🚚 Move shader code to GLSL files

resources/shaders/fire.glsl

@@ -0,0 +1,32 @@
+// Get a noise value which moves vertically in time.
+vec2 uv = cogl_tex_coord_in[0].st * uSize / vec2(400, 600) / uScale;
+uv.y += uTime * uMovementSpeed;
+
+float noise = u3DNoise ? simplex3DFractal(vec3(uv * 4.0, uTime* uMovementSpeed * 1.5))
+                       : simplex2DFractal(uv * 4.0);
+
+// Modulate noise by effect mask.
+vec2 effectMask = effectMask(HIDE_TIME, FADE_WIDTH, EDGE_FADE);
+noise *= effectMask.y;
+
+// Map noise value to color.
+vec4 fire = getFireColor(noise);
+
+// Get the window texture.
+cogl_color_out = texture2D(uTexture, cogl_tex_coord_in[0].st);
+
+// Shell.GLSLEffect uses straight alpha. So we have to convert from premultiplied.
+if (cogl_color_out.a > 0) {
+  cogl_color_out.rgb /= cogl_color_out.a;
+}
+
+// Fade the window according to the effect mask.
+cogl_color_out.a *= effectMask.x;
+
+// Add the fire to the window.
+cogl_color_out = alphaOver(cogl_color_out, fire);
+
+// These are pretty useful for understanding how this works.
+// cogl_color_out = vec4(vec3(noise), 1);
+// cogl_color_out = vec4(vec3(effectMask.x), 1);
+// cogl_color_out = vec4(vec3(effectMask.y), 1);