raylib/examples/textures_particles_trail_blending.c
2016-01-16 12:52:55 +01:00

133 lines
4.9 KiB
C

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