[require]
shader model >= 4.0

[vertex shader]
struct vs_in
{
    uint instance_id : SV_InstanceId;
    uint vertex_id : SV_VertexId;
};

struct vs_out
{
    float4 position : SV_Position;
    float4 color : Color;
};

void main(vs_in i, out vs_out o)
{
    float2 vertices[] =
    {
        {0.0, 0.0}, { 0.0,  2.0}, {-2.0,  0.0},
        {0.0, 0.0}, { 2.0,  0.0}, { 0.0,  2.0},
        {0.0, 0.0}, { 0.0, -2.0}, { 2.0,  0.0},
        {0.0, 0.0}, {-2.0,  0.0}, { 0.0, -2.0},
    };
    uint pos = i.vertex_id % 3;
    o.position = float4(vertices[pos + i.instance_id * 3], 0.0, 1.0);
    float color = 0.25 + i.instance_id * 0.25;
    o.color = float4(0.0, color, 0.0, color);
}

[pixel shader]
struct vs_out
{
    float4 position : SV_Position;
    float4 color : Color;
};

float4 main(vs_out i) : SV_Target
{
    return i.color;
}

[test]
todo(glsl | msl) draw triangle list 3 4
probe rtv 0 (160, 120) rgba (0.0, 0.25, 0.0, 0.25)
probe rtv 0 (480, 120) rgba (0.0, 0.5, 0.0, 0.5)
probe rtv 0 (480, 360) rgba (0.0, 0.75, 0.0, 0.75)
probe rtv 0 (160, 360) rgba (0.0, 1.0, 0.0, 1.0)