/*******************************************************************************************
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								*
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								*   raylib example - particles trail blending
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								*
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								*   This example has been created using raylib 1.3 (www.raylib.com)
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								*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
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								*
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								*   Copyright (c) 2015 Ramon Santamaria (@raysan5)
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								*
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								********************************************************************************************/
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								#include "raylib.h"
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								#define MAX_PARTICLES 200
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								// Particle structure with basic data
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								typedef struct {
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								    Vector2 position;
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								    Color color;
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								    float alpha;
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								    float size;
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								    float rotation;
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								    bool active;        // NOTE: Use it to activate/deactive particle
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								} Particle;
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								int main()
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								{
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								    // Initialization
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								    //--------------------------------------------------------------------------------------
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								    int screenWidth = 800;
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								    int screenHeight = 450;
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								    InitWindow(screenWidth, screenHeight, "raylib [textures] example - particles trail blending");
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								    // Particles pool, reuse them!
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								    Particle mouseTail[MAX_PARTICLES]; 
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								    // Initialize particles
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								    for (int i = 0; i < MAX_PARTICLES; i++)
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								    {
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								        mouseTail[i].position = (Vector2){ 0, 0 };
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								        mouseTail[i].color = (Color){ GetRandomValue(0, 255), GetRandomValue(0, 255), GetRandomValue(0, 255), 255 };
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								        mouseTail[i].alpha = 1.0f;
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								        mouseTail[i].size = (float)GetRandomValue(1, 30)/20.0f;
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								        mouseTail[i].rotation = GetRandomValue(0, 360);
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								        mouseTail[i].active = false;
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								    }
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								    float gravity = 3.0f;
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								    Texture2D smoke = LoadTexture("resources/smoke.png");
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								    int blending = BLEND_ALPHA;
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								    SetTargetFPS(60);
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								    //--------------------------------------------------------------------------------------
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								    // Main game loop
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								    while (!WindowShouldClose())    // Detect window close button or ESC key
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								    {
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								        // Update
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								        //----------------------------------------------------------------------------------
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								        // Activate one particle every frame and Update active particles
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								        // NOTE: Particles initial position should be mouse position when activated
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								        // NOTE: Particles fall down with gravity and rotation... and disappear after 2 seconds (alpha = 0)
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								        // NOTE: When a particle disappears, active = false and it can be reused.
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								        for (int i = 0; i < MAX_PARTICLES; i++)
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								        {
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								            if (!mouseTail[i].active)
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								            {
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								                mouseTail[i].active = true;
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								                mouseTail[i].alpha = 1.0f;
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								                mouseTail[i].position = GetMousePosition();
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								                i = MAX_PARTICLES;
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								            }
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								        }
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								        for (int i = 0; i < MAX_PARTICLES; i++)
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								        {
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								            if (mouseTail[i].active)
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								            {
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								                mouseTail[i].position.y += gravity;
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								                mouseTail[i].alpha -= 0.01f;
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								                if (mouseTail[i].alpha <= 0.0f) mouseTail[i].active = false;
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								                mouseTail[i].rotation += 5.0f;
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								            }
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								        }
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								        if (IsKeyPressed(KEY_SPACE))
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								        {
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								            if (blending == BLEND_ALPHA) blending = BLEND_ADDITIVE;
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								            else blending = BLEND_ALPHA;
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								        }
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								        //----------------------------------------------------------------------------------
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								        // Draw
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								        //----------------------------------------------------------------------------------
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								        BeginDrawing();
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								            ClearBackground(DARKGRAY);
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								            BeginBlendMode(blending);
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								                // Draw active particles
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								                for (int i = 0; i < MAX_PARTICLES; i++)
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								                {
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								                    if (mouseTail[i].active) DrawTexturePro(smoke, (Rectangle){ 0, 0, smoke.width, smoke.height }, 
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								                                                           (Rectangle){ mouseTail[i].position.x, mouseTail[i].position.y, smoke.width*mouseTail[i].size, smoke.height*mouseTail[i].size },
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								                                                           (Vector2){ smoke.width*mouseTail[i].size/2, smoke.height*mouseTail[i].size/2 }, mouseTail[i].rotation,
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								                                                           Fade(mouseTail[i].color, mouseTail[i].alpha));
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								                }
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								            EndBlendMode();
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								            DrawText("PRESS SPACE to CHANGE BLENDING MODE", 180, 20, 20, BLACK);
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								            if (blending == BLEND_ALPHA) DrawText("ALPHA BLENDING", 290, screenHeight - 40, 20, BLACK);
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								            else DrawText("ADDITIVE BLENDING", 280, screenHeight - 40, 20, RAYWHITE);
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								        EndDrawing();
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								        //----------------------------------------------------------------------------------
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								    }
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								    // De-Initialization
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								    //--------------------------------------------------------------------------------------
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								    UnloadTexture(smoke);
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								    CloseWindow();        // Close window and OpenGL context
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								    //--------------------------------------------------------------------------------------
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								    return 0;
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								}
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