

@@ -62,27 +62,101 @@ void game_destroy () {
     balls_destroy ();
 }
 
-static guint timeout_source_id = 0;
+static guint animation_timeout_id = 0;
-gboolean timeout (gpointer user_data);
+gboolean animation_timeout (gpointer user_data);
 
 static bool game_paused () {
-    return timeout_source_id == 0;
+    return animation_timeout_id == 0;
 }
 
 void game_animation_on_off () {
-    if (timeout_source_id == 0) {
+    if (animation_timeout_id == 0) {
-	timeout_source_id = g_timeout_add (delta * 1000, timeout, canvas);
+	animation_timeout_id = g_timeout_add (delta * 1000, animation_timeout, canvas);
     } else {
-	g_source_remove (timeout_source_id);
+	g_source_remove (animation_timeout_id);
-	timeout_source_id = 0;
+	animation_timeout_id = 0;
     }
 }
 
+struct param_controls {
+    void (*draw) (cairo_t * cr);
+    gint (*keyboard_input) (GdkEventKey *event);
+    gboolean (*mouse_scroll) (GtkWidget *widget, GdkEvent *event, gpointer user_data);
+};
+
+gint gravity_controls_keyboard_input (GdkEventKey *event) {
+    switch(event->keyval) {
+    case GDK_KEY_Up:
+	gravity_change (0, -10);
+	return TRUE;
+    case GDK_KEY_Down:
+	gravity_change (0, 10);
+	return TRUE;
+    case GDK_KEY_Left:
+	gravity_change (-10, 0);
+	return TRUE;
+    case GDK_KEY_Right:
+	gravity_change (10, 0);
+	return TRUE;
+    }
+    return FALSE;
+}
+
+param_controls gravity_control = {
+    .draw = gravity_draw,
+    .keyboard_input = gravity_controls_keyboard_input,
+};
+
+gint restitution_coefficient_controls_keyboard_input (GdkEventKey *event) {
+    switch(event->keyval) {
+    case GDK_KEY_Up:
+	restitution_coefficient_change (0.01);
+	return TRUE;
+    case GDK_KEY_Down:
+	restitution_coefficient_change (-0.01);
+	return TRUE;
+    case GDK_KEY_Left:
+	restitution_coefficient_change (-0.01);
+	return TRUE;
+    case GDK_KEY_Right:
+	restitution_coefficient_change (0.01);
+	return TRUE;
+    }
+    return FALSE;
+}
+
+param_controls restitution_coefficient_control = {
+    .draw = restitution_coefficient_draw,
+    .keyboard_input = restitution_coefficient_controls_keyboard_input,
+};
+
+
+
+static param_controls * param_control = nullptr;
+static guint param_control_timeout_id = 0;
+static const guint param_control_active_ms = 3000;
+
+gboolean param_control_timeout (gpointer user_data) {
+    param_control = nullptr;
+    param_control_timeout_id = 0;
+    gtk_widget_queue_draw(canvas);
+    return FALSE;
+}
+
+void param_control_activate (struct param_controls * ctrl) {
+    if (param_control) 
+	g_source_remove (param_control_timeout_id);
+    param_control = ctrl;
+    param_control_timeout_id = g_timeout_add (param_control_active_ms, param_control_timeout, canvas);
+    gtk_widget_queue_draw(canvas);
+}
+
 gboolean draw_frame (GtkWidget * widget, cairo_t *cr, gpointer data) {
     cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0);
     cairo_paint(cr);
-    gravity_draw (cr);
+    if (param_control)
-    restitution_coefficient_draw (cr);
+	param_control->draw (cr);
+    gravity_draw_visible_field (cr);
     balls_draw (cr);
     spaceship_draw (cr);
     return FALSE;
@@ -104,33 +178,21 @@ gint configure_event (GtkWidget *widget, GdkEventConfigure * event) {
 gint keyboard_input (GtkWidget *widget, GdkEventKey *event) {
     if (event->type != GDK_KEY_PRESS)
 	return FALSE;
-    if (! game_paused ()) {
+    if (param_control && param_control->keyboard_input (event)) {
+	gtk_widget_queue_draw(canvas);
+	g_source_remove (param_control_timeout_id);
+	param_control_timeout_id = g_timeout_add (param_control_active_ms, param_control_timeout, canvas);
+	return TRUE;
+    }
     switch(event->keyval) {
-	case GDK_KEY_Up:
-	    gravity_change (0, -10);
-	    return TRUE;
-	case GDK_KEY_Down:
-	    gravity_change (0, 10);
-	    return TRUE;
-	case GDK_KEY_Left:
-	    gravity_change (-10, 0);
-	    return TRUE;
-	case GDK_KEY_Right:
-	    gravity_change (10, 0);
-	    return TRUE;
     case GDK_KEY_R:
-	    restitution_coefficient_change (0.01);
-	    return TRUE;
     case GDK_KEY_r:
-	    restitution_coefficient_change (-0.01);
+	param_control_activate (&restitution_coefficient_control);
 	return TRUE;
     case GDK_KEY_G:
     case GDK_KEY_g:
-	    gravity_show ();
+	param_control_activate (&gravity_control);
 	return TRUE;
-	}
-    }
-    switch(event->keyval) {
     case GDK_KEY_P:
     case GDK_KEY_p:
 	game_animation_on_off ();
@@ -201,7 +263,7 @@ gboolean draw_event (GtkWidget *widget, cairo_t * cr, gpointer data) {
     return FALSE;
 }
 
-gboolean timeout (gpointer user_data) {
+gboolean animation_timeout (gpointer user_data) {
     if (stats_sampling > 0) {
 	guint64 start = g_get_monotonic_time ();
 	update_state();