From f19edacadfd124dae0d6666a86fb1b6ca4df8969 Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Wed, 27 Jul 2016 08:02:38 +0300
Subject: [PATCH] pulsing grid

---
 src/app.cc      |    2 ++
 src/app.h       |    1 +
 src/backdrop.cc |    7 ++++++-
 src/main.cc     |    1 +
 src/sdr.c       |   14 ++++++++++++++
 src/sdr.h       |    2 ++
 6 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/app.cc b/src/app.cc
index 730302e..aaee8cb 100644
--- a/src/app.cc
+++ b/src/app.cc
@@ -12,6 +12,7 @@
 int win_width, win_height;
 float win_aspect;
 long time_msec;
+double time_sec;
 Mat4 view_matrix;
 
 static bool should_swap;
@@ -128,6 +129,7 @@ void app_draw()
 		draw_backdrop();
 
 		app_swap_buffers();
+		app_redraw();	// since we added animation we need to redisplay even in non-VR mode
 	}
 	assert(glGetError() == GL_NO_ERROR);
 }
diff --git a/src/app.h b/src/app.h
index aecf645..93f5f37 100644
--- a/src/app.h
+++ b/src/app.h
@@ -6,6 +6,7 @@
 extern int win_width, win_height;
 extern float win_aspect;
 extern long time_msec;
+extern double time_sec;
 
 extern Mat4 view_matrix;
 
diff --git a/src/backdrop.cc b/src/backdrop.cc
index 91c709a..2a11c97 100644
--- a/src/backdrop.cc
+++ b/src/backdrop.cc
@@ -14,10 +14,12 @@ static Texture *tex_grid;
 static Mesh *mesh_skydome;
 static unsigned int sdr_skydome;
 
+static Vec3 grid_color;
+static int uloc_grid_color;
 
 bool init_backdrop()
 {
-	Vec3 grid_color = color(1.0, 0.07, 1.0);
+	grid_color = color(1.0, 0.07, 1.0);
 	Vec3 mid_color = color(0.133, 0.006, 0.612);
 	Vec3 horiz_color = color(0.612, 0.006, 1.0);
 	Vec3 zenith_color = color(0.029, 0.029, 0.029);
@@ -26,6 +28,7 @@ bool init_backdrop()
 	if(!(sdr_grid = create_program_load("sdr/grid.v.glsl", "sdr/grid.p.glsl"))) {
 		return false;
 	}
+	uloc_grid_color = get_uniform_loc(sdr_grid, "grid_color");
 	set_uniform_float3(sdr_grid, "grid_color", grid_color.x, grid_color.y, grid_color.z);
 	set_uniform_float3(sdr_grid, "fog_color", fog_color.x, fog_color.y, fog_color.z);
 
@@ -84,6 +87,8 @@ void draw_backdrop()
 	glMultMatrixf(xform[0]);
 
 	bind_program(sdr_grid);
+	float pulse = 1.0 + sin(time_sec * 3.0) * 0.25;
+	glUniform3f(uloc_grid_color, grid_color.x * pulse, grid_color.y * pulse, grid_color.z * pulse);
 	bind_texture(tex_grid);
 
 	glBegin(GL_QUADS);
diff --git a/src/main.cc b/src/main.cc
index d7dea97..ae84abd 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -55,6 +55,7 @@ int main(int argc, char **argv)
 		}
 
 		time_msec = app_get_msec();
+		time_sec = (double)time_msec / 1000.0;
 		while(SDL_PollEvent(&ev)) {
 			process_event(&ev);
 			if(quit) goto break_evloop;
diff --git a/src/sdr.c b/src/sdr.c
index 7103fb0..5ccf7fe 100644
--- a/src/sdr.c
+++ b/src/sdr.c
@@ -302,6 +302,20 @@ int bind_program(unsigned int prog)
 	} \
 	return loc == -1 ? -1 : 0
 
+int get_uniform_loc(unsigned int prog, const char *name)
+{
+	int loc, curr_prog;
+	glGetIntegerv(GL_CURRENT_PROGRAM, &curr_prog);
+	if((unsigned int)curr_prog != prog && bind_program(prog) == -1) {
+		return -1;
+	}
+	loc = glGetUniformLocation(prog, name);
+	if((unsigned int)curr_prog != prog) {
+		bind_program(curr_prog);
+	}
+	return loc;
+}
+
 int set_uniform_int(unsigned int prog, const char *name, int val)
 {
 	BEGIN_UNIFORM_CODE {
diff --git a/src/sdr.h b/src/sdr.h
index df23bcd..d411202 100644
--- a/src/sdr.h
+++ b/src/sdr.h
@@ -34,6 +34,8 @@ void attach_shader(unsigned int prog, unsigned int sdr);
 int link_program(unsigned int prog);
 int bind_program(unsigned int prog);
 
+int get_uniform_loc(unsigned int prog, const char *name);
+
 int set_uniform_int(unsigned int prog, const char *name, int val);
 int set_uniform_float(unsigned int prog, const char *name, float val);
 int set_uniform_float2(unsigned int prog, const char *name, float x, float y);
-- 
1.7.10.4