[Metal] iOS Metalのちょっとしたメモ ref: http://qiita.com/edo_m18/items/5e03f7fa317b922b5a42

file0.txt

float4x4 mat = float4x4(float4( 1,  2,  3,  4),
                        float4( 5,  6,  7,  8),
                        float4( 9, 10, 11, 12),
                        float4(13, 14, 15, 16));

file1.m

static const float mat[4][4] = {
    { 1,  2,  3,  4},
    { 5,  6,  7,  8},
    { 9, 10, 11, 12},
    {13, 14, 15, 16},
};

file2.txt

fragment half4 frag(VertexOut input [[stage_in]]) {
    half4 color = half4(input.color);

    // なにがしかの条件を判定する
    if (anyCondition) {
        discard_fragment();
    }

    return color;
}

file3.txt

struct VertexOut {
    float4 position [[position]];
};

struct Uniforms {
    float2 resolution;
};

fragment half4 frag(VertexOut input [[stage_in]],
                      constant Uniforms &uniforms [[buffer(0)]]) {
    float2 position = (input.position.xy * 2.0 - uniforms.resolution) / min(uniforms.resolution.x, uniforms.resolution.y);

    // ...
}

file4.txt

fragment half4 frag(VertexOut input [[stage_in]], constant Uniforms &uniforms  [[buufer(0)]]) {
    float2 resolution = float2(uniforms.resolution[0], uniforms.resolution[1]);
    float2 position = (input.position.xy * 2.0 - resolution) / min(resolution.x, resolution.y);
    return half4(position.x, position.y, 0.0, 1.0);
}

webgl-ver

#ifdef GL_ES
precision mediump float;
#endif

uniform float time;
uniform vec2 mouse;
uniform vec2 resolution;

void main( void ) {

    vec2 position = ( gl_FragCoord.xy  * 2.0 -  resolution ) / min(resolution.x, resolution.y);

    gl_FragColor = vec4(position, 0.0, 1.0);

}