pig: show sad face on shader errors

Introduces sad-node.[ch] implementing a simple sad face shader node,
normally inactive but made active when the shader files fail to reload.

5 files changed, 171 insertions, 2 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 168d4d1..0088044 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -14,6 +14,8 @@ pig_SOURCES = \
 	macros.h \
 	main.c \
 	m4f.h \
+	sad-node.c \
+	sad-node.h \
 	shader.c \
 	shader.h \
 	shader-node.c \
diff --git a/src/pig.c b/src/pig.c
index 1af910f..97d09fe 100644
--- a/src/pig.c
+++ b/src/pig.c
@@ -27,6 +27,7 @@
 #include "m4f.h"
 #include "macros.h"
 #include "pig.h"
+#include "sad-node.h"
 #include "shader-node.h"
 #include "shader.h"
 
@@ -63,8 +64,12 @@ static void pig_uniforms_func(shader_t *shader, void *uniforms_ctxt, void *rende
 	unsigned	t0, t1;
 	float		r = randf();
 
-	if (play_ticks_elapsed(play, PLAY_TICKS_TIMER2, 1000))
-		shader_reload_files(shader);
+	if (play_ticks_elapsed(play, PLAY_TICKS_TIMER2, 1000)) {
+		if (shader_reload_files(shader) < 0)
+			stage_set_active(pig->sadface, 1);
+		else
+			stage_set_active(pig->sadface, 0);
+	}
 
 	/* this one just keeps increasing */
 	t0 = play_ticks(play, PLAY_TICKS_TIMER0);
@@ -212,6 +217,17 @@ static void * pig_init(play_t *play, int argc, char *argv[], unsigned flags)
 		&pig->color
 	);
 
+	pig->sadface = sad_node_new(&(stage_conf_t){
+			.parent = pig->stage,
+			.name = "sadface",
+			.layer = 3,
+			.active = 0,
+			.alpha = 1.f,
+		},
+		&pig->transform,
+		&pig->color
+	);
+
 	(void) shader_node_new_files(&(stage_conf_t){
 			.parent = pig->stage,
 			.name = "shader",
diff --git a/src/pig.h b/src/pig.h
index 3f0a24c..849e290 100644
--- a/src/pig.h
+++ b/src/pig.h
@@ -28,6 +28,7 @@ typedef struct pig_t {
 	SDL_Window	*window;
 	SDL_GLContext	*gl;
 	stage_t		*stage;
+	stage_t		*sadface;
 	unsigned	window_width, window_height;
 	unsigned	windowed:1;
 	m4f_t		transform;
diff --git a/src/sad-node.c b/src/sad-node.c
new file mode 100644
index 0000000..6ec7a6c
--- /dev/null
+++ b/src/sad-node.c
@@ -0,0 +1,123 @@
+/*
+ *  Copyright (C) 2018-2020 - Vito Caputo - <vcaputo@pengaru.com>
+ *
+ *  This program is free software: you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 3 as published
+ *  by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <SDL.h>
+
+#include <stage.h>
+
+#include "glad.h"
+#include "m4f.h"
+#include "sad-node.h"
+#include "shader-node.h"
+#include "v3f.h"
+
+
+static const char	*sad_vs = ""
+	"#version 120\n"
+
+	"uniform mat4 model_x;"
+
+	"attribute vec3 i_vertex;"
+	"attribute vec2 i_texcoord;"
+
+	"void main()"
+	"{"
+	"	gl_TexCoord[0].xy = i_texcoord;"
+	"	gl_Position = model_x * vec4(i_vertex, 1.f);"
+	"}"
+"";
+
+
+static const char	*sad_fs = ""
+	"#version 120\n"
+
+	"uniform float alpha;"
+	"uniform float time;"
+	"uniform float T;"
+	"uniform vec3 color;"
+	"uniform float seed; "
+	"uniform float rand;"
+
+	"const vec2	leye = vec2(-.5f, .5f);"
+	"const vec2	reye = vec2(.5f, .5f);"
+	"const vec2	frown = vec2(0.f, -1.2f);"
+	"const float	eye_radius = .2f;"
+	"const float	frown_radius = 1.f;"
+	"const float	lip_thickness = .1f;"
+
+	"void eye(in vec2 center, inout vec4 c)"
+	"{"
+	"	float	r = length(center - gl_TexCoord[0].st);"
+
+	"	if (r <= eye_radius) {"
+	"		float	v = (1.f / eye_radius) * r;"
+
+	"		v = 1.f - pow(v, 20);"
+	"		c = vec4(color * v, v);"
+	"	}"
+	"}"
+
+	"void arc(vec2 center, inout vec4 c)"
+	"{"
+	"	float	r = length(center - gl_TexCoord[0].st);"
+
+	"	if (r >= frown_radius - lip_thickness &&"
+	"	    r <= frown_radius + lip_thickness) {"
+	"		float	v = cos((r - (frown_radius + lip_thickness)) * 1.f / (lip_thickness * 2.f) * 6.28) * .5f + .5f;"
+
+	"		v = 1.f - pow(v, 20);"
+	"		c = vec4(color * v, v);"
+	"	}"
+	"}"
+
+	"void main()"
+	"{"
+	"	float	r = length(gl_TexCoord[0].st);"
+	"	vec4	c = vec4(0.f, 0.f, 0.f, 0.f);"
+
+	"	eye(leye, c);"
+	"	eye(reye, c);"
+	"	arc(frown, c);"
+
+	"	gl_FragColor = c;"
+	"}"
+"";
+
+
+static void sad_uniforms(shader_t *shader, void *uniforms_ctxt, void *render_ctxt, unsigned n_uniforms, const int *uniforms, const m4f_t *model_x, float alpha)
+{
+	v3f_t	*color = uniforms_ctxt;
+
+	glUniform1f(uniforms[0], alpha);
+	glUniformMatrix4fv(uniforms[1], 1, GL_FALSE, &model_x->m[0][0]);
+	glUniform3f(uniforms[2], color->x, color->y, color->z);
+}
+
+
+/* create sad face rendering stage */
+stage_t * sad_node_new(const stage_conf_t *conf, const m4f_t *model_x, const v3f_t *color)
+{
+	assert(model_x);
+	assert(color);
+
+	return	shader_node_new_src(conf, sad_vs, sad_fs, model_x, sad_uniforms, (void *)color, 3,
+			(const char *[]){
+				"alpha",
+				"model_x",
+				"color",
+			}
+		);
+}
diff --git a/src/sad-node.h b/src/sad-node.h
new file mode 100644
index 0000000..8bbfd9c
--- /dev/null
+++ b/src/sad-node.h
@@ -0,0 +1,27 @@
+/*
+ *  Copyright (C) 2018-2020 - Vito Caputo - <vcaputo@pengaru.com>
+ *
+ *  This program is free software: you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 3 as published
+ *  by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _SAD_NODE_H
+#define _SAD_NODE_H
+
+typedef struct stage_t stage_t;
+typedef struct stage_conf_t stage_conf_t;
+typedef struct m4f_t m4f_t;
+typedef struct v3f_t v3f_t;
+
+stage_t * sad_node_new(const stage_conf_t *conf, const m4f_t *model_x, const v3f_t *color);
+
+#endif