Add the ability to record depth in color buffer. This should solve depth buffer resolution problem for older NVidia cards.

Effects/tree.eff

@@ -67,6 +67,7 @@
 			<program>
 				<vertex-shader>Shaders/deferred-tree.vert</vertex-shader>
 				<fragment-shader>Shaders/deferred-tree.frag</fragment-shader>
+				<fragment-shader>Shaders/gbuffer-functions.frag</fragment-shader>
 			</program>
 			<uniform>
 				<name>texture</name>

Shaders/deferred-gbuffer.frag

@@ -1,15 +1,15 @@
 #extension GL_EXT_gpu_shader4 : enable
+// -*- mode: C; -*-
+// Licence: GPL v2
+// Author: Frederic Bouvier.
 //
-// attachment 0:  normal.x  |  normal.x  |  normal.y  |  normal.y
-// attachment 1: diffuse.r  | diffuse.g  | diffuse.b  | material Id
-// attachment 2: specular.l | shininess  | emission.l |  unused
-//
+
 varying vec3 ecNormal;
 varying float alpha;
 uniform int materialID;
 uniform sampler2D texture;
 
-vec2 normal_encode(vec3 n);
+void encode_gbuffer(vec3 normal, vec3 color, int mId, float specular, float shininess, float emission, float depth);
 
 void main() {
     vec4 texel = texture2D(texture, gl_TexCoord[0].st);
@@ -19,8 +19,6 @@ void main() {
     float shininess = gl_FrontMaterial.shininess;
     float emission = dot( gl_FrontLightModelProduct.sceneColor.rgb, vec3( 0.3, 0.59, 0.11 ) );
     
-	vec3 normal2 = normalize( (2.0 * gl_Color.a - 1.0) * ecNormal );
-    gl_FragData[0] = vec4( normal_encode(normal2), 0.0, 1.0 );
-    gl_FragData[1] = vec4( gl_Color.rgb * texel.rgb, float( materialID ) / 255.0 );
-    gl_FragData[2] = vec4( specular, shininess / 128.0, emission, 1.0 );
+    vec3 normal2 = normalize( (2.0 * gl_Color.a - 1.0) * ecNormal );
+    encode_gbuffer(normal2, gl_Color.rgb * texel.rgb, materialID, specular, shininess, emission, gl_FragCoord.z);
 }

Shaders/deferred-gbuffer.vert

@@ -1,8 +1,8 @@
+// -*- mode: C; -*-
+// Licence: GPL v2
+// Author: Frederic Bouvier.
 //
-// attachment 0:  normal.x  |  normal.x  |  normal.y  |  normal.y
-// attachment 1: diffuse.r  | diffuse.g  | diffuse.b  | material Id
-// attachment 2: specular.l | shininess  | emission.l |  unused
-//
+
 varying vec3 ecNormal;
 varying float alpha;
 void main() {

Shaders/deferred-tree.frag

@@ -6,6 +6,7 @@
 //
 uniform int materialID;
 uniform sampler2D texture;
+void encode_gbuffer(vec3 normal, vec3 color, int mId, float specular, float shininess, float emission, float depth);
 void main() {
     vec4 texel = texture2D(texture, gl_TexCoord[0].st);
     if (texel.a < 0.1)
@@ -14,9 +15,6 @@ void main() {
     float shininess = 0.1;
     float emission = 0.0;
         
-	  // Normal is straight towards the viewer.
-	  vec3 normal2 = vec3(0.0, 0.0, 0.0);
-    gl_FragData[0] = vec4( 0.5, 0.5, 0.0, 1.0 );
-    gl_FragData[1] = vec4( gl_Color.rgb * texel.rgb, float( materialID ) / 255.0 );
-    gl_FragData[2] = vec4( specular, shininess / 255.0, emission, 1.0 );
+    // Normal is straight towards the viewer. (FB: Are they really billboards ? )
+    encode_gbuffer(vec3(0.5, 0.5, 0.0), gl_Color.rgb * texel.rgb, materialID, specular, shininess, emission, gl_FragCoord.z);
 }

