Hi There,
First my disclaimer: I am an complete beginner with any game developement - especially shaders, currently shader code might as well be in greek - I wouldn’t know the diffrence.
I found some samples and just want to get it to work, then from there I’ll start figuring the rest out. PS. I am not intensionally starting with shaders, I am simply trying
to create a certain effect. I tried diffrent BlendState with multiple spriteBatches, but couldn’t get it right either with those.
I have a strange problem when applying a shader. The whole scene seems to be turned upside-down, and zoomed out. I have been messing about whole day but just can’t get it right.
Here is the scene witout apply shader effect:
Here is the same scene with shader effect:
By only commenting this line in and out flips it around:
lightingEffect.CurrentTechnique.Passes[0].Apply();
Please can anybody help?
Any help will be much appreciated.
Thank you very much.
Here is the sample I am trying to get going:
Shader:
texture lightMask;
sampler mainSampler : register(s0);
sampler lightSampler = sampler_state{ Texture = ; };
struct PixelShaderInput
{
float4 TextureCoords: TEXCOORD0;
};
float4 PixelShaderFunction(PixelShaderInput input) : COLOR0
{
float2 texCoord = input.TextureCoords;
float4 mainColor = tex2D(mainSampler, texCoord);
float4 lightColor = tex2D(lightSampler, texCoord);
lightColor.rgb * float3(1.2f, 1.2f, 1.2f);
mainColor.rgb /= mainColor.a;
return saturate(mainColor * lightColor) * 4;
}
technique Technique1
{
pass Pass1
{
PixelShader = compile ps_4_0_level_9_1 PixelShaderFunction();
}
}
c#
using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using System.Collections.Generic;
using Microsoft.Xna.Framework.Input;
namespace Game1
{
public class Game1 : Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
Texture2D background;
Texture2D blackSquare;
Texture2D ground;
Texture2D torch;
Texture2D lightmask;
RenderTarget2D mainScene;
RenderTarget2D lightMask;
Effect lightingEffect;
List<Vector2> torchPositions;
Vector2 mousePosition = Vector2.Zero;
const int LIGHTOFFSET = 115;
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
}
protected override void Initialize()
{
torchPositions = new List<Vector2>();
torchPositions.Add(new Vector2(40, 420));
torchPositions.Add(new Vector2(340, 420));
torchPositions.Add(new Vector2(640, 420));
GraphicsDevice.SamplerStates[1] = SamplerState.LinearClamp;
base.Initialize();
}
protected override void LoadContent()
{
spriteBatch = new SpriteBatch(GraphicsDevice);
background = Content.Load<Texture2D>("Effects/bg5");
ground = Content.Load<Texture2D>("Effects/ground");
torch = Content.Load<Texture2D>("Effects/torch");
lightmask = Content.Load<Texture2D>("Effects/lightmask");
blackSquare = Content.Load<Texture2D>("Effects/blacksquare");
lightingEffect = Content.Load<Effect>("Effects/lighting");
var pp = GraphicsDevice.PresentationParameters;
mainScene = new RenderTarget2D(GraphicsDevice, pp.BackBufferWidth, pp.BackBufferHeight);
lightMask = new RenderTarget2D(GraphicsDevice, pp.BackBufferWidth, pp.BackBufferHeight);
}
protected override void Update(GameTime gameTime)
{
if (Keyboard.GetState().IsKeyDown(Keys.Escape))
this.Exit();
var mouse = Mouse.GetState();
mousePosition = new Vector2(mouse.X, mouse.Y);
base.Update(gameTime);
}
private void drawMain(GameTime gameTime)
{
GraphicsDevice.SetRenderTarget(mainScene);
GraphicsDevice.Clear(Color.Black);
spriteBatch.Begin();
// Draws a background image.
spriteBatch.Draw(background, new Vector2(0, 0), Color.White);
// Lays out some torches based on torch positions and mouse
foreach (var position in torchPositions)
{
spriteBatch.Draw(torch, position, Color.White);
}
spriteBatch.Draw(torch, mousePosition, Color.White);
// Lay out some ground.
for (var idx = 0; idx < 25; idx++)
{
spriteBatch.Draw(ground, new Vector2(32 * idx, 450), Color.White);
}
spriteBatch.End();
GraphicsDevice.SetRenderTarget(null);
}
private void drawLightMask(GameTime gameTime)
{
GraphicsDevice.SetRenderTarget(lightMask);
GraphicsDevice.Clear(Color.Black);
// Create a Black Background
spriteBatch.Begin();
spriteBatch.Draw(blackSquare, new Vector2(0, 0), new Rectangle(0, 0, 800, 800), Color.White);
spriteBatch.End();
spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.Additive);
// Draw out lightmasks based on torch positions.
foreach (var position in torchPositions)
{
var new_pos = new Vector2(position.X - LIGHTOFFSET, position.Y - LIGHTOFFSET);
spriteBatch.Draw(lightmask, new_pos, Color.White);
}
spriteBatch.Draw(lightmask, new Vector2(mousePosition.X - LIGHTOFFSET, mousePosition.Y - LIGHTOFFSET), Color.White);
spriteBatch.End();
GraphicsDevice.SetRenderTarget(null);
}
protected override void Draw(GameTime gameTime)
{
drawMain(gameTime);
drawLightMask(gameTime);
GraphicsDevice.Clear(Color.Black);
spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend);
lightingEffect.Parameters["lightMask"].SetValue(lightMask);
lightingEffect.CurrentTechnique.Passes[0].Apply();
spriteBatch.Draw(mainScene, new Vector2(0, 0), Color.White);
spriteBatch.End();
base.Draw(gameTime);
}
}
}
