From 6b8af9cf83851c075c6c9514b1deaa931c2b19a4 Mon Sep 17 00:00:00 2001
From: Thomas Guillermo Albers Raviola <thomas@thomaslabs.org>
Date: Fri, 16 Jan 2026 23:02:32 +0100
Subject: Initial commit

---
 08-august/src/util/util.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 08-august/src/util/util.c

(limited to '08-august/src/util/util.c')

diff --git a/08-august/src/util/util.c b/08-august/src/util/util.c
new file mode 100644
index 0000000..ad0f1ce
--- /dev/null
+++ b/08-august/src/util/util.c
@@ -0,0 +1,87 @@
+#include "util.h"
+
+#include <SDL2/SDL.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+void Util_FatalError( const char *error, ... )
+{
+    fprintf(stderr, "Fatal Error:\n");
+
+    va_list args;
+    va_start(args, error);
+    vfprintf(stderr, error, args);
+    va_end(args);
+
+    SDL_Quit();
+    exit(1);
+}
+
+char *Util_LoadFile( const char *path )
+{
+	FILE* file = fopen( path, "r" );
+
+	if(file == NULL)
+    {
+        Util_FatalError("File %s could not be found!\n", path);
+    }
+
+	fseek( file, 0, SEEK_END );
+	size_t sizeOfFile = ftell( file );
+	fseek( file, 0, SEEK_SET );
+	char* file_data = (char *) malloc( sizeof(char) * sizeOfFile + 1 );
+	fread( file_data, sizeof(char), sizeOfFile, file );
+	file_data[sizeOfFile] = '\0';
+	fclose(file);
+	return file_data;
+}
+
+float Util_RandomF(float min, float max)
+{
+    return ( min + (float)rand() ) / ( (float)RAND_MAX / (max-min) );
+}
+
+int Util_RandomI(int min, int max)
+{
+    return ( rand() % (max-min) ) + min;
+}
+
+vec3_t
+Util_GetMouseRay(int screenWidth, int screenHeigth, mat4_t *viewMatrix, mat4_t *projectionMatrix,
+                 int mouseX, int mouseY)
+{
+    vec4_t eyeCoords;
+    vec3_t mouseRay;
+    /* Normalized device coords NOTE: -y becouse for SDL y = 0 is the top of the screen */
+    GLfloat normalX = ( 2.0f * (GLfloat)mouseX ) / (GLfloat) screenWidth - 1.0f;
+    GLfloat normalY = 1.0f - (2.0f * (GLfloat)mouseY) / (GLfloat) screenHeigth;
+
+    /* clipCoords include 4th component */
+    vec4_t clipCoords = { normalX, normalY, -1.0f, 1.0f };
+
+    /* Remove perpective */
+    {
+        mat4_t invertedProjection = mat4_inverse(projectionMatrix);
+        eyeCoords = mat4_mul_vec4(&invertedProjection, &clipCoords);
+        eyeCoords.z = -1.0f;
+        eyeCoords.w = 0.0f;
+    }
+
+    /* Remove view matrix*/
+    {
+        mat4_t invertedViewMatrix = mat4_inverse(viewMatrix);
+        vec4_t temp = mat4_mul_vec4(&invertedViewMatrix, &eyeCoords);
+
+        mouseRay.x = temp.x;
+        mouseRay.y = temp.y;
+        mouseRay.z = temp.z;
+
+        mouseRay = vec3_normalize(&mouseRay);
+    }
+
+    /* Return the ray in world coordinates */
+    return mouseRay;
+}
-- 
cgit v1.2.3