Example for Sprite or Fullscreen shader

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MikeHart

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Posted: 14th Nov 2014 20:48 Edited at: 14th Nov 2014 21:24

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Hi folks,

all the examples of shader usage I saw in here and in the code samples load shaders via a vertex and pixel shader.

But there is LoadFullScreenShader and LoadSpriteShader. Do you know of any example so I can see how it is done?

What I am after is a simple bloom shading for my sprites and for a full screen sepia effect.

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baxslash

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Posted: 18th Nov 2014 14:40 Edited at: 18th Nov 2014 14:42

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There is a bloom shader example with AGK. Just load the pixel shader without the need for the quad vertex shader in that example.

Here's a sepia shader for you... getting into these now:

+ Code Snippet

#ifdef GL_ES
	#ifdef GL_FRAGMENT_PRECISION_HIGH   
		precision highp float;
	#else
		precision mediump float;
	#endif
#endif

uniform sampler2D texture0;
varying vec2 uvVarying;

vec4 sepia(vec4 inColor)
{
	float avg = (inColor.r + inColor.g + inColor.b) * 0.33333334;
	return vec4(avg + 0.07843, avg, avg - 0.07843, inColor.a);
}

void main()
{
	gl_FragColor = sepia(texture2D(texture0, uvVarying.xy));
}

EDIT: Attached example code too

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MikeHart

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Posted: 18th Nov 2014 17:11 Edited at: 18th Nov 2014 17:12

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Thanks. So you say that the bloom shader should work with LoadSpriteShader alone? All the examples show always the usage with a vertex shader. Somehow I can't get this to work. Will check again. Thanks for the example. Will test later when I am home.

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baxslash

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Posted: 18th Nov 2014 20:21

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The bloom shader should work fine as it is designed to be used with the quad object removing the need for the quad vertex shader. I tested it with my example and it works fine. Simplifies the code a little.

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MikeHart

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Posted: 18th Nov 2014 22:17 Edited at: 18th Nov 2014 22:25

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Ok,I was able to run your code. Two shaders reported errors but the sepia and another one ran. Thanks to that.

But I can't get the sprite shader to work int AGK2. Maybe I am not understanding the concept.

Here is the code:

+ Code Snippet

// Project: SpriteShaderTest 
// Created: 2014-11-18

// set window properties
SetWindowTitle( "SpriteShaderTest" )
SetWindowSize( 1024, 768, 0 )

// set display properties
SetVirtualResolution( 1024, 768 )
SetClearColor(100,100,100)
local sprite as integer
sprite = CreateSprite(LoadImage("blue.png"))
SetSpritePosition(sprite,100,100)
local shader as integer
shader = LoadSpriteShader("Bloom.ps")
SetSpriteShader(sprite, shader)
do
    

    Print( ScreenFPS() )
    Sync()
loop

Would be awesome if you could help me with that one.

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baxslash

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Posted: 18th Nov 2014 22:27

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I would take a look at using a quad object for the bloom shader as shown in the example project. It's pretty complicated.

What error did you get with the other shaders?

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MikeHart

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Posted: 18th Nov 2014 23:00

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With Loadshader and an according vertex shader I get things to work. Slowly I think that LoadSpriteShader is buggy. I try to find someone who can provide an example that works or shares my oppinion.

Attached is the screenshot of one error. The other shader has a similar error.

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janbo

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Posted: 19th Nov 2014 16:18 Edited at: 19th Nov 2014 16:20

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Hi MikeHart,

Quote: " Slowly I think that LoadSpriteShader is buggy"

I can not confirm that, for me LoadSpriteShader works.
[AGKv2] 2D Normalmapping

You can't use a "3D shader" for LoadSpriteShader.
Im sure LoadSpriteShader loads a default vertex shader, so you have to setup your fragment shader for it
and I don't know how the vertex shader for the LoadFullScreenShader command looks like.

Your possibilities may be:
1. Write/Convert a Bloom shader(fragment) for Sprites and make the sprite fit the screen.
2. Write/Convert a Bloom shader(fragment) for LoadFullScreenShader..never seen an example of it.
3. Just use the Bloom shader(fragment and vertex) of the agk example with the quad object.
4. May be LoadSpriteShader is buggy and I had luck

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baxslash

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Posted: 19th Nov 2014 17:31

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Quote: "Attached is the screenshot of one error. The other shader has a similar error."

I'm not sure how that can be the case... here is the code for the subtractive shader. It doesn't create any vec3 or vec4 directly just uses the texture2D which creates a vec4 in both cases (I believe). The only change here is that I found multiplying worked better than subtracting:

+ Code Snippet

#ifdef GL_ES
	#ifdef GL_FRAGMENT_PRECISION_HIGH   
		precision highp float;
	#else
		precision mediump float;
	#endif
#endif

uniform sampler2D texture0;
uniform sampler2D texture1;
varying vec2 uvVarying;

void main()
{
	gl_FragColor = texture2D(texture0, uvVarying.xy) * texture2D(texture1, uvVarying.xy);
}

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AppGameKit Classic Chat / Example for Sprite or Fullscreen shader

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