Shaders/fog.frag

@@ -7,7 +7,7 @@ uniform float fg_FogDensity;
 uniform vec3 fg_Planes;
 varying vec3 ray;
 
-vec3 position( vec3 viewdir, float depth );
+vec3 position( vec3 viewDir, vec2 coords, sampler2D depth_tex );
 
 void main() {
     vec2 coords = gl_TexCoord[0].xy;
@@ -15,11 +15,7 @@ void main() {
     if ( initialized < 0.1 )
         discard;
     vec3 normal;
-    normal.xy = texture2D( normal_tex, coords ).rg * 2.0 - vec2(1.0,1.0);
-    normal.z = sqrt( 1.0 - dot( normal.xy, normal.xy ) );
-    float len = length(normal);
-    normal /= len;
-    vec3 pos = position( normalize(ray), texture2D( depth_tex, coords ).r );
+    vec3 pos = position( normalize(ray), coords, depth_tex );
 
     float fogFactor = 0.0;
     const float LOG2 = 1.442695;

Shaders/gbuffer-functions.frag

@@ -1,4 +1,9 @@
+// -*- mode: C; -*-
+// Licence: GPL v2
+// Author: Frederic Bouvier.
+
 uniform vec3 fg_Planes;
+uniform bool fg_DepthInColor;
 
 // normal compression functions from 
 //   http://aras-p.info/texts/CompactNormalStorage.html#method04spheremap
@@ -19,10 +24,60 @@ vec3 normal_decode(vec2 enc)
     return n;
 }
 
+// depth to color encoding and decoding functions from
+//   Deferred Shading Tutorial by Fabio Policarpo and Francisco Fonseca
+//   (corrected by Frederic Bouvier)
+vec3 float_to_color(in float f)
+{
+    vec3 color;
+    f *= 255.0;
+    color.x = floor(f);
+    f = (f-color.x)*255.0;
+    color.y = floor(f);
+    color.z = f-color.y;
+    color.xy /= 255.0;
+    return color;
+}
+
+float color_to_float(vec3 color)
+{
+    const vec3 byte_to_float = vec3(1.0, 1.0/255.0, 1.0/(255.0*255.0));
+    return dot(color,byte_to_float);
+}
+
 vec3 position( vec3 viewDir, float depth )
 {
     vec3 pos;
     pos.z = - fg_Planes.y / (fg_Planes.x + depth * fg_Planes.z);
     pos.xy = viewDir.xy / viewDir.z * pos.z;
-	return pos;
+    return pos;
+}
+
+vec3 position( vec3 viewDir, vec3 depthColor )
+{
+    return position( viewDir, color_to_float(depthColor) );
+}
+
+vec3 position( vec3 viewDir, vec2 coords, sampler2D depth_tex )
+{
+    float depth;
+    if (fg_DepthInColor)
+        depth = color_to_float( texture2D( depth_tex, coords ).rgb );
+    else
+        depth = texture2D( depth_tex, coords ).r;
+    return position( viewDir, depth );
+}
+
+// attachment 0:  normal.x  |  normal.y  |    0.0     |    1.0
+// attachment 1: diffuse.r  | diffuse.g  | diffuse.b  | material Id
+// attachment 2: specular.l | shininess  | emission.l |  unused
+// attachment 3:     ---------- depth ------------    |  unused        (optional)
+//
+void encode_gbuffer(vec3 normal, vec3 color, int mId, float specular, float shininess, float emission, float depth)
+{
+    gl_FragData[0] = vec4( normal_encode(normal), 0.0, 1.0 );
+    gl_FragData[1] = vec4( color, float( mId ) / 255.0 );
+    gl_FragData[2] = vec4( specular, shininess / 128.0, emission, 1.0 );
+    if (fg_DepthInColor)
+        gl_FragData[3] = vec4(float_to_color(depth), 1.0);
 }

