1 files changed, 138 insertions, 0 deletions
diff --git a/09-september/tomcat/util/util.c b/09-september/tomcat/util/util.c
new file mode 100644
index 0000000..22eb0fc
--- /dev/null
+++ b/09-september/tomcat/util/util.c
@@ -0,0 +1,138 @@
+#include "util.h"
+
+#include <SDL2/SDL.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+unsigned int Util_Hash( const char *str )
+{
+    unsigned int hash, i, length;
+    length = strlen(str);
+
+    for(hash = i = 0; i < length; ++i)
+    {
+        hash += str[i];
+        hash += (hash << 10);
+        hash ^= (hash >> 6);
+    }
+
+    hash += (hash << 3);
+    hash ^= (hash >> 11);
+    hash += (hash << 15);
+
+    return hash;
+}
+
+void Util_FatalError( const char *fmt, ... )
+{
+    fprintf(stderr, "Fatal Error:\n");
+
+    va_list args;
+    va_start(args, fmt);
+    vfprintf(stderr, fmt, args);
+    va_end(args);
+
+    SDL_Quit();
+    exit(1);
+}
+
+void Util_CheckGLError()
+{
+    GLenum error = glGetError();
+    switch(error)
+    {
+        case GL_INVALID_ENUM:
+            fprintf(stderr, "WARNING: GL_INVALID_ENUM\n");
+            break;
+        case GL_INVALID_VALUE:
+            fprintf(stderr, "WARNING: GL_INVALID_VALUE\n");
+            break;
+        case GL_INVALID_OPERATION:
+            fprintf(stderr, "WARNING: GL_INVALID_OPERATION\n");
+            break;
+        case GL_INVALID_FRAMEBUFFER_OPERATION:
+            fprintf(stderr, "WARNING: GL_INVALID_FRAMEBUFFER_OPERATION\n");
+            break;
+        case GL_OUT_OF_MEMORY:
+            fprintf(stderr, "WARNING: GL_OUT_OF_MEMORY\n");
+            break;
+        case GL_STACK_UNDERFLOW:
+            fprintf(stderr, "WARNING: GL_STACK_UNDERFLOW\n");
+            break;
+        case GL_STACK_OVERFLOW:
+            fprintf(stderr, "WARNING: GL_STACK_OVERFLOW\n");
+            break;
+
+        default:
+            break;
+    }
+}
+
+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 = 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
+Util_GetMouseRay(int screenWidth, int screenHeigth, Mat4 *viewMatrix, Mat4 *projectionMatrix,
+                 int mouseX, int mouseY)
+{
+    Vec4 eyeCoords;
+    Vec3 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 clipCoords = { normalX, normalY, -1.0f, 1.0f };
+
+    /* Remove perpective */
+    {
+        Mat4 invertedProjection = mat4_inverse(projectionMatrix);
+        eyeCoords = mat4_mul_vec4(&invertedProjection, &clipCoords);
+        eyeCoords.z = -1.0f;
+        eyeCoords.w = 0.0f;
+    }
+
+    /* Remove view matrix*/
+    {
+        Mat4 invertedViewMatrix = mat4_inverse(viewMatrix);
+        Vec4 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;
+}