1 files changed, 131 insertions, 0 deletions
diff --git a/client/shaders/object_shader/opengl_fragment.glsl b/client/shaders/object_shader/opengl_fragment.glsl
new file mode 100644
index 000000000..bb9e40637
--- /dev/null
+++ b/client/shaders/object_shader/opengl_fragment.glsl
@@ -0,0 +1,131 @@
+uniform sampler2D baseTexture;
+uniform sampler2D normalTexture;
+uniform sampler2D textureFlags;
+
+uniform vec4 emissiveColor;
+uniform vec4 skyBgColor;
+uniform float fogDistance;
+uniform vec3 eyePosition;
+
+varying vec3 vNormal;
+varying vec3 vPosition;
+varying vec3 worldPosition;
+
+varying vec3 eyeVec;
+varying vec3 lightVec;
+varying float vIDiff;
+
+bool normalTexturePresent = false;
+bool texTileableHorizontal = false;
+bool texTileableVertical = false;
+bool texSeamless = false;
+
+const float e = 2.718281828459;
+const float BS = 10.0;
+const float fogStart = FOG_START;
+const float fogShadingParameter = 1 / ( 1 - fogStart);
+
+void get_texture_flags()
+{
+	vec4 flags = texture2D(textureFlags, vec2(0.0, 0.0));
+	if (flags.r > 0.5) {
+		normalTexturePresent = true;
+	}
+	if (flags.g > 0.5) {
+		texTileableHorizontal = true;
+	}
+	if (flags.b > 0.5) {
+		texTileableVertical = true;
+	}
+	if (texTileableHorizontal && texTileableVertical) {
+		texSeamless = true;
+	}
+}
+
+float intensity(vec3 color)
+{
+	return (color.r + color.g + color.b) / 3.0;
+}
+
+float get_rgb_height(vec2 uv)
+{
+	if (texSeamless) {
+		return intensity(texture2D(baseTexture, uv).rgb);
+	} else {
+		return intensity(texture2D(baseTexture, clamp(uv, 0.0, 0.999)).rgb);
+	}
+}
+
+vec4 get_normal_map(vec2 uv)
+{
+	vec4 bump = texture2D(normalTexture, uv).rgba;
+	bump.xyz = normalize(bump.xyz * 2.0 - 1.0);
+	return bump;
+}
+
+void main(void)
+{
+	vec3 color;
+	vec4 bump;
+	vec2 uv = gl_TexCoord[0].st;
+	bool use_normalmap = false;
+	get_texture_flags();
+
+#if USE_NORMALMAPS == 1
+	if (normalTexturePresent) {
+		bump = get_normal_map(uv);
+		use_normalmap = true;
+	}
+#endif
+
+#if GENERATE_NORMALMAPS == 1
+	if (normalTexturePresent == false) {
+		float tl = get_rgb_height(vec2(uv.x - SAMPLE_STEP, uv.y + SAMPLE_STEP));
+		float t  = get_rgb_height(vec2(uv.x - SAMPLE_STEP, uv.y - SAMPLE_STEP));
+		float tr = get_rgb_height(vec2(uv.x + SAMPLE_STEP, uv.y + SAMPLE_STEP));
+		float r  = get_rgb_height(vec2(uv.x + SAMPLE_STEP, uv.y));
+		float br = get_rgb_height(vec2(uv.x + SAMPLE_STEP, uv.y - SAMPLE_STEP));
+		float b  = get_rgb_height(vec2(uv.x, uv.y - SAMPLE_STEP));
+		float bl = get_rgb_height(vec2(uv.x -SAMPLE_STEP, uv.y - SAMPLE_STEP));
+		float l  = get_rgb_height(vec2(uv.x - SAMPLE_STEP, uv.y));
+		float dX = (tr + 2.0 * r + br) - (tl + 2.0 * l + bl);
+		float dY = (bl + 2.0 * b + br) - (tl + 2.0 * t + tr);
+		bump = vec4(normalize(vec3 (dX, dY, NORMALMAPS_STRENGTH)), 1.0);
+		use_normalmap = true;
+	}
+#endif
+
+	vec4 base = texture2D(baseTexture, uv).rgba;
+
+#ifdef ENABLE_BUMPMAPPING
+	if (use_normalmap) {
+		vec3 L = normalize(lightVec);
+		vec3 E = normalize(eyeVec);
+		float specular = pow(clamp(dot(reflect(L, bump.xyz), E), 0.0, 1.0), 1.0);
+		float diffuse = dot(-E,bump.xyz);
+		color = (diffuse + 0.1 * specular) * base.rgb;
+	} else {
+		color = base.rgb;
+	}
+#else
+	color = base.rgb;
+#endif
+
+	vec4 col = vec4(color.rgb, base.a);
+
+	col.rgb *= emissiveColor.rgb * vIDiff;
+	// Due to a bug in some (older ?) graphics stacks (possibly in the glsl compiler ?),
+	// the fog will only be rendered correctly if the last operation before the
+	// clamp() is an addition. Else, the clamp() seems to be ignored.
+	// E.g. the following won't work:
+	//      float clarity = clamp(fogShadingParameter
+	//		* (fogDistance - length(eyeVec)) / fogDistance), 0.0, 1.0);
+	// As additions usually come for free following a multiplication, the new formula
+	// should be more efficient as well.
+	// Note: clarity = (1 - fogginess)
+	float clarity = clamp(fogShadingParameter
+		- fogShadingParameter * length(eyeVec) / fogDistance, 0.0, 1.0);
+	col = mix(skyBgColor, col, clarity);
+
+	gl_FragColor = vec4(col.rgb, base.a);
+}