util/gpu/demo-vertex.glsl

/*
 * Copyright 2026 Behdad Esfahbod. All Rights Reserved.
 */

uniform mat4 u_matViewProjection;
uniform vec2 u_viewport;

in vec2 a_position;
in vec2 a_texcoord;
in vec2 a_normal;
in float a_emPerPos;
in uint a_glyphLoc;

out vec2 v_texcoord;
flat out uint v_glyphLoc;

void main ()
{
  vec2 pos = a_position;
  vec2 tex = a_texcoord;

  vec4 jac = vec4 (a_emPerPos, 0.0, 0.0, -a_emPerPos);

  hb_gpu_dilate (pos, tex, a_normal, jac,
		 u_matViewProjection, u_viewport);

  gl_Position = u_matViewProjection * vec4 (pos, 0.0, 1.0);
  v_texcoord = tex;
  v_glyphLoc = a_glyphLoc;
}