From: Alexis Laferrière <alexis.laf@xymus.net>
Date: Sun, 18 Jun 2017 00:31:46 +0000 (-0400)
Subject: gamnit: pass the elapsed time in the world of each sprite set to the shader
X-Git-Url: http://nitlanguage.org

gamnit: pass the elapsed time in the world of each sprite set to the shader

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
---

diff --git a/lib/gamnit/flat.nit b/lib/gamnit/flat.nit
index b278029..b70d010 100644
--- a/lib/gamnit/flat.nit
+++ b/lib/gamnit/flat.nit
@@ -393,6 +393,7 @@ redef class App
 		perf_clock_main.lapse
 		var dt = clock.lapse.to_f
 		update dt
+		frame_dt = dt
 		sys.perfs["gamnit flat update client"].add perf_clock_main.lapse
 
 		# Draw and flip screen
@@ -404,6 +405,8 @@ redef class App
 		assert gl_error == gl_NO_ERROR else print_error gl_error
 	end
 
+	private var frame_dt = 0.0
+
 	# Draw the whole screen, all `glDraw...` calls should be executed here
 	protected fun frame_core_draw(display: GamnitDisplay)
 	do
@@ -425,6 +428,9 @@ redef class App
 		simple_2d_program.use
 		simple_2d_program.mvp.uniform camera.mvp_matrix
 
+		sprite_set.time += frame_dt*sprite_set.time_mod
+		simple_2d_program.time.uniform sprite_set.time
+
 		# draw
 		sprite_set.draw
 	end
@@ -507,6 +513,9 @@ private class Simple2dProgram
 		// Model view projection matrix
 		uniform mat4 mvp;
 
+		// Current world time, in seconds
+		uniform float time;
+
 		// Rotation matrix
 		attribute vec4 rotation_row0;
 		attribute vec4 rotation_row1;
@@ -675,6 +684,12 @@ private class SpriteSet
 	# Sprites needing resorting in `contexts_map`
 	var sprites_to_remap = new Array[Sprite]
 
+	# Animation speed multiplier (0.0 to pause, 1.0 for normal speed, etc.)
+	var time_mod = 1.0 is writable
+
+	# Seconds elapsed since the launch of the program, in world time responding to `time_mod`
+	var time = 0.0
+
 	# Add a sprite to the appropriate context
 	fun map_sprite(sprite: Sprite)
 	do