nice example with comments, also nice errors

4 files changed, 76 insertions, 17 deletions

diff --git a/main.c b/main.c
index 5fd77b9..d40625e 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,6 @@
 // @TODO:
-//  - nice examples with comments
 //  - readme
+//  - more examples
 /*
 Anyone is free to modify/distribute/use/sell/etc
 this software for any purpose by any means.
@@ -56,7 +56,7 @@ static void APIENTRY gl_message_callback(GLenum source, GLenum type, unsigned in
 
 static GLuint g_grain_vshader, g_update_vshader;
 
-static void function_init(Function *f, const char *wind_formula, uint32_t ngrains) {
+static void function_init(Function *f, const char *config_filename, int config_line_number, const char *wind_formula, uint32_t ngrains) {
 	memset(f, 0, sizeof *f);
 	{
 		GLuint tex[2] = {0};
@@ -101,8 +101,35 @@ static void function_init(Function *f, const char *wind_formula, uint32_t ngrain
 			wind_formula
 		);
 
-		GLuint fshader = V_gl_shader_compile_code("updatef.glsl", NULL, fshader_code, GL_FRAGMENT_SHADER);
+		GLuint fshader = gl.CreateShader(GL_FRAGMENT_SHADER);
+		const GLchar *sources[2];
 		GLint status = 0;
+
+		char header[256];
+		strbuf_print(header,
+			"#version %d\n"
+			"#define GLSL_VERSION %d\n"
+			"#define PI 3.14159265\n"
+			"#define pi PI\n"
+			"#line 1\n", V_glsl_version(), V_glsl_version());
+		sources[0] = header;
+		sources[1] = fshader_code;
+
+		gl.ShaderSource(fshader, 2, sources, NULL);
+		gl.CompileShader(fshader);
+		{
+			gl.GetShaderiv(fshader, GL_COMPILE_STATUS, &status);
+			if (status == 1) {
+				// all good!
+			} else {
+				char log[256];
+				strbuf_print(log, "Your formula on line %d of %s has errors. Details:\n", config_line_number, config_filename);
+				gl.GetShaderInfoLog(fshader, (GLsizei)(sizeof log - strlen(log)), NULL, log + strlen(log));
+				window_message_box_error("Formula error", log);
+				exit(-1);
+			}
+		}
+
 		GLuint prog = gl.CreateProgram();
 		gl.AttachShader(prog, g_update_vshader);
 		gl.AttachShader(prog, fshader);
@@ -118,6 +145,7 @@ static void function_init(Function *f, const char *wind_formula, uint32_t ngrain
 	{
 		static char fshader_code[65536];
 		strbuf_print(fshader_code,
+			"#define pi PI\n"
 			"uniform vec4 u_color1, u_color2;\n"
 			"uniform float u_color_scale;\n"
 			"varying vec3 pos;\n"
@@ -242,7 +270,7 @@ static Function *sandbox_create(const char *config_filename, Player *player) {
 		} while (0)
 
 			line[strcspn(line, "\r\n")] = '\0';
-			if (line[0] == '#' || line[0] == '\0') break;
+			if (line[0] == '#' || line[0] == '\0') continue;
 
 			char *command = line;
 			char *args = strchr(command, ' ');
@@ -254,7 +282,7 @@ static Function *sandbox_create(const char *config_filename, Player *player) {
 			}
 			if (strcmp(command, "add") == 0) {
 				Function *f = arr_addp(functions);
-				function_init(f, args, ngrains);
+				function_init(f, config_filename, line_number, args, ngrains);
 				uint32_t nnew = (uint32_t)(grain_refresh_rate * (float)ngrains);
 				f->new_grains_per_second = nnew == 0 ? 1 : nnew;
 				f->grain_gen_radius = grain_gen_radius;
diff --git a/sandboxes/EXAMPLE_circulation.txt b/sandboxes/EXAMPLE_circulation.txt
new file mode 100644
index 0000000..1293dad
--- /dev/null
+++ b/sandboxes/EXAMPLE_circulation.txt
@@ -0,0 +1,43 @@
+# This file controls the behavior of function sandbox.
+# Here I'll explain what all the settings do, so you can make your own sandboxes.
+# Any empty line or line beginning with the '#' character (like these first three) is ignored
+
+# This sets the number of grains used in the simulation to 20,000
+grains 20000
+# The grain "refresh rate" is the proportion of the grains which are
+# regenerated (replaced by new ones in the starting area) every second
+grain_refresh_rate 0.01
+# This controls the size of the starting area grains are added to
+start_radius 3
+# Set the color of the grains (you can look up "color picker" to find tools for finding color codes)
+color #ffaabb
+# Let's add a function now!
+# The functions are written in the GLSL language (check out https://www.khronos.org/opengles/sdk/docs/manglsl/docbook4/).
+# You can use all sorts of functions like sin, cos, sqrt,
+# etc. For multiplication you use * and to take a to the power of b you need to use pow(a, b).
+# You can use x,y,z to get the coordinates of the grain, or p to get them as a vector.
+add vec3(z, 0, -sin(y)*x)
+
+# We can add more functions in this same file. We can change settings before adding our next function
+# to make them only apply to it.
+# We'll use more grains for this one.
+grains 30000
+# For this function, let's color-code grains based on speed. First, we can set the two colors,
+# for "slow" grains and "fast" grains.
+color #0000ff
+color2 #ff0000
+# And now we need to specify the "scaling", i.e. how much change in speed corresponds to
+# change in color.
+color_scale 1
+# Now let's add the function.
+add vec3(y, -x*cos(x), 0)
+
+# We can also control some settings which don't apply to any particular function. You can put these anywhere.
+# This controls your movement speed.
+move_speed 5.0
+# Now we get to some technical settings, which you can just leave set to the defaults
+# Field of view in degrees
+fov 50
+# Near and far clipping planes, respectively
+clipping_planes 1 100
+
diff --git a/sandboxes/test.txt b/sandboxes/test.txt
deleted file mode 100644
index 32195f5..0000000
--- a/sandboxes/test.txt
+++ /dev/null
@@ -1,11 +0,0 @@
-clipping_planes 0.1 10
-move_speed 0
-fov 45
-grains 100000
-grain_refresh_rate 0.01
-color   #0000ff
-color2  #ff00ff
-color_scale 0.5
-add vec3(-z, 0.0, x)
-color2  #ffff00
-add vec3(-y, x, 0.0)
diff --git a/sandboxes/test2.txt b/sandboxes/test2.txt
deleted file mode 100644
index d30da32..0000000
--- a/sandboxes/test2.txt
+++ /dev/null
@@ -1 +0,0 @@
-add vec3(-z, 0, x)