From 7b28b5621f6f833c77dae1353f856fa97bf2ef68 Mon Sep 17 00:00:00 2001
From: Luca Conte <main@lugico.de>
Date: Tue, 11 Mar 2025 11:41:26 +0100
Subject: [PATCH] u03-3

---
 src/main.c              | 125 +++++-----------------------------------
 src/shaders/vertex.glsl |   6 +-
 2 files changed, 15 insertions(+), 116 deletions(-)

diff --git a/src/main.c b/src/main.c
index fd763cb..b0c8c5a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -22,6 +22,8 @@ GLuint initialWindowHeight = 600;
 int frameCount = 0;
 struct timespec last_time, current_time;
 
+unsigned int resolution = 50;
+
 typedef struct ColorRGB {
 	GLfloat r;
 	GLfloat g;
@@ -106,105 +108,17 @@ void init(void) {
 
 	INFO("Shader Program Done.");
 
-	// create triangle buffer
-	/**
-	 * -0.35              0.35
-	 * |     -0.2    0.2  |
-	 * |    |        |    |
-	 * 
-	 * +----+        +----+    ---  0.6
-	 * |    |        |    |    
-	 * |    |        |    |
-	 * |    +--------+    |    ---  0.1
-	 * |                  |
-	 * |    +--------+    |    --- -0.1
-	 * |    |        |    |
-	 * |    |        |    |
-	 * +----+        +----+    --- -0.6
-	 *
-	 * +------------------+    --- -0.7
-	 * |                  |
-	 * +------------------+    --- -0.9
-	 *   
-	 */    
+	GLfloat innerRadius = 0.2f;
+	GLfloat outerRadius = 0.8f;
 
-	GLfloat vertices[] = {
-		// X  // Y
-
-		// left vertical bar
-		-0.35f, -0.6f,
-		-0.35f, 0.6f,
-		-0.2f, 0.6f,
-
-		-0.35f, -0.6f,
-		-0.2f, 0.6f,
-		-0.2f, -0.6f,
-
-		// right vertical bar
-		0.35f, -0.6f,
-		0.35f, 0.6f,
-		0.2f, 0.6f,
-
-		0.35f, -0.6f,
-		0.2f, 0.6f,
-		0.2f, -0.6f,
-
-		// middle bar
-		-0.2f, -0.1f,
-		-0.2f, 0.1f,
-		0.2f, 0.1f,
-
-		-0.2f, -0.1f,
-		0.2f, 0.1f,
-		0.2f, -0.1f,
-
-		// bottom bar
-		-0.35f, -0.7f,
-		-0.35f, -0.9f,
-		0.35f, -0.9f,
-
-		-0.35f, -0.7f,
-		0.35f, -0.9f,
-		0.35f, -0.7f
-	};
-
-	GLfloat colors[] = {
-		// R  // G  // B
-		1.0f, 0.0f, 0.0f,
-		1.0f, 0.0f, 0.3f,
-		1.0f, 0.3f, 0.0f,
-
-		1.0f, 0.3f, 0.3f,
-		1.0f, 0.3f, 0.6f,
-		1.0f, 0.6f, 0.3f,
-
-
-		0.0f, 1.0f, 0.0f,
-		0.0f, 1.0f, 0.3f,
-		0.3f, 1.0f, 0.0f,
-
-		0.3f, 1.0f, 0.3f,
-		0.3f, 1.0f, 0.6f,
-		0.6f, 1.0f, 0.3f,
-
-
-		0.3f, 0.3f, 1.0f,
-		0.3f, 0.6f, 1.0f,
-		0.6f, 0.3f, 1.0f,
-
-		0.3f, 0.3f, 1.0f,
-		0.3f, 0.6f, 1.0f,
-		0.6f, 0.3f, 1.0f,
-
-
-		1.0f, 1.0f, 0.0f,
-		1.0f, 1.0f, 0.1f,
-		1.0f, 1.0f, 0.2f,
-
-		1.0f, 1.0f, 0.7f,
-		1.0f, 1.0f, 0.8f,
-		1.0f, 1.0f, 0.9f
-	};
+	GLfloat vertices[(resolution + 1) * 2 * 2];
+	for (unsigned int i = 0; i <= resolution; i++) {
+		GLfloat angle = ((float)i) / resolution * 2 * M_PI;
+		vertices[4 * i + 0] = innerRadius * cos(angle);
+		vertices[4 * i + 1] = innerRadius * sin(angle);
+		vertices[4 * i + 2] = outerRadius * cos(angle);
+		vertices[4 * i + 3] = outerRadius * sin(angle);
+	}
 
 	DEBUG("Creating vertext buffer");
 	GLuint vertexBuffer;
@@ -213,13 +127,6 @@ void init(void) {
 	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 
-	DEBUG("Creating colour buffer");
-	GLuint colorBuffer;
-	glGenBuffers(1, &colorBuffer);
-	glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
-	glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW);
-	glBindBuffer(GL_ARRAY_BUFFER, 0);
-
 	DEBUG("Creating vertex array object");
 	// create vertex array object
 	glGenVertexArrays(1, &vertexArrayObject);
@@ -237,12 +144,6 @@ void init(void) {
 	);
 	glEnableVertexAttribArray(0);
 
-	// vertex color data
-	glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
-	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), 0);
-	glEnableVertexAttribArray(1);
-
-
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 	glBindVertexArray(0);
 
@@ -269,7 +170,7 @@ void draw(void) {
 	glUniform2f(positionLocation, cos(currentHue * 2 * M_PI) * 0.2f, sin(currentHue * 2 * M_PI) * 0.2f);
 
 	glBindVertexArray(vertexArrayObject);
-	glDrawArrays(GL_TRIANGLES, 0, 48);
+	glDrawArrays(GL_TRIANGLE_STRIP, 0, (resolution + 1) * 2);
 }
 
 void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
diff --git a/src/shaders/vertex.glsl b/src/shaders/vertex.glsl
index eb6ebd9..efc881d 100644
--- a/src/shaders/vertex.glsl
+++ b/src/shaders/vertex.glsl
@@ -1,11 +1,9 @@
 #version 330 core
 layout (location = 0) in vec2 aPosition;
-layout (location = 1) in vec3 aColor;
-uniform vec2 uPosition;
 
 out vec3 vertexColor;
 
 void main() {
-	vertexColor = aColor;
-	gl_Position = vec4(uPosition + aPosition, 0.0, 1.0);
+	vertexColor = vec3(1.0, 0.0, 0.0);
+	gl_Position = vec4(aPosition, 0.0, 1.0);
 }
\ No newline at end of file