Render voxels with an approximately-correct z-offset.

glsl/rgba.frag

@@ -1,7 +1,25 @@
 uniform sampler2D DiffuseTexture;
+uniform bool EnableDepthPreview;
+
 varying vec4 vTexCoord;
 
 void main()
 {
-	gl_FragColor = texture2D(DiffuseTexture, vTexCoord.st);
+	vec4 c = texture2D(DiffuseTexture, vTexCoord.st);
+	// Discard any transparent fragments (both color and depth)
+	if (c.a == 0.0)
+		discard;
+
+	float depth = gl_FragCoord.z;
+
+	// Convert to window coords
+	gl_FragDepth = 0.5 * depth + 0.5;
+
+	if (EnableDepthPreview)
+	{
+		// Front of the depth buffer is at 0, but we want to render it as bright
+		gl_FragColor = vec4(vec3(1.0 - gl_FragDepth), 1.0);
+	}
+	else
+		gl_FragColor = c;
 }