/*******************************************************************************************
*
*   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>

int main()
{
    // Initialization
    //--------------------------------------------------------------------------------------
    int screenWidth = 800;
    int screenHeight = 450;

    InitWindow(screenWidth, screenHeight, "raylib [shaders] example - shapes and texture shaders");
    
    Texture2D sonic = LoadTexture("resources/texture_formats/sonic.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");
                               
    // Shader usage is also different than models/postprocessing, shader is just activated when required
    
    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);
                DrawRectangleGradient(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((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
            BeginShaderMode(shader);

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

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

    return 0;
}