From dccf1139df9108002fc0643c13f1e4990cae5700 Mon Sep 17 00:00:00 2001
From: Luca Giuliano Conte <main@lugico.de>
Date: Thu, 21 Mar 2024 13:54:39 +0100
Subject: [PATCH] u02

---
 u02/main.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 69 insertions(+), 6 deletions(-)

diff --git a/u02/main.c b/u02/main.c
index db5f411..bb42ca8 100644
--- a/u02/main.c
+++ b/u02/main.c
@@ -3,9 +3,20 @@
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
 
+#include <math.h>
+
 GLuint program;
 GLuint vao;
 
+GLfloat hue = 0.0f;
+GLfloat hueshift = 0.1f;
+
+GLfloat offsetX = -0.75f;
+GLfloat offsetY = 0.4f;
+
+GLfloat speedX = 0.0005f;
+GLfloat speedY = -0.0005f;
+
 #define NUM_TRIANGLES 8
 
 void createRect(GLfloat* vertexArray, GLfloat posx, GLfloat posy, GLfloat width, GLfloat height) {
@@ -38,9 +49,10 @@ void init(void) {
 		"#version 330 core\n"
 		"layout (location = 0) in vec2 aPosition;\n"
 		"uniform vec3 color;\n"
+		"uniform vec2 offset;"
 		"out vec3 vertexColor;\n"
 		"void main() {\n"
-		"  gl_Position = vec4(aPosition, 0.0, 1.0);\n"
+		"  gl_Position = vec4(aPosition + offset, 0.0, 1.0);\n"
 		"  vertexColor = color;"
 		"}\n";
 	GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
@@ -118,10 +130,10 @@ void init(void) {
 	// 	};
 	GLfloat triangleVertices[48];
 
-	createCenterRect(&triangleVertices[0], -0.3f, 0.0f, 0.1f, 1.2f);
-	createCenterRect(&triangleVertices[12],  0.3f, 0.0f, 0.1f, 1.2f);
-	createCenterRect(&triangleVertices[24],  0.0f, 0.0f, 0.5f, 0.1f);
-	createCenterRect(&triangleVertices[36],  0.0f, -0.8f, 0.7f, 0.1f);
+	createCenterRect(&triangleVertices[0], -0.2f, 0.0f, 0.1f, 1.2f);
+	createCenterRect(&triangleVertices[12],  0.2f, 0.0f, 0.1f, 1.2f);
+	createCenterRect(&triangleVertices[24],  0.0f, 0.0f, 0.3f, 0.1f);
+	createCenterRect(&triangleVertices[36],  0.0f, -0.8f, 0.5f, 0.1f);
 
 
 	GLuint triangleVertexBufferObject;
@@ -152,13 +164,64 @@ void init(void) {
 	glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
 }
 
+void hueToRgb(GLfloat hue, GLfloat* r, GLfloat* g, GLfloat* b) {
+	GLfloat x = hue / 60;
+	while (x > 2) x -= 2;
+	x = x - 1;
+	x = 1 - fabs(x);
+
+	if (hue < 60) {
+		*r = 1.0f;
+		*g = x;
+		*b = 0;
+	} else if (hue < 120) {
+		*r = x;
+		*g = 1.0f;
+		*b = 0;
+	} else if (hue < 180) {
+		*r = 0;
+		*g = 1.0f;
+		*b = x;
+	} else if (hue < 240) {
+		*r = 0;
+		*g = x;
+		*b = 1.0f;
+	} else if (hue < 300) {
+		*r = x;
+		*g = 0;
+		*b = 1.0f;
+	} else {
+		*r = 1.0f;
+		*g = 0;
+		*b = x;
+	}
+
+}
+
 void draw(void) {
 	glClear(GL_COLOR_BUFFER_BIT);
 	glUseProgram(program);
 	glBindVertexArray(vao);
 
+	hue += hueshift;
+	if (hue > 360) hue -= 360;
+
+
+	offsetX += speedX;
+	offsetY += speedY;
+
+	if (offsetX >= 0.75f || offsetX <= -0.75f) speedX *= -1;
+	if (offsetY >= 0.4f || offsetY <=-0.15f) speedY *= -1;
+
+	GLfloat r;
+	GLfloat g;
+	GLfloat b;
+	hueToRgb(hue, &r, &g, &b);
+
 	// SET COLOR
-	glUniform3f(glGetUniformLocation(program, "color"), 0.7719f, 0.2105f, 0.0175f);
+	// glUniform3f(glGetUniformLocation(program, "color"), 0.7719f, 0.2105f, 0.0175f);
+	glUniform3f(glGetUniformLocation(program, "color"), r, g, b);
+	glUniform2f(glGetUniformLocation(program, "offset"), offsetX, offsetY);
 
 
 	glDrawArrays(GL_TRIANGLES, 0, NUM_TRIANGLES * 3);