examples: add render-pass-ext exmaple

examples/render-pass-ext/gles2/shaders/meson.build

@@ -0,0 +1,22 @@
+custom_pass_embed = find_program('../../../../render/gles2/shaders/embed.sh', native: true)
+triangle_vert = custom_target(
+	'custom-render-pass-triangle-vert',
+	command: [custom_pass_embed, 'custom_triangle_vert'],
+	input: 'triangle.vert',
+	output: 'triangle_vert.h',
+	feed: true,
+	capture: true,
+)
+triangle_frag = custom_target(
+	'custom-render-pass-triangle-frag',
+	command: [custom_pass_embed, 'custom_triangle_frag'],
+	input: 'triangle.frag',
+	output: 'triangle_frag.h',
+	feed: true,
+	capture: true,
+)
+
+gles2_shader_sources = [
+	triangle_vert,
+	triangle_frag,
+]

examples/render-pass-ext/gles2/shaders/triangle.frag

@@ -0,0 +1,11 @@
+#ifdef GL_FRAGMENT_PRECISION_HIGH
+precision highp float;
+#else
+precision mediump float;
+#endif
+
+varying vec3 v_color;
+
+void main() {
+	gl_FragColor = vec4(v_color, 1.0);
+}

examples/render-pass-ext/gles2/shaders/triangle.vert

@@ -0,0 +1,8 @@
+attribute vec2 pos;
+attribute vec3 color;
+varying vec3 v_color;
+
+void main() {
+	gl_Position = vec4(pos, 0.0, 1.0);
+	v_color = color;
+}