struct View {
  viewProj: mat4x4f,
  lightViewProj: mat4x4f,
  lightPosition: vec4f,
  eyePosition: vec4f,
  aspect: f32,
};

struct Config {
  scale: f32,
  translateX: f32,
  translateY: f32,
};

struct GlyphBuffer {
  texPosition: vec2f,
  texSize: vec2f,
  size: vec2f,
  unused: vec2f,
};

struct LayoutBuffer {
  position: vec4f, // glyph_index w
};

@group(0) @binding(0) var<uniform> view: View;

@group(1) @binding(0) var linearSampler: sampler;
@group(1) @binding(1) var fontTexture: texture_2d<f32>;
@group(1) @binding(2) var<storage> glyphBuffer: array<GlyphBuffer>;

@group(2) @binding(0) var<storage> layoutBuffer: array<LayoutBuffer>;
@group(2) @binding(1) var<uniform> config: Config;

struct VertexInput {
  @builtin(vertex_index) vertex_index: u32,
  @builtin(instance_index) instance_index: u32,
};

struct VertexOutput {
  @builtin(position) position: vec4f,
  @location(0) texture: vec2f,
  @location(1) @interpolate(flat) glyphIndex: u32,
  @location(2) foo: vec4f,
};

const vertices = array(
  vec2f(1.0, 0.0),
  vec2f(0.0, 1.0),
  vec2f(0.0, 0.0),
  vec2f(1.0, 1.0),
);

@vertex
fn vertexMain(input: VertexInput) -> VertexOutput
{
  let texture = vertices[input.vertex_index];

  let position = vec2f(texture.x, 1.0 - texture.y);

  let glyphIndex = u32(layoutBuffer[input.instance_index].position.w);
  let viewPosition = position * glyphBuffer[glyphIndex].size + layoutBuffer[input.instance_index].position.xy;
  let screenPosition = viewPosition * vec2f(1 / view.aspect, 1) * config.scale + vec2f(config.translateX, config.translateY);

  var output: VertexOutput;
  output.position = vec4f(screenPosition, 0.0, 1.0);
  output.texture = texture;
  output.glyphIndex = glyphIndex;
  output.foo = vec4f(layoutBuffer[glyphIndex].position.xy, 0, 0);
  return output;
}

@fragment
fn fragmentMain(input: VertexOutput) -> @location(0) vec4f
{
  var color = vec3f(input.texture.xy, 0);

  let p = glyphBuffer[input.glyphIndex].texPosition;
  let s = glyphBuffer[input.glyphIndex].texSize;

  let base = textureSample(fontTexture, linearSampler, input.texture * s + p);

  let t = f32(base.x > 0.5);

  if (base.x < 0.5) {
    discard;
  }

  return vec4f(t, t, t, 1);
}