From fdb86173bc35422315859e37ed27f9ad63fa7aec Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Wed, 3 Feb 2016 10:13:49 +0100
Subject: Add support for modifiable parameters

---
 examples/symmetry.frag |  7 +++++--
 glslview.c             | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/examples/symmetry.frag b/examples/symmetry.frag
index faebd75..f1a72ad 100644
--- a/examples/symmetry.frag
+++ b/examples/symmetry.frag
@@ -5,6 +5,9 @@ out vec4 fragColor;
 uniform vec2 res;
 uniform float time;
 
+uniform int param_l;
+uniform int param_m;
+
 const float sharpness = 300;
 
 const float PI = 3.14159265358979323846;
@@ -31,8 +34,8 @@ void main(void) {
 
 	float scene = 0;
 
-	int n = 32;
-	float k = 0;
+	int n = param_l + 32;
+	float k = param_m;
 	for (int i = 0; i < n; i++) {
 		float c = square(vec2(0.5, 0) * rot(PI/2*(4.0*i/n)) * vec2(1, 1), 0.3, -PI/2*(k*i/n + time/1500), p);
 		scene = abs(scene - c);
diff --git a/glslview.c b/glslview.c
index 10235c9..4061282 100644
--- a/glslview.c
+++ b/glslview.c
@@ -53,6 +53,14 @@
 static float speed = 1.0;
 static unsigned previous_ticks = 0;
 
+static GLint param_k = 0;
+static GLint param_l = 0;
+static GLint param_m = 0;
+
+static GLint param_k_loc;
+static GLint param_l_loc;
+static GLint param_m_loc;
+
 #ifdef USE_INOTIFY
 static int inotify_fd = -1;
 static int inotify_watch = -1;
@@ -141,6 +149,12 @@ static void load(void) {
 	time_loc = glGetUniformLocation(program, "time");
 	res_loc = glGetUniformLocation(program, "res");
 
+#ifndef GLSLWRITE
+	param_k_loc = glGetUniformLocation(program, "param_k");
+	param_l_loc = glGetUniformLocation(program, "param_l");
+	param_m_loc = glGetUniformLocation(program, "param_m");
+#endif
+
 	glUseProgram(program);
 
 	free(shader);
@@ -250,6 +264,10 @@ static void render(int width, int height) {
 	unsigned ticks = SDL_GetTicks();
 	current_time += speed * (ticks - previous_ticks);
 	previous_ticks = ticks;
+
+	glUniform1i(param_k_loc, param_k);
+	glUniform1i(param_l_loc, param_l);
+	glUniform1i(param_m_loc, param_m);
 #endif
 
 	glUniform1f(time_loc, current_time);
@@ -278,6 +296,10 @@ static void handle_input(const char *input) {
 			current_time = 0;
 			break;
 
+		case 'R':
+			param_k = param_l = param_m = 0;
+			break;
+
 		case '+':
 			speed *= 1.1;
 			break;
@@ -341,6 +363,33 @@ int main(int argc, char *argv[]) {
 			switch (e.type) {
 			case SDL_KEYDOWN:
 				switch (e.key.keysym.sym) {
+#ifndef GLSLWRITE
+				case SDLK_PAGEDOWN:
+					param_k++;
+					break;
+
+				case SDLK_PAGEUP:
+					param_k--;
+					break;
+
+				case SDLK_RIGHT:
+					param_l++;
+					break;
+
+				case SDLK_LEFT:
+					param_l--;
+					break;
+
+				case SDLK_DOWN:
+					param_m++;
+					break;
+
+				case SDLK_UP:
+					param_m--;
+					break;
+
+#endif
+
 				case SDLK_ESCAPE:
 					goto quit;
 				}
-- 
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