[orx-jumpflood] Make module multiplatform

orx-jumpflood/src/shaders/glsl/id-contours.frag

@@ -0,0 +1,25 @@
+uniform sampler2D tex0;
+in vec2 v_texCoord0;
+
+out vec4 o_color;
+
+void main() {
+vec4 colorMask = vec4(0.0, 0.0, 1.0, 0.0);
+    vec2 stepSize = 1.0 / vec2(textureSize(tex0, 0));
+    vec4 ref = texture(tex0, v_texCoord0);
+
+    float laplacian = 0.0;
+
+    laplacian += abs(texture(tex0, v_texCoord0 + vec2(stepSize.x, 0.0)).b-ref.b);
+    laplacian += abs(texture(tex0, v_texCoord0 - vec2(stepSize.x, 0.0)).b-ref.b);
+    laplacian += abs(texture(tex0, v_texCoord0 + vec2(0.0, stepSize.y)).b-ref.b);
+    laplacian += abs(texture(tex0, v_texCoord0 - vec2(0.0, stepSize.y)).b-ref.b);
+
+    float contour = step(0.0, laplacian);
+
+    if (laplacian > 0.001) {
+        o_color = vec4(v_texCoord0.x, v_texCoord0.y, ref.b, 1.0);
+    } else {
+        o_color = vec4(-1.0, -1.0, -1.0, 1.0);
+    }
+}