GLSL shader - GameCreators Forum

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Zapa

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Posted: 3rd May 2018 15:27

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Hi,

I'm wondering is there a way to convert a GLSL shader to AppGameKit? From what I've read in the documentation the AppGameKit shader language is based on GLSL. However all examples of GLSL shaders that I used do not work in agk. Here's an example:

.ps

uniform sampler2D sceneTex; // 0
uniform float vx_offset;
uniform float rt_w; // GeeXLab built-in
uniform float rt_h; // GeeXLab built-in
uniform float hatch_y_offset; // 5.0
uniform float lum_threshold_1; // 1.0
uniform float lum_threshold_2; // 0.7
uniform float lum_threshold_3; // 0.5
uniform float lum_threshold_4; // 0.3
void main() 
{ 
  vec2 uv = gl_TexCoord[0].xy;
  
  vec3 tc = vec3(1.0, 0.0, 0.0);
  if (uv.x < (vx_offset-0.005))
  {
    float lum = length(texture2D(sceneTex, uv).rgb);
    tc = vec3(1.0, 1.0, 1.0);
  
    if (lum < lum_threshold_1) 
    {
      if (mod(gl_FragCoord.x + gl_FragCoord.y, 10.0) == 0.0) 
        tc = vec3(0.0, 0.0, 0.0);
    }  
  
    if (lum < lum_threshold_2) 
    {
      if (mod(gl_FragCoord.x - gl_FragCoord.y, 10.0) == 0.0) 
        tc = vec3(0.0, 0.0, 0.0);
    }  
  
    if (lum < lum_threshold_3) 
    {
      if (mod(gl_FragCoord.x + gl_FragCoord.y - hatch_y_offset, 10.0) == 0.0) 
        tc = vec3(0.0, 0.0, 0.0);
    }  
  
    if (lum < lum_threshold_4) 
    {
      if (mod(gl_FragCoord.x - gl_FragCoord.y - hatch_y_offset, 10.0) == 0.0) 
        tc = vec3(0.0, 0.0, 0.0);
    }
  }
  else if (uv.x>=(vx_offset+0.005))
  {
    tc = texture2D(sceneTex, uv).rgb;
  }
  
  gl_FragColor = vec4(tc, 1.0);
}

+ Code Snippet

uniform sampler2D sceneTex; // 0
uniform float vx_offset;
uniform float rt_w; // GeeXLab built-in
uniform float rt_h; // GeeXLab built-in
uniform float hatch_y_offset; // 5.0
uniform float lum_threshold_1; // 1.0
uniform float lum_threshold_2; // 0.7
uniform float lum_threshold_3; // 0.5
uniform float lum_threshold_4; // 0.3
void main() 
{ 
  vec2 uv = gl_TexCoord[0].xy;
  
  vec3 tc = vec3(1.0, 0.0, 0.0);
  if (uv.x < (vx_offset-0.005))
  {
    float lum = length(texture2D(sceneTex, uv).rgb);
    tc = vec3(1.0, 1.0, 1.0);
  
    if (lum < lum_threshold_1) 
    {
      if (mod(gl_FragCoord.x + gl_FragCoord.y, 10.0) == 0.0) 
        tc = vec3(0.0, 0.0, 0.0);
    }  
  
    if (lum < lum_threshold_2) 
    {
      if (mod(gl_FragCoord.x - gl_FragCoord.y, 10.0) == 0.0) 
        tc = vec3(0.0, 0.0, 0.0);
    }  
  
    if (lum < lum_threshold_3) 
    {
      if (mod(gl_FragCoord.x + gl_FragCoord.y - hatch_y_offset, 10.0) == 0.0) 
        tc = vec3(0.0, 0.0, 0.0);
    }  
  
    if (lum < lum_threshold_4) 
    {
      if (mod(gl_FragCoord.x - gl_FragCoord.y - hatch_y_offset, 10.0) == 0.0) 
        tc = vec3(0.0, 0.0, 0.0);
    }
  }
  else if (uv.x>=(vx_offset+0.005))
  {
    tc = texture2D(sceneTex, uv).rgb;
  }
  
  gl_FragColor = vec4(tc, 1.0);
}

.vs

+ Code Snippet


void main(void)
{
  gl_Position = ftransform();
  gl_TexCoord[0] = gl_MultiTexCoord0;
}

The shader loads fine but when I apply it to a cube (CreateObjectBox) that cube 's color becomes black.