Shaders/light-point.frag

@@ -15,7 +15,7 @@ uniform float Far;
 
 varying vec4 ecPosition;
 
-vec3 position( vec3 viewdir, float depth );
+vec3 position( vec3 viewDir, vec2 coords, sampler2D depth_tex );
 vec3 normal_decode(vec2 enc);
 
 void main() {
@@ -27,7 +27,7 @@ void main() {
 	vec3 normal = normal_decode(texture2D( normal_tex, coords ).rg);
 	vec4 spec_emis = texture2D( spec_emis_tex, coords );
 	
-    vec3 pos = position(viewDir, texture2D( depth_tex, coords ).r);
+    vec3 pos = position(viewDir, coords, depth_tex);
 	
 	if ( pos.z < ecPos3.z ) // Negative direction in z
 		discard; // Don't light surface outside the light volume

Shaders/light-spot.frag

@@ -19,7 +19,7 @@ uniform float Far;
 
 varying vec4 ecPosition;
 
-vec3 position( vec3 viewdir, float depth );
+vec3 position( vec3 viewDir, vec2 coords, sampler2D depth_tex );
 vec3 normal_decode(vec2 enc);
 
 void main() {
@@ -31,7 +31,7 @@ void main() {
 	vec3 normal = normal_decode(texture2D( normal_tex, coords ).rg);
 	vec4 spec_emis = texture2D( spec_emis_tex, coords );
 	
-    vec3 pos = position(viewDir, texture2D( depth_tex, coords ).r);
+    vec3 pos = position(viewDir, coords, depth_tex);
 
 	if ( pos.z < ecPos3.z ) // Negative direction in z
 		discard; // Don't light surface outside the light volume

Shaders/sunlight-nofiltering.frag

@@ -12,7 +12,7 @@ uniform int fg_ShadowNumber;
 uniform vec4 fg_ShadowDistances;
 varying vec3 ray;
 
-vec3 position( vec3 viewdir, float depth );
+vec3 position( vec3 viewDir, vec2 coords, sampler2D depth_tex );
 vec3 normal_decode(vec2 enc);
 
 vec4 DynamicShadow( in vec4 ecPosition, out vec4 tint )
@@ -57,7 +57,7 @@ void main() {
     float len = length(normal);
     normal /= len;
     vec3 viewDir = normalize(ray);
-    vec3 pos = position( viewDir, texture2D( depth_tex, coords ).r );
+    vec3 pos = position( viewDir, coords, depth_tex );
 
     vec4 tint;
     float shadow = shadow2DProj( shadow_tex, DynamicShadow( vec4( pos, 1.0 ), tint ) ).r;

Shaders/sunlight-simple.frag

@@ -17,7 +17,7 @@ varying vec4 eyePlaneT;
 varying vec4 eyePlaneR;
 varying vec4 eyePlaneQ;
 
-vec3 position( vec3 viewdir, float depth );
+vec3 position( vec3 viewDir, vec2 coords, sampler2D depth_tex );
 vec3 normal_decode(vec2 enc);
 
 vec4 DynamicShadow( in vec4 ecPosition, out vec4 tint )
@@ -43,7 +43,7 @@ void main() {
     float len = length(normal);
     normal /= len;
     vec3 viewDir = normalize(ray);
-    vec3 pos = position( viewDir, texture2D( depth_tex, coords ).r );
+    vec3 pos = position( viewDir, coords, depth_tex );
 
     vec4 tint;
     float shadow;

Shaders/sunlight.frag

@@ -14,7 +14,7 @@ uniform vec4 fg_ShadowDistances;
 uniform int filtering;
 varying vec3 ray;
 
-vec3 position( vec3 viewdir, float depth );
+vec3 position( vec3 viewDir, vec2 coords, sampler2D depth_tex );
 vec3 normal_decode(vec2 enc);
 
 vec4 DynamicShadow( in vec4 ecPosition, out vec4 tint )
@@ -59,7 +59,7 @@ void main() {
     float len = length(normal);
     normal /= len;
     vec3 viewDir = normalize(ray);
-    vec3 pos = position( viewDir, texture2D( depth_tex, coords ).r );
+    vec3 pos = position( viewDir, coords, depth_tex );
 
     vec4 tint;
     float shadow = 0.0;

Shaders/ubershader-gbuffer.frag

@@ -56,7 +56,7 @@ uniform vec3 dirt_g_color;
 uniform vec3 dirt_b_color;
 
 //uniform vec4 fg_SunAmbientColor;
-vec2 normal_encode(vec3 n);
+void encode_gbuffer(vec3 normal, vec3 color, int mId, float specular, float shininess, float emission, float depth);
 
 ///fog include//////////////////////
 uniform int fogType;
@@ -180,7 +180,5 @@ void main (void)
 // END lightmap
 /////////////////////////////////////////////////////////////////////
 
-	gl_FragData[0]=vec4(normal_encode(N), 0.0, 1.0);
-	gl_FragData[1]=vec4(fragColor.rgb,1.0/255.0);
-	gl_FragData[2]=vec4(specular, gl_FrontMaterial.shininess/128.0, emission, 1.0);
+	encode_gbuffer(N, fragColor.rgb, 1, specular, gl_FrontMaterial.shininess, emission, gl_FragCoord.z);
 }

Shaders/urban-gbuffer.frag

@@ -37,7 +37,7 @@ int linear_search_steps = 10;
 int GlobalIterationCount = 0;
 int gIterationCap = 64;
 
-vec2 normal_encode(vec3 n);
+void encode_gbuffer(vec3 normal, vec3 color, int mId, float specular, float shininess, float emission, float depth);
 
 void QDM(inout vec3 p, inout vec3 v)
 {
@@ -190,7 +190,6 @@ void main (void)
     N.z = sqrt(1.0 - min(1.0,dot(N.xy, N.xy)));
     float Nz = N.z;
     N = normalize(N.x * tangent + N.y * binormal + N.z * normal);
-	gl_FragData[0] = vec4( normal_encode(N), 0.0, 1.0 );
 
     vec4 ambient_light = constantColor + vec4(gl_Color.rgb, 1.0);
 
@@ -216,9 +215,6 @@ void main (void)
 
     vec4 p = vec4( ecPos3 + tile_size * V * (d-1.0) * depth_factor / s.z, 1.0 );
 
-    gl_FragData[1] = vec4( finalColor.rgb, 1.0 / 255.0 );
-    gl_FragData[2] = vec4( dot(specular.xyz,vec3(0.3, 0.59, 0.11 )), specular.w/128.0, 0.0, 1.0 );
-
     if (dot(normal,-V) > 0.1) {
         vec4 iproj = gl_ProjectionMatrix * p;
         iproj /= iproj.w;
@@ -226,4 +222,5 @@ void main (void)
     } else {
         gl_FragDepth = gl_FragCoord.z;
     }
+    encode_gbuffer(N, finalColor.rgb, 1, dot(specular.xyz,vec3(0.3, 0.59, 0.11 )), specular.w, 0.0, gl_FragDepth);
 }

preferences.xml

@@ -68,6 +68,7 @@ Started September 2000 by David Megginson, david@megginson.com
 			<show-buffers type="bool" userarchive="y">true</show-buffers>
 			<ambient-occlusion type="bool" userarchive="y">false</ambient-occlusion>
 			<exposure type="float" userarchive="y">1.0</exposure>
+			<use-color-for-depth type="bool">false</use-color-for-depth>
 			<debug type="bool">false</debug>
 			<realism type="int">5</realism>
 			<filtering type="int">8</filtering>