[GLSL] Hello World

 

https://thebookofshaders.com/02/

The Book of Shaders

---

#ifdef GL_ES
precision mediump float;
#endif

void main() {
    gl_FragColor = vec4(1.0,0.0,1.0,1.0);
}

 

1. Shader Language is C-flavored language.

2. The final pixel color is assigned to the reserved global variable gl_FragColor.

3. Shader Language has the types like 'vec3' and 'vec2'.

4. Float types are vital in shaders, so the level of precision is crucial. Lower precision means faster rendering, but at the cost of quality. You can be picky and specify the precision of each variable that uses floating point. In the first line (precision mediump float;) we are setting all floats to medium precision. But we can choose to set them to low (precision lowp float;) or high (precision highp float;).

5. The last, and maybe most important, detail is that GLSL specs don’t guarantee that variables will be automatically casted. So don't forget the floating points.

 

vec4 color = vec4(vec3(1.0,0.0,1.0),1.0); //it means 'vec4(1.0,0.0,1.0,1.0);