/*******************************************************************************************
*
*   raylib [shaders] example - Raymarching shapes generation
*
*   NOTE: This example requires raylib OpenGL 3.3 or ES2 versions for shaders support,
*         OpenGL 1.1 does not support shaders, recompile raylib to OpenGL 3.3 version.
*
*   NOTE: Shaders used in this example are #version 330 (OpenGL 3.3), to test this example
*         on OpenGL ES 2.0 platforms (Android, Raspberry Pi, HTML5), use #version 100 shaders
*         raylib comes with shaders ready for both versions, check raylib/shaders install folder
*
*   This example has been created using raylib 2.0 (www.raylib.com)
*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
*   Copyright (c) 2018 Ramon Santamaria (@raysan5)
*
********************************************************************************************/

#include "raylib.h"

int main()
{
    // Initialization
    //--------------------------------------------------------------------------------------
    int screenWidth = 800;
    int screenHeight = 450;
    
    InitWindow(screenWidth, screenHeight, "raymarching");

    Camera camera = { 0 };
    camera.position = (Vector3){ 2.5f, 2.5f, 3.0f };    // Camera position
    camera.target = (Vector3){ 0.0f, 0.0f, 0.7f };      // Camera looking at point
    camera.up = (Vector3){ 0.0f, 1.0f, 0.0f };          // Camera up vector (rotation towards target)
    camera.fovy = 65.0f;                                // Camera field-of-view Y
    
    SetCameraMode(camera, CAMERA_FREE);                 // Set camera mode
   
    // Load raymarching shader
    // NOTE: Defining 0 (NULL) for vertex shader forces usage of internal default vertex shader
    Shader shader = LoadShader(0, "resources/shaders/glsl330/raymarching.fs");
    
    // Get shader locations for required uniforms
    int viewEyeLoc = GetShaderLocation(shader, "viewEye");
    int viewCenterLoc = GetShaderLocation(shader, "viewCenter");
    int viewUpLoc = GetShaderLocation(shader, "viewUp");
    int deltaTimeLoc = GetShaderLocation(shader, "deltaTime");
    int runTimeLoc = GetShaderLocation(shader, "runTime");
    int resolutionLoc = GetShaderLocation(shader, "resolution");
    
    float resolution[2] = { screenWidth, screenHeight };
    SetShaderValue(shader, resolutionLoc, resolution, 2);
    
    float runTime = 0.0f;
    
    SetTargetFPS(60);                       // Set our game to run at 60 frames-per-second
    //--------------------------------------------------------------------------------------

    // Main game loop
    while (!WindowShouldClose())            // Detect window close button or ESC key
    {
        // Update
        //----------------------------------------------------------------------------------
        UpdateCamera(&camera);              // Update camera
        
        float cameraPos[3] = { camera.position.x, camera.position.y, camera.position.z };
        float cameraTarget[3] = { camera.target.x, camera.target.y, camera.target.z };
        float cameraUp[3] = { camera.up.x, camera.up.y, camera.up.z };

        float deltaTime = GetFrameTime();  
        runTime += deltaTime;
        
        // Set shader required uniform values
        SetShaderValue(shader, viewEyeLoc, cameraPos, 3);
        SetShaderValue(shader, viewCenterLoc, cameraTarget, 3);
        SetShaderValue(shader, viewUpLoc, cameraUp, 3);
        SetShaderValue(shader, deltaTimeLoc, &deltaTime, 1);
        SetShaderValue(shader, runTimeLoc, &runTime, 1);
        //----------------------------------------------------------------------------------

        // Draw
        //----------------------------------------------------------------------------------
        BeginDrawing();

            ClearBackground(RAYWHITE);

            // We only draw a white full-screen rectangle,
            // frame is generated in shader using raymarching
            BeginShaderMode(shader);
                DrawRectangle(0, 0, screenWidth, screenHeight, WHITE);                          
            EndShaderMode();
            
            DrawText("(c) Raymarching shader by Iñigo Quilez. MIT License.", screenWidth - 280, screenHeight - 20, 10, GRAY);

        EndDrawing();
        //----------------------------------------------------------------------------------
    }

    // De-Initialization
    //--------------------------------------------------------------------------------------
    UnloadShader(shader);           // Unload shader

    CloseWindow();                  // Close window and OpenGL context
    //--------------------------------------------------------------------------------------

    return 0;
}