/*******************************************************************************************
*
* raylib [shaders] example - Simple shader mask
*
* This example has been created using raylib 2.5 (www.raylib.com)
* raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
* Example contributed by Chris Camacho (@chriscamacho - http://bedroomcoders.co.uk/)
* and reviewed by Ramon Santamaria (@raysan5)
*
* Copyright (c) 2019 Chris Camacho (@chriscamacho) and Ramon Santamaria (@raysan5)
*
********************************************************************************************
*
* The shader makes alpha holes in the forground to give the apearance of a top
* down look at a spotlight casting a pool of light...
*
* The right hand side of the screen there is just enough light to see whats
* going on without the spot light, great for a stealth type game where you
* have to avoid the spotlights.
*
* The left hand side of the screen is in pitch dark except for where the spotlights are.
*
* Although this example doesn't scale like the letterbox example, you could integrate
* the two techniques, but by scaling the actual colour of the render texture rather
* than using alpha as a mask.
*
********************************************************************************************/
using System;
using System.Numerics;
using static Raylib_cs.Raylib;
namespace Examples.Shaders;
public class Spotlight
{
// NOTE: It must be the same as define in shader
const int MaxSpots = 3;
const int MaxStars = 400;
// Spot data
struct Spot
{
public Vector2 pos;
public Vector2 vel;
public float inner;
public float radius;
// Shader locations
public int posLoc;
public int innerLoc;
public int radiusLoc;
}
// Stars in the star field have a position and velocity
struct Star
{
public Vector2 pos;
public Vector2 vel;
}
public static int Main()
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
InitWindow(screenWidth, screenHeight, "raylib - shader spotlight");
HideCursor();
Texture2D texRay = LoadTexture("resources/raysan.png");
Star[] stars = new Star[MaxStars];
for (int n = 0; n < MaxStars; n++)
{
ResetStar(ref stars[n]);
}
// Progress all the stars on, so they don't all start in the centre
for (int m = 0; m < screenWidth / 2.0; m++)
{
for (int n = 0; n < MaxStars; n++)
{
UpdateStar(ref stars[n]);
}
}
int frameCounter = 0;
// Use default vert shader
Shader shdrSpot = LoadShader(null, "resources/shaders/glsl330/spotlight.fs");
// Get the locations of spots in the shader
Spot[] spots = new Spot[MaxSpots];
for (int i = 0; i < MaxSpots; i++)
{
string posName = $"spots[{i}].pos";
string innerName = $"spots[{i}].inner";
string radiusName = $"spots[{i}].radius";
spots[i].posLoc = GetShaderLocation(shdrSpot, posName);
spots[i].innerLoc = GetShaderLocation(shdrSpot, innerName);
spots[i].radiusLoc = GetShaderLocation(shdrSpot, radiusName);
}
// Tell the shader how wide the screen is so we can have
// a pitch Color.black half and a dimly lit half.