Shader example from here

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GaborD

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Joined: 3rd Dec 2017

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Posted: 3rd May 2018 17:40 Edited at: 3rd May 2018 17:57

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Seems to be set up as a post shader (is looking into a prerendered sceneTex for the color info), are you providing it with a rendertex of the scene?
Also, are the threshold values and offsets set with SetShaderConstantByName?

If you want to skip all the post shenanigans and just use it as a simple object shader that takes the diffuse texture, applies stock lighting and then quickly crosshatches it, you can try something like this: (just a few changes needed)
I hardcoded the thresholds for simplicity, so that it works with any AppGameKit project, you can ofcourse put those back into uniforms and then set them from your AppGameKit code.

vs

+ Code Snippet

attribute vec3 position;
attribute mediump vec3 normal;
attribute mediump vec2 uv;

varying vec2 uv0Varying;
varying vec3 posVarying;
varying vec3 normalVarying;

uniform mediump vec4 uvBounds0;
uniform mat4 agk_WorldViewProj;
uniform mat4 agk_World;
uniform mat4 agk_ViewProj;
uniform mat3 agk_WorldNormal;

void main(){	
	vec4 pos = agk_World * vec4(position,1);
    gl_Position = agk_ViewProj * pos;
    normalVarying = agk_WorldNormal * normal;
	posVarying = pos.xyz;
    uv0Varying = uv * uvBounds0.xy + uvBounds0.zw;
}

ps

#ifdef GL_ES
   #ifdef GL_FRAGMENT_PRECISION_HIGH   
      precision highp float;
   #else
      precision mediump float;
   #endif
#endif
 
uniform sampler2D texture0; // D

varying vec2 uv0Varying;
varying vec3 normalVarying;
varying vec3 posVarying;

mediump vec3 GetPSLighting( mediump vec3 normal, highp vec3 pos );

void main() {
    vec3 norm = normalize(normalVarying);
	vec3 albedo = texture2D(texture0, uv0Varying).rgb;
	vec3 diff = GetPSLighting( norm, posVarying ); 
	vec3 amb = vec3(0.1,0.14,0.16);
	vec3 col = albedo*(diff+amb);
	
	vec3 tc = vec3(1.0, 0.0, 0.0);

float lum = length(col);
	tc = vec3(1.0, 1.0, 1.0);
  
	if (lum < 1.0) {
		if (mod(gl_FragCoord.x + gl_FragCoord.y, 10.0) == 0.0) tc = vec3(0.0, 0.0, 0.0);
	}  
  
	if (lum < 0.7) {
		if (mod(gl_FragCoord.x - gl_FragCoord.y, 10.0) == 0.0) tc = vec3(0.0, 0.0, 0.0);
	}  
  
	if (lum < 0.5) {
		if (mod(gl_FragCoord.x + gl_FragCoord.y - 5.0, 10.0) == 0.0) tc = vec3(0.0, 0.0, 0.0);
	}  
  	
	if (lum < 0.3) {
		if (mod(gl_FragCoord.x - gl_FragCoord.y - 5.0, 10.0) == 0.0) tc = vec3(0.0, 0.0, 0.0);
	}
	
    gl_FragColor = vec4(tc, 1.0);
}

+ Code Snippet

#ifdef GL_ES
   #ifdef GL_FRAGMENT_PRECISION_HIGH   
      precision highp float;
   #else
      precision mediump float;
   #endif
#endif
 
uniform sampler2D texture0; // D

varying vec2 uv0Varying;
varying vec3 normalVarying;
varying vec3 posVarying;

mediump vec3 GetPSLighting( mediump vec3 normal, highp vec3 pos );


