CODEWITHSUNDEEP
javaandroidopengl-esshader
Anonymous Person
Anonymous Person

Reputation: 305

OpenGL Shader Compiles on Desktop, But Not Android

I recently started learning opengl and still don't know very much about it. I was following a tutorial and wrote these two shaders:

Vertex Shader:

#version 400

in vec4 s_vPosition;
in vec4 s_vColor;
out vec4 color;

void main() {
    color = s_vColor;
    gl_Position = s_vPosition;
}

Fragment Shader:

#version 400

in vec4 color;
out vec4 fColor;

void main() {
    fColor = color;
}

They compile and work just fine on the desktop with OpenGL 3, but don't compile with OpenGL ES 2 on Android. I tried checking the shader output log, but it returned a blank string. Again, I am very new to this and my mistake is probably very simple, but any help would be highly appreciated.

Upvotes: 0

Views: 198

Answers (1)

samgak
samgak

Reputation: 24417

In OpenGLES2 you don't use the in and out variable prefixes like in 3.0. Instead you use the following keywords:

  • attribute Values that are passed in to the vertex shader per vertex
  • varying Values that are passed from the vertex shader to the fragment shader
  • uniform Global variables that you can set on a shader for all vertices and fragments (includes things like textures, but can also be scalar or vector types).

An attribute corresponds to an in in a vertex shader. A varying corresponds to an out in a vertex shader and an in in a fragment shader. So, change your vertex shader to this:

attribute vec4 s_vPosition;
attribute vec4 s_vColor;
varying vec4 color;

void main() {
    color = s_vColor;
    gl_Position = s_vPosition;
}

and your fragment shader to this:

varying vec4 color;

void main() {
    gl_FragColor = color;
}

gl_FragColor is a specially defined variable like gl_Position used for outputting the color from a fragment shader.

Upvotes: 4

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