int wLoc = GetShaderLocation(shdrSpot, "screenWidth");
float sw = (float)GetScreenWidth();
Raylib.SetShaderValue(shdrSpot, wLoc, sw, ShaderUniformDataType.SHADER_UNIFORM_FLOAT);
// Randomise the locations and velocities of the spotlights
// and initialise the shader locations
for (int i = 0; i < MaxSpots; i++)
{
spots[i].pos.X = GetRandomValue(64, screenWidth - 64);
spots[i].pos.Y = GetRandomValue(64, screenHeight - 64);
spots[i].vel = new Vector2(0, 0);
while ((MathF.Abs(spots[i].vel.X) + MathF.Abs(spots[i].vel.Y)) < 2)
{
spots[i].vel.X = GetRandomValue(-40, 40) / 10.0f;
spots[i].vel.Y = GetRandomValue(-40, 40) / 10.0f;
}
spots[i].inner = 28.0f * (i + 1);
spots[i].radius = 48.0f * (i + 1);
Raylib.SetShaderValue(
shdrSpot,
spots[i].posLoc,
spots[i].pos,
ShaderUniformDataType.SHADER_UNIFORM_VEC2
);
Raylib.SetShaderValue(
shdrSpot,
spots[i].innerLoc,
spots[i].inner,
ShaderUniformDataType.SHADER_UNIFORM_FLOAT
);
Raylib.SetShaderValue(
shdrSpot,
spots[i].radiusLoc,
spots[i].radius,
ShaderUniformDataType.SHADER_UNIFORM_FLOAT
);
}
SetTargetFPS(60);
//--------------------------------------------------------------------------------------
// Main game loop
while (!WindowShouldClose())
{
// Update
//----------------------------------------------------------------------------------
frameCounter++;
// Move the stars, resetting them if the go offscreen
for (int n = 0; n < MaxStars; n++)
{
UpdateStar(ref stars[n]);
}
// Update the spots, send them to the shader
for (int i = 0; i < MaxSpots; i++)
{
if (i == 0)
{
Vector2 mp = GetMousePosition();
spots[i].pos.X = mp.X;
spots[i].pos.Y = screenHeight - mp.Y;
}
else
{
spots[i].pos.X += spots[i].vel.X;
spots[i].pos.Y += spots[i].vel.Y;
if (spots[i].pos.X < 64)
{
spots[i].vel.X = -spots[i].vel.X;
}
if (spots[i].pos.X > (screenWidth - 64))
{
spots[i].vel.X = -spots[i].vel.X;
}
if (spots[i].pos.Y < 64)
{
spots[i].vel.Y = -spots[i].vel.Y;
}
if (spots[i].pos.Y > (screenHeight - 64))
{
spots[i].vel.Y = -spots[i].vel.Y;
}
}
Raylib.SetShaderValue(
shdrSpot,
spots[i].posLoc,
spots[i].pos,
ShaderUniformDataType.SHADER_UNIFORM_VEC2
);
}
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(Color.DARKBLUE);
// Draw stars and bobs
for (int n = 0; n < MaxStars; n++)
{
// MathF.Single pixel is just too small these days!
DrawRectangle((int)stars[n].pos.X, (int)stars[n].pos.Y, 2, 2, Color.WHITE);
}
for (int i = 0; i < 16; i++)
{
DrawTexture(
texRay,
(int)((screenWidth / 2.0) + MathF.Cos((frameCounter + i * 8) / 51.45f) * (screenWidth / 2.2) - 32),
(int)((screenHeight / 2.0) + MathF.Sin((frameCounter + i * 8) / 17.87f) * (screenHeight / 4.2)),
Color.WHITE
);
}
// Draw spot lights
BeginShaderMode(shdrSpot);
// Instead of a blank rectangle you could render a render texture of the full screen used to do screen
// scaling (slight adjustment to shader would be required to actually pay attention to the colour!)
DrawRectangle(0, 0, screenWidth, screenHeight, Color.WHITE);
EndShaderMode();
DrawFPS(10, 10);
DrawText("Move the mouse!", 10, 30, 20, Color.GREEN);
DrawText("Pitch Color.Black", (int)(screenWidth * 0.2f), screenHeight / 2, 20, Color.GREEN);
DrawText("Dark", (int)(screenWidth * 0.66f), screenHeight / 2, 20, Color.GREEN);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
UnloadTexture(texRay);
UnloadShader(shdrSpot);
CloseWindow();
//--------------------------------------------------------------------------------------
return 0;
}
static void ResetStar(ref Star s)
{
s.pos = new Vector2(GetScreenWidth() / 2.0f, GetScreenHeight() / 2.0f);
do
{
s.vel.X = (float)GetRandomValue(-1000, 1000) / 100.0f;
s.vel.Y = (float)GetRandomValue(-1000, 1000) / 100.0f;
} while (!((MathF.Abs(s.vel.X) + (MathF.Abs(s.vel.Y)) > 1)));
s.pos += s.pos + (s.vel * new Vector2(8.0f, 8.0f));
}
static void UpdateStar(ref Star s)
{
s.pos += s.vel;
if ((s.pos.X < 0) || (s.pos.X > GetScreenWidth()) ||
(s.pos.Y < 0) || (s.pos.Y > GetScreenHeight()))
{
ResetStar(ref s);
}
}
}