void main() {
    vec3 norm = normalize(normalVarying);
	vec3 albedo = texture2D(texture0, uv0Varying).rgb;
	vec3 diff = GetPSLighting( norm, posVarying ); 
	vec3 amb = vec3(0.1,0.14,0.16);
	vec3 col = albedo*(diff+amb);
	
	vec3 tc = vec3(1.0, 0.0, 0.0);

	float lum = length(col);
	tc = vec3(1.0, 1.0, 1.0);
  
	if (lum < 1.0) {
		if (mod(gl_FragCoord.x + gl_FragCoord.y, 10.0) == 0.0) tc = vec3(0.0, 0.0, 0.0);
	}  
  
	if (lum < 0.7) {
		if (mod(gl_FragCoord.x - gl_FragCoord.y, 10.0) == 0.0) tc = vec3(0.0, 0.0, 0.0);
	}  
  
	if (lum < 0.5) {
		if (mod(gl_FragCoord.x + gl_FragCoord.y - 5.0, 10.0) == 0.0) tc = vec3(0.0, 0.0, 0.0);
	}  
  	
	if (lum < 0.3) {
		if (mod(gl_FragCoord.x - gl_FragCoord.y - 5.0, 10.0) == 0.0) tc = vec3(0.0, 0.0, 0.0);
	}
	
    gl_FragColor = vec4(tc, 1.0);
}

Works fine on loaded models, just need to add a stock AppGameKit light. Test-screenshot attached.
You can prolly get more performance out of it if you convert it to not use so many conditionals, but then again, it runs pretty fast as it is.

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Zapa

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Joined: 20th Apr 2018

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Posted: 4th May 2018 08:09 Edited at: 4th May 2018 09:12

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Hey,

Thanks for the quick reply! I applied the shader to the scene and setup some custom colors. All objects have normal maps on them. It looks good except that the back of the models/objects have no texture. It applies to all the objects loaded or created. Without the shader, their texture and normal map is applied correctly. This is how it looks like:

I also created a point light and set it's position to the camera's position. Switched it's PointLightMode between Vertex and Pixel. Lighting seems to not influence the scene and I'm wondering if GetPSLighting actually does anything.

This can be recreated using your code with just the TC vallues being changed a bit to give the mathpaper outline colors.
Can you point me in the right direction?

Edit: It seems that by modifying the amb value get's all faces to shade properly. Now only the light problems remains.

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fubarpk

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Joined: 11th Jan 2005

Playing: AGK is my friend

Posted: 8th May 2018 18:52 Edited at: 8th May 2018 19:13

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For light to have an effect when a shader is used you have to add "varying mediump vec3 lightVarying;"
it has to be in the vs shader and ps shader you then multiply by lightvaring when you are setting the pixels
an example of a color being set for a pixel is something like this

+ Code Snippet

uniform sampler2D texture0;
varying highp vec3 posVarying;
varying mediump vec3 normalVarying;
varying mediump vec2 uvVarying;
varying mediump vec3 lightVarying;
mediump vec3 ApplyFog( mediump vec3 color, highp vec3 pointPos );




{
mediump vec3 norm = normalize(normalVarying);
varying mediump vec2 uvVarying;;
mediump vec3 light = lightVarying + GetPSLighting( norm, posVarying );
color = texture2D(texture0, uvVarying).rgb*light *agk_MeshDiffuse;
mediump vec3 colorFinal = ApplyFog( color, posVarying );
gl_FragColor = vec4(colorFinal,1.0);
}

the above is only a snippet and part of what I think needs to be added but should give you an idea
on whats needed to be added because you need light varying and possibly may want to add fog later
the thread Useful Community shaders has allot of example shaders and altho is quite large should
help explain allot of these conceptshttps://forum.thegamecreators.com/thread/214598 and
when you get it sorted the way you like it would be great to share there for others to see and use

The AppGameKit Documentation also tries to clarify this and has a list down the bottom Shader Variables
and explains allot about using shaders in AppGameKit https://www.appgamekit.com/documentation/guides/13_shaders.htm
Which should help with converting shaders

fubar

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