Rendering

Takeaways:

• The output variables of one shader are used as the input variables to the next shader.
• Native: The types of the variables passed from one shader to the next shader need to match.
• WASM: The names and types of the variables passed from one shader to the next shader need to match.
• Github issue(s): amethyst#2192, amethyst#2205, amethyst#2247

In Amethyst, rendering is done with a standard graphics pipeline. Shaders are little programs along the pipeline that transform data to be drawn on screen.

A shader looks like this:

#version 450

// some details removed

// input parameters
in vec2 var_in_0;
in vec2 var_in_1;

// output parameters
out vec2 var_0;
out vec4 var_1;

void main() {
    // code
}

Native

The types of the output variables from one shader need to match the types of the input variables of the next shader:

• ✂️ Vertex shader

  out vec2 tex_coords;
  out vec4 color;
  

• 🖍️ Fragment shader

  // Variable types match up.
  in vec2 in_tex_coords;
  in vec4 in_color;
  

WASM

The names and types of the output variables from one shader need to match the names and types of the input variables of the next shader:

• ✂️ Vertex shader

  out vec2 vert_out_tex_coords;
  out vec4 vert_out_color;
  

• 🖍️ Fragment shader

  // Variable names and types match up.
  in vec2 vert_out_tex_coords;
  in vec4 vert_out_color;