From 448f44dad78f51e0b2250aac7ab25420c5cf3469 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Anton=20Luka=20=C5=A0ijanec?= <anton@sijanec.eu>
Date: Mon, 9 May 2022 22:38:58 +0200
Subject: helmholtz gl

---
 fiz/naloga/gl/fragment.glsl | 73 +++++++++++++++++++++++++++++++++++++++++++++
 fiz/naloga/gl/helmholtz.c   | 48 ++++++++++++++++++++++++++---
 fiz/naloga/gl/vertex.glsl   | 10 +++++++
 3 files changed, 127 insertions(+), 4 deletions(-)

diff --git a/fiz/naloga/gl/fragment.glsl b/fiz/naloga/gl/fragment.glsl
index e69de29..c4952c4 100644
--- a/fiz/naloga/gl/fragment.glsl
+++ b/fiz/naloga/gl/fragment.glsl
@@ -0,0 +1,73 @@
+#version 330
+#pragma optionNV (unroll 1)
+
+#define show_vec
+
+#define SEG 32
+
+#define R .8
+#define I .5
+#define n 100.
+
+#define PI 3.1415
+
+in vec2 UVo;
+
+uniform float time;
+uniform int OPTIONS;
+
+out vec4 fragColor;
+
+vec3 tuljava (vec3 pz) {
+	float dr = 2. * PI / float(SEG);
+	vec3 sum = vec3(0);
+	for (int i = 0; i < SEG; i++){
+		float theta = dr * float(i);
+		// jebi se, zakaj neza? pisat ?ita linearno >:(
+		vec3 dl = vec3(0,cos(theta),-sin(theta))*dr*R;
+		vec3 r  = vec3(0,sin(theta),cos(theta))*R;
+		r+=pz;
+		sum+=cross(dl,r)/(length(r)*length(r)*length(r));
+	}
+	sum *= 1e-6;
+	return sum;
+}
+
+void main () {
+	vec2 uv = UVo;
+	vec3 poz = vec3(uv*2.,sin(time/10.)*R);
+	vec3 offset = vec3(R/2.,0,0);
+
+	vec3 rez = tuljava(poz+offset)*n*I +
+		tuljava(poz-offset)*n*I;
+	rez *= 1000.;
+#ifdef show_vec
+	fragColor = vec4(rez, 1);
+#else
+	fragColor = vec4(vec3(length(rez)), 1);
+#endif
+}
+/*
+   uniform float time;
+   uform int OPTIONS;
+//uniform mat2 bounds;
+
+out vec4 frag_colour;
+
+
+void main() {
+vec2 UV = UVo;
+float scale = 1.1;
+vec2 complex=UV*scale;
+vec2 ot=vec2(0);
+int tmpy=OPTIONS;
+for (int x = 0; x < 16; x++){
+ot=vec2(complex.x*ot.x-complex.y*ot.y,complex.x*ot.y+complex.y*ot.x);
+int swch = tmpy & 1;
+ot+=complex * (swch*2-1);
+tmpy>>=1;
+}
+
+frag_colour = vec4(vec3(smoothstep(.05,0,length(ot))), 1.);
+}
+ */
diff --git a/fiz/naloga/gl/helmholtz.c b/fiz/naloga/gl/helmholtz.c
index 7d8171b..cbc1db3 100644
--- a/fiz/naloga/gl/helmholtz.c
+++ b/fiz/naloga/gl/helmholtz.c
@@ -41,11 +41,37 @@ int main (void) {
 	glfwSwapInterval(1); // vsync
 	glfwSetKeyCallback(okno, key_callback);
 	GLuint program = glCreateProgram();
+	float points[] = {
+		-1.0f, 1.0f, -1.0f,
+		-1.0f, -1.0f, -1.0f,
+		1.0f, -1.0f, -1.0f,
+		1.0f, -1.0f, -1.0f,
+		1.0f, 1.0f, -1.0f,
+		-1.0f, 1.0f, -1.0f
+	};
+	// <black box>
+	GLuint points_vbo, vao;
+	glGenBuffers(1, &points_vbo);
+	glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
+	glBufferData(GL_ARRAY_BUFFER, sizeof points, points, GL_STATIC_DRAW);
+	glGenVertexArrays(1, &vao);
+	glBindVertexArray(vao);
+	glEnableVertexAttribArray(0);
+	glBindBuffer(GL_ARRAY_BUFFER, points_vbo);
+	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);
+	// </black box>
+	const char * vertex = _binary_vertex_glsl_start;
+	const char * fragment = _binary_fragment_glsl_start;
 #define DO_SHADER(whi, WHI) \
+	fprintf(stderr, "shader code:\n%.*s\n", whi##_len, whi); \
+	fprintf(stderr, "glCreateShader ...\n"); \
 	GLuint whi##_shader = glCreateShader(GL_##WHI##_SHADER); \
-	glShaderSource(whi##_shader, 1, (const GLchar **) &_binary_##whi##_glsl_start, &whi##_len); \
+	fprintf(stderr, "glShaderSource ...\n"); \
+	glShaderSource(whi##_shader, 1, &whi, &whi##_len); \
+	fprintf(stderr, "glCompileShader ...\n"); \
 	glCompileShader(whi##_shader); \
 	GLint whi##_success = 0; \
+	fprintf(stderr, "glGetShaderiv ...\n"); \
 	glGetShaderiv(whi##_shader, GL_COMPILE_STATUS, &whi##_success); \
 	if (whi##_success == GL_FALSE) { \
 		GLint logSize = 0; \
@@ -59,6 +85,9 @@ int main (void) {
 	glAttachShader(program, whi##_shader);
 	DO_SHADER(vertex, VERTEX);
 	DO_SHADER(fragment, FRAGMENT);
+	// <black box>
+	glBindAttribLocation(program, 0, "vertex_position");
+	// </black box>
 	glLinkProgram(program);
 	GLint isLinked = 0;
 	glGetProgramiv(program, GL_LINK_STATUS, &isLinked);
@@ -73,13 +102,24 @@ int main (void) {
 		glDeleteProgram(program);
 		return 5;
 	}
-	glDetachShader(program, vertex_shader); // TODO: ali lahko glDeleteShader po linku?
-	glDetachShader(program, fragment_shader);
+	// glDetachShader(program, vertex_shader);
+	// glDetachShader(program, fragment_shader);
+	// glDeleteShader(fragment_shader); // testiraj, mogoče se to sme
+	// glDeleteShader(vertex_shader);
+	GLuint timeI = glGetUniformLocation(program, "time");
+	GLuint optI = glGetUniformLocation(program, "OPTIONS");
+	uint32_t opts = 123456;
+	glClearColor(0.1, 0.2, 0.3, 1);
 	while (!glfwWindowShouldClose(okno)) {
 		int w, h;
 		glfwGetFramebufferSize(okno, &w, &h);
 		glViewport(0, 0, w, h);
-		
+		glClear(GL_COLOR_BUFFER_BIT);
+		glUseProgram(program); // testiraj, mogoče se to sme dat iz loopa gor
+		glUniform1f(timeI, glfwGetTime());
+		glUniform1i(optI, opts++);
+		glBindVertexArray(vao);
+		glDrawArrays(GL_TRIANGLES, 0, 6 /* dva triangla po 3 */);
 		glfwSwapBuffers(okno);
 		glfwWaitEvents(); // glfwPollEvents pa returna takoj
 	}
diff --git a/fiz/naloga/gl/vertex.glsl b/fiz/naloga/gl/vertex.glsl
index e69de29..d17b522 100644
--- a/fiz/naloga/gl/vertex.glsl
+++ b/fiz/naloga/gl/vertex.glsl
@@ -0,0 +1,10 @@
+#version 330
+
+layout(location = 0) in vec3 vertex_position;
+
+out vec2 UVo;
+
+void main() {
+	UVo = vertex_position.xy;
+	gl_Position = vec4(vertex_position, 1.0);
+}
-- 
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