[orx-jumpflood] Make module multiplatform

orx-jumpflood/src/shaders/glsl/sdf-blend.frag

@@ -0,0 +1,13 @@
+uniform sampler2D tex0;// signed distance
+uniform sampler2D tex1;// signed distance
+uniform float factor;
+
+in vec2 v_texCoord0;
+out vec4 o_color;
+
+void main() {
+    float d0 = texture(tex0, v_texCoord0).r;
+    float d1 = texture(tex1, v_texCoord0).r;
+    float d = mix(d0, d1, factor);
+    o_color = vec4(d, 0.0, 0.0, 1.0);
+}