render_helpers: Add GradientFadeTexture

1 files changed, 47 insertions, 0 deletions

diff --git a/src/render_helpers/shaders/gradient_fade.frag b/src/render_helpers/shaders/gradient_fade.frag
new file mode 100644
index 00000000..eccc7066
--- /dev/null
+++ b/src/render_helpers/shaders/gradient_fade.frag
@@ -0,0 +1,47 @@
+#version 100
+
+//_DEFINES_
+
+#if defined(EXTERNAL)
+#extension GL_OES_EGL_image_external : require
+#endif
+
+precision highp float;
+#if defined(EXTERNAL)
+uniform samplerExternalOES tex;
+#else
+uniform sampler2D tex;
+#endif
+
+uniform float alpha;
+varying vec2 v_coords;
+
+#if defined(DEBUG_FLAGS)
+uniform float tint;
+#endif
+
+// x is left edge, y is right edge of the gradient.
+uniform vec2 cutoff;
+
+void main() {
+    // Sample the texture.
+    vec4 color = texture2D(tex, v_coords);
+#if defined(NO_ALPHA)
+    color = vec4(color.rgb, 1.0);
+#endif
+
+    if (cutoff.x < cutoff.y) {
+        float fade = clamp((cutoff.y - v_coords.x) / (cutoff.y - cutoff.x), 0.0, 1.0);
+        color = color * fade;
+    }
+
+    // Apply final alpha and tint.
+    color = color * alpha;
+
+#if defined(DEBUG_FLAGS)
+    if (tint == 1.0)
+        color = vec4(0.0, 0.2, 0.0, 0.2) + color * 0.8;
+#endif
+
+    gl_FragColor = color;
+}