generic_fp.glsl

/*
===========================================================================
Copyright (C) 2006-2011 Robert Beckebans <trebor_7@users.sourceforge.net>

This file is part of XreaL source code.

XreaL source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

XreaL source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with XreaL source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

/* generic_fp.glsl */

#define GENERIC_GLSL

uniform sampler2D	u_ColorMap;
uniform float		u_AlphaThreshold;

#if defined(USE_MATERIAL_SYSTEM)
	uniform bool u_ShowTris;
	uniform vec3 u_MaterialColour;
#endif

IN(smooth) vec2		var_TexCoords;
IN(smooth) vec4		var_Color;

#if defined(USE_DEPTH_FADE)
	#define DEPTHMAP_GLSL

IN(smooth) float        var_FadeDepth;
uniform sampler2D       u_DepthMap;
#endif

#if defined(USE_ALPHAGEN_PORTAL)
uniform float u_InversePortalRange;
uniform mat4 u_UnprojectMatrix;
#endif

#insert shaderProfiler_fp

DECLARE_OUTPUT(vec4)

void	main()
{
	#insert material_fp

	#if defined(USE_MATERIAL_SYSTEM)
		if( u_ShowTris ) {
			outputColor = vec4( 0.0, 0.0, 1.0, 1.0 );
			return;
		}
	#endif

	vec4 color = texture2D(u_ColorMap, var_TexCoords);

	color *= var_Color;

	if( abs(color.a + u_AlphaThreshold) <= 1.0 )
	{
		discard;
		return;
	}

	// Normally alpha modulation is supposed to be done before the alpha test, but this looks
	// better for the ancient-remains foliage combining alphagen portal with an alpha-tested
	// plant image: fades out to 0 smoothly instead of cutting off at 0.5.
#if defined(USE_ALPHAGEN_PORTAL)
	vec4 position = u_UnprojectMatrix * vec4(gl_FragCoord.xyz, 1.0);
	float portalAlpha = length(position.xyz / position.w) * u_InversePortalRange;
portalAlpha = length(position.xyz / position.w) * (1.0/256.0);
	color.a *= clamp(portalAlpha, 0.0, 1.0);
#endif

#if defined(USE_DEPTH_FADE)
	float depth = texture2D(u_DepthMap, gl_FragCoord.xy / r_FBufSize).x;

	// convert z from normalized device coordinates [-1, 1]
	// to window coordinates [0, 1]
	float fadeDepth = 0.5 * var_FadeDepth + 0.5;

	// HACK: the (distance from triangle to object behind it) / (shader's depthFade distance) ratio
	// is calculated by using (nonlinear) depth values instead of the correct world units, so the
	// fade curve will be different depending on the distance to the viewer and znear/zfar
	color.a *= smoothstep(gl_FragCoord.z, fadeDepth, depth);
#endif
	
	SHADER_PROFILER_SET( color )

	outputColor = color;

// Debugging.
#if defined(USE_MATERIAL_SYSTEM) && defined(r_showGlobalMaterials)
	outputColor.rgb = u_MaterialColour;
#endif
}