Support multiple sample2D on batch drawing #1333

examples/shaders/resources/shaders/glsl100/color_mix.fs

@@ -0,0 +1,21 @@
+#version 100
+
+precision mediump float;
+
+// Input vertex attributes (from vertex shader)
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform sampler2D texture1;
+uniform vec4 colDiffuse;
+
+void main()
+{
+    // Texel color fetching from texture sampler
+    vec4 texelColor0 = texture2D(texture0, fragTexCoord);
+    vec4 texelColor1 = texture2D(texture1, fragTexCoord);
+
+    gl_FragColor = (texelColor0 + texelColor1)*0.5f;
+}