/*******************************************************************************************
*
*   raylib [shaders] example - Apply a shader to some shape or texture
*
*   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 1.3 (www.raylib.com)
*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
*   Copyright (c) 2015 Ramon Santamaria (@raysan5)
*
********************************************************************************************/

#include "raylib.h"

#include <stdio.h>
#include <stdlib.h>

#if defined(PLATFORM_WEB)
    #include <emscripten/emscripten.h>
#endif

//----------------------------------------------------------------------------------
// Global Variables Definition
//----------------------------------------------------------------------------------
int screenWidth = 800;
int screenHeight = 450;

Texture2D sonic;
Shader shader;

//----------------------------------------------------------------------------------
// Module Functions Declaration
//----------------------------------------------------------------------------------
void UpdateDrawFrame(void);     // Update and Draw one frame

//----------------------------------------------------------------------------------
// Main Enry Point
//----------------------------------------------------------------------------------
int main()
{
    // Initialization
    //--------------------------------------------------------------------------------------
    InitWindow(screenWidth, screenHeight, "raylib [shaders] example - shapes and texture shaders");
    
    sonic = LoadTexture("resources/texture_formats/sonic.png");

    // NOTE: This shader is a bit different than model/postprocessing shaders,
    // it requires the color data for every vertice to use it in every shape or texture independently
    shader = LoadShader("resources/shaders/shapes_base.vs", "resources/shaders/shapes_grayscale.fs");
                               
    // Shader usage is also different than models/postprocessing, shader is just activated when required
    
#if defined(PLATFORM_WEB)
    emscripten_set_main_loop(UpdateDrawFrame, 0, 1);
#else
    SetTargetFPS(60);   // Set our game to run at 60 frames-per-second
    //--------------------------------------------------------------------------------------
    
    // Main game loop
    while (!WindowShouldClose())    // Detect window close button or ESC key
    {
        UpdateDrawFrame();
    }
#endif

    // De-Initialization
    //--------------------------------------------------------------------------------------
    UnloadShader(shader);   // Unload shader
    UnloadTexture(sonic);   // Unload texture
    
    CloseWindow();          // Close window and OpenGL context
    //--------------------------------------------------------------------------------------

    return 0;
}

//----------------------------------------------------------------------------------
// Module Functions Definition
//----------------------------------------------------------------------------------
void UpdateDrawFrame(void)
{
    // Update
    //----------------------------------------------------------------------------------
    // TODO: Update your variables here
    //----------------------------------------------------------------------------------

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

        ClearBackground(RAYWHITE);
        
        // Start drawing with default shader

        DrawText("USING DEFAULT SHADER", 20, 40, 10, RED);
        
        DrawCircle(80, 120, 35, DARKBLUE);
        DrawCircleGradient(80, 220, 60, GREEN, SKYBLUE);
        DrawCircleLines(80, 340, 80, DARKBLUE);

        
        // Activate our custom shader to be applied on next shapes/textures drawings
        SetCustomShader(shader);
        
        DrawText("USING CUSTOM SHADER", 190, 40, 10, RED);

        DrawRectangle(250 - 60, 90, 120, 60, RED);
        DrawRectangleGradient(250 - 90, 170, 180, 130, MAROON, GOLD);
        DrawRectangleLines(250 - 40, 320, 80, 60, ORANGE);

        // Activate our default shader for next drawings
        SetDefaultShader();
        
        DrawText("USING DEFAULT SHADER", 370, 40, 10, RED);
        
        DrawTriangle((Vector2){430, 80},
                     (Vector2){430 - 60, 150},
                     (Vector2){430 + 60, 150}, VIOLET);
                     
        DrawTriangleLines((Vector2){430, 160},
                          (Vector2){430 - 20, 230},
                          (Vector2){430 + 20, 230}, DARKBLUE);

        DrawPoly((Vector2){430, 320}, 6, 80, 0, BROWN);
        
        // Activate our custom shader to be applied on next shapes/textures drawings
        SetCustomShader(shader);

        DrawTexture(sonic, 380, -10, WHITE);    // Using custom shader
        
        // Activate our default shader for next drawings
        SetDefaultShader();
        
    EndDrawing();
    //----------------------------------------------------------------------------------
}