REXM: Updated some examples inconsistencies

examples/others/resources/shaders/glsl120/point_particle.vs

@@ -0,0 +1,24 @@
+#version 120
+
+// Input vertex attributes
+attribute vec3 vertexPosition;
+
+// Input uniform values
+uniform mat4 mvp;
+uniform float currentTime;
+
+// NOTE: Add your custom variables here
+
+void main()
+{
+    // Unpack data from vertexPosition
+    vec2  pos    = vertexPosition.xy;
+    float period = vertexPosition.z;
+
+    // Calculate final vertex position (jiggle it around a bit horizontally)
+    pos += vec2(100.0, 0.0)*sin(period*currentTime);
+    gl_Position = mvp*vec4(pos.x, pos.y, 0.0, 1.0);
+
+    // Calculate the screen space size of this particle (also vary it over time)
+    gl_PointSize = 10.0 - 5.0*abs(sin(period*currentTime));
+}