4 files changed, 177 insertions, 0 deletions
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;
+}
diff --git a/08-august/src/util/util.h b/08-august/src/util/util.h
new file mode 100644
index 0000000..7227547
--- /dev/null
+++ b/08-august/src/util/util.h
@@ -0,0 +1,25 @@
+#ifndef UTIL_H
+#define UTIL_H
+
+#include "../math/matrix4x4.h"
+
+#define toRadians(degrees) (degrees * 3.1415926 / 180.0f)
+#define toDegrees(radians) (radians * 180.0f / 3.1415926)
+
+#ifdef DEBUG
+#include <stdio.h>
+#define myAssert(expr) expr ? 1==1 : fprintf(stderr, "The expresion was not true\n")
+#else
+#define myAssert(expr)
+#endif // DEBUG
+
+extern void Util_FatalError( const char* error, ... );
+extern char* Util_LoadFile( const char* path );
+extern float Util_RandomF(float min, float max);
+extern int Util_RandomI(int min, int max);
+
+extern vec3_t
+Util_GetMouseRay(int screenWidth, int screenHeigth, mat4_t *viewMatrix, mat4_t *projectionMatrix,
+                 int mouseX, int mouseY);
+
+#endif // UTIL_H
diff --git a/08-august/src/util/util_time.c b/08-august/src/util/util_time.c
new file mode 100644
index 0000000..b601379
--- /dev/null
+++ b/08-august/src/util/util_time.c
@@ -0,0 +1,52 @@
+#include "util_time.h"
+
+static struct
+{
+    float max_ticks_per_frame; //< cuantos ticks (tiempo demora) un frame
+    Uint32 counted_frames; //< cuantos frames han pasado
+    Uint32 start_ticks;    //< ticks al iniciar la iteracion del loop
+    Uint32 beg_ticks;      //< ticks desde el inicio del juego
+    Uint32 time_per_frame;
+} TIME = {
+    1000.0f / 60.0f,
+    0, 0, 0, 0
+};
+
+void Time_Init()
+{
+    TIME.beg_ticks = SDL_GetTicks();
+}
+
+void Time_Begin()
+{
+    TIME.start_ticks = SDL_GetTicks();
+}
+
+float Time_End()
+{
+    TIME.counted_frames += 1;
+    float FPS = TIME.counted_frames / ( (float)(SDL_GetTicks() - TIME.beg_ticks) / 1000.f );
+
+    float frameTicks = (float)(SDL_GetTicks() - TIME.start_ticks);
+    TIME.time_per_frame = frameTicks;
+    if(frameTicks < TIME.max_ticks_per_frame){
+        SDL_Delay( (Uint32)(TIME.max_ticks_per_frame - frameTicks) );
+    }
+
+    return FPS;
+}
+
+float Time_GetFrameTime()
+{
+    return (float)TIME.time_per_frame / 1000.0f;
+}
+
+void Time_SetMaxFramesPerSecond(Uint32 frames)
+{
+    TIME.max_ticks_per_frame = 1000.0f / (float)frames;
+}
+
+Uint32 Time_GetCountedFrames()
+{
+    return TIME.counted_frames;
+}
diff --git a/08-august/src/util/util_time.h b/08-august/src/util/util_time.h
new file mode 100644
index 0000000..3c3e470
--- /dev/null
+++ b/08-august/src/util/util_time.h
@@ -0,0 +1,13 @@
+#ifndef UTIL_TIME_H
+#define UTIL_TIME_H
+
+#include <SDL2/SDL.h>
+
+extern void Time_Init( void );
+extern void Time_Begin( void );
+extern float Time_End( void );
+extern void Time_SetMaxFramesPerSecond(Uint32 frames);
+extern float Time_GetFrameTime( void );
+extern Uint32 Time_GetCountedFrames( void );
+
+#endif // UTIL_TIME_H