Shaders

Make sure your vertex and fragment shaders are declared in the same file. The function will separate them for you. Write up a vertex and fragment shader with the header #shader vertex or #shader fragment. The example code below details how this should be done.

You should then load this into a drawable component by first declaring a shader and then setting your GLSL code as active.

rune::Shader mySprite;
 
mySprite.changeShader("path to your shader");

Vertex Shader

This will set up a new vertex and fragment shader to be used by the sprite object.

#shader vertex
#version 330 core
 
layout(location = 0) in vec2 aPos;
layout(location = 1) in vec4 aColor;
layout(location = 2) in vec2 aTexCoord;
 
uniform vec2 cameraPos = vec2(0, 0);
uniform float cameraZoom = 1;
uniform float rotation = 0;
uniform vec2 origin = vec2(0,0);
uniform float aspectRatio = 1;
 
out vec4 ourColor;
out vec2 TexCoord;
 
void main()
{
 
  vec2 vertices = cameraZoom*aPos - cameraPos;
 
  if(rotation != 0)
  {
    float angle = radians(rotation);
    mat2 rotationMatrix = mat2(cos(angle), aspectRatio*sin(angle), -sin(angle)/aspectRatio, cos(angle));
 
    vertices = vertices - (cameraZoom*origin - cameraPos);
    vertices = rotationMatrix * vertices;
    vertices = vertices + (cameraZoom*origin - cameraPos);
  }
 
  ourColor = aColor;
  gl_Position = vec4(vertices,0,1);
 
  TexCoord = aTexCoord;
 
}

Fragment Shader

#shader fragment
#version 330 core
 
out vec4 FragColor;
 
in vec4 ourColor;
in vec2 TexCoord;
 
uniform sampler2D ourTexture;
 
void main()
{
  FragColor = texture(ourTexture, TexCoord) * ourColor;
}