using Raylib;
using static Raylib.Raylib;

public partial class shaders_shapes_textures
{
    /*******************************************************************************************
    *
    *   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 1.7 (www.raylib.com)
    *   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
    *
    *   Copyright (c) 2015 Ramon Santamaria (@raysan5)
    *
    ********************************************************************************************/


    public static int Main()
    {
        // Initialization
        //--------------------------------------------------------------------------------------
        int screenWidth = 800;
        int screenHeight = 450;

        InitWindow(screenWidth, screenHeight, "raylib [shaders] example - shapes and texture shaders");

        Texture2D fudesumi = LoadTexture("resources/fudesumi.png");

        // NOTE: Using GLSL 330 shader version, on OpenGL ES 2.0 use GLSL 100 shader version
        Shader shader = LoadShader("resources/shaders/glsl330/base.vs",
                                   "resources/shaders/glsl330/grayscale.fs");

        SetTargetFPS(60);
        //--------------------------------------------------------------------------------------

        // Main game loop
        while (!WindowShouldClose())    // Detect window close button or ESC key
        {
            // 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
                BeginShaderMode(shader);

                    DrawText("USING CUSTOM SHADER", 190, 40, 10, RED);

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

                // Activate our default shader for next drawings
                EndShaderMode();

                DrawText("USING DEFAULT SHADER", 370, 40, 10, RED);

                DrawTriangle(new Vector2(430, 80),
                             new Vector2(430 - 60, 150),
                             new Vector2(430 + 60, 150), VIOLET);

                DrawTriangleLines(new Vector2(430, 160),
                                  new Vector2(430 - 20, 230),
                                  new Vector2(430 + 20, 230), DARKBLUE);

                DrawPoly(new Vector2(430, 320), 6, 80, 0, BROWN);

                // Activate our custom shader to be applied on next shapes/textures drawings
                BeginShaderMode(shader);

                    DrawTexture(fudesumi, 500, -30, WHITE);    // Using custom shader

                // Activate our default shader for next drawings
                EndShaderMode();

                DrawText("(c) Fudesumi sprite by Eiden Marsal", 380, screenHeight - 20, 10, GRAY);

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

        // De-Initialization
        //--------------------------------------------------------------------------------------
        UnloadShader(shader);       // Unload shader
        UnloadTexture(fudesumi);    // Unload texture

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

        return 0;
    }
}