still wip modularisation, game somehow boots

assets/crt.frag

@@ -0,0 +1,44 @@
+#version 120
+#ifdef GL_ES
+    precision mediump float;
+#endif
+
+
+varying vec4 v_color;
+varying vec2 v_texCoords;
+uniform sampler2D u_texture;
+
+uniform vec2 resolution;
+
+uniform vec3 phosphor_colour = vec3(1.3, 0.8567, 0.0);
+vec3 scanline_darkening = vec3(0.45, 0.45, 0.45);
+
+// 0: every odd line will get darkened; 1: every even line will get darkened
+uniform float alternative_scanline = 0.0; // 1.0: true
+
+uniform float blur_blend = 0.3;
+
+void main(void) {
+    vec3 color = texture2D(u_texture, v_texCoords).rgb;
+    vec3 color_pre =  texture2D(u_texture, (gl_FragCoord + vec2(-1.0, 0.0)) / resolution).rgb;
+    vec3 color_next = texture2D(u_texture, (gl_FragCoord + vec2( 1.0, 0.0)) / resolution).rgb;
+
+    color = color * (1.0 - blur_blend) + color_pre * (blur_blend / 2.0) + color_next * (blur_blend / 2.0);
+
+    bool is_scanline = mod(int(gl_FragCoord.y), 2) == int(alternative_scanline);
+
+    float color_luminosity = (
+        3.0 * color.r +
+        4.0 * color.g +
+        1.0 * color.b
+    ) / 8.0;
+
+    // out colour
+    color = vec3(color_luminosity) * phosphor_colour;
+
+    if (is_scanline) {
+        color = color * scanline_darkening;
+    }
+
+    gl_FragColor = vec4(color, 1.0);